ANATOMY OF THE INVERTEBRATA BY TC.T. Tv, SIEBOLD, Translated from the German with Additions and NotesBY WALDO I. BURNETT, M.De BOSTON~ JAMES CAMPBELL, 18 TREMONT STREET, 18 74. Entered according to Act of Congress, in the year 1S54, by GOULD & LINCOLN, In the Clerk's Office of the District Court for the District of Massachusetts. Entered according to Act of Congress, in the year 1874, by JAMES CAMPBELL, in the Office of the Librarian of Congress at Washington. PRINTED BY J. E. FARWELL & CO., 34 MERCHANTS RoW, BOSTO N. IIY ESTEEMED FRIEND, LO U I S AGA S S I Z, PROFESSOR OF ZOOLOGY, &c., IN WHOSE WELL-KNOWN RELATIONS TO COMPARATIVE ANATOMY RBEQUIR1B t0 MENTION HERE, AND WHOSE SPLENDID GENIUS HAS DONE SO MUCH TO AWAKEN, IN THIS COUNTRY ESPECIALLY, A LIVELY INTEREST IN OBJECTS OF NATURAL HISTORY, b laorbxtn this Bfzumt WITH ADMIRATION AND SINCERE GRATITUDlo WTALDO L. BURNETT. 1 PUBLISHER'S NOTICE. For some years there has been a constant and increasing demand for a thorough and reliable text-book on the Anatomy of the Invertebrata; and no other book having appeared upon the subject to meet the requirements and to supersede Dr. Burnett's translation of Von Siebold's Lerhbuck der vergleichenden Anatomie, which, together with the translator's valuable and extensive notes, is believed to be incomparably the best and most complete treatise on the science, and the same having been highly commended by Professors Agassiz, Silliman, Hitchcock and others, the publisher feels himself justified in offering this edition to the student, confident that it will supply a want not at present met by any other work in our lanaguage. Boston, May, 1874. NOTICE OF THE TRANSLATOR AND EDITORI IN issuing an English translation of the Lehrbucl der vergleichenden Anatomie of VON SIEBOLD and STANNIUS, any formal account of the work is quite unnecessary. To all Anatomists it is a treatise already well and favorably known, and it has justly been regarded as the most complete and comprehensive work of its kind now extant in any language. The high position and distinguished reputation of its authors have been fully sustained by this portion of their labors. But there are several features in this work which should be mentioned, since by them it is favorably distinguished from all other treatises of the kind that have preceded it. In the text will be found a lucid yet succinct exposition of the anatomical structure of organs, arranged as far as practicable undeir distinct types. The details on which this typical summary is based, are comprised in notes which are as remarkable for their erudition as for their copiousness; indeed, the utmost care has been taken in the literature of the various subjects treated, and the student will here find the most reliable and t,it the same time the fullest reference to the bibliography of nearly every subject in Comparative Anatomy. In this way, the work as a whole furnishes a complete dictionary of the science, and will prove invaluable even as a work of suggestion and reference, to those who would pursue any special line of inquiry and research in this department. It may be truly said that the Microscope lies at the foundation of all our best knowledge of anatomy, and especially that of the Invertebrata. This is the case, not only on account of the small size of most of the animals, but because, as Von &iebold has said in his preface, the anatomy of these lower forms is scarcely reliable unless based upon histological investigations. VIII NOTICE OF THE TRANSLATOR AND EDITOR. Hence, that part of the work treating of the anatomy of the Invertebrata, by Von Siebold, is rich in the results of microscopical researches; and their value in the elucidation of the subject will be readily appreciated. This plan of procedure has not the same urgency with the higher animals, where the character of an organ or part can generally be ascertained from its position, &Cc.; and, in the second part of the work, on the Anatomy of the Vertebrata, by Stannius, details of microscopical structure are comparatively little insisted upon. But, within a few years, the histological compo-:sition of organs, even though their character and function is well known, has become of great and increasing interest; and details of this kind, as far as they would be understood without the aid of figures, I have sought to add in their regular order and place. As to the notes and additions generally, they stand by themselves with ED. affixed, and almost invariably refer to some point treated of in the text or notes of the original, and for the most part relate to the correction, confirmation, or extension of some statements there made. These notes were drawn from all the sources accessible to me; but from the many difficulties in the way of the early receipt of foreign works in this country, they are not as complete a record of the recent progress of the science as would be desired. As to the translation, I may say, that not being a German scholar, but having read the German language chiefly for scientific purposes,.I trust that any inelegances of diction or idiom will be excused. But, throughout, I have endeavored to give a faithful rendering of the author's meaning, and to express this in as simple and terse a form as possible. In conclusion, I wish to express my gratitude to my friends who have kindly aided me in this work; - prominent among these is Mr. Edward Capen of this city, who has been of invaluable assistance to me in the labor of passing the sheets of this volume through the press; —of others, such as Professors Agassiz, Dana, Leidy, and Wyman, their names will be found honorably recorded by their own important labors in science, to which I have so frequently referred in these volumes. W. I. B. ]BOSToN, Nov. 1853. P R E F C E. As- latterly, Zootomists have given much greater attention to the invertebrate animals than formerly; and as, with these investigations they have united, as much as possible, others upon the generation and development of these animals, such a mass of material, composed, in part, of entirely new and very remarkable facts, has accumulated, that the manuals of Zootomy hitherto published are of a scale quite inadequate to receive them. It is unnecessary, therefore, for me to offer further reason for the task I have undertaken of arranging these materials and reducing them to a systematic form. But the order in which I have disposed them may not meet with general approval, for, hitherto, in works of comparative anatomy, the organs, and not the zoological classes, have served as the basis of the order pursued. But, in the present state of Science, and at least provisionally, it appears to me that the anatomical order should not be followed, for, the types, which, until now, have been recognized in the developmental series of the several organs, appear no longer valid and permanent. Indeed, extended researches made upon a great number of animals, have shown that these types, hitherto regarded as expressive of fundamental laws, may almost be taken as the exceptions. Such genera as Hydra, Luzmbricus, Hirudo, Unio, Astacus, &, can now no longer be regarded as the representatives of certain animal classes or orders, for their organization is far from affording the requisite type of that of allied animals. It appears now clearly determined that the types of the development and disposition of the various organs of the Invertebrata are more numerous and varied than hitherto supposed, and that, in this respect, a rule wholly different from that of those of the Vertebrata must here be applied. But as the numberless details which we now possess upon the organization of the Invertebrata, have not been thoroughly worked out and systematized in all the orders, it is really a task too difficult to here distinguish the rule from the exception, and the type from that which is only a secondary modification. X PREFACE. I have especially devoted myself to the collecting and collating as completely as practicable, the numerous new and important facts in the organization of the invertebrate animals, which have as yet been developed. And as occasion presented, I have verified with my own eyes the particular results; and when I have been obliged to refer to the discoveries and observations of others, I have cited exactly their works. I could not exclude Embryology and Histology from this work, for, in these branches, often lies our only means not only to ascertain the true nature of many larval forms among the lower animals, but also to arrive at the correct interpretation of many organs which, in form, position, and arrangements, have no analogues among the higher animal forms. It is only by the aid of Histology that we are able to show that this or that organ is a branchia, a liver, a kidney, an ovary, or a testicle; while, in the Vertebrata, which are organized after a few principal types, the signification of most of the organs can usually be easily determined by their position and connection. In order to avoid long descriptions, I have, when practicable, referred to plates and figures; but in so doing I have always endeavored to cite the good and original representations, for I am convinced that many figures which are transferred from one book to another, become, at last, so changed as to be quite dissimilar to the original. The elaboration c-~ this work having been commenced in 1845, but its completion having been delayed by my change of residence from Erlangen to Freiburg, and partly by a pretty long sojourn of mine on the Adriatic Sea, I have been unable to use the important works which have been published during the last few years, except in the form of a Supplement [additional notes] which will serve to complete, to confirm, or to rectify what has been advanced in the body of the work. I take this opportunity to publicly express my gratitude to A. K'lliker, H. Koch, A. Krohn, C. Vogt, and H. Stannius, for the friendly and important aid they have rendered me in the completion of this difficult task - not only by the transmission to me of interesting and rare marine animals, but also in the communication of important manuscripts and letters, the contents of which they have allowed me to freely use for my work. FREIBURG (IN BREISGAU), Feb. 27, 1848. C. TH. v. SIEBOLD. TABLE OF CONTENTS. SECTIOS Classification of the Invertebrate Animals,................. 1 Bibliography,.......................... 2 Introductory N'ote to the Infusoria. I. THE INFUSORIA AND RHIZOPODA. Classification and Bibliography,.................. 3-5 1. External Covering,.............. *.. 6 2. Muscular System, and Locomotive Organs,.7-8 3, 4. Nervous System, and Organs of Sense,.............. 9-10 6. Digestive Apparatus,.....................11-15 6, 7. Circulatory and Respiratory Systems,...............16-18 8. Organs of Secretion,.. 9 e a 9 e v 19 9. Organs of Reproduction,................... 20-23 Introductory.Note to the Zoophyta. H. THE POLYPI. Classification and Bibliography,............... 24 1. Cutaneous Envelope and Skeleton,................. 25-28 2. Muscular System, and Organs of Locomotion,...... 29-32 3, 4. Nervous System, and Organs of Sense,.... 8......... 33-34 5. Digestive Apparatus,....35-36 Digestive Cavity of the Anthozoa,... 37 Digestive Cavity of the Bryozoa,................. 38 6, 7. Circulatory and Respiratory Systems,............. 39-41 8. Organs of Secretion,..... 42 9. Organs of Generation,......................43-52 mI. THE ACALEPHAE. Classification and Bibliography,............. 53 1. Skin and Cutaneous Skeleton,.......5..........4-56 2. Muscular System, and Organs of Locomotion,............5 7-58 S. Nervous System,............. 59 4. Organs of Sense,............ 60 6. Digestive Apparatus................ 61 6. Circulatory System,................. e e 62 7. Respiratory System s...................... 63-64 XII CONTENTS. BECTION 8. Organs of Secretion,.............. 65 9. Organs of Generation,........66-70 IV. THE ECHINODERMATA Classificati3n and Bibliography................ 71 1. Cutaneous Envelope and Skeleton,................ 72-75 2. Muscular System, and Organs of Locomotion,.... 76-78 3. Nervous System................ 79-80 4. Organs of Sense,....................... 81 5. Digestive Apparatus,............ 82-86 6. Circulatory System,..............87-88 7. Respiratory System...................... 89-93 8. Organs of Secretion,..................... 94 9. Organs of Generation,.........9......5..a 95-98. V. THE HELMINTHES. Classification and Bibliography,........... 99 1. Cutaneous System...................... 100-101 2. Muscular System, and Organs of Locomotion........... 102-103 3. Nervous System..................... 104 4. Organs of Sense.................... 105 5. Digestive Apparatus,....................106-109 6. Circulatory System,................... i 110-111 7. Respiratory System,............ 112 8. Organs of Secretion,................... 113 9. Organs of Generation..................114-119 VI. THE TURBELLARIA. Classification and Bibliography,.... 120 1. Cutaneous System,.................... 121 2. Muscular System, and Locomotive Organs,.. 122 3, 4. Nervous System, and Organs of Sense,............ 123- 124 6. Digestive Apparatus,.......... 125 6, 7. Circulatory and Respiratory Systems,... 126 8. Organs of Secretion................. 127 9. Organs of Generation,................. 128-129 VII. THE ROTATORIA. Classification and Bibliography................. 130 1. Cutaneous System,.................. 131 2. Muscular System, and Locomotive Organs,....182-133 3, 4. Nervous System, and Organs of Sense,.............134-135 5. Digestive Apparatus................. 136 6, 7. Circulatory and Respiratory Systems,.137-138 8. Organs of Secretion,..1................. 39 9. Organs of Generation,...................... 140-141 VIII. THE ANNELIDES. Classification and Bibliography,........ 142 I. Cutaneous System,..................... 143 2. Muscular System, and Locomotive Organs,.144-145 CONTENTS. XIII SECTION 3. Nervous System,.......................146 —148 4 Organs of Sense,................. 149-151 I. Organs of Touch,..................... 149 IL Organs of Vision,.................... 150 IIl. Organs of Hearing,............... 151 5.. Digestive Apparatus,..152-155 I. Organs of Deglutition and Mastication,............ 153 II. Intestinal Canal...................... 154 III. Glandular Appendages,.................. 155 6. Circulatory System...................... 156-157 7. Respiratory System,......................158-160 8. Organs of Secretion,................ 161 9. Organs of Generation,................... 162-169 IX. THE ACEPHALA. Classification and Bibliography................. 170 1. Cutaneous System,..................... 171-175 2. Muscular System, and Organs of Locomotion,............ 176-180 3. Nervous System,......................... 81-184 4. Organs of Sense,........................185-187 5. Digestive Apparatus,.....................188-190 6 Circulatory System,........................191-192 7. Respiratory System,....................... 198-195 8. Organs of Secretion,........ 196 9. Organs of Generation,.................... 197-200 X. THE CEPHALOPHORA. Classification and Bibliography.................. 201 1. Cutaneous System,...................... 202-203 2. Muscular System, and Organs of Locomotion,........... 204-205 8. Nervous System.................... 206-209 4. Organs of Sense,......... 210-212 5. Digestive Apparatus,........... 213-215 6. Circulatory System.................... 216-218 7. Respiratory System,...................219-222 I. Branchiae,...................... 220 II. Lungs,................. 221 III. Aquiferous System,..... 222 8. Organs of Secretion................. 223-224 I. Urinary Organs,................ 223 H. Organs of Peculiar Secretions,............. 224 9. Organs of Generation...............225-229 XI. THE CEPIIALOPHODA. Classification and Bibliography............... 20 1. Internal Skeleton,................. 221-282 2. Cutaneous Envelope,................'233-235 38. Muscular System, and Organs of Locomotion,..... 236-238 4. Nervous System,.............239-242 5. Organs of Sense,................243-247 6. Digestive Apparatus,.....................248-250 7. Circulatory System,.............251-552 8. Respiratory Organs..........,.253-254 2 XIV CONTENTS. BECTIOI 9. Organs of Secretion,....,.25.-256 I. Urinary Organs,............... 255 II. Organs of Special Secretions,............. 256 10. Organs of Generation,............. 257-261 Introductory Note to the Crustacea. XII. THE CRUSTACEA. Classification and Bibliography................ 262 1. External Envelope, and Cutaneous Skeleton,...... 263-266 2. Muscular System, and Organs of Locomotion,... -...... 267-269 aS Nervous System,.............270-273 4. Organs of Sense,......................274 —277 5. Digestive Apparatus,.............. 278 —281 6. Circulatory System....................... 282-284 7. Respiratory System...................... 285-287 8. Organs of Secretion,...................... 288-289 I. Urinary Organs,.... 288 II. Organs of Special Secretions................. 289 9. Organs of Generation,........., 290-294 I. Hermaphrodite Crustacea................... 291 I. Female Crustacea,.................., 292 ~II. Male Crustacea,......... 293 XIII. THE ARACHNOIDAE. Classificatlon and Bibliography,................. 295 1. External Envelope, and Cutaneous Skeleton.........296-397 2. Muscular System, and Organs of Locomotion,........... 298-299 8. Nervous System,...............3300-302 4. Organs of Sense......................... 303-305 5. Digestive Apparatus..................... 306-308 6. Circulatory System,.....309-310 7. Respiratory System,............... 311-313 S. Organs of Secretion,........................314-315 I. Urinary Organs.................. 311 II. Organs of Special Secretions,............ 315 9. Organs of Generation,.............316-320 I. Hermaphrodite Arachnoidae.................. 317 II Female Arachnoidae,..................... 318 III. Male Arachnoidae,.................... 319 XIV. THE INSECTA. Classification and Bibliography,.. ~................ 321 1. External Envelope, and Cutaneous Skeleton,.........322-323 2. Muscular System, and Locomotive and Soniferous Organs,... 3 825-327 3. Nervous System,.........................328-331 4. Organs of Sense,.......................... 332-336 5. Digestive Apparatus,.............. 337-339 6. Circulatory System....................... 340 7. Respiratory System,..................... 341-344 8. Organs of Secretion,......................345-347 I. Urinary Organs,.~..........345-346 II. Organs of Special Secretions,.............347 9. Organs of Generation,............ 348-355 I. Female Genital Organs,............... 349-351 II. Male Genital Organs,..............-.. 352-354 Index.. ~ ~ ~ ~... ~.... CLASSIFICATION OF THE INVERTEBRATE ANIMALS. ~ 1. TiE invertebrate animals are organized after various types, the limits of which are not always clearly defined. There is, therefore, a greater number of classes among them than among the vertebrates. But, as the details of their organization are yet but imperfectly known, they have not been satisfactorily classified in a natural manner. There are among them many intermediate forms, which make it difficult to decide upon the exact limits of various groups. The following division, however, from the lowest to the highest forms of organization, appears at present the best: ANIMALIA EVERTEBRATA. INVERTEBRATEB ANIMALS. Brain, spinal cord, and vertebral column, absent. FIRST GROUP. PROTOZOA. Animals in which the different systems of organs are not distinctly sep. arated, and whose irregular form and simple organization is reducible to the type of a cell. CLASS I. INFUSORIA. CLASS II. RHIZOPODA. SECOND GROUP. ZOOPHYTA. Animals of regular form, and whose organs are arranged in a ray-like manner around a centre, or a longitudinal axis; the central masses of the nervous system forming a ring, which encircles the oesophagus. CLASS III. POLYP!. CLASS IV. ACALEPHIC. C"LASS V. ECHINODERMATA. 16 CLASSIFICATION. ~ 2, THIRD GROUP. VERMES. Animals with an elongated, symmetrical body, and whose organs are arranged along a longitudinal axis; so that right and left, dorsal and ventral aspects may be indicated. The central nervous mass consists of a cervical ganglion, with or with. out a chain of abdominal ganglia. CLASS VI. HELMINTHES. CLASS VII. TURBELLARII. CLASS VIII. ROTATORII. CLASS IX. ANNULATI. FOURTH GROUP. MOLLUSCA. Animals of a varied form, and whose bodies are surrounded by a fleshy' mantle. The central nervous masses consist of ganglia, some of which surround the oesophagus, and others, connected by nervous filaments, are scattered through the body. CLASS X. ACEPHALA. CLASS XI. CEPHALOPHORA. CLASS XII. CEPHALOPODA. FIFTH GROUP. ARTHROPODA. Animals having a perfectly symmetrical form, and articulated organs of locomotion. The central masses of the nervous system consist of a. ring of ganglia surrounding the oesophagus, from which proceeds a chain of abdominal ganglia. CLASS XIII. CRUSTACEA. CLASS XIV. ARACHNIDA. CLASS XV. INSECTA. BIBLIOGRAPHY. 2. Besides the various ancient and modern works upon general comparative. anatomy, —such as those of Blumenbach, () G. Cuvier, 2) F. Meckel,(3) E. Home,(4) Blainville,O5) Delle Chiaje,(6) Carus, ) Grant,(8) Rymer Jones, (9) Strauss 1 Handbuch der vergleichenden Anatomie. Got- 6 De l'Organisation des A.nimaux, ou Principes tingen, 1824. d'Anatomie compar~e. Tom. I. Paris, 18324 2 Lemons d'Anatomie comparee. Paris, 1799- 6 Istituzioni di Anotomia e Fisiologia Comparata. 1805. Translated into German and published with Napoli, 1832. notes and additions by Meckel and Froriep. 4 vols. 7 Lehrbuch der vergleichenden Anatomie. 2nd Leipzig, 1809-10. 2nd edit. Paris, 1835-45. ed. Leipzigi 1834. 3 System der vergleichenden Anatomie. 6 vols. 8 Outlines of Comparative Anatomy. London,. Ialle, 1821-33. 1841. 4 Lectures on Comparative Anatomy. 6 vols.'9 A General Outline of the Animal Kingdom, and London. 1814-29. Manual of Comparative Anatomy. London, 1841L ~ 2. BIBLIOGRAPHY. 1t Diirckheim,a~o) R. Wagner,(-)- there exist various contributions upon the relations of these animals in the physiological works of Treviranus,(12) Rudolphi,(13).Duges,(14) Burdach,(1) J. Miiler,l() R. Wagner,(l7) and in the, Medical Zoology of Brandt and Batzeburg.(~8) The iconographic illustrations by Carus and Otto,1(9) and by R. Wagner,(2~) contain many plates representing these animals; and in Guerin's ]conographuie,(l2) and Cuvier's (22) Regne Animal, edited by several French naturalists, are many illustrations of their internal structure. The following are some of the anatomical works which treat specially upon these animals: Schweigger. — Handbuch der Naturgeschichte der skelettlosen unge — gliederten Thiere. Leipzig, 1820. Delle Chiaje. - Memorie su la Storia e Notomia degli Animali senza Vertebre del regno di Napoli. 4 vol. Napoli, 1823-29. 109 tavole. A second and enlarged edition of this memoir has been published under the following title: Deserizione e notomia degli animali invertebrati della Sicilia citeriore. 1-5, vol. Napoli, 1841. Con tavol. I.-CLXXII. Sars. -Beskrivelser og Jagttagelser over nogle moerkelige eller nye i Hlavet ved den Bergenske Kyst levende Dyr af Polypernes, Acalephernes, Radiaternes, Annelidernes og Molluskernes Classer. Bergen, 1835. Lamarck.- Histoire Naturelle des Animaux sans Vertebres. Deuxs edit., par Deshayes et Milne Edwards. 11 vols. Paris, 1835-45. Milne Edwards. - El6mens de Zoologie, ou Lecons sur l'Anatomie, la Physiologie, la Classification, et les Moeurs des Animaux. Deux. 6dit. Animaux sans Vertebres. Paris, 1843. Richard Owen. - Lectures on the Comparative Anatomy and Physiology of the Invertebrate Animals. London, 1843. H. Frey and R. Leuckart. - Beitriige zur Kenntniss wirbelloser Thiere mit besonderer Berficksichtigung der Fauna des norddeutschen MIeeres. Braunschweig, 1847. These same naturalists have prepared the second part of WTlagner's Lehrbuch der Zootomie, under the special title of: Lehrbuch der Anatomie der wirbellosen Thiere. Leipzig, 1847. Stef. Andr. Renier. - Osservazioni postume di Zoologia adviatica pubblicate per cura dell' istituto veneto di scienze, lettere ed arti a studio del Prof. G. Meneghini. Venezia, 1847. Con tavo. I.-XVI. 10 Traitd pratique et thdoretique d'Anatomie 17 Lehrbuch der Physiologie. 2nd edit. Leipzig,. comparke. 2 vol. Paris, 1842. 1843. 11 Lehrbuch der Zootomie. 2nd edit., entirely re- 18 Medicinische Zoologie. 2 vol. Berlin, 1829-33.. vised; or "Lehrbuch der vergleichenden Anato- 19 Erliluterungstafeln zur vergleichenden Anato — mie." Leipzig, 1842. mie. 6 heft. Leipzig, 1826-43. 12 Biologie. 6 vol. Goittingen, 1802-22. Also; 20 Icones physiologicee. Erlfuterungstafeln zurErscheinungen und Gesetze des organischen Le- Physiologie und Entwickelungsgeschichte. Leipbens. 2 vol. Bremen, 1831 —33. zig, 1839. Also, Icones Zootomict. Handatlas. 13 Grundriss der Physiologie. 2 vol. Berlin, zur vergleichenden Anatomie. Ieipzig, 1841. 1821-28. 21 Iconographie du R{dgne Animal de G. Cuvier,. 14 Traits de Physiologie compar6e de l'Homme et ou Repr6sentation d'aprls nature de l'une les. des Animaux. 3 vol. Montpellier, 1838-39. espkces les plus remarquables et souvent non en-* 15 Die Physiologie als Erfahrungswissenschaft, core figur6es de chaque genre d'Animaux* pour erste Auflage, mit BeitrAgen: von C. v. Baer, servir d'atlas 4 tous les Traitls de 7oologie. 7 vol. Dieffenbach, J. Miiller, R. Wagner. 6 vol. avec 450 planches. Paris, 1830-38. Leipzig, 1826-40. 2 te Auflage, mit Beitragen von 22 R6gne Animal de Cuvier, nouvelle edition, acE. Meyer, H. Rathkc, C. v. Siebold und G. Val- compagnCe de planches gravees, &c. &c. Pari& entin. 2 vol. Leipzig, 1835-37. 1836-47. Still unfinished. 10 Handbuch der Physiologie des Menschen. 2 Vol. 4th edit. Coblentz, 1844. 2* INTRODUCTORY NOTE TO THE INFUSORIA. CONSTANT labors in the whole department of microscopy, and that, too, with greatly improved instruments, during the past few years, have materially changed the face of the class Infusoria since the issue of this work. There have been numerous and signal researches among all the lower forms of animal life; and the imperfect and undeveloped forms of others, which are higher, have been wrought out with an accuracy and detail before unknown. These movements -have all tended to diminish the numbers of the socalled Infusoria, and it remains to be seen how large the proper class will be when these researches shall have been further extended. By some even it is believed that it will be entirely resolved into other classes; this view, however, would appear far from being warranted by our present knowledge; for, while, on the one hand, whole genera have been shown to be only larval worms (Bursaria, Paramecium, &c., from Planaria ),* yet, on the other, some forms have manifested phenomena and changes leading us to place them almost unhesitatingly among individual animals. In its best aspects, however, the subject has many perplexing points; and, in its present unsettled state, it is almost hazardous for a scientific man to entertain anything like positive views thereon. I need scarcely allude to the vegetable, algous character which whole sections of the Polygastrica have recently assumed; and the limits of this work will not allow me to discuss in detail this and other interesting points. But there are. two or three topics of the highest physiological import, which are prominently introduced by these studies. These are, What is a plant? What is an animal? and, Are the animal and vegetable kingdoms on their lowest confines separate and distinct from each other? As is well known, all the older criteria by which animals were separated from plants have long since been regarded invalid; and some of those which in late years have been regarded among the most constant, have, quite recently, been declared as equally unsound. Cellulose has been shown to be a component of animal as well as of vegetable structures, and Killiker t has insisted that some forms which have neither mouth nor stom. *Agassiz, Ann. Nat. list. VI. 1850, p. t Killiker. Siebold and Kolliker's Zeitsch. 156. I. 1849, p. 198. INTRODUCTORY NOTE TO TILE INFUSORIA. 19 ach, but consist of a homogeneous mass, are true animals. If these premises are correct, nothing will remain, as I conceive, for a distinctive characteristic, but voluntary motion. This, when positive, is indubitable evidence of any given form being of an animal character; and it must remain for each individual observer to determine what is, and what is not, voluntary action, in each particular case. Moreover, even should Kclliker's view of a stomachless animal prove correct, the inverse condition of a true stomachal cavity being present,must, I think, be regarded as positive evidence of the animal nature of the form in question; for this must always be a distinctive characteristic of the two kingdoms, when present. In regard to the other point, What constitutes an animal? observers are very far from being agreed. Siebold, Kalliker, and others, have taken the ground that individual animal forms may be unicellular; or, in other vwords, that an animal may be composed of only a single cell.* This view is principally due to K6lliker's observations and statements upon Gregarinae.t The facts are indeed striking, but the evidence does not appear to mne sufficient, as yet, to settle such a vexed and important question; and more especially so since Bruch $ has raised the point of their belonging to the Worms. But, aside from such grounds, I was led, some time since, after considerable study of infusoria-forms, to venture an opinion quite at variance with that just mentioned of Siebold and Kclliker. I then made the following statement: In regard to the question, What characteristic in organic animal matter shall constitute an individual? I feel satisfied of this much, - that cell processes, however closely interwoven they may be with the expressions of individual life, cannot be considered as constituting the ground-work of its definition.~ This statement was made more than two years since; and subsequent observations, some of them of a special character, have not led me to a change of opinion. True individual animal life seems to involve a cycle of relations not implied in simple cells; in,other words, these last must always lose their character as such, in a definite form which belongs to the individual. On this account I regard the Infusoria proper, or those which have been shown to be of an undoubted animal character, as in a completely transition state; and, although it may be well to arrange these forms systematically, for the sake of convenience, yet they cannot be considered as holding fixed zoological positions. Further research in this direction, and upon "' Alternation of Generation," will, I think, widely clear up this obscure, yet most interesting field of study. EDITOR. * Siebold. Siebold and K5lliker's Zeitsch.: Bruch. Siebold and Kolliker's Zeitsch. I. p. 270. II. p. 110. t Kolliker. Siebold and Kolliker's Zeitsch. ~ Burnett. Proceed. Boston Soc. Nat. I. p. 1. Hist. V. p. 124. BOOK FIRST. INFUSORIA AND RIIIZOPODA. CLASSIFICATION. ~ 3. THE Infusoria, using this word in a restricted sense, are far fiom being the highly-organized animals Ehrenberg has supposed. In the first place, on account of their more complicated structure, the Rotifera must be quite separated from them, as has already been done by Wieg'mann, Burmeister, B. Wagner, Milne Edwards, Rymer Jones, and others. The same may be said of the so-called Polygastrica. In fact, a great number of the forms included under Closterina, Bacillaria, Volvocina, and others placed by Ehrenberg among the anenteric Polygastrica, belong, properly, to the: vegetable kingdom. Indeed, this author has very arbitrarily taken for digestive, sexual, and nervous organs, the rigid vesicles, and the colored or colorless granular masses, which are met with in simple vegetable forms,. but which are always absent in those low organisms of undoubtedly an. animal nature. Cell-structure and fiee motion are the only two characteristics in common of the lowest animal and vegetable forms; and since; Schwann (1) has shown the uniformity of development and structure of animals and plants, it will not appear strange that the lowest conditions. of each should resemble each other in their simple-cell nature. As to. motion, the voluntary movements of Infusoria should be distinguished from those which are involuntary, of simple vegetable formns; a distinction not insisted upon until lately. Thus, in watching carefully the motions of Vorticellina, Trachelina, Kolpodea, Oxytrichina, &c., one quickly perceives their voluntary character. The same is true of the power of contracting and expanding their bodies. But in the motions of vegetable forms other conditions are perceived and there is no appearance of volition in either change of place or form,. their locomotion being accomplished either by means of cilia, or other physical causes not yet well understood. Cilia, therefore, belong to vegetable as well as to animal forms, and in this connection it is not a little remarkable that in animals they should be under the control of volition. With vegetable forms these organs are met with either in the shape of ciliated epithelium, as upon the spores of Vaucheria,e() or as long, waving.filaments, as upon the earlier forms of many conferve,(3) in which last can 1 Mikroskopische Untersuchungen, &c. Berlin, teurs des spores des Algues. Ann. des Sc. NaL 1839 Botan. 1843, XLX. p. 266. P1. XI. fig. 29-30. 2 Thuret. Recherches sur les organes locomo- 3 The same. Pl. X. ~4 4, 5. INFUSORIA AND RHIZOPODA. 21,often be seer, the so-called organization of Ehrenberg's Monadina and Volvocina. Until the fact that ciliated organs belong to both animals and vegetables was decided, the real place of many low organisms had to remain undetermined.(4) However, notwithstanding their free motion from place to place by means of cilia, the vegetable nature of many organisms:seemed clearly indicated by the rigid, non-contractile character of their forms. It is from a misapprehension of the true nature of these facts, that some modern naturalists have denied the existence of limits between the two kingdoms.(5) With Bacillarere and Diatomaceme, this question has another aspect. 3]any of these organisms have been taken for animals from their so-called voluntary movements, which truly entirely want the character of volition. In the movements of the rigid Diatomaceve, for instance, the whole plant has oscillatory motions like a magnetic needle, at the same time slightly,changing its place forward and backward. WVhen small floating particles come in contact with such an organism, they immediately assume the same motion. This may be well observed with the Oscillatoria. There are here, undoubtedly, no ciliary organs; in fact, they could not, if present, produce this kind of motion. According to z:ihrenberg,(6) the Naviculae can protrude ciliary locomotive organs through openingo, of their carapace; but this has not been observed by other naturalists. ~ 4. The Rhizopoda, whose internal structure is as yet imperfectly known, are closely allied to the Infusoria. Like these last, their bodies are cellular, containing nuclear corpuscles, but no system of distinct organs. These two classes of Protozoa differ, however, in their external form, and the structure of their locomotive organs. The body of the Infusoria, notwithstanding its contractility, has a definite form, and moves chiefly by means of vibratile organs. That of the Rhizopoda, on the other hand, although equally contractile, has no definite form; their movements also are not due to ciliated organs, but to a change of the form of the body by various prolongations and digitations. ~ 5. Owing to the present incomplete details upon the organization of these animals, little can here be said about them; and therefore, instead of devoting to them a separate chapter, it will be proper to treat of them with the Infusoria in general. As the division of the Polygastric Infusoria, by Elhrenbeig, into two 4 As an example, may be mentioned the various Also, Kiitzing, FTeber die Yerwandlung der and dissimilar opinions of naturalists upon the Infusorien in niedere Algenformen. Nordlhausen, question of the animal or vegetable nature of the 1844. "red snow;" a question upon which Flotol, In an academic paper (Dissertatio de finibus after the most careful studies, is still undecided. inter regnum anitmale et vegetabile constituendis, See Flotou, "Ueber Haernatococcus pluvialis, "' Erlangae, 1844), I have attempted to show that this in Nov. Act. Acad. Leop. Carol, vol. XX. part ii. confusion between the two kingdoms does not exist. p. 18. 6 Abhandlungen der Akademie der Wissen5 See Unger, Die Pflanze im Momente der schaften zu Berlin, 1836, p. 134, Taf. I. fig. 19, and Thierwerdung. Wien. 1843. 1839, p. 102, Taf. IV. fig. 5. 22 INFUSORIA AND RHIZOPODA. ~ O. orders, Anentera and Enterodela, appears unfounded, the following clas. ification seems more natural: PROTOZOA. CLASS INFUSORIA. Organs of locomotion chiefly vibratile. ORDER I. ASTOMA. Without an oral aperture. FAMILY: ASTASIAEA. Genera: Amblyophis, Euglena, Chlorogonium FAMILY: PERIDINAEA. Genera: Peridinium, Glenodinium. FAMILY: OPALINAEA. Genus: Opalina. ORDER II. STOMA TODA. With a distinct oral aperture and oesophagus. FAMILY: VORTICELLINA. Genera: Stentor, Trichodina, Vorticella, Epistylis, Carchesiurn. FAMILY: OPHRYDINA. Genera: Vaginicola, Cothurnia. FAMILY: ENCHELIA. Genera: Actinophrys, Leucophrys, Prorodon. FAMILY: TRACHELINA. Genera: Glaucoma, Spirostomum, Trachelius, Loxodes, Chilodon, I'hialinqa Bursaria, Nassula. FAMILY: KOLPODEA. Genera: Kolpoda, Paramcecium, Amphileptus. FAMILY: OXYTRICHINA. Genera: Oxytricha, Stylonychia, Urostyla. FAMILY: EUPLOTA. Genera: Euplotes, Himantophorus, Chlamidodon. ~ 5. INFUSORIA AND RHIZOPODA. 23 CLAss RHIZOPODA. Organs of locomotion consisting of completely retractile, ramifying prolongations of the body. ORDER I. MONOSOMATIA. FAMILY: AMOEBAEA. Genus: Amoeba. FAMILY: ARCELLINA. Genera: Arcella, Difflugia, Gromia, Miliola, Euglypha, Trinema. ORDER II. POLYSOMATIA. Genera: Vorticialis, Geoponus, Nonionina.(1) BIBLIOGRAPHY O. F. Miller. Animalcula Infusoria. tIafnioe, 1786. Ehrenberg. Die Infusionsthierchen als vollkommene Organismen. Leipzig, 1838. Also his numerous and important memoirs upon the Infusoria and Rhizopoda in the Memoirs of the Berlin Academy, and its Monthly Bulletin. Andrew Pritchard. A History of Infusoria, living and fossil, arranged according to the " Infusionsthierchen," of Ehrenberg. Illustrated by nearly 800 colored engravings of these curious creatures, highly magnified. London, 1841. Kutorga. Naturgeschichte der Infusionsthierchen, vorziiglich nach Eho renberg's Beobachtungen bearbeitet. Calsruhe, 1841. Dujardin. Histoire Naturelle des Zoophytes. Infusoires, Paris, 1841. This work treats also of the Rhizopoda. ADDITIONAL BIBLIOGRAPHY. Besides the various articles quoted in the additional notes I have made the following are among the more important recent writings on this subject: Cohn. Beitraige zur Entwickelungsgeschichte der Infusorien, in Siebold & Kalliker's Zeitsch. III. Hft. 3, and IV. Hft. 3. Ecker. Zur Entwickelungsgeschichte der Infusorien, in Siebold & Ko1liker's Zeitsch. III. Hft. 4. Stein. Neue Beitr. zur Kenntn. d. Entwickelungsg. u. d. feineren Baues d. Infusionsthiere, in Siebold & K&lliker's Zeitsch. III. p. 475. Pritchard. A History of Infusorial Animalcules, living and fossil, &c., with illustrations, new edition. London, 1852. See also numerous notes in the Annales des Sciences Naturelles, since 1847. - ED. 1 In this table are mentioned the families and genera of those only which have been the objects of anatomical study. 24 INFUSORIA AND RHIZOPODA. %c 6, 7, 8. CHAPTER I. EXTERNAL COVERING. ~ 6. The PROTOZOA are surrounded by a very delicate cutaneous envelope, which is sometimes smooth,(1) and sometimes covered with thickly-set cilia.(2)'Generally these cilia are arranged in longitudinal rows; () but in ActinopItrys they consist of long contractile filaments of a special nature. CHAPTER II. MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS. ~ 7. With the PROTOZOA a distinct muscular tissue cannot be made out, but the gelatinous substance of their body is throughout contractile. It is only in the contractile peduncle of certain Vorticellina, that there can be perceived a distinct longitudinal muscle, which, assuming a spiral form, can contract suddenly like a spring.(') 6 8. THE VIBRATILE ORGANS on the surface of Infusoria serve as organs of locomotion. 5With many species they are found much developed at certain points,.and are arranged in a remarkable order and manner. With Peridinium, a crown of them encircles the body; with Stylony. chia, they are quite long, and surround the flattened body like a fringe; while the Vorticellina, have the anterior portion of their body surrounded, by retractile cilia, arranged in a circular or spiral manner. In Trichodina there is, upon the ventral surface, besides a crown of these cilia upon the back, a very delicate ciliated membranous border, which is attached to a ring which is dentated, and composed of a compact homogeneous tissue. With Trichodina pediculus this border is whole and entire; but it is'broken or ragged with Trichodina mitra.(i) By means of this organ these animals swim with facility, or invade with skill the arm-polyps and Planaria.(2) With many Infusoria, the vibratile organs are situated at the anterior extremity of the body, as simple or double non-retractile filaments, which move in a manner to produce a vor1 Euglena, Amoeba, -c. 1 This Infusorium was discovered by me as a 2 Trachelius, Paramcecium, Nassula, r-c. parasite in many Planarieae. a3 mphileptus, Chiilodon, Opalina, 4-c. 2 Ehrenberg has entirely overlooked the ciliated 1 The peduncle is simple with Vorticella, but border of Trichodina pediiculus, and has regarded -ramified with Carchesilum.'With Epistylis it is the stiff serrations of the ring as movable hooks. uot muscular. See " Die Infusionsthierchen,' p. 206. :~ 9, 10. INFUSORIA AND RHIZOPODA. 25 tical action of the water.(3) But with others the locomotive organ is a long retractile proboscis. 4) With the Oxytrichina and Euplota, there are fleshy movable points (UNCINI) upon the ventral surface, by which these animals move about as upon feet. During these movements with the Oxytrichina, the posterior portion of the body is supported by many setose.and styloid processes, which point backward. The singularly varied and branching locomotive organs of the Rhizopoda are short, and digitated with Amceba, Diffugia and Arcella.() But in the other genera they are elongated and filamentous.(6) CHAPTERS III. AND IV. NERVOUS SYSTEM AND ORGANS OF SENSE. ~ 9. Although the Infusoria clearly evince in their actions the existence of nensation and volition, and appear susceptible of sensitive impressions, yet no nervous tissue whatever has as yet been found in them. If Ehrenberg supposed the Polygastric Infusoria to possess a nervous system, he did so because, having decided that the red pigment points of these animals were eyes, he inferred that they necessarily had a nervous ganglion at their base. ~ 10. With the naked Infusoria the sense of touch exists, undoubtedly, over the whole body. But beside this, it appears specially developed, in many ipecios, in the long cilia forming vibratile circles, or in those movable foot-like and snout-like prolongations of the body. In the same manner, it is probable they have the sense of taste also; for they seem to exercise a choice in their food, although no gustatory organ has yet been found. All species, whether they have red pigment points or not, seem affected by light. Without doubt, therefore, their vision consists simply in discriminating light from darkness, which is accomplished by the general surface of the body, and without the aid of a special optical organ. The simple pigment point of many Infusoria, (1) and which Ehrenberg has generally regarded as an eye,(2! has no cornea, and contains no body capable of refracting light; there is, moreover, connected with it no nervous.substance. Ehrenberg attaches here too great an importance to the red color of the 3 4mblyophis, Euglena and Peridinium, have Sc. Nat. Zool. IV. 1835, p. 343, pl. IX. * also, V.,a simple flagelliform cilium, but with Chlorogo- 1836, p. 196, pl. IX. fig. A. See, also, his Ilistoire nium it is double. des Infusoires, 1841. p. 249. pl. I. fig. 14-17; 1:1. 4 Trachelius trichophorus feels about with a II. fig. 1, 2, 7-10; p1l. IV. fig. 1)i Geopoonus stellong snout of this kind, without, however, produc- la borealis, Nonionina germasnica, according to ing a vortical action on the water. Ehrenberg. Abhland. d. Berliner Akad. 1839, 5 See Ehrenberg, "'Die Infusionsthierchen," p. 106, Taf. I. II. Taf. VIII. and IX. 1 Amblyophis, Euglesa, Chlorozonium, 4-c. s Gromia fluviatilis, M3iliola vulgaris, Vor- 2 Ablhandl. l. Berliner Akad. 1831) p. 12; als, ticialis strigilata, Euzglypha tuberculosa, Tri- "Die Infusionsthierchcn," p. 491. tzema acinus, according to Dsujardin (Ann. des 3 26 INFUSORIA AND RHIZOPODA. 11, 12 pigment,(3) for the blue, violet and green pigments, seen in the eyes of insects and crustacea, show clearly that the red pigment is not essential to the eye.* CHAPTER V. DIGESTIVE APPARATUS. The Infusoria are nourished, either by taking solid food into the interior of their body, or by absorbing by its entire surface nutritive fluids which occur in the media in which they live. This last mode is illustrated in the Astoma, which have no distinct oral aperture or digestive apparatus. By the ingenious experiment first performed by Gleichen,(l' of feeding these animals with colored liquids, no trace of these organs could be found. Ehrenberg, who also had observed that they did not eat, regarded their internal vesicles as stomachal organs, which were in connection with the mouth by tubes. The correctness of this opinion, however, has not been verified. Indeed, the genus Opalina(2) refutes it; here the species are quite large and visible to the naked eye, yet an oral aperture can be detected upon no part of their body, and never do they admit into its interior colored particles. Solid substances found in them cannot be regarded as food. That fluids are here introduced by surface-imbibition is shown by Opalina ranarum; this animal is found in bile in the rectum of frogs, and assumes a green color. When Opalina requiring only a certain quantity of liquid are placed in water, they quickly absorb it, become greatly swollen,. and shortly after die. In such cases, the absorbed liquid is seen as clear, vesicular globules under the surface, and these globules have been taken by Ehrenberg as stomiachal vesicles (VENTRICULI), and by Dujardin as VACUOLAE. ~ 12. Those Infusoria which are nourished by solid food have a mouth at a certain place, and an oesophagus traversing the parenchyma of the body. Through this last the food is received, and is finally dissolved in the semi-liquid parenchyma of the body, without passing through stomachal or intestinal cavities. In many cases there is at the end of the body opposite the mouth an ANUS, through which the refuse material is expelled. But, when this is 3 " Die Infusionsthiec hen," p. 492. 2 The genus Opalina was first established by 1 Auserlesene mikroskopische Eutdeckungen, Purkinje 4- Valentin. Many species are found: 1777, p. 51; also, Abhandlung iiber die Saamen- in the rectum of frogs, and it is not rare to meet und Infusionsthierchen, 1778, p. 140. with them in the alimentary canal of Planarieae.t * Some recent researches of Thuret (Ann. d. Sc. fact is a very interesting one in this connection. - Nat. 3rd ser. XIV. 1850) on the reproductive germs ED. of Algae prove that these bodies have red eye- t [~ 11, note 2.] According to BAgassiz (Amer. like specks, resembling those seen in the Polygas- Jour. Sc. XIII. 1852, p. 425), Opalina is only a trica, but which disappear when the Zoospores at- larval form of Distomna. - ED. tach themselves and germination proceeds. The 512. INFUSORIA AND RHIIZOPODA. 2T wanting, its function is often performed by the mouth. According to Ehrenberg, the Infusoria polygastrica, such as we have just been describing, differ from the Infusoria rotatoria, in having a great number of stomachs, which connect by hollow peduncles with the mouth in the division Anentera, and with the intestine in that of Enterodela. This organization, which, from its high authority, has generally been admitted by naturalists, is not, however, met with in any infusorium.'1) The vesicular cavities in the bodies of these animals, and which have been regarded by Ehrenberg as stomachal-pouches, never have a hollow peduncle, either connecting with the mouth (Anentera) or with the intestine (Enterodela). Indeed, it is doubtful if a digestive canal can be made out in these Infusoria. The vesicular, irregular contracting cavities of their body contain a clear liquid, evidently the same as that in which they live, which, with the Astoma, has been absorbed through the surface of the body. But, with those having a mouth and oesophagus, it is received through them, and taken up by the yielding parenchyma of the body. If the methods of feeding of Gleichen and Ehrenberg are employed, the colored particles are taken in by a vortical action of the water, caused by the cilia surrounding the mouth. This water, with its molecules, accumulates at the lower portion of the oesophagus, and so distends there the parenchyma as to cause the appearance of a vesicle. Thus situated, the whole has much the aspect of a pedunculated vesicle. But when, from contractions of the oesophagus, this water escapes into the parenchyma, it appears there as an unpedunculated globule, in which the colored particles still float. When the Stomatoda are full-fed in this manner, there appear many of these globules in various parts of the body; and thus substances previously ingested are taken up and disseminated throughout the body. If the globules thus containing solid particles are closely aggregated, it sometimes happens that they fuse together; a fact which proves that they are not surrounded by a special membrane. The solid particles of food of the Stomatoda, which are often the lower Algae, such as the Diatomaceae and Oscillatoria, and often other Infusoria, are sometimes deposited in the parenchyma without being surrounded by a vesicular liquid.* From' observations made upon Amaba, Arcella'and Diftiugia, it appears that the Rhizopoda ingest their food like the Stomatode Infusoria. I Focke (Isis, 1836, p. 785) has already raised neck. ( Muller's Arch. 1839, p. 80; also Monatsdoubts as to the existence in Infusoria of the bericht der Berliner Akad. 1841, p. 103.) But, destomachs described by Ehrenberg. IEhrenberg tailed as they may be (seeEhrenberg Abhandl. d. has also opponents in Dujardin (Ann. des Sc. Nat. Ber. Akad. 1830, Taf. III.; 1831, T af. III. also "Die Zool. IV. 1835, p. 364; V. 1836, p. 193; X. 1838, Infusionsthierchen," Taf. XXXII. XXXVI. and p. 230; also Hist. Nat. des Infus. 1841, p. 57), in XXXIX.), they are not representations of nature. Meyen (Miiller's Arch. 1839, p. 74) and in Ry. The organ which in Trachelius ovum has been mer Jones (Ann. of Nat. Hist. III. 1839, p. 105; taken by Ehrenberg ("Die Infusionsthierchen," also, " A General Outline of the Animal Kingdom," p. 323, Taf. XXXIII. fig. xiii. 1) for a branching di1841, p. 56). gestive tube, has always appeared to me only as a, He has attempted to reply to the objections here solid fibrous cord, traversing the soft parenchyma urged by very detailed illustrations of the organ- of the body, and by its ramifications presenting a ization of the Polygastrica, made by him and Wer- coarse meshed aspect. * Bailey (Amer. Jour. Sc. May, 1853, p. 341) imagine a bag made of some soft extensible matehas recently published an account, accompanied rial, so thin as to be transparent like glass, so soft with numerous figures, of a new animalcule, which as to yield readily to extension when subjected to is so remarkable in this connection that I give here internal pressure, and so small as to be microscophis description. lie says: "If the reader will ic i this bag, filled with particles of sand, sbells of 28 l1NFU0oAJX AND RIIIZOPODA. ~ 13, 14. ~ 13. If the vesicular cavities containing the liquid and colorless food of the Stomatoda be examined under the microscope by a horizontal central incision, their contents appear colorless; but by changing the focus, viewing alternately the convex and concave surfaces of the vesicle, the points of junction between the colorless globules and the parenchyma appear colored pale-red. This appearance, due to an optical illusion, might easily deceive one into the opinion that the vesicles which are really colorless are colored. From this it is probable that Ehrenberg has described Bursaria vernalis and Trachelius meleagris as having a red gastric juice.(l) The violet points which are found upon the back and neck of Nassula elegcans and Chilodon ornatus are only collections of pigment granules, which, in the first case, are often absent, and in the second are often partially dissolved. This last violet liquid has been regarded by Ehrenberg(21 as a gastric juice resembling bile ~ 14. The solid particles of food, whether surrounded by the parenchyma or enclosed in a liquid vesicle, are moved hither and thither in the gelatinous tissue of the body, during the contracting and expanding movements of the animal. In some, the parenchyma with its contained food moves in a regularly circular manner, like the liquid contained in the articulated tubes of Chara. (1) In Loxodes bursaria (2) this circulation is remarkable, and of much physiological interest. Its cause is yet quite unknown, for in no case is it lue to cilia, and it may be observed in individuals entirely at rest. Ehrenlerng,(3) therefore, is incorrect in regarding it as due solely to a contratile power of the parenchylna, displacing the molecules. Much less is his explanation (4) satisfactory, since the digestive tube of an infusorium can be extended at the expense of its stomachal pouches, so as to fill the whole body, giving it the appearance of having a circulation of molecules through. out its entire extent. I"-Die Infusionsthierchen," pp. 321, 326, 329. 1836, p. 786; also Meyen, Muiller's Arch. 1839, Ehrenberg' hats, moreover, in 7'racheliuts melea- p. 75. gris, confountedethe contractile cavities with those 2 Focke loc. cit.; also Erdl, AMiller's Arch. 1841, non-contractile, and which receive the food. p. 278. 2 Abhandl. d. Berliner Akad. 1833, p. 179; also s L,)c. cit. p. 262. "Die Infusionsthierchen," pp. 319, 338, 339.* 4 3uller's Archiv. 1839, p. 81. 1 Vagizicold and Vosrticella. See F'ocke, Isis, Diatomaceee, portions of Algae or Desmidieae, and those of any animalcule with which we are ac with fragments of variously colored cotton, woolen, quainted. - ED. and linen fibres, will give a picture of the animal; [~ 13, note 2.1 In this connection should be to complete which, it is only necessary to add a noticed the experiments of Will (Miiller's Arch. few loose strings to the bag to represent the varia- 1848, p. 509). HIe found evidences of a biliary apble radiant processes which it possesses around the paratus, with Vorticella, Epistylis, and Bursaria. mouth." This animal, which is often found with These evidences are based on chemical reaction, bits of cotton protruding from its mouth, assumes and he describes no anatomical apparatus. I menthe most bizarre shapes. They appear to multi- tion this fact here, although Vorticella belongs ply by fissuration and gemmation even when filled truly to the Bryozoa, and Bursaria to the Planawith tnese heterogeneous particles, and, on the ria. - ED. whole, present characteristics as remarkable as ~~ 15, 16. INFUSORIA AND RHIZOPODA. 29 ~ 15. The round or elongated oval mouth of Tnfusoria varies as to its position. Sometimes it is in front, sometimes behind; and in some cases, near the middle third of the body. Rarely naked,(') its borders are generally ciliated,(2) and often its circumference is provided with a very remarkable ciliary apparatus. By the aid of this, these animals not only move about, but when quiet produce vortical actions of the water, which are felt at quite a distance; and all minute particles within its reach are quickly drawn towards its mouth, and then swallowed or rejected according to the option of the individual.(") It is rare that this oral aperture is provided with a dental apparatus.(41 The oral cavity, generally infundibuliform, extends into a longer or shorter, straight or curved (esophagus, which is lined throughout by a very delicate ciliated epitheliumn.() The anus, situated usually upon the dorsal surface of the posterior por. tion of the body, is sometimes, though rarely, indicated by a slight external projection.(6) CHAPTERS VI. AND VII. CIRCULATORY AND RESPIRATORY SYSTEMIS. ~ 16. A vascular system entirely distinct by closed walls from the other organs is not found in the Protozoa. But with very many (with all the Stonomatoda, without exception) there are contractile pulsatory cavities, the form,' number and arrangement of which is quite varied. They are situated in the denser and outer layers of the parenchyma of the body, and during the diastole they become swollen by a clear, transparent, colorless liquid, whith, during the systole, entirely disappears. 1 Ictinophrys. The mouth is naked also in the while it is long and arcuate in Bursaria truncagenera Difelugia and Arcella of the Rhizopoda.* tella and cordtformis. 2 Bursaria, Paramuecium, Urostyla and Sty- 6 The undigested matters accumulate about the lonychia. In Glaucoma scintillans the ciliated anus, and when this opens are expelle(l from the crown of the mouth is replaced by a special semi- parenchyma with a certain force. With Nassula lunar ciliated lobe. elegans, the greater or less portions of the Oscil3 In Stentor, Vorticella, Epistylis and Tricho- latoria gracillimna (Kdtzin-) upon which it dina, this apparatus is retractile, and produces in a feeds, and which are of a blue-green color, disparticular way the vortical actions. In Spirosto- solve into granules of this color. But these, durmum ambi-guum, there is a long, narrow, ciliated ing the process of digestion, gradually assume a furrow, through which the food is conducted to the brown color, and form irregular masses in the posmouth, situated at the posterior portion of the body. terior portion of the body, and are from time to 4 Prorodon, Nassula, Chilodon and Chlansido- time expelled as brown fceces. These green grandon. Here the hair-li, teeth are arranged in a ules are not therefore eggs, as Ehrenberg (loc. cylinder so as to resemble a weir. cit. p. 339) has supposed. This Nassula when 5 The cesophagus is short in Oxytricha, Sty- young is perfectly colorless, with the exception of lonychia, and Euplotes; but is elongated or spi- a beautiful blue spot. ral in Vorticella, Carchesium and Epistylis; * ~ 15, note 1.] Klliker (Siebold and Kolli- stance. Yet this remarkable animal lives on other ker's Zeitsch. I. 1849, p. 198) has given a long and Infusoria, Algae, &c., and avails itself of them by detailed description of Actinophrys sol. Accord- seizing and afterwards invaginating them in its pa. ing to him, it is without mouth or stomach proper, renchyma, until they finally are included within itS and internally is composed of a homogeneous sub- interior. - ED. c. 30 INFUSORIA AND RHIZOPODA. ~ 17. These movements succeed each other at more or less regular intervals. When these cavities are numerous, a certain order in the succession and alternation of their contractions cannot always be observed. It is very probable that their liquid contained during the diastole is only the nutritive fluid of the parenchyma, and to which it returns during the systole. In this way it has a constant renewal, and all stagnation is prevented. This arrangement constitutes the first appearance of a circulatory system, and thefirst attempt at a circulation of nutritive fluids. From an optical illusion similar to the one mentioned as belonging to the vacuolke (~ 13) the liquid of these pulsating cavities has a reddish hue. () ~ 17. A round, pulsating cavity is found in the genera Vorticella, Epistylis, Loxodes, and in the following species: —Ameba diffluens, Paramacrium kolpoda, Stylonychia mytilus, Euplotes patella, 4c. With Actinophrys, Bursaria, Trichodina, there are from one to two; with Arcella vulgaris, three to four; with Nassula elegans, there are four placed in a longitudinal line on the dorsal surface. With Trachelius meleagris, there is a series of eight to twelve upon the sides of the body, and with the various species of Amphileptus there are fifteen to sixteen arranged more or less regularly. With Stentor, there is a large cavity in the anterior portion of the body, and many similar cavities appear upon the sides, united sometimes into one long canal. A similar canal traverses the entire body of Spirostomum ambiguum, and Opalina planariarum. With Parameciuzm aurelia, the two round cavities present a remarkable aspect, being surrounded by five or seven others, small and pyriform, the top of which being directed outward, the whole has a star-like appearance.(l' During the pulsation, often the entire star disappears, sometimes only the two central cavities, and in some cases the rays only. These cavities, entirely disappearing in the systole, reappear in the diastole, and usually in the same place and with the same form and number. This would lead us to conclude that they are not simple excavations in parenchyma, but real vesicles or vessels, the walls of which are so excessively thin as to elude the highest microscopic power. In some individuals, as, for instance, vwith Trachelius laimella, there appear, during the diastole, two or three small vesicles at the extremity of the body, which, after having increased in size, blend into one which is very large. These are probably only globules of nutritive fluid, separated from the parenchyma. Similar phenomena are observed in Phialina vermiculnris and Bursaria cordiformis. It sometimes happens with these animals that a forcible contraction of the whole body divides an elongated cavity into two spherical portions, as I Ehrenberg (loc. cit. p. 321, Taf. XXXIII. fig. in the body. It really seems very strange that viiL), deceived by this illusion, has taken the eight these animals should practise uninterruptedly these to twelve contractile cavities of Trachelius melea- pollutions throughout their entire life. These anigris for stomachal cells, filled with red gastric juice. mals have neither testicles nor ovaries, and the ie has also regarded these cavities, when simple or function of these cavities is not, therefore, that double, as seminal vesicles. (Abhandl. d. Berliner assigned to them by fEhrenberg, —but is, as I Akad. 1833, p. 172,-1835 p. 158.) In species think, with Wiegmann (Arch. f. Naturg. 1835, I. having but few, he has very arbitrarily decided that p. 12), analogous to that of a heart. some are seminal vesicles, others stomachal pouches, I) Dujardin, Ann. d. Sc. Nat. Zool. tome X. Pl. as, for example, in Amphileptus (loc. cit. p. 355). XV. fig. 3; also, " Infusoires," P1. VIII. fig. 6. According to him, the seminal vesicles, upon con- Ehrenzberg's plates of these star-like vesicles are traction, pour the sperm upon the eggs contained incorrect. 5$ 18, 19. INFUSORIA AND RHIZOPODA. 31 though it were a drop of oil. The observation of these phenomena would make it'doubtful whether or not these'cavities are true vesicles or vessels. These cavities have been met with in only a few of the Astoma, and these are, Cryptomonas ovata (2) and Opalina planariarum. ~ 18s.'The Infusoria appear to respire solely by the skin. In those species whose bodies are covered with vibratile cilia this function is promoted by the vortical action of the water caused by these organs. In others, the contractile cavities just described are situated immediately under the skin, and the opinion may be entertained that the water so communicates with their liquid contents as to perform a respiratory function. In this repect Actinophrys sol is quite remarkable, for its contractile cavities are so superficial that when filled they raise the skin in the form of aqueous vesicles,(l) which, however, are so elastic as entirely to disappear in the parenchyma. Here it is plain that a mutual relation between the external water and the contents of these cavities might easily take place. CHAPTER VIII. ORGANS OF SECRETION. -~ 19. No special organ of secretion has been found in the Protozoa; their skin, however, has a power of secreting various materials, which in some species harden and form a carapace, or a head of a particular shape; while in others it serves to glue together foreign particles, forming a case, in which the animal retreats. Among those having a carapace, may be mentioned Vaginicola, Cothurnia, and Arcella. This more or less hard envelope does not resist fire, and is probably of a corneous nature. In the Rhizopoda, however, it is usually calcareous, like the shells of Mollusca, and is not affected by heat. The Di/flugiae carry about with them an envelope of this kind, composed of grains of sand. 2 Ehrenberg, loc. cit. p. 41, Taf. II. fig. xvii. 1 Ehrenberg (Ibid. p. 303, Taf. XXXI. fig. vi. 1 ) appears to have taken the protrusion of these coo. tractile vesicles for that of a snout. 32 INFUSORIA AND RIIIZOPODA. ~~ 20, 21, 22 CHAPTER IX. ORGANS OF REPRODUCTION. ~ 20. The Infusoria propagate by fissuration and gemnation, and never by eggs.() They have therefore no proper sexual organs. This fissuration occurs longitudinally with somne,~2) transversely withl others,~3 and in many of them by both at once.(4) Gemmation, on the; contrary, is very rare.(~) ~ 21. Nearly all the Infusoria and Rhizopoda have in their interior a nicelydefined body, a kind of a nucleus, which is quite different, in its compact texture, from the parenchyma by which it is surrounded. This nucleus,. which, in different species, varies much in number and form, performs an essential part in the fissuration. For, every time the individual divides either longitudinally or transversely, this nucleus, which is usually situated in the middle, divides also. So that, in the end, each of the two new individuals has a nucleus. When an animal is about to undergo fissuration, there is generally first perceived a change in the nucleus. Thus, in Paramaecium, Bursaria and Chilodon, the nucleus is sulcated longitudinally or trans — versely, or even entirely divided,(') before the surface of the body presents any constriction. This nucleus, which is of a finely granular aspect and dense structure, retains perfectly its form when the animal is pressed between two plates of glass, and the other parts are spread out in various ways. By direct light its color appears pale yellow. It appears to lie very loosely in the parenchyma, and sometimes individuals may be observed turning their bodies around it as it rests motionless in the centre. From all this, it cannot be supposed that this nucleus attaches itself to other parts of the animal, and especially to the pulsatory cavities (Vesiculce seminales of Ehrenberg).(2) ~ 22. A simple, round, or oval nucleus is found in Euglena, Actinophrys, Arcella, Amonba, Bursaria, Paramecium. Glaucoma, Nassula and Chilo — don. But there are two which are round, and placed one after the other in Amphileptus anser and fasciola, in Trachelias meleagr-is, and Oxytricha pellionella. With Stylonychia mytilus, there are four. 1 That which Ehrenberg has arbitrarily taken 3 This may be easily observed with Stentor,. for eggs is sometimes granules of the parenchyma Leucophrys, Loxodes, and Bursaria. or pigment corpuscles, sometimes bits of food. He 4 Bursaria, Opalinla, Glaucoma, Chilodlon, Padid not perceive that these bodies want all that which ramcecium, Stylonychia and Euplotes. is necessary to make up an egg, - such as chorion, 5 Vorticella, Carchesizum and Epistylis. vitellus, and germinative vesicle and dot. It is on 1 Ehrenberg, loc. cit. Taf. XXXVI. fig. vii. 13 this account that he declares that he never has to 19, Taf. XXXIX. fig. ix. 4, 5, 11-13. observed the hatching of young Infusoria. (Ab- 2 Ehrenberg, from a strange fancy, has taken handl. d. Berliner Akad. 1835, p. 156.) this nucleus for a seminal gland. (Abhandl. d1, 2 Vorticella, Carchesium. Berliner Akad. 1835, p. 163. Also, loc. cit.) ~ 23. INFUSORIA AND RHIZOPODA. 35 It is not rare that a variable number of these round nuclei, arranged in a row, traverse the body in a tortuous manner. This is so in Stenztor coeruleus and polymorp/ius, in Spirostomum ambiguum, and in Trachelims 7noniliger. In many instances the nucleus has the form of an elongated band, which is slightly curved in Vorticella convallaria, Epistylis leuc(a, Prorodon niveus and Bur-saria truTzcatella. In Stentor Rueselii, it is spiral, and in Euplotes patella and Trichodina mitra. it is shaped like a. horse-shoe. In Loxodes bursaria, it is kidney-form, and encloses in one of its extremities a small corpuscle (nucleolus). The round nucleus of Eugalena viridis has in its centre a transparent dot. In Chilodon cucullulus, the nucleolus has a similar dot, and thus the nucleus as a whole resembles a cell. ~ 23. These nuclei, which make Infusoria resemble cells, deserve a special attention, since they do not die with the animal. Thus the nucleus of Euglena viridis, which, according to Ehrenberg, () is globular when dying, and surrounded by a kind of cyst, remains unchanged a long time, or even increases in size, having no appearance of a dead body. It may be that the life of this animal, under these circumstances, is not finished, but only assumes another formn.(2) t Loc. cit. p. 110. That the nucleus contained in Inlfusoria plays an 2 Perhaps this nucleus, of which the animal is important part in the propagation of those animalonly a temporary envelope, is ultimately developed cules, is supported also by a recent observation of into a particular animal. Indeed, perhaps this:'och-e,, vwho witnessed the development of several species, as well as many others, are only the larval young iridividuals in the nucleus of Loxodes burstates of other animals, whose metamorphoses are csc ia., See: Amtl. Bericht fiber die 22 tr. Yersaaml. e.t unknown. It may properly be asked, if this deutsoh. Natur'forscher. in Bremen, Abth. ii. p>,i-f,<,eus has not, relative to the body containing it, 110. tl-e sotme signification as have the tubulous larvaof Moon.stomu.m mutabile (see below) to the emrtyoo tihey surround. INTRODUCTORY NOTE TO THE ZOOPHYTA. VWITHIN the past six or seven years the Zoophytes have received more attention from naturalists than any other division of the animal kingdom.'The labors of many, if not most of our ablest naturalists, have been directed towards an investigation of the humblest forms of animal life. This fact, combined with the recent improved methods and means for research, would alone be prophetic of the most signal advances in this group.; indeed, our knowledge of all these forms has been so modified, as well as increased, that previous writings need rather to be re-written than revised. Dana, Agassiz, Milne Edwards, Forbes, Dalyell, Miiller, Busch, and others, not to mention the continued labors of older observers, have,effected these changes in this group. The work of Dana is most excellent, and will remain a standard of au-. thority in this department for a long time to come. Aside from the many details of structure, in it may be found the first and best philosophical exposition of the relations of organic development with these lower plantlike forms. Had this work been better known in Europe, there would have -been saved the constant repetition of the most grave errors. On the labors of Agassiz no comment need be made; those who are in this department, whether as minute Anatomists or philosophical Zoologists, will not fail to understand and appreciate him. In the same field is Busch, who was extended his brief though excellent labors over the three classes of this whole group; as for the remaining authors mentioned, excepting Miller, their position in this department has long been established. Miller's researches have been mostly on the Echinoderms, and the careful tracing of the phases of their development and metamorphoses; but where so much has been done, I fear the limits of this book will preclude full details with this class. This note would be unnecessary, were it not to show that I do not ignore the changes and advance which have been made in this group within the past few years; and more especially so, as I have allowed, in this edition, the classification to stand as in the original. Any great changes of this INTRODUCTORY NOTE TO THE ZOOPHYTA. 35 kind I could not think of making without the consent of the authors, who, although they would undoubtedly fully sanction them, are not sufficiently accessible to me just now, as these pages are going to press. So, however much the present classification may offend the eye of the Zoologist, yet the Anatomist will find under each head the proper details. Thus, he will find as full a description of the anatomical structures of the Bryozoa and Eydroid Polypi, as though they were referred to the Mollusca and Acalephae, where truly they respectively belong. EDITOR. BOOK SECOND. P OLY P)I. CLASSIFICATION. ~ 24. THE POLYPI are either immovably fixed, or seated on a locomotive foot. Their soft body is in part enveloped by a solid support, the polypary. This last is often, for the most part, horny or calcareous; and by it numbers of these animals are united into greater or less groups. The central mouth is always surrounded by a coronet of contractile tentacles. The digestive apparatus is organized after two different types, upon which is based a division of these animals into two orders. The sexual apparatus is always without copulatory organs. ORDER I. ANTHOZOA. The digestive canal is without an anus, and opens into the general cavity of the body. FAMILY: MADREPORINA. Genera: Oculina, Millepora, Madrepora, Caryophyllia, Astraea, Desmophyllum, Maeandrina, Monticularia, Agaricia, Favia. FAMILY: GORGONINA. Genus: Gorgonia.:FAMILY: ISIDEA. Genera: Corallium, Isis. FAMILY: TUBIPORINA. Genus: Tubipora. FAMILY: ALCYONINA. Genera; Alcyonium, Lobularia, Alcyonidium. FAMILY: PENNATULINA. Genera: Veretillum, Pennatula, Virgularia. ~ 24. THE POLYPI. 3T FAMILY: SERTULARINA. Genera: Sertularia, Campanularia. FAMILY: ZOANTIHINA. Genus: Zoanthus. FAMILY: HYDRINA. C-snera: Hydra, Eleutheria, Synhydra, Coryne, Syncoryne, Corymorpha. FAMILY: ACTININA. Genera: Actinia, Eumenides, Edwardsia. ORDER I. BRYOZOA. The digestive canal is closed from the general cavity of the body, and opens behind through an anus. FAMILY: RETEPORINA. Genera: Eschara, Cellepora, Flustra, Bicellaria, Retepora, Telegraphina, Tendra. FAMILY: ALCYONELLINA. -Genera: Cristatella, Alcyonella, Bowerbankia, Vesicularia, Lagenella, Plumatella, Lophopus. ( BIBLIOGRAPHY. Ellis. Essai sur l'Histoire naturelle des Corallines et d'autres productions marines du meme genre. La Haye, 1756. Pallas. Elenchus zoophytorum. Hagae 1766. Cavolini. Memorie per servire alla storia dei'olipi marini. Napoli, 1785. Rapp. Ueber die Polypen im Allgemeinen und die Aktinien insbesondere. Weimar, 1829. Ehrenberg. Die Corallenthiere des rothen Meeres, in the Abhandl. d. Berliner Akad. 1832. Johnston. A History of the British Zoophytes. Edinburgh, 1838. Besides the important work of Dana, which will be often quoted in my notes, the additions to the literature of the true polyps have been few since the issue of this work, and have generally been published in the form of articles in the various periodicals, to which reference will be made in my notes. But the Bryozoa have been specially studied, and particularly in the following papers: 1 There are here enumerated only those families This remark applies equally to the following whose organization has been specially studied. classes. 4 38 THE POLYPI. ~~ 25. 26. Van Beneden. Recherches sur l'Anatomie, la Physiologie et le developpement des Bryozoaires. MIsm. Acad. Brux. Tomes XVIII. XIX. Recherches sur les Bryozoaires fiuviatiles de Belgique. Ibid. Tom. XXI. For further literature on the Bryozoa, see the writings quoted in my notes, and especially those of Allman. ED. CHAPTER I. CUTANEOUS ENVELOPE AND SKELETON. ~ 25. The Polypi are composed of either entirely soft parts,(1) or have for their support a solid frame, which may be calcareous, corneous, or coriaceous. This frame is always the product of the general skin, and ought therefore to be compared to a cutaneous skeleton.* This skeleton, known by the name of polypary, is formed partly internally, and partly externally, by these animals. In the first case it is called an axial, and in the second a tubular polypary. The axial polypary consists, with some polyps,(2) of a dense substance, apparently unorganized and composed of carbonate of lime; with others,(3) of a corneous substance, equally unorganized. When the polypary is coriaceous, it is often covered by a variable number of calcareous, fusiform corpuscles, usually bossed or dentated.(4) With some calcareous polyparies (5) this is also true, and then the corpuscles are arranged in compact reticulated masses. The tubular polyparies serve as a refuge for the animals living in them, and in many cases, being common to many individuals, these last are in direct relation to each other by the canals which traverse the branching tubes. In the axial polyparies there are often cavities or depressions of a variable size,(6) in which the animals can conceal themselves. When, however, these are wanting,(71 they retire, as is the case with many soft polyps,(8 beneath their mantle. Sometimes,1t) these cavities are closed by a movable operculum. ~ 26. The skin of polyps is very transparent, and should be carefully distinguished from the parenchyma which it envelops. It is smooth, or it is covered with ciliated epithelium. And, since it has been shown that many 1 The Actinina and Hydrina. p. 403, Taf. I.-III.) has described and figured these 2 Corallium. spicula under the names of Spongolithis and 3 The Gorgonina. LitLhostylidium. 4 These corpuscles are easily seen in Alcyonium 5 The Madreporina. and Lobularia. (Milne Edwards, Ann. d. Sc. 6 Millepora, Madrepora, Oculina and Astraea. Nat., Zool. IV. 1835, pl. XIII. fig. 9; P1. XV. fig. 7 Gorgonia, Isis and Corallium. 10 —11.) Spicula of this kind are found in the 8 The Actiniae. interior of their tissues, as well as on the surface. 9 Eschara and Cellepora. Ehrenberg (Abhand. d. Berl. Akad. 1841, Th. I. * It should here be remarked that the old, and with Madrepora, Astraea, 4-c. For the formation as now regarded, mistaken view of the formation of of Coral, see Dana, loc. cit.; and for the relations of the frame of Polyps is here repeated; for the frame the corallium carried out in detail, see Edwards and. Is generally an internal skeleton, as. for instance, Haime, Ann. d. Sc. Nat. 1849,'50,'51.- ED. $~ 27, 28. THE POLYPI. 89 Anthozoa have the skin, and especially the tentacles, covered with cilia of this nature,() these last cannot be regarded as forming a differential characteristic between them and the Bryozoa, as has been done by Ehrenberg. (2) ~ 27. The skin of many polyps is quite remarkable in having nettling or poisonous organs, to which it is only of late that the attention has been directed. They consist of transparent vesicles, having a dense membrane, of a round, oval, or cylindrical form, containing a clear liquid, and a very delicate filament of variable length, which is usually spirally coiled. By the least irritation of the skin, the filament is thrown out of the vesicle, of which it appears to be only a prolongation. These filaments adhere to objects coming in contact with the skin, and in this way the vesicles in question are separated from it.(') These organs are probably the cause of the nettling sensation felt when certain polyps are handled. ~ 28. Still more interesting are organs analogous to those just mentioned, and' which belong to various species of Hydra.') They are found not only on the arms, but also upon the skin of the body and foot. They consist of oval vesicles, having a very long and delicate filament, which is slightly swollen and viscous at its free extremity, while the opposite one is directly continuous with the conical neck of the vesicle. The neck of each vesicle is surrounded by three hooks curved backwards. These are always elevated when the skin of the animal is irritated, and especially that of the arms when they seize their prey. This last is then wound about by the free, viscous end of the filament, and the attached vesicle being torn from the body, the whole is often entangled in the arms of adjacent polyps. When this occurs, the vesicles hang by their hooks to the arms of the polyps; and it is this that has given Ehrenberg the opinion that the vesicles are detached by their round extremity, that' these animals watch their prey with the hooks erected, and that the vesicles and filaments can return into the interior of the arms.(2) But it is probable that they (the hooks) act more as poisonous than as prehensile organs; for if those from the arm of a Hydra seize upon a Nais, a Daphnia, or a larva of Chironomus, these last quickly die, even if they escape immediately after being taken. 1 Erdl has seen very distinct ciliated epithelium (Ehrenberg), I have seen these cylindrical organs: in Actinia and Veretillum.. (See MUiller's having a long spiral filament. lWith Edwardsia, Arch. 1841, p. 423.) Quatrefages has found these organs upon the 2 Abhandl. d. Berl. Akad. 1834, p. 255, 377. whole surface of the body, as well as upon the 1 These nettling organs, which are much more arms. (Ann. d. Sc. Nat., Zool. 1842, XVIII. p. 81, common in the lower orders of the animal kingdom P1. II. fig. 4-6.) For the nettling organs of the than was at first supposed, are yet quite imper- Tubulariae and the Actiniae, see also tWagner in fectly known. Wagner first discovered them in Miiller's Arch. 1847, p. 195, Taf. VIII. the Actinia, although he regarded them at first 1 These were first described by Ehrenberg. as the spermatic particles of these animals. (Wieg- (Mittheil. a. d. Verhandl. d. Gesellschaft naturf. Lmann's Arch. 1835, II. p. 215, Taf III. fig. 7, also Freunde zu Berlin 2 tes. Quartal, 1836, p. 28; also, 1841, I. p. 41; Icones Zoot. Tab. XXXIV. fig. 24.) Abhandl. d. Berl. Akad. 1835, p. 147; 1836, p. These researches have been extended by Erdl, 133, Taf. II.) They have been carefully studied who has shown that they also exist with Veretillum by Erdl (illIller's Arch. 1841, p. 429. Taf. XV. and Alcyonium. (Miiller's Arch. 1841, p. 423, fig. 10 —13). Taf. XV. fig. 3 —6 and 8, 9.) In Alcyonium, Erdl 2 Ehrenberz has figured, ideally (Abhandl. d. has observed the filament take, on its departure ]Berl. Akad. 1836, p. 13.3, Taf. II. fig. 1) an Hydra from the vesicle, first a riband-like, and then a in the act of seizing its prey with extended hooks. spiral aspect. In Desmophyllum stellaria In reality this animal is never thus seen. 40 THE POLYPI. 28. These poisonous and prehensile organs are destroyed by use, which is also true of the nettling organs. But this loss is probably repaired by their speedy reproduction. This last circumstance may explain the various descriptions given them by different authors, for, probably they have been observed at dissimilar stages of development.'3) 3 Erdl, who has discovered a great number of served (Beitrage z. Kenntniss d. Geschlechtsverthese nettling organs, saw, in some cases, the thread hkltnisse u. d. Samenfliissigkeit wirbelloser Tlhiere, directly continuous with the neck of the vesicle; in 1841, p. 44, fig. 14). Erdl asks if these variations others, these necks appeared furnished with spines of form are not coincident with an increasing or -directed backwards exactly as Wagner had decreasing activity of the sexual organs (see before described, and as K6lliker had often ob- Miiuller's Arch. 1842, p. 305). * [~ 28, note 3.] These nettling organs of the point, they almost elude the highest and best microPolypi have recently been very successfully studied scopic powers. These barbels all point backwards by Agassiz, who has enjoyed the most enviable when the lasso is extended, and serve, no doubt, as advantages with the Polypi and Acalephae of the teeth, to prevent it from slipping on the objects over North American coast. He has changed the entire which it is thrown. But these most delicate strucaspect of the subject, besides almost exhausting it for tures, which in beauty transcend that of all other future research. His special studies were made on tissues, can be better appreciated by figures than the coral polyp of our southern coast, the Astrangia by the most minute description; see Agassiz's Danae, Agass. The complexity of structure of Memoir on Astrangia Danae (forthcoming in the these lasso-cells, as he has very appropriately "Smithsonian Contributions to Knowledge"), P1. termed them, is truly wonderful for such minute VI. These observations, however, were made in forms. As I have also studied these forms, I will 1848; see Proceed. Amer. Assoc. Advancem. Sc. use my own language, in the description of what 1848, p. 68. Prof. 4Agassiz has seen. There are several varieties From my own observations there would, indeed, of these cells or capsules, depending upon the ar- be nothing to add on the special points studied rangement and structure of the lasso; sometimes by Agassiz; but a remark or two may be made as this last is a simple coil, sometimes it is coiled about to the development of these forms. a staff which is erected from the base, but which is The lasso-vesicle is, originally, only an epithelial also a part of the projectile apparatus. In the first cell, of a spheroidal shape. It soon elongates, its case, the lasso is much the longer and may be fifty contents become cloudy, after which, the coil is *or seventy-five times the length of the vesicle; while, seen, very faintly marked, lying on the inner wall, in the second case, it rarely exceeds the length of It would seem probable, therefore, that its formathis last by more than sixteen or twenty times. In tion was somewhat similar to that of the spiral all cases, the essential feature of these organs is the vessels in plants, although it is true that the lassolasso or internal coil, which is of a most curious coils and these spiral vessels are analogous only in structure. In the first place, it is, in general terms, form and position, and not in structure. The details only an inverted portion of the vesicle or cell itself, of the formation are unknown. an internal instead of an external cilium, coiled These lasso-cells are more widely distributed up in a regular manner. When thrown out, there- among the Radiata than hitherto supposed..Agasfore, it is wholly inverted, and its projection consists siz (as he has informed me by letter) has observed of an instantaneous turning of the whole inside out. them on most of the Polypi and Acalephae, and even But the lasso, delicate as it is, has still more delicate with seme of the Mollusca, and although their structures on its surface. These consist of barbels general structure is the same, there are points of:arranged in regular spiral rows, which extend difference of even a zoological value. to the very extremity of the lasso. At this last EDITOR. -~~ 29, 30. THE POLYPI. 41 CHAPTER II. MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION. ~ 29. The movements of Polyps are performed, partly by contractions of the sides of their body, in which are found no muscular fibres, and partly by a true muscular tissue. The fibres of this tissue have not regular transverse strie, although during their contractions there are sometimes, though -rarely, seen irregular transverse bands.'l' ~ 30. In those Polyps having a true muscular system, this tissue is composed Dof interlaced fibres, forming a layer beneath the skin. A coarse net-work of this kind is seen in the arms of Hydra, although in the foot and rest of the body there is scarce anything comparable to muscular fibres.(') Under the skin of Synhydra(1) and in the arms of Eleutheria(3 this muscular system is much more apparent. A similar layer, very distinct, is observed in Actinzia, which, in their mantle, is composed of both longitudinal and circular fibres, the contraction of which draws the tentacles together, and this, combined with that of the radiating fibres of the foot, gives rise to the various.forms of these animals.04) The Bryozoa have the muscular system more apparent; in the cavity of their body completely isolated fasciculi are seen, composed of parallel fibres, serving especially for the withdrawal of these animals into their cells.'These fasciculi arise from the internal surface of the body, and are inserted partly into the base of the tentacles, and partly into the neck and digest-;ive canal, - thus serving almost exclusively as retractors of these last.(~ 1 Milne Edwards, who declares he has seen 2 Quatrefages, Ann. d. Sc. Nat. XX. 1843, p. -striated muscular fibres in Eschara (Ann. d. Sc. 238, pl. IX. fig. i-5. Nat. VI. 1836, p. 3), must have been deceived. I 3 Quatrefages, Ibid. XVIII. 1842, p. 281, pl. have been unable to perceive them in Eschara, Al- VIII. fig. 3..cyonella, Cristatella, and other species. NWord- 4 Berthold, Beitr. zur Anat. u. Physiol. 1831, p...ann also has not found them in Cellaria. (Ob- 16 also in the body of Edwardsia, Quatrefagres serv. sur la Faune Pontique, 1840, p. 679; also has found longitudinal and circular fibres (Ann. d. ~Miiller's Arch. 1842, p. ccviii.) The irregular bands Sc. Nat. XVIII. p. 81). appearing during contraction, but afterwards disap- 5 Similar muscles have been observed by Farre goearing, have been observed by Quatrefaoes with (Phil. Trans. 1837, p. 387) in Bowerbanslia, Vesi-.Edwardsia (Ann. d. Sc. Nat. XVIII. 1812, p. 84, cularia, Ladenella and other Bryozoa. Milne pl; II. fig. 7, a-b).* Edwards has seen them in Tubulipora and Es1 Corda, Nov. Act. Acad. C. L. C. Nat. Cur. chara. (Ann. d. Se. Nat. VIII. 1837, p. 3241; VI. XVIII. 1839, p. 299. Also Ann. d. Sc. Nat. VIII. 1836, p. 23, pl. I. fig. 1, c, 1, Id pl. II. fig. 1, a.) 1837, p. 363. Coste has given a very detailed description of the * [ ~ 29, note 1.] Busk has described and figured cies examined no such form of muscle is present. >the striated form of this tissue with Anguinaria Quite lately, however, the subject has been care-qpatulata and Notamia bursaria. (Trans. Micro- fully examined by Atlman (Rep. Brit. Assoc. 1850, -scop. Soc. of London, II.) I have been unable, p. 318), and his descriptions are such as to leave however, after considerable search upon many Bry- no doubt upon the existence of the striated fibre,ozoa, among which were several Alcyonella, to with the species he has examined, among which detect any appearances of this kind; and I would are he Paludiccellae. -ED. venture a pretty confident opinion that in the spe4* 42 THE POLYPI. ~~ 31, 32. With Eschara there are, moreover, two fasciculi in each cell, which moveits operculum, and thus close the entrance of this cavity.(6) ~ 31. Locomotion is performed by the Polyps in various ways. With the Hydrae, by their long-stretching arms; with Actiniae, by the contractions of the disc of their foot; (l) while the Edwardsiae, having elongated bodies which are not attached by a, foot, progress by vermiform movements.(2) With Cristatella mirabilis, the whole colony moves itself along by the foot-like basis, like the Actiniae.(3) Some Polyps, at a certain period of their development, move freely in, the water by discoid contractions of their body, like the pulmograde Acalephae. () ~ 32. A very remarkable peculiarity is the presence, in certain Bryozoa, of organs shaped like a bird's head, and which swing to and fro at the base of their cells. In some species, these organs have the form of lobster's claws, being composed of both a fixed and a movable piece. This last is corneous, and moved by a muscle which arises from a cavity in the first. It is not yet known by what means either this beak is opened, or the whole organ moves to and fro.l) Equally unknown is the function of these singular organs, the movements of which persist after the death of the animal, and of which, therefore, they are independent.(2) They are perhaps organs of defence or prehension, and analogous to the Pedicellarice of the Echinoderms. muscles of Plumatella (Comp. rend. XII. 1841, p. 1 These organs were first described by Ellis 724; Miiller's Arch. 1842, p. ccx).* (Essai surl'Hist. Nat. des Corall. 1756, p. 51, pl.'6 Milne Edwards, Ann. d. Sc. Nat. loc. cit. p. XX. fig. A). Nordmann (Observ. sur la Faune 24, pl. I. fig. 1, e. Pontique, 1840, p. 679, pl. III. fig. 4) has described 1 Berthold, loc. cit. p. 14. and figured them with much accuracy. In Cel2 Quatrefages, Ann. d. Sc. Nat. XVIII. p. 74; laria avicularis, Bicellaria ciliata and Flustra also Forbes, Ann. of Nat. Hist. VIII. 1842, p. 243. avicularis, they are formed like lobster's claws. 3 I have been able to confirm the observation of In Retepora cellulosa they are pincer-like, and in Dalyell (Froriep's Notizen 1834, No. 920, p. 276) Telegraphina they are articulated stings. See upon this motion in Cristatella. Trembley, also, also Krohn in Froriep's Notizen, 1844, No. 533, has observed that the corallum of Plumatella p. 70.. cristata moved half an inch in eight days (see For the organs having the form of a bird's head his Mimoire pour servir a lHist. des Polypes d'eau and a lash, and which are present in certain Brydouce, 1775, p. 298). ozoa, see also Van Beneden, Recherch. sur l'anat. 4 See the observations of Steenstrup (Ueber d. &c., des Bryozoaires, in the Nouv. M1m. de BruxGenerationswechsel, 1842, p. 20) upon Coryneff'i- elles, XVIII. 1845, p. 14, pi 1I. III., and Reid in tillaria; also those of Van Beneden (I4em. sur les the Ann. of Nat. Hist. XVI. 1845, p. 385, pl. XII. Campanulaires, 1843, p. 29, or Froriep's neue Noti- 2 Darwin's Voyage of the Beagle, 1844, pt. I. zen, 1844, No. 663, p. 38) upon Campanularia ge- p. 252.t latinosa. * [ ~ 30, note 5.1 AI-man (Report Brit. Assoc. With Paludicella, the muscular system is some1850, p. 314) has described a very complete mus- what different; there are here five sets, - the 1st. cular system in the fresh-water Bryozoa. In the 5th, 6th, and 7th of the preceding, and the pariespecies with bilateral lophophores, there are seven tal muscles. But with the 1st there is here only a distinct sets: 1. Retractor muscles of the polypide; single instead of a double fasciculus. - ED. 2. The rotatory muscles of the crown; 3. The t [ 32, note 2.] See Hincks (Ann. Nat. Hist. tentacular muscles; 4. The elevator muscle of the VIII. 1851, p. 353), Who regards these avicularia valve; 5. Superior parieto-vaginal muscles; 6. as organs of defence, and has observed them seizInferior parieto-vaginal muscles; 7.Vaginal sphinc- ing and retaining foreign bodies. - ED. ter. The walls of the stomach also contain circular muscular fibres. ,Q 33, 34. THE POLYPI. 13 CHAPTERS III. AND IV. NERVOUS SYSTEMI AND ORGANS OF SENSE. ~ 33. As yet only a very rudimentary and imperfectly distinguished nervous system has been made out in the Polyps; this consists of round masses, which are regarded as composed of nervous matter (ganglia), situated in the parenchyma. A ganglion of this kind has been supposed to have been observed about the mouth.(1) ~ 34. Investigations upon their organs of sense have not been more successful. However, the sense of touch appears developed over the whole surface of the body, but specially so in the extremely irritable arms and tentacles. But, as yet, no tactile nerves have been found in these parts. In the same manner, light, to which these animals show a greater or less sensibility, is perceived rather by the general surface of the body than by special organs. There are, however, in some species, at particular stages of development, during which they swim freely about, certain nicely-defined bodies situated upon the sides of the body, and which may be regarded as special organs of light and sound. This is the case with Syncoryne;(1) and Coryne() has in their place four red organs which correspond exactly to those found on the border of the disc of the pulmograde Acalephwe, and which have been regarded as organs of sense. The organ seen at the base of the six arms of Eleutheria dichotoma has quite the appearance of an eye; that is, there can be distinguished in 1 A double cesophageal ganglion has been ob- Nat. XIV. 1840, p. 222). Coste asserts the presence served by Dumortier (MI6m. sur 1' Anat. et la of a nervous system in Pennatula (Froriep's neue Physiol. d. Polypiers compos6s d'eau douce 1836, Notizen, 1842, No. 450, p. 154). That which Spix p. 41, pl. II. fig. 2) in Lophopus cristallinus (Plu- pretended to have discovered in the foot of Actimatella cristata of Lamarck); and by Coste nia (Ann. d. Mus. d'Hist. Nat. 1809, p. 443, pl. (Comp. rend. XII. 1841, p. 724)in the Plumatellae XXXIII. fig. 4) has been properly rejected by in general. Nordmann also has seen a similar most modern zootomists, as an illusion. See Berganglion under the mouth of Plumatella camnpa- thold, loc. cit. p. 6.* nulata (Lamarck) (loc cit. p. 709), and of Tendra 1 Loven, Wiegmann's Arch. 1837, I. p. 323. zostericola (Ann. d. Sc. Nat. XI. 1838, p. 190). 2 Steenstrup, Ueber den Generationswechsel, p. According to Van Beneden, a nervous ring sur- 23. rounds the cesophagus of Alcyonella (Ann. d. Sc. * [ 33, note 1.] Allman has observed with uted in the substance of this last organ. Arid, Cristatella mucedo a small roundish body situated finally, another set of filaments were distributed it at the upper end of the'pharynx, and which he re- the organs about the mouth. See Report of the gards as a nervous ganglion (Rep. Brit. Assoc. Ad- same, for 1849, p. 72. According to a late Report, vancem. of Sc. 1846, p. 88). This observation he this observer appears to have been able to make subsequently confirmed, and has observed with out a distinct nervous system in all the fresh-waPlumatella, repens this ganglion (which he terms ter Bryozoa, except Paludicella. He has, hoewthe great cesophageal ganglion) send off a large ever, been able to detect no certain organ of spo. filament to each of the tentaculiferous lobes; also cial sense. See report of the same for 1850, p. a smaller one passing off at each side to embrace 319.- ED. the cesophagus, while a very short one was distrib 44 THIE POLYPI. ~5 35, 36. it a cornea, a crystalline lens and a red pigment layer surrounding the whole.'3) Furthermore, there are upon the border of the disc of the campanulate Cam7panularia, colorless corpuscles, containing a calcareous nucleus, which is transparent as a crystal and soluble in acid. These organs should probably be regarded as the most simple form of the auditory organs, for they have only a simple vestibule with its single otolite. (4) CHAPTER V. DIGESTIVE APPARATUS. ~ 35. The digestive apparatus of Polyps is formed after two different types. With the Anthozoa it consists of a mouth and a simple stomachal sac without an anus. But with the Bryozoa, there is a mouth and anus, and a digestive canal which may be divided into the sections of cesophagus, stomach, small intestine and rectum. ~36. The mouth of Polyps is usually surrounded by a circle of long, very contractile tentacles or arms. These tentacles are tubular, and connect with the cavity of the body.(') They are simple,(t) or penlnate,() and may be disposed around the mouth in a single(4) or a multiples5) circle; they are also frequently covered with cilia.()1 Thus, the cylindrical tentacles of Actinia are entirely covered by ciliated epitheliunl. With the Bryozoa, on the contrary, the slightly-flattened ten3 Quatrf.ages, Ann. d. Sc. Nat. XVIII. 1842, does not open outwards at the extremity of these p 240, pl. VIII. fig. 1, d, d, and fig. 6. organs. I doubt, in fact, if the Actinina are an ex4 See Krohn (Miller's Arch. 18-13, p. 176) and ception to this. It therefore appears singular that fbIlliker (Froriep's neue Notizen, 1843, No. 534, p. Rymer Jones (A General Outline of the Animal 81). fain Beneden has perceived in the campa- King. p. 41'; fig. 13), and lesson (Duperrey, Voyltlshte and flee individuals of Campanularia ge- age autour du Monde. Zoophytes, p. 82, No. 1, fig.,/atinosa and geniculata, not only eight marginal 1), expressly mention and distinctly, figure these Thdies, each containing a calcareous nucleus, but openings; the first with an Actinzia, the second also four nervous ganglia about the base of the with an Eumenides. According to Van'Beneden sFnrach (Mhem. sur les Campanulaires de la cote (loc. cit. p. 15) the tentacles of Campanularia d'0fstende, 1843, p. 24-27, pl. II. III.). I am yet are witheut these cavities. But this is contradictundetermined ulpon the question ewhether, as Van ed by Loven (Wiegmann's Arch. 1837, Bd. 1, p. Ben.eden thinks, these bodies have sometimes the 252). In Hydra the cavities open distinctly into ficition of organs of vision, and sometimes that the stomach, as is probably the case with many other of organs of hearing. I am also ill doubt as to the Hydrina. Frey and Leuckcart likewise doubt the opjinion of Husc/hke (Lehre von den Eingeweiden constant presence of an orifice at the apex of the ti.ld Sinnesorganen, 1844, p. 880), who regards as tentacles of the Actiniae.* etolites the calcareous bodies which have been ob- 2 Actinia, Hydra, Flustra and Camrpanoularia. served in the peduncle of Veretillum cynomo- 3 Veretillum, Lobularia, Isis, Gorgonia, and rieum. Nordmann (Versuch. einer Monogr. des Zoanthus. Ttrgipes, p. 88) has described as auditory organs 4 Hydra, Fluestra, Zoanthus and Veretillum. the marginal bodies of the free-swimming Canzpa- 3 Actinia and Caryophyllia. vaulaqiaer 6 Veretillum, Flustra, Eschara, Cristatella 1 This cavity which is in the arms of most Polyps and Tubulipora. 1 36, note 1.] Subsequent researches have Structure and Classification of Zoophytes. Phil. sthown that the cavity of the tentacles does open 1846, p. 32. - ED. externally through a small papilla. See Dana, 8 37. THE POLYPI. 45 tacles have only a single row of cilia, which move regularly and voluntarily, like the rotatory organs of the Rotatoria. By means of the currents produced by the cilia of their tentacles, many Polyps draw towards their mouth light particles of food; 0 othels malke use of their ciliated arms to seize larger portions.(8) This act is aidefd by the nettling and various prehensile organs, which are more usually found upon those Polyp-arms having no cilia.t0) These organs are found upon tLih tentacles of Actinia, Edwardsia, Veretillum and Alcyonium, and without doubt serve for the seizing of the prey as well as its retention until deaih. But these should not be confounded with special prehensile organs found on the tentacles of certain species. These consist of a small coriiae ous capsule, from which the animal can project a kind of sting.(10) By means of these organs, the animal can attach itself like a bur to external objects, and not by suction, as is generally supposed. The circular or oval mouth is always situated in the centre of the anterior extremity of the body; it is often surrounded by a lip formed of circular fibres.(l) In a few species, the mouth projects like a cone at the base of the tentacles.(') With the Plumnatellae (3) the mouth is topped by a tonguelet covered with, rapidly moving cilia. Some of the Anthozoa, which capture animals of considerable size, can, in swallowing them, dilate their mouth to an astonishing width.(14) DIGESTIVE CAVITY OF ANTHOZOA. ~ 37. The simple stomach of Anthozoa, which is of a variable length, opens in general directly external by means of the mouth,(9) and with a few species, only, is there a muscular oesophagus.(2) With some, the stomach blends with the walls of the body,() but usually it is more or less isolated. There remains, therefore, a cavity of the body of variable size, and which is directly continuous with the cavities of the arms. In those Polyps living in colonies, it is prolonged into canals traversing the corallum, and in this way the cavities of the bodies of all the 7 Flustra, Eschara, Tubulipora and Crista- ment is still unprojected (see his Memoir in the tella. Nov. Act. physico-imedica. XVIII. p. 300, Tab. XV. 8 Actinina. fig. 5, 9, 10). Perhaps the organs which Erdl 9 Hydra, Coryne, Eleutheria, Sertularia, Cam- (Muller's Arch. 1841, p. 424, Taf. XV. fig. 3) has panularia and Alcyonium. seen upon the tactile lobules of Veretillum cyno10 Such prehensile organs have been observed by morium are of this kind. Quatrefages upon the clavate tentacles of Eleu- 11 Actinia and Edwardsia. theria.. He thinks also he has observed two mus- 12 Hydra, Coryne and Campanularia. cles in their capsules, by which the retractile sting 13 1dlcyonella and Cristatella. is projected (Ann. d. Sc. Nat. XVIII. 1842, p. 276 14 Actinia and Hydra. and 283, pl. VIII.; or Froriep's neue Notizen, 1 Veretillum, Alcyonium, Actinict an(d Hydra. 1843, No. 543, p. 230). The oval vesicles which 2 Edwardsia. See Quatrefages (Ann. d. Sc. Nat. roughen the tentacles of Ca-npanularia, and which XVIII. pl. I. figr. 2; pl. II. fig. 1, 2). Lovien (lWiegmann's Arch. 1837, I. p). 252) has de- 3 Hydra. The stomach of the arm-polyps is not, scribed as small spinous warts, are probably of the as has been formerly supposed, a simple excavation same nature. In Hydra each hook-organ upon the in the body. It has proper walls distinct fromn arm is surrounded by a group of similar vesicles, in those of the body, by which, however, they are the interior of which is a rigid bristle. These or- closely embraced. There is, therefore, in Hydra gans are here found only upon the arms. They no cavity of the body, and the cqavities of the telnare distinguished from the organs having hooks by tacles open directly into the stomach. This is also their less size, and from their having no project- true of Eleutheria (Quatrefages, Ann. d. Sc. Nat. ing filament. Corda has not properly distin- XVIII. p. 283). guished them from the hook-organs, whose fila 46 THE POLYPI. 37 Polyps are placed in direct intercommunication. It is not rare to find this general cavity divided into chambers by mesenteric membranes stretching longitudinally from it to the external surface of the stomach.(4) The base of the stomach of many, and perhaps all of the Anthozoa, is pierced by one or mnore valvular openings, which communicate with the cavity of the body.5) These animals, by controlling at will these orifices, can allow to pass into the cavity of the body the proper materials, which are probably water and liquid chyle.6)' This digestive apparatus thus communicating with the cavity of the body, reminds one of the organization of the Infusoria.(17) The cavity of the stomach is lined by very delicate ciliated epithelium, which is continuous through the orifices upon every surface of the cavity of the body and arms, and even into the intercommunicating canals of the corallum. The color of the walls of the stomach is quite varied, and is due to certain pigment cells which very probably perform the function of a liver; for these animals are entirely wanting in any other glandular appendix of the alimentary canal, analogous to a liver. (8)' 4'There are often eight of these longitudinal 21) has found with a Lucernaria a stomach opening chambers, as in Veretillum. Alcyonium and Al- inferiorly, and communicating directly with the cyonidium (see Icones zoot. Tab. XXXIV. fig. 2; cavity of the body. This communication has been also Ann. d. Sc. Nat. IV. 1835, pl. XVI. fig. 3, and observed also by Frey and Leuckart (Beitr. p. pl. XII. fig. 3, 4). In Actinza there are seven 3) with the Actiniae and several other Anthozoa.t more. With Edwardsia the eighth mesenteric di- 6 Quatrefages (Ann. d. Sc. Nat. XVIII. p. 87, visions do not reach the sides of the body (Qua- 91) has seen the stomach of Edwardsia entirely tref ges loc. cit. pl. I. fig. 2).* filled with Spirorbis, and other solid food, without 5These orifices were long ago observed by the any of it passing into the cavity of the body. elder anatomists upon various Polyps. Aftelr- With Infusoria, the lower end of the cesophagus wards their existence was incorrectly doubted by is free, so that the food passes directly from it into other naturalists; for lately they have been dis- the parenchyma of the body, whelre it forms a cavtinctly made out. Thus, in Verelillum cynomo- ity but with the Ailthozoa, there is a stomach, vium (Rapp, Nov. Act. physico-medica XIV. 1829, from which chyle alone can pass into the cavity of p. 650), in Alcyonidium and Alcyonium. (Milne the body. Edwiuards, ALnn. d. Sc. Nat. IV. p. 325, 1)1. XV. fig. 8 These cells are white in Edewardsia, yellow in 6), and in Edcardlesia (QuLatrefages Ann. d. Sc. Alcyonidiun and Alcyonium, and brown in VereNat. XVIII. p. 91). tillunz and Hydra. Ill the last, the brown is disIn Sertularia and Campanularia there are tinctly due to irregular pigment granules of that openings between the stomach and the tubulous color, floating in the clear liquid of the cell. Probcavities of the corallum (Lister, Phil. Trans. 1834, ably these cells, by bursting, empty their contents p. 371, and Van Beneden, Mom. sur les Campanu- into the stomach; at least, I have been able to find laires, loc. cit. p. 17). There must be direct com- no excretory duct, such as Corda has figured with munication of this kind with the Actisiae, since the Hydrafusca (Nov. Act. Acad. physico-medica they regularly reject by their mouth nettling fila- XVIII. p. 302, Tab. XV. fig. 15-17; or Ann. d. mlents, from the chambers of their body. With Sc. Nat..II. p. 366, pl. XIX. fig. 15-17). Hydra, the stomach communicates, by an orifice In Hydra viridis, these brown cells of the stomsituated at its base, with the narrow tubulous cavity ach can easily be distinguished from the layer of of its cylindrical foot. But at the extremity of this green pigment belonging to the parenchyma of the tube there is noovalopening,and thetube itself can- body. Moreover, if a transverse section of this not be regarded as a rectum, for it receives neither animal is made, there appears awide difference of feces, nor fragments of food, and is not affected by organization between the internal and external surthe frequent enormous dilatations of these animals face of the stomach; the first has ciliated epithefrom surfeit. Corda therefore is incorrect in as- lium and hepatic cells, the second a bare skin with si-ning an anus to these animals. (Nov. Act. phys- prehensile organs. This being so, how can these ico-medica XVIII. p. 302, Tab. XIV. fig. 2, E.) He animals be everted like the finger of a -love, as some appears to have entirely neglected the foot of this naturalists have affilrmed, and yet live? for the two saimal,which, however, has been well figured by surfaces of the stomach, so different, could not reEhrenberg (Abhandl. d. Bell. Akad. 1836, p. 134, place each other, and then again the cavities of the L'at II. fig. 1); and since Roesel (Insekteribel. III. arms would open directly outwvard. Indeed, it is Taf. LXXVIII. and LXXIX. fig. 2, and IXXXvI. not possible to return unmutilated an everted LXXXVII. fig. 6) has perceived it in all unmuti- Polyp, since the isextensible cavity of its foot canIated arm-polyps. Sars (Faus. littoral. Norveg, p. not leave the body with impunity. The gastric * [ 37, note 1.] With all the Actinaria the lam- cates with the cavity of the body by a single oriellm of the viscemal cavity are the multiples of fice only, which may be closed by muscles. See six; all the Alcyosaria have eight of these lamellae. Dana, loc. cit. p. 40, 44, pl. XXX. fig. 3, a, b, c, d. Fee Dana loc. cit. p. 49. -ED. It has been since verified by Cobbold, Ann. Nat. t 37, note 5 ) With the Actisoidea, recent Hist XI. 1853, p. 121, with figures. - ED. researches have shown that the stomach communi -~ 38, 39. THE POLYPI. 47 DIGESTIVE CAVITY OF BRYOZOA. ~ 38. The very complicated digestive canal of the Bryozoa floats freely in the spacious cavity of their body. It is composed of an (esophagus which, at its lower extremity, dilates into a round or oval muscular crop;(1) upon this immediately succeeds a coecal stomach, from the upper portion of which a small intestine arises and passes upwards in front. This, after a course of variable length, ends by a constriction in a short but large rectum, which opens in the vicinity of the mouth, at the external side of the base of the tentacles.(2) The digestive canal here, therefore, is not in communication with the cavity of the body. Its whole inner surface is lined with very active, ciliated epithelium, which keeps its contents in motion, and especially the fseces of the rectum. The sides of the stomach are often colored brown, yellow or green, from the presence of hepatic cells.t CHAPTERS VI. AND VII. CIRCULATORY AND RESPIRATORY SYSTEMS. ~ 39. A vascular system has yet been found only with a few Polyps; but there it is so apparent that its presence in others may be inferred. The bloodvessels exist upon both the sides of the body and of the stomach, and are:in part longitudinal, in part circular, ending in a capillary net-work. They are not simple canals excavated in the parenchyma, but have proper walls, and circulate a liquid containing a great number of white (blood) globules.('l juice of the Anthozoa must have a very great 1 Milne Edowards has perceived a vascular netdigestive power, since the Actinia eat hard-shelled work of this kind in the sides of the body, with crustacea, and even the soft Hydrae quickly dis- Alcyonidium elegans, and Alcyonium palmnasolve the larva of Nais and Chironomus. But teum and stellatum. (Ann. d. Sc. Nat. IV. p. the indigestible parts ot these animals, such as epi- 338). Quite recently, Will has described the vasdermis, bristles, hooks and jaws, are afterwards cular system of Alcyoniumepalmatum (Froriep's -ejected by the mouth. neue Notizen, 1843, No. 599, p. 68). According to 1 In Bowerbaonkia (Farre, Phil. Trans. 1837, him, white vessels may be perceived, even with the p. 392, Pi. XX. fig. 5; P1. XXI. fig. 7) this crop naked eye, upon the longitudinal furrows of this is composed of pyramidal corpuscles, with the animal. These enter the lobules on the border of:apices pointing inward, so as to act like teeth. I the body, and there form a dense net-work, from have observed a very similar structure in Alcyo- which a branch is sent to each arm, and this last rella staynorum. gives off laterally a twig to each tactile lobule. The 2 In Bowerbankia and Vesicularia the small principal trunk of the longitudinal vessels conintestine is very long (Farre. loc. cit. P1. XX. and tinues upon the sides of the stomach to the base of XXII). I have observed it very short with Cris the tentacles. At the point whele the bodies of otatella mirabilis.* the Polyps continue with the corallum, there are * t~ 98, note 2.1 According to Allman (Report wide at first, passes along the side of the cardiac Brit. Assoc. 1850, p. 310), the esophagus succeeds cavity and oesophagus, and rapidly decreases in the stomach without the intervention of any dis diameter, until it terminates in a distinct anus just tinct crop with all the fresh-water Bryozoa. The below the mouth. -ED. stomach is large and thick-walled, and may be t [Note at end of 5 38.] See in this connection -divided into a cardiac and a pyloric portion. The my note under ~ 13, note 2.- ED. pylorus is distinctly valvular, and the intestine, 4C9 THiE POLYTr. ~f 40, 4L. ~ 40. All Anthozoa and Bryozoa have a proper circulation; for there rises. and falls in the cavity of their body a liquid, which is usually clear, and often contains round and colorless corpuscles. This rises even to the end of the cavity of the tentacles, and then returns into that of the body generally. In the colonial Polyps, these currents, by traversing the canals of the corallum, thereby pass from one animal to another. This movement, is caused by ciliated epithelium, which, as we have just seen, lines all the! cavities of these animals. With the Bryozoa, the cavity of whose stomach does not communicate with that of the body, these currents are continuous. regular, and have a definite direction. But with the Anthozoa they are changed by the reciprocal action through the stomachic orifices of the liquids of the stomach and cavity of the body. These currents are perceived in the arms, even when the cavities of these organs open directly into the: stomach. (l ~ 41. Nothing can yet be positively said as to the nature of this circulating liquid,. for it is still doubtful whether this whole phenomenon should be regardedl as an aqueous or a sanguineous circulation. If we refer to the fact that the Anthozoa can introduce water into the system through the apertures of the stomach, it should be admitted that this system has an aqueous character, performing, perhaps, the function of an internal respiratory apparatus, given off from the eight principal longitudinal was first pointed out by Grant (The new Edinb, vessels numerous lateral branches, which anasto- Phil. Jour. 1827, p. 107; or Outl. of Comp. Anat. mose frequently in the canals of the corallum, and 1841, p. 430), who observed these currents ink finally form a capillary net-work. The white, Flustra, Lobularia, Virgularia and Pennatula. semi-transparent corpuscles contained in thin Nordmann, who has examined this circulation in blood have, according to Will, a diameter of the body and tentacles of Alcyonsella diaphana, about 1-1200 of an inch, and out of the vessels and Plumatella campanulata, and other Bryozoa, have a globular aspect. According to this same did not find any cilia. He compared the currents! observer, there is a similar vascular system in to those seen in the joints of Chara (Microg. Actinia.* Beitrag II. p. 75, or Obser. sur la Faune Pontique, 1 The circulation in question has been observed p. 709). I feel positive about the presence of cilia by many investigators. Trembley (Mkm. pour in the body of Cristatella m.irabilis and Allcyoservir A l'Histoire des Polyps, p. 219) has per- nella stagnorum. Lister has carefully described. ceived it in Plumatella cristata. Dumortier this circulation with Tubuzlaria, Sertularia and. (MHm. sur l'Anat. et la Physiol. des Polypes, p. 47) Campanularia; and finding no adequate cause, has confirmed this observation. Cavolini (see his has lilened it to that of Chara (Phil. Trans. 1834,. Memoir on the Anthozoa, p. 56, 87) has seen it in p. 366, et seq.). Ehrenberg (Abhandl. d. Berl. the tubes of several Sertularina. There are various Akad. 1832, p. 299) and Lovne (Wiegmann's opinions as to the cause of these currents. Gruit- Arch. 1837, I. p. 254) attribute these currents in hutsen (Isis. 1828, p. 506) studied them in the Sertularia and Campanulsaria to a peristaltic arms of Hydra, and regarded them due to a com- movement of the canals of the body; which, howmunication with a circular vessel surrounding the ever, Van Beneden (3Mm. sur les Campan. loc. mouth. But, according to the observations of cit. p. 18) has been unable to see in these Polyps.. Meyen (Brown's Miscellaneous Botanical writings, Erdl (Miller's Arch. 1841, p. 426) attributes it,, IV. p. 490), of Ehrenberg (Mittheil. aus. d. Ver- in Veretillum cynomorium, to cilia; and Will handl. d. Gesellsch. naturf. Freunde z. Berlin, (Froriep's neue Notizen, 1843, No. 599, p. 69) has. 1836, p. 27) and myself, the cavities of the arms found all the cavities of the body and corallum of open directly into the stomach. Alcyonium palmatum lined with cilia. It is, The movements of the liquid in the arms of Hydra moreover, certain that the currents observed by are due not only to the general contractions of the Erdl (Miiller's Arch. 1841, p. 428) and Dumorbody, as Gruithuisen and Meyen have supposed tier (Mim. loc. cit. p. 52) in the tentacles of'but- also to the: cilia covering these parts. This Actinia are due to ciliary action. * [6 39, note 1.1 Subsequent researches have their nutritive and digestive systems are combined; failed to detect any true circulatory system with the and, as with them also, the circulating, nutritive real Polyps, and there now can be but little doubt liquid is chyme. See also Dana loc. cit.. p. 35. Ahat no such system exists. As with the Acalephs, - ED. ~ 41. THE POLYPI. 49 while the tentacles, in the cavities of which are regular currents, serve as external organs of respiration, similar to branchiae. But, if we regard the whole as a true circulation, the contained liquid. with its corpuscles will be analogous to blood. But this view is opposed. by the fact that, with Alcyonium, with Actinia, and perhaps many other Polyps, there is a true vascular sanguineous system.l') We ought, therefore, to compare the liquid in question to chyle, which passes from the stomach to the general cavity of the body, in the Bryozoa by exosmose, but in the Anthozoa by the orifices of the stomach.(' The opinion that these currents form a vascular system, moreover, is not reconcilable with the fact that the Anthozoa can at will empty the contents, of their stomach into it, or in the same way shut off from it the water. We are obliged, then, to regard all these cavities as constituting a vascular aqueous system, performing a respiratory function, by which, in the Anthozoa, all the internal parts are constantly bathed with fresh water. This renewal of water is effected by its alternate ingress andegress through the stomach,'3' during which chyle-corpuscles could easily, by being mixed with water, be carried into this aqueous system. With the Bryozoa, where this system is, without doubt, equally one of respiration, we shall have to seek fbr the openings by which this renewal of water takes place. These are situated near the anus, and place the cavity of the body in direct communication with the external water.*(4) 1 See ~ 39, note 1. which may be called aquiferous mouths, for by 2 Ehrenberg and Lovdn regard the canals of thlenl the water enters the cavity of the body. the corallure of Campanularia and Sertularia as This is perhaps the case with Actinia, also; for direct prolongations of the stomach, and designate Rapp (Ueb. die Polypen u. die Aktinien, loc. cit.. them as intestinal tubes, and their contents as p. 47) has here fiund numerous small orifices chyme. scattered over the whole surface of the body, andt 3 This alternate ingestion and egestion of water through which are emitted jets of water when the has been positively observed by Lister, Loven and animal is squeezed, thus showing that they belong Van Benreden, in Sertularia and Tubularia. to an aquiferous system. It is quite improbable 4 By an opening of this kind, Meyen (Isis 1828, that the hollow tentacles of Actinia are open by p. 1228) saw escape the eggs of.4lcyonella stag- an oridice at their apex for the circulation of water, nalis, which were free in the cavity of the body. as many naturalists have supposed. QuatreVan Beneden (Ann. d. Sc. Nat. XIV. 1840, p. fages (Aml. d. Sc. Nat. XVII. p. 96) is quite 222) declares that he has observed at the base of opposedl to this opinion. See also above ~ 36,. the tentacles of Alcyonella a series of orifices, note 1.t * [End of ~ 41.1 In this connection should be udes through the walls of the alimentary canal. mentioned branchia-like organs, described by Dana But the apertures for the introduction of this water' (loc. cit. p. 42) with the Zoanthina. A pair of them have not yet been clearly seen. It is true that is attached to each of the larger lamellse. He Van Beneden thlinks he has found "Bouches aquiremarks, "The structure of these organs is such fires," as above mentioned, but their existence that we can hardly doubt their branchial nature; there has not been fully verified, an0f is even yet no circulating fluid was detected within them." denied by Allman. At present, therefore it cannot. I find no other mention of these parts, except by be said that the Bryozoa have a true aquiferous, Lesueur (Jour. Acad. Nat. Sc. Philad. I. 183-185, system, like the Anthozoa. The perigastric fluid P1. VIII. fig. 1, 5, 9), who regarded them as of an is, separated from the water, most probably the hepatic nature. - ED. elaborated product of digestion, and the corpuscles. t I ~ 41, note 4.] The true nature and relations therein contained chyle-corpuscles. Allmoan's of the respiratory and circulatory systems of the view, therefore (Report Brit. Assoc. 1850, p. 319),. Bryozoa are yet imperfectly understood. There appears the most correct: "The perigastric circucan be but little doubt that water is by some means lation, therefore, unites in itself the triple function introduced into the general cavity of the body, and of a chyliferous, sanguiniferous and respiratory there, mingles with the nutritive fluid, which trans- system." - ED. 50 THE POLYPI. 9j 42, 43. CIHAPTER VIII. ORGANS OF SECRETION. ~ 42. Nothing like urinary organs have yet been found in Polyps. Perhaps the borders of the mantles of the cellular Polyps should be regarded as organs of special secretion, since by them the increase and production of these cells take place.(1) CHAPTER IX. ORGANS OF GENERATION. ~ 43. Polyps reproduce by gemmation, fissuration, and by eggs. 1. Fissuration is comparatively rare; it takes place nearly always longitudinally, and the division may or may not be complete.'l) 2. Genlmation is their most common mode of reproduction. The new individuals may be completely detached, or may remain connected with the parent corallum. a: In gemmation, complete separation of the young individual is, on the whole, rare. It is best known in Hydra, with which the buds always appear upon a certain part of the body, - that is, at its union with the foot.(2) A bud of this kind consists always of a simple fold of the wall,of the stomach and the skin, so that the stomach of the young individual is in direct communication with that of the parent, and the chyme can pass freely from one to the other. When the foot of this new being has acquired a proper development, it is completely detached at its inferior extremity. b: Gemmation without separation of the new beings is quite common with Polyps, and occurs with very various modifications. The buds are formed sometimes upon the sides, sometimes upon the base of the body. In the first case, the coralla have a dendroid aspect; in the second, they are more lamelliform, spherical or lapidescent. These variations are not limited to certain genera or species, being often due to external influences, 1 The calcareous tubes of Tubipora, and the and Caryophyllia; but, when incomplete, the cells,corneous ones of the Sertularina and other Bryozoa, are branched, lobulated, and of irregular contour, are, without doubt, secreted by the bolder of the as in Ag aricia, Maeandrisna, and X1onticularia,:mantle, as in true of the shells of mollusks. &c. 1 According to Roesel (Insektenbelust. III. p. 2. Roesel(loc. cit. III. Taf. LXXXV. fig. 2, 3, 5, -504, 525. Taf. LXXXIII. fig. 3), fissuration takes Taf. LXXXVI. and LXXXVIII. fig. g. h. and Taf. place transversely with Hydra. Longitudinal LXXXIX. fig. 4). The exceptions to this rule, fissuration is principally observed with the Madre- which are sometimes observed, are probably due porina. When it is complete the cells of the coral- to lesions of an accidental nature. him are definitely limited, as in Astraea, Favia, $$ 44, 45. THE POLYPI. 51 and especially the nature of the soil upon which the colony may have been fixed.* (3) ~ 44. 3. It is probable that all Polyps reproduce by eggs. This requires two kinds of organs, one to produce the egg, the other the semen. Both kinds, ovary and testicle, have already been described in many species. Their distribution is quite varied. In some, the sexes are united in the same individual,(') in others they are distinct;(2) with the colonial polyps the sexes are separate, and each colony(3) may be composed of individuals which are androgynous, or those of one sex alone.(4) Some species are sexless, and remain so; but they produce by gemmation individuals of a particular character, which have sexual organs.()) These last, which have usually either a campanulate or discoid form, are separated -from the corallum often before the sexual organs have been formed, and -which they do not acquire until an advanced period of their lives. During thi, time they swim freely about, like the pulmograde Acalephae,~6) for which, as well as for young Polyps, they are often taken.(7) ~45. That the relations just described really exist, may be learned from the -following facts: In Coryne echinataand vulgaris, there are formed at their base, quadrangular and campanulate individuals, which lay numerous eggs.(l) In like manner also, ovigerous capsules are formed about the base -of Syncoryne ramosa.(2) In Coryne fritillaria,(3) the new individuals are -completely detached and swim freely about. closely resembling Medusae. In this condition they are developed, and their eggs come to maturity.(41 3 Eschara and Flustra have a lamellated form 4 According to Erdl (Froriep's neue Notizen, when fixed to stones, shells, or the broad leaves of 1839, No. 249, p. 101) the coralla of Veretillum Algae; but are tubular when attached to the cynomorium and Alcyonium have always either stems of plants. Alcyonella stagnorum under- male or female individuals alone. Krohn has goes similar changes in the form of its corallum. perceived the same of Sertularia (kliiller's Arch. It divides in a regular dichotomous manner 1843, p. 181). , Taf. II. fig. 18 (Cassiopeia). t cit. Taf. I. fig. A. B.) have figured the eggs of Cy- 3 It may be that the stout linear and active anea pelagia, and of a Medusa. bodies, seen by Will (loc. cit. p. 78, 81, Taf. II. fig. 2 The spermatic particles of Eucharis and Be- 26) in the respiratory cavity, the stomach and the roe consist of a round body, having a delicate and general cavity of the body of Diphyes and Ersaea,. very movable tail (Will, loc. cit. Taf. I. fig. 6, 24). and which he was inclined to regard as Entozoa, In Cydippe they are similar (Krohn, Froriep's are the spermatic particles of these animals, since neue Not. No. 356, 1841, p. 52). This is likewise they quite resemble those of Alcyonella and Cristrue of those of the Discophora; see Siebold, tatella. Beitrage loc. cit. Taf. I. fig. c. (Medusa); Kolli- According to Sars (Faun. littor. &c. p. 38), the ker, Beitrage loc. cit. Taf. I. fig. 8, 9, 10; and spermatic particles of Agalmopsis have a cercaMilne Edwards, Ann. d. Sc. Nat. XVI. PI. I. fig. ria-form.. 1, d. (Rhizostomum, Chrysaora and Aequorea); * [ ~ 66, note 3.] Reproduction by fissuration form, like those of the Polyps, and like which, also, has been observed with the Discophora by Kulli they are developed in special daughter-cells. - ED. ker (Siebold and K5lliker's Zeitsch. IV. p. 325), I [~ 67, note 3.1 These bodies mentioned by he witnessed this phenomena with Stomobrachium Will as spermatic particles have since been exammirabile. It does not appear, however, that he ined by Huxley (loc. cit.), who thinks they are not has observed this process with adult forms i for he of this nature, a view which is otherwise probable remarks that there is reason to believe that this from the fact that he found no male generative sacs, Stomobrachium is only a young, imperfect form and also because, as I have shown (see my note of his Mesonema coeruzlescens. - ED. after d 46, note 5), these particles with Alcyonella t [~ 67, note 2.] The spermatic parti les of the have a cercaria-form. - ED. Acalephae have invariably, I think.' cercaria 69. THE ACALEPHAE. 71 ~ 69. The position of the sexual organs varies in the different orders, in the following manner: 1. With the Ctenophora, which are hermaphrodites, they are situated along the sides, under the form of elongated utricles, the testicles being on one side and the ovaries on the other. They have a nodulated appearance, and from the lower part of each passes off an excretory duct, which runs toward the mouth, but the terminal opening of which has not yet been well made out.(l) 2. With many Discophora, these organs are arranged like rays, passing from the centre to the border of the disc. In Oceania, Cytaeis, Geryonia' and Thaumantias, the four saccular ovaries or testicles form at the centre of the disc a cross, which is traversed by four aquiferous canals.(2) Their excretory ducts pass towards the base of the stomach, but their terminal openings are not distinct.(3) In the disc of Aequorea violacea, seventy-four ray-like bands are spread out, and the free plicated borders of these hang beneath the inferior surface of the disc, thus permitting the free escape of the eggs and sperm into the water.(4) 3. Another group of the Discophora have at the base of their tentacles four large openings, which lead into as many cavities in the disc.(~) At the base of these cavities, which formerly were regarded as respiratory organs,: the genital organs are situated in the form of plicated bands. These as four bands (testicles or ovaries) are bent either into an angle or the arc of a circle, forming sometimes a star with four rays,(6) and sometimes a four-lobed rosette.(7) If these cavities increase in number, the genital organs increase in the same proportion.(') The border of these organs is generally provided with numerous tentacles which project into the cavity.9) In the ribandlike testicles numerous small sacs are observed; each one of these opens separately into the genital cavity, while the eggs, on the contrary, are separated from the similarly-formed ovary only by a gradual constriction of the latter. (0) 4. With the 8iphonophora, all the relations of these genital organs still require much investigation. With the Diphyidae, they consist of sacs communicating with the general cavity of the body. l() During the epoch 1 Will, Horae tergest. p. 38, Taf. I. fig. 22, 23. cit. Taf. VII.; and Wagner, Icon. zoot. Tab. 2 Wagner, Icones. zoot. Tab. XXXIII. fig. 26, XXXIII. fig. 13. a. a.; Will, loc. cit. Taf. II. fig. 5, 7, 8, 14, 16; 10 Siebold, Beitriige loc. cit. Taf. I. fig. 20, 23; Blainville, Manuel d'Actinol. 1831, O' YXXVII. and K6iiliker, Beitraige loc. cit. p. 40. fig. 3 and Sars, Beskrivelser loc. cit. Ps. v. ug. 11 In Diphyes and Ersaea, a sac filled with cells 12, 13. opens into the general cavity of the body, and 3 Will, loc. cit. p. 71. communicates beside with the stomachs and respi4 Milne Edwards, Ann. d. Sc. Nat. XVI. p. 198, ratory cavities. Will (Horae tergest. p. 78, 81, P1. I. fig. 1, a. b. Taf. II. fig. 23, c.) regards this sac as a sexual 5 Gaede, Beitrdge loc. cit. Taf. I. fig. 1, c. (Me- organ; and Meyen (Nov. Act. physico-med. XVI. dusa); and Lesson in Duperrey, Voyage loc. cit. Suppl. 1, 1834, p. 214, Tab. XXXVI. fig. 2, h. and No. 12, 13 (Chrysaora). fig. 6, 7) asserts to have seen eggs in it. Accord6 Rhizostomnum. ing to Philippi (Miiller's Arch. 1843, p. 63, Taf. 7 Chrysaora, Medusa, Pelagia and Aurelia. V. fig. 10, a. b.), the grape-like clustered genital See Ehrenberg, Abhandl. d. Berl. Akad. 1835, organs, with Physophora, are situated between the Taf. I. fig. 1; W agner, Icon. zoot. Tab. XXXIII. prehensile organs; the smallest containing in each fig. 1; and Brandt, 3M1m. de l'Acad. de St. Peters- lobule six to ten eggs, and the largest a granular burg, IV. PI. IX. X. With the male and the female liquid (Sperm?). Cephea, I have found the testicles and the ovaries Hollard (Ann. d. Sc. Nat. III. 184f;' 51. Pl. disposed exactly as with the Medutss9 IV. bis. fig. 33, 34) has found botryola. mrasses of 8 In Cassiopea, these qrgans are eignt in number. ovaries at th, base of the tubuliform tentacles 9 Medusa and Pelag x; see Ehrenberg, loc. (stomachs). cas,ot,.;it. p. 37, P1. V.) has also 72 THE ACALEPHAE. 5 70.,of procreation, the females of some Discophora are easily distinguished from the males by the numerous pouches of their tentacles, and in which,eggs and newly-hatched young are carried for a short time.(12' ~ 70. As yet, the development of a few only of the Acalephae has been traced. It is attended by a remarkable metamorphosis. After the usual segmentation of the vitellus, ovoid embryos resembling infusoria are developed; these turn freely on their axis, and swim about in the water by means of ciliated epithelium.(l) Shortly after, they become -attached by the anterior extremity to some object. Upon the opposite firee exttremity tentacles appear, and between them the mouth. The animal has then the form of a Polyp.(2) It is during this period that the young animal reproduces by gemmation,(3) and sometimes by transverse Jissuration. This last niode occurs in the following remarkable manner: The polyp.like animal increases in length, and its body divides transversely into many segments. Around each of these segments eight bifid processes are developed; after this, each segment is successively separated fronm before to behind, and they float about for a time as eight-rayed Aca1ephae, but soon attain, however, their adult condition.'4:seen genital organs of the same form between the "`"'"2 " He has also seen them develop pedi. tentacles'of Agalmopsis; but he found at the same citb Lroull the end of which new individuals would.time (loc. cit. p. 38, 43), in the campanuliform individ- appear, which resembled Polyps. See Wiegmann's tuals produced from buds, testicles with Agalmopsis, Arch. loc. cit. p. 26, Taf. I. fig. 37, 41, 42, 38, 39, 40. and ovaries with Diphyes. It may therefore be 4 These young Medusae, whilst composed of rings, justly supposed that these various Siphonophora have been taken for a new genus (Scyphistoma) of are compound, sexless individuals, which, like the Polyps by Sars (Isis. 1833, p. 222, Taf. X. fig. 2). 1Iydrina. and Srtularina, reproduce by alternation Steenstrup (Ueber d. Generationswechsel, p. 17) of generation, - that is, by buds,- individuals has regarded them as nurses of the Medusae. At &having sex. a latter period, when the rings have been separated 12 Medusa aurita and Cyanea capillata; see and have acquired the bifid prolongations, Sars -Ehrenberg, Abhandl. &c. loc. cit. Taf. III. fig. 1, (Isis. 1833, p. 224, Taf. X. fig. 4; and Beskrivel2, Taf. VIII. fig. 1 also, Sars in Wiegmann's ser, &c., p. 16. P1. III.) has described them as a Arch. 1841, I. p. 19. new species of Medusae (Strobila octoradiata). 1 The development and metamorphosis of Me- But lately he has perceived that they are the young,dusa aurita and of Cyanea capillata have been of Mledusa aurita (Wiegmann's Arch. 1837, I. observed by Siebold (Beitrage loc. cit. p. 21, Taf. p. 406); it did not occur to him, however, that these I. II.; and Froriep's neue Not. No. 166, 1838, p. young constitute, very probably, the genus Ephyra 177); and by Sars (Wiegmann's Arch. 1841, I. p. of Eschscholtz (see Wiegmann's Arch. 1841, Th. 19, Taf. I.-IV.). In the first stage of development I. p. 10). It will probably be discovered that!(see Ehrenberg, Abhandl. &c. loc. cit. Taf. VIII. many small campanulate or discoid Medusae fig. 15-18; also, Siebold, Beitrage loc. cit. Taf. I. are only the young of other Acalephae; for it is very fig. 17-19; and Sars, Wiegmann's Arch. loc. cit. likely that they all undergo a similar metamorpho-?Taf. I. fig. 1-6), these infusoria-like Medusae have sis. It may also prove that many naked Polyps been regarded by Baer as the larvae (Meckel's are only transitionary forms of known species of Deutsches Arch. VIII. 1823, p. 389). Acalephae. In this connection the observation of 2 Siebold, Beitrage loc. cit. p. 29, Taf. I. fig. Dujardin (Comp. rend. 1843, p. 1132) deserves:25-33, Taf. II. fig. 34; and Sars, Wiegmann's the attention of naturalists. In tracing the develArch. loc. cit. Taf. I. fig. 7-31. During my last opment of on, of the Discophora allied to Oceania, visit at Trieste (autumn of 1847), I convinced he observed that axhis animal in its early condition;myself that the young of Cephea Wagneri are separated from a corallum resembling that of Syn-,developed wholly like those of IMedusae, by passing coryne, and was of a form quite like an Eleutheifrom infusoria-like forms to polypoid young ani- ria. However various these developing forms may:mals.* be, that one must be regarded as the real one 8 The reproduction of the polyp-form Medusae which exists during the development of the testiby buds has been observed by Sars in Cyanea cles and ovaries.t * [ ~ 70, note 2.] See, also, for recent researches bold and K6lliker's Zeitsch. f. Zool. IV. p. 118, on the development of Cephea, Ecker, Bericht ib. June, 1852. - ED. die Verhandl. d. naturf. Gesellsch. in Basel. VIII. t [ ~ 70, note 4.] In regard to the development 1849, p. 51; Busch, Beobachtungen ib. die Anat. of the Acalephae, it may be mentioned that recent.&c. Berlin, 1851, p. 30; and Frantzius, in Sie- researches, few as they are, have verified some O 70. THE ACALEPHAE. 73 of the hypotheses suggested in the above note. the embryos of M.dusae and Polypi may be the Hitherto there has been much confusion on this foundation of many other important changes. At subject, from the want of complete series of obser- present, however, broad generalizations must be vations; even now the whole class can be regarded deferred until we have extensive and serial re-.onlyin a somewhat transitionary state, in a zoological searches in the embryology of these animals. For point of view. Many genera which have hitherto separate details on the development of some forms, been regarded good and permanent will no doubt, see Busch, loc. cit. (Sarsia, Lizzia, Cephea, Euas Siebold has remarked, prove to be only unde- doxia, Diphyes); Huxley, loc. cit. (Diphyidae, veloped forms of well-known species. As already Physophoridae); Agassiz and Desor, loc. cit, stated, Agassiz regards the HIydroid Polypi as true (Medusidae). - ED. Acalephae, and the analogy which exists between 7 BOOK FOURTH. ECHINODERMATA. CLASSIFICATION 71. THE ECHINODERMS have a more or less coriaceous envelope, filled with calcareous, reticulated corpuscles. These last are sometimes so numerous that they form a real shell, composed of plates, movable, or tightly bound together. In the ray-like, symmetrically-arranged systems of organs, the quinquenary number prevails. In many species the digestive canal is asymmetrical. All are marine, and most of them move by means of particular, erectile suckers. Others progress by vermiform motions, and some swim freely by moving their rays like oars. Only a few are stationary. All are without copulatory organs. ORDER I. CRINOIDEA. The calcareous shell, composed of movable pieces, forms a true cutaneous skeleton. The body is ray-like; the digestive canal, asymmetrical. FAMILY: ENCRINIDAE. Genus: Pentacrinus. FAMILY: COMATULINAE. Genus: Comatula. ORDER II. ASTEROIDEA. The calcareous shell, composed of movable pieces, forms an internal skeleton. The cutaneous covering is sometimes coriaceous, and sometimes calcareous. The body is ray-like, and the digestive canal symmetrical. FAMILY: OPHIURIDAE. Genera Astrophyton, Ophionyx, Ophiothrix, Ophiomastix, Ophiocoma, Ophiolepis, Ophioderma. 71. THE ECHINODERMATA. 75 FAMILY: ASTEROIDAE. Genera: Luidia, Astropecten, Ctenodiscus, Archaster, Stellaster, Astrogo. nium, Oreaster, Pteraster, Asteriscus, Culcita, Ophidiaster, Chaetaster, Solaster, Echinaster, Asteracanthion. ORDER III. ECHINOIDEA. The calcareous shell forms a spherical or discoid shield, composed of ir. movable plates. The digestive canal is asymmetrical. FAMILY: ECHINIDAE. Genera: Echinus, Cidaris. FAMILY: CLYPEASTRIDAE. Genera: Laganunm, Scutella, Encope, Rotula, Lobophora, Echinocyamus, Mellita, Echinanthus. FAMILY: SPATANGIDAE. Genus: Spatangus. ORDER IV. HOLOTHURIOIDEA. In place of a calcareous shell, the cutaneous envelope contains a greater or less number of calcareous reticulated corpuscles. The esophagus is surrounded by a calcareous ring, constituting the rudiment of an internal skeleton. The body is cylindrical. The digestive canal, generally asymmetrical. FAMILY: HOLOTHURINAE. Genera: Holothuria, Pentacta, Bohadschia, Cladolabes. FAMILY: SYNAPTINAE. Genera: Synapta, Chirodota. ORDER V. SIP UNCULOIDEA..ile cutaneous envelope is coriaceous, and free from calcareous corpuscles. There is no calcareous ring about the( Esophagus. The body is cylindrical; the digestive canal, usually asymmetrical. FAMILY: SIPUNCULIDAE. Genera: Sipunculus, Phascolosoma. FAMILY: ECIIIURIDAE. Genera: Thalassertwia, Echiurus. 76 TTE ECHINODERMATA. ~ 72. BIBLIOGRAPHY. Tiedemann. Anatomie der Rohrenholothurie, des pomeranzenfarbigen Seesterns und Steinseeigels. Landshut, 1816. Sharpey. Cyclop. of Anat. and Physiol. Art. Echinodermata, vol. II. p. W0. London, 1839. I Agassiz:. Monographies d'Echinodermes vivans et fossiles. Neuchatel, 1838, 1-3e, Livr. Valentin. L'Anat. du Genre Echinus. Neuchatel, 1842. 4e Livr. des Monographies d'Echinodermes. Forbes. A History of the British Star-fishes, and other animals of the class Echinodermata. London, 1841. Muiller und Troschel. System der Asteriden. Braunschweig, 1842.:ADDITIONAL BIBLIOGRAPHY. Mi;ler. Ueber die Larven und die Metamorphose der Ophiuren. In the Transact. Berlin Acad. 1846. Ueber die Larven und die Metamorphose der Echinodermen. Ibid. 1848. Ueber die Larven und die Metamorphose der Holothurien und Asterien. Ibid. 1849-50. Anatomische Studien fiber die Echinodermen. Miidler's Arch. 1850. IWft. II. Berichtigung und Nachtrag zu den Anatomischen Studien fiber die Echinodermen. Ibid. Hft. III. Fortsetzung der Untersuchungen fiber die Metamorphose der Echinodermen. Ibid. Hft. V. Ueber die Optlureniarven dcs Adriat,'bcn Meeres. Ibid. 1851. Hft. I. Ueber die Larven und die Metamorphose der Echinodermen, vierte Abhandlung. Read to the Berlin Acad. 7, Nov. 1850; 28 April and 10 Nov. 1851, and published in 1852. Agassiz. Twelve Lectures on Comparative Embryology, delivered before the Lowell Institute, in Boston, Dec. and Jan., 1848-49. Boston, 1849. Busch. Beobachtungen fiber Anatomie und Entwickelung einiger wirbellosen Seethiere. Berlin, 1851. These writings relate chiefly to development; but, for many special points of Anatomy, see the writings of Midiler, Krohn, Peters, and others referred to in my notes.- ED. CHAPTER I. CUTANEOUS ENVELOPE AND SKELETON. ~ 72. WithI the exception of the apodal Sipunculidae, the Echinoderms have a eutaneous skeleton moditied in the different orders in the following manner.:: ~ 72. THE ECHINODERMATA. 77 I. In the lHolothurioi'dea, irregular calcareous corpuscles, Which often have reticulated openings, are scattered through the skin.(') II. In the Echinoidea, the calcareous substance is separated from the soft skin, and composed of plates of a definite form, pierced by openings. These plates are immovably united together by means of sutures. These last are easily seen in the Echinidae, but are indistinct in the Clypeastridae; they entirely disappear with age in some species.(2) Among these plates which are arranged in a regular series, those called amb2tlacral should be mentioned; these are perforated, having upon their outer surface the pedicles, and upon their inner the amrnbulacral vesicles. They form, usually, five double rows, so placed between the other plates that their openings form, sometimes five longitudinal rows extending from the mouth to the arm,(3) sometimes a rosette of five lobes (4) on the dorsal surface of the skeleton.5) III. The coriaceous skin of the Asteroi'dea, like that of the Holothurioidea, contains numerous calcareous corpuscles, of which the smallest are irregular, the largest porous. But beneath this is a cutaneous skeleton, composed of porous calcareous pieces, movably articulated, and extending on the ventral surface from the mouth to the end of the rays. In many species, the larger corpuscles, pressed together, form a reticulated support, which is either simple~( or composed of plates.(7) With the internal skeleton, each articulation is usually composed.of many pieces, the intervening lacunae of which are the ambulacral pores. The principal middle pieces unite at an obtuse angle, thus forming an abdominal furrow.t( The Ophiuridae have also an articulated internal skeleton, but the articulations are simple. But the external envelope of their arms consists of calcareous scales, closely knit together, and which so tightly close up the internal skeleton that the cavity of the body does not extend between the skin and the internal skeleton into these appendages, as in the Asteroidae. IV. In the Crinoidea, the skin is soft only on the ventral surface; that of the back is wholly calcareous, and converted into an articulated skeleton, which extends upon the arms and lateral branches. The mobility of these articulations is due to an elastic, interarticular tissue. They constitute discs or short cylinders, which, joined together, form arms, lateral branches (pinnulae), cirri, and in some species a peduncle.(9) There is a canal in axis of all these parts of the skeleton, and upon the 1 These irregular and usually perforated calca- 2 Scutella and Clypeaster. reous corpuscles are mixed with the sand of the 3 Echinus and Cidaris. sea, after the death and decomposition of the ani- 4 Encope, Rotula, Scutella, 4-c. mal, but can then easily be distinguished with the 5 A very detailed description of the shell of microscope. Quatrefages (Ann. d. Sc. Nat. Echinu.s will be found in Meckel's System der XVIt. 1842, P1. III. IV.) has figured many of them vergleich. Anat. II. Abth. 1, 1824, p. 31 i andl in belonging to Synapta. Similar microscopic cor- the monograph of Valeztin, Anat. du genre puscles, of various forms, are found in the soft Echinus, 1841, p. 5. He has also published very parts of most of the Echinoderms. It is very exact researches, with figures, upon the intimate desirable that, as has already been commenced by structure of the calcareous plates of this animal.Ehrenberg (Abhandl. d. Berl. Akad. 1841, p. 408), (Ibid. p. 17, P1. II.). they should be subjected to careful investigation i 6 Asteracanthion, Solaster. for by this way alone can correct views be ob- 7 Asteracantlhionl, Oreaster, Solaster, 4c. tained upon many enigmatical bodies of this kind 8 See the figure by Sharpey, Cyclop. Anat. andt seen by the naturalist. Phys. loc. cit. p. 31, fig. 8, 9; and Meckel's. verFor the calcereous corpuscles imbedded in'the gleich. Anat. II. Abth, 1, p. 19. skin of the Holothurinae, see Koren in Froriep's 9 Pentacrinus. neue Not. XXXV. p. 18, fig. 6-9 - and in the Arch. skandin. Beitr. f. Naturg. I. p. 449. 7* 78 THE ECHINODERMATA. $~ 73, 74. ventral surfatce of the arms and pinnulae, a furrow, over which the soft skin (perisoma) passes in a bridge-like manner.(~) ~ 73. In many Echinoidea the buccal cavity is provided with processes pointing perpendicularly into the interior of the shell. and which are the points of attachment of the masticatory muscles and ligaments. This osseous circle is most developed in the Echinidae.(1) and is composed of five processes. Between each of these is a smaller one, corresponding to as many ambulacral ones. each of which is perforated by a large opening.(2) In the Clypeastridae. there are five simple processes only;(3) and in the Spatangidae they are wholly absent. The sub-cutaneous osseous ring about the oesophagus, in the Holothurioidea, corresponds probably to this circle. Usually composed of ten pieces, it may be regarded as a rudimentary internal skeleton, for it is the point of attachment of both muscles and tentacles. In Holothuria tubulosa its anterior border is denticulated;(4) and in Synapta it is composed of twelve pieces, five of which have oval openings for the free passage of the aquiferous canals. () ~ 74. The general envelope of many Asteroidea is more or less covered with various calcareous productions. These have the forms of lamellae, knobs, callosities, granules, immovable rays both sharp and blunt, rough and smooth movable points, double hooks, &c.(l In the Echinoidea, there are points of very variable size united to knobs which are scattered over the external surface of the shell. These points project thlrough the thin skin covering this shell, having at their base a kind of capsular articulation.(2) Remarkable cutaneous organs are found in Synapta. These are small anchor-like hooks, by which these animals attach themselves to objects. Each of them is obliquely inserted under a small sub-cutaneous scale, which is perforated by a canal.(3) 1itIn the Crinoidea, as well as in the Echino- bristled points, project from the surface of Soderms generally, the parts of the skeleton have a laster and Chaetaster. With Ophiocoma and calcareous, reticulated structure; see Muller's Ophiomastix, the margins of the arms are covered Arch. 1837, p. 93, and Ueber d. Bau. d. Pentacri- with smooth points, which in Ophiothrix are nus caput Medusae, in the Abhandl. d. Berl. Akad. spinous. In Ophionyx these spinous points have 1841, Taf. I. fig. 3. movable double hooks; see the beautiful figures 1 Echinus, Cidaris. of Miiller and Troschel (System d. Asteriden). 2 Valentin, Monogr. ioc. cit. P1. II. fig. 15. 2 The spines of the Echinoidea have, over their 8 Agassiz, Monogr. d'Echinodermes, 21le Livr. whole extent, numerous, denticulated ribs; see containing the Scutellal, P1. XIII. fig. 3, P1. Valentin, Monogr. loc. cit. P1. III. fig. 26. In XXVII. fig. 7 (Lobophora and Echinocyamus). Spatangus the spines are spatulate, and in the 4 Tiedemann, Anat. d. Rithrenholothurie, &c., Clypeastridae (Mellita, Encope, Laganum) they p. 26, Taf. II. fig. 5; also Wagner, Icon. zoot. are clavate. The minute researches of Valentin Tab. XXXII. fig. 15. (Monogr. loc. cit. p. 24, P1. III) have shown the Koren has observed that the osseous ring is structure of the spines of the Echinoidea to be very composed of ten pieces with Thyone fuscus and complex. Cuvieria squamata of the Holothurinae. 3 The burr-like roughness of the skin of Synapta 6 Quatrefages, Ann. d. Sc. Nat. XVII. 1842, has already been observed by Eschscholtz (Zool. p. 47, P1. 1V. fig. 5; P1. V. fig. 7, c. c. Atlas, Hft. 2, 1829, p. 12). Jaeger (De Holothu1 With Oreaster and Culcita, the whole body is riis dissertatio, 1833, Tab. I. fig. 3) first figured covered with knobs and granulations. With As- the cutaneous hooksof Synapta Beselii. Quatretropecten and Stellaster, you find flattened points fages (Ann. d. Sc. Nat. XVII. p. 33, P1. III.) has and marginal lamellae. Innumerable rays, with given a very exact description of those of Synapta ~ 75, 76. THE ECHINODERMATA. 79 ~75. A peculiar calcareous plate (the madreporic plate) is observed upon the cutaneous skeleton of the Asteroidea and Echinoidea. In the last it is always situated in the centre of the dorsal surface, but in the first its position varies. In the proper Asteroidae there are often several, having an excentric dorsal situation; while in the Ophiuridae(l) it is found upon the ventral surface, and especially in the angle formed by the junction of the two arms with the tortuous mouth. In some Asteroidae a membranous sac (stony canal), filled with organized calcareous particles, is attached' to this plate; in others, an articulated calcareous cord stretches obliquely across the body towards the border of the mouth. The use of these parts is not yet positively known.(2) CHAPTER II. MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION. ~ 76. In the Echinoderms the muscular system is well developed. Its primitive fibres are fiat, and without transverse striae.(1) In the ventral surface, and between each joint of the arms and pinnulae of the Crinoidea, there are one or two small muscles, antagonistic to which, upon the opposite surface, is an interarticular elastic tissue.(2) In the Asteroidea, the interarticular lacunae of the internal skeleton are filled with muscles.(3) The skin of these animals does not aid the motions of the arms, except by its elasticity. But in the Echinidae the skin Duvernaea. The similar hooks found in the sea- 1834, p. 580) has shown that they do not contain ormud of Vera Cruz have been taken by Ehrenberg dinary calcareous matter, but rather that which is for stony concretions belonging to a sponge, and organized and perforated in a reticulated manner. figured and named Spongolithis anchora (Ab- A calcareous cord of a special structure is found in hand. d. Berl. Akad. 1841, p. 323, Taf. III. No. Asteracanthion; see Siebold, IAVller's Arch. VII. fig. 36). He has also taken the perforated 1836, p. 291, Taf. X. fig. 14-18; and Sharpey,. supports of these hooks for an Infusorium with a Cyclop. Anat. &c. loc. cit. II. p. 35, fig. 12, 13, s.* siliceous carapace, described as Dictyocha splen- 1 According to Wagner (Mialler's Arch. 1835, dlens (Ibid. fig. 35). But, more lately, he has p. 319), the Echinoderms do not have transversely perceived their true nature (Ibid. p. 407, 443). striated muscles. This has been confirmed by'The discovery of analogous cutaneous organs in the Muiller (Abhand. d. Berl. Akad. loc. cit. p. 214, Taf. marl near Streitberg, by Count Miinster (Beitr. IV. fig. 9) in the genera Pentacrinus and Coma-.z. Petrefak. Hft. VI. 1843, p. 92, 96, Taf. IV. fig. tula. For my own part, I have failed to perceive_9), is very interesting, since it shows the antedilu- them in Echinus, Asterias, Ophiurus, Holothuvian existence of Synapta. ria, and Sipunculus. Valentin (Monogr. loc. cit. Beside the cutaneous corpuscles of carbonate of p. 101, PI. VIII. fig. 153-155) asserts to have lime, Quatrefages (loc. cit. p. 36, P1. III. fig. 15) seen strive upon the fibres of the masticatory, spinhas found others which are of a spherical form in ous and anal muscles of Echinus; and Quatrethe skin of Synapta Duvernaea; and, as they fages (Ann. de. So. Nat. loc. cit. p. 43, P1. IIL have protractile filaments, he compares them to fig. 17) has observed transverse wrinkles during the nettling organs. contraction of the longitudinal muscles of Synapta. 1 Astrophyton. 2 Miiller, Abhand. d. Berl. Akad. loc. cit. p. 214, 2 These parts are found in Astropecten. Ac- 220, Taf. II. fig. 8, 12. eording to Tiedemann (loc. cit. p. 54), they furnish 3 The interarticular muscular layer of the the necessary calcareous matter for the skeleton of Asteroidae has been accurately described by the Asteroidae. But Ehrenberg (Miiller's Arch. Meckel (System d. vergleich. Anat. III. p. 14). * [ ~ 75, note 2.] See, for further details on this stone-canal with the Ophiuridae, Miller, Arch. 180o, p. 122. - ED. 80 THE ECHINODERMATA.; 7TT covering the shell has distinct muscular bands for the motions of the; points. (4) In the Holothurioidea and Sipunculoidea there is a very thick subcutaneous muscular layer. This is itself composed of two layers, - the first and upper being made up of circular, the second and lower of longitudinal fibres. In the Holothurioidea,5) these fibres form five large, thick,. widely-spread bundles, which are inserted into the osseous ring. In the, Sipunculoidea, these bundles are more numerous, but more compactly bound together. 6) The muscles of mastication, of the digestive canal, and of the tentacles, will be treated hereafter. ~ 77. With the exception of the Synaptinae and Sipunculoidea, the Echinoderms; have special, tentacular, locomotive organs (ambulacra). These are hollow and very contractile prolongations of the skin, and communicate through, the ambulacral pores with small contractile sacs (ambulacral vesicles), found upon the internal surface of the coriaceous or calcareous envelope of the body. The ambulacra and their vesicles have transverse, longitudinal fibres,. and contain a clear liquid, which, from contractions, oscillates from one to, the other through the pores. In this way the ambulacra are capable of erection and elongation, and the animal uses them as feelers to find a proper object of attachment; and on this account, also, they have in some, species a suctorial extremity. These organs, which are sometimes locomotive, sometimes prehensile; have the following variations of structure and form: I. With the Crinoidea they are small, delicate and cylindrical, and are found upon the borders of a furrow, which runs from the mouth along the soft perisoma covering the arms and pinnulae. Each one of them is covered with small cylindrical, clavate tentacles.(l) II. The Ophiuridae have upon their arms, and between the plates, pores which connect with small cylindrical ambulacra; these last, from numerous small warts, present a studded aspect.(2) III. With the Asteroidae they are situated in a double or quadruple row, in the ventral furrows which extend from the mouth to the end of the rays. They form compact cylinders of'considerable size, the acute or truncated extremity of each of which has a sucker.()3 IV. With the Echinoidea they are situated upon an elongated stalk, and have a sucker. They are found both upon the ambulacral plates an~i immediately around the mouth.(4) Being extremely movable, they are 4 Valentin, Monogr. loc. cit. p. 35, Pl. III. fig. dae are attached to surrounding objects; see 3'9. Erdl in YWiegmann's Arch. 1842, I. p. 58, Taft 5 The cutaneous muscular system of Holothuria II. fig. 1, a. ~has been described by Tiedernan (loc. cit. p. 27, 3 Beside the very correct description given of' Taf. II. IV.)- and that of Synapta by Quatre- these organs by Tiedemann (loc. cit. p. 56), see. fages (Ann. d. Sc. Nat. loc. cit. p. 41). Rymer Jones (A Gen. Outl. of the Anim. King.. 6 For the muscular system of Sipunculus nu- p. 148, fig. 65). It appears that in Astropectendus, see Grube, in Muiller's Arch. 1837, p. 240, the extremity of the ambulacra can be inverted,, Taf. XI. fig. 1. thus compensating for the sucker found in Echi1 The ambulacra of Comatula, which have ac- naster, Asteriscus, and A.steracanthion. tive vermicular movements, have no opening at 4 With Echinus the suckers, which exactly retheir free extremity; see Miiller, Abhand. d. Berl. semble the other ambulacra, are fixed upon the..Akad. loc. cit. p. 222, Tab. IV. fig. 13, 14.. contractile membrane surrounding the mouth. 2 By these the very active arms of the Ophiuri- With. Spatangus and Echinanthus there is ~ 78. THE ECHINODERMATA. 81 chiefly locomotive; for from them numerous points are prolonged, by, which they adhere to objects, and to which they become afterwards fixed by their sucker. They are covered with ciliated epithelium, and their suckers are made firm by a coarse calcareous network. Elongated calcareous corpuscles of the same nature are found also in their walls, - some branching and others hook-like.(5) V. With those Holothurioidea which have them, they have a more or less complete sucker, and are scattered irregularly over the entire surface of the body, or disposed in regular rows. Usually very short, they can be retracted deeply in the skin; but they are capable of equal prolongation, and thus perform well the function of suckers."') The ambulacral vesicles, which are intimately connected with the circulatory and respiratory systems, will be fully treated hereafter. ~ 78. With the Echinoidea, and Asteroidae, there are other movable organs (pedicellariae), which, scattered over the surface of the body, are prehensile, and used in a pincer-like manner. With the Asteroidae, they usually consist of two delicate forceps-like pieces (pedicellariae forcipatae), or of two large valvular flaps (pedicellariae valvulatae). Generally they are not pediculated.(i) Those of the Echino'icldea have been carefully studied in Echinus. They are numerous, and occur for the most part about the: mouth, presenting three different forms: 1. Those composed of three, short, lenticular pieces (pedicellariae geinmiformes). 2. Those formed of three long delicate pieces, laterally denticulated (pedicellariae tridactyli).. 3. Those with three laterally denticulated spoon-like pieces (pedicellariae ophiocephali). They are supported by a base of calcareous, reticulated substance; and in the Echinoidea, always rest upon a stalk, the lower part of which contains a cylindrical, calcareous nucleus, while the remaining portion is soft, and capable of a spiral contraction.'2) Here also they are: covered with ciliated epithelium, and can, by means of movable processes,. seize hold of objects, which, being passed along, may be conveyed even from the dorsal surface to the mouth. near the mouth, and opposite the ambulacral Astrogonium, they are valvular and without a rosette, a row of ambulacra having special pores. pedicle; see 3IQller and Troschel, loc. cit. p. 5 See Valentin, Monogr. loc. cit. p. 37, P1. IV. 10, Taf. VI. fig. 3-6. V., and Erdl in FWiegmsanno's Arch. 1842, I. p. 2 The pedicellariae of Echinus. were, at first, 55, Taf. II. fig. 10. The corpuscles found by taken for parasitic Polypi by 0. F. uiiller (Zool. Ehrenberg (Abhandl. d. Berl. Akad. 1841, p. 324, Dan. I. 1777, p. 16, Tab. XVI.). See Lamarck,. Taf. III. No. VII. fig. 37, a. b.) in the marine Hist. Nat. des Aniln. sans Vertdbres, II. p. 75. sand of Vera Cruz, and figured under the name More recently, Agassiz (Valentin's Monogr. loc. of Spongolithis u'ncinata, are only the cruciform cit. p. 51) has expressed the opinion that they were parts of the skeleton of Echinus. This will be young individuals. The researches of Delle Chiaje, evident from comparing them with the calcareous (Memor. sulla storia e notom. clegli Anim. seiza. corpuscles figured by Valentin (Monogr. loc. cit. Vertebr. II. 1823, p. 324, Tab. XXIII.) and of PI. V. fig. 65). Sars (Beskrivelser, &c., p. 42, Tab. IX.) upon 6 Catalogue of the Physiol. series of Comp..EchinuLs, Cidaris, and Spatangus, have dispelled Anat. contained in the Royal Ceoll. of Surgeons, all doubts as to the real nature of these organs. London, IV. 1838, p. 196, P1. XLIX. fig. 3-5. Very correct descriptions of them have lately been 1 With Luidia, there are, however, three tongue- published by Valenltin (Monogr. loc. cit. p. 46, like pedicellariae. In Asteracanthionz, they have PI. IV.), and by Erdl (Wiegmann's Arch. loc. a soft pedicle. In Asteropsis, Slellaster, and cit. p. 49. Taf. II. fig. 1-9).* * [~ 78, note 2.] See Adams (Ann. of Nac. vespertilio; he thinks, therefore, that they are Hist. VIII. 1851, p. 237), who has found what he independent parasitic organisms.- Ed. regards as Pedicellariae on the skin of VQluta 82 THE ECHINODERMATA. 0 79, 80. CHAPTER III. NERVOUS SYSTEM. ~ 79. The central portion of the nervous system consists of a ring which is usually pentagonal, and surrounds the commencement of the esophagus.'The main nervous branches are given off from this, and pass to the other end of the body along the median line of the rays, or their corresponding parts. The form of this ring is mainly due to that of the mouth; and therefore, with the reniform mouth of Spatauzgts, it is unequally pentagonal.(l) Ganglia have not yet been found in it. But in Echinus and Holothuria, the nerves passing from it have between their fibres, violet, green, or red pigment granules.(2) ~ s0.'The principal nervous trunks have a longitudinal furrow, as if composed,of double cords, and give off from each side, during their course, branches which go to the ambulacra.(1) With the Crinoidea, a nervous cord passes beneath the furrow formed by the perisoma on the ventral surface of the arms; this has a slight swelling opposite each pinnula, to which it sends off a branch.(2) With the Asteroidae, the nervous trunks which pass off from the oesophageal ring are lodged in the ventral furrows of the rays.(3) But in the Ophiuridae, they pass in a canal, concealed by the ventral plates of the arms. The five nerves, analogous to those of the Echinoidea, pass along the internal surface of the ambulacral plates, between the vesicles, even to the centre of the dorsal region. In Echinus, there are, moreover, special nerves directly from the oesophageal ring, for the organs of mastication and digestive canal.(4) In Holothuria, this ring is situated directly on the anterior border of the osseous circle, and sends off five nerves which pass along the median line of the longitudinal muscles, even to the end of the body;(*) it sends off also special nerves to the oral tentacles. (6) 1 Krohn (MPiiler's Arch 1841, p. 8, Taf. I. fig. furrows of the articulations of the rays, in Aster3, 4). acanthion rubens, and glacialis, are probably 2 Krohn, loc. cit. only tendinous fibres. 1 Krohn, ibid. p. 4, 10. 4 Krohn, who has studied the nervous system 2 Miller (Abhandl. d. Berl. Akad. loc. cit. p. of Echinus and Spatangus, has traced the fila233, Taf. IV. fig. 11, i.; Taf. V. fig'. 16). ments given off from the main trunks, across the 3 The nervous system of the Asteroidae was first ambulacral pores, to the suckers of the ambulacra. clearly shown by Tiiedemann (loc. cit. p. 62, See also Valentin's figures of this system, in Taf. IX. and 3Ieckel's Deutsch. Archiv. I. 1815, Echinus (Monogr. loc. cit. p. 98, P1. VIII. IX.). p. 69, Taf. III. fig. 1). This anatomist, like 5 The cesophageal ring of Holothuria, observed Krohn (loc. cit. p. 4), did not perceive the ganglia by Kr'ohn (Iiiller's Arch. 1841, p. 9, Taf. I. fig. of the cesophageal ring, observed by Wagner 5), sends off its principal nerves across the fissures.(Vergleich. Anat. 1834, p. 372). of the dentations of the five great pieces of the The ganglia and nerves that Spix (Ann. du osseous rings. Their lateral filaments, going to the 3Mus. d'Hist. Nat. XIII. 1809, p. 439, P1. XXXII. ambulacral vesicles, are so fine that Krohn could fig. 3, 6) and'onrad (De Asteriarum fabrica scarcely find them. dissert. 1814, p. 13, fig. 3, o.) affirm to have seen 6 Grant, loc. cit. p. 184.*.on the internal (dorsal) surface, opposite the ventral * [~ 80, note 6.1 Miiller has furnished some Holothurioidea; see Arch. 1850, p. 226. lIe valuable contributions on the nervous system of the makes this statement, which is worthy of remem 81. THE ECHINODI0ERMATA. 83 With the Sipunculidae, as with the other worm-like Echinoderms which approach the Annelids, the arrangement of the nervous system is quite different. Here, the nervous ring is a simple, aganglionic thread extending to the posterior end of the body, and may be regarded as the first trace of a ventral cord.(7) CHAPTER IV. ORGANS OF SENSE. ~ 81. The sense of touch is well developed with the Echinoderms, and seems to have its seat in the oral tentacles, the ambulacra, and pedicellariae.:With the Asteroidea, and Echinoidea, no organs of vision have yet been found. As such, however, have been regarded the red pigment dots situated, with the former, at the extremity of their rays,(') and with the latter,'in the middle of the dorsal region upon five ocellary plates which alternate regularly with those of the genital organs.(2>) These ocellary plates are perforated each by a very fine canal, through which passes a delicate filament from the main nerve for the pigment dot.(3) Although these pigment dots have thus a nervous connection, no proper organ to refract the light has yet been found in them.(4) 7 According to Krohn (Miller's Arch. 1839, According to Quatrefages, Echiurus Gaertneri p. 348), the cesophageal ring of Sipunculus nudus has an abdominal cord which possesses ganglia, has two super-cesophageal ganglia blended to- and by this character the Echinidae approach the gether. These had already been observed by Annelida; see Ann. d. Sc. Nat. VII. 1847, p. Delle Chiaje (Memor. loc. cit. I. p. 15, Tav. I. 332, P1. VI. fig. 4.* fig. 6. i.); but more lately Grube had taken them for 1 In the Clypeastridae and Echinidae. cartilaginous rudiments of the osseous circle 2 These dots, which Vahl (Adiialler Zool. Dan. (Miiller's Arch. 1837, p. 244). He has also con- Tab. CXXXI.) had already observed in Pteraster founded with the muscular system the two lateral militaris, were first regarded as eyes'by Ehren nerves of this ring, and its abdominal branch berg (Aiitller's Arch. 1834, p. 577, and Abhand. which in its course sends off laterally branches to d. Berl. Akad. 1835, p. 209, Taf. VIII. fig. 11, 12). the muscular layer and to the skin, and termi- He has seen in Asteracanthsios violaceus, a small nating at the end of the body in a swelling. Then, swelling at the extremity of the nerve of the ocel)on the other hand, the filaments surrounding the lary dot. Forbes (Hist. of the Brit. Star-fishes, digestive tube, and taken by him for nerves, 1841, p. 152) first noticed these dots in Ecinus, appear to be only cellular fibres (loc. cit. p. 244, and their presenc has been confirmed by a -ssi2 Taf. XI. fig. 4). and Valenztin (Ionogr. I,)c. cit. p. 10, 100, P1. According to Forbes and Goodsir (Froriep's II. fig. 12, P1. IX. fig. 188, 189). neue Not. No. 392, 1841, p. 279), the nervous sys- 3 Valentin, loc. cit. P1. IX. fig. 190. tern of Echilurus is composed of an cesophageal 4 Valentin has failed to discover in these organs -ring, with an abdominal cord, from which pass off a crystalline lens. Although in Echinsus they are.asymmetrical branches. upon the back, and therefore favorable to vision,'brance: "It is a noticeable fact that the nervous united so as to form a single cordiform mass - the;trunks of these animals throughout are contained brain, which is situated under the muscles of the in a sheath, which, after the maceration of its proboscis. From this brain passes off a cord on,contents, has exactly the aspect of a blood-vessel." each side, forming a collar about the oesophagus i'The nervous system of these animals cannot, there- these unite below, and then continue as a ventral fore, be properly studied from alcoholic speci- cord to the posterior extremity of the body. This rmens. —ED. cord has slight swellings along its course, which * [ ~ 80, note 7.] See also Blanchard (Ann. d. may be regarded as ganglia; they send nerves to Sc. Nat. 1849, XII. p. 57), who has well made out the integuments. the nervous system with Sipunculus rufo-fim- This anatomist has also observed here a very briatus. It consists of two cerebral ganglia distinct splanchnic system of nerves. - Ed. 84 THE ECHINODERMATA. ~ 82, 8a. CHAPTER V. DIGESTIVE APPARATUS. ~ s2. The alimentary canal is situated in the cavity of the body, isolated, but is retained in its place by a kind of mesentery which is composed of fibres,ol) or of a thin membrane.(2) The mouth, which is usually central, is often surrounded by a circle of tentacles.t3) In the Asteroidea, the digestive canal is a large central pouch,. an anus and appendages extending into the rays being present in some(4) and wanting in others.(5) In the other Echinoderms, the digestive canal has usually thin walls, is of a variable length, and tortuous quite to the anus. The position of the anus is quite varied. In the Echinidae, and Asteroidae, it is in the centre of the back, exactly opposite the mouth. In the: Holothurioidea, it is at the posterior end of the body; while in the Clypeastridae, and Spatangidae, it opens laterally upon the margins of the shell. In the Crinoidea, it is near the mouth upon the ventral surface, and in the Sipunculoidea, it has a similar position. The internal surface of this canal has generally been found lined witk ciliated epithelium.~(" ~ 83. With the Asteroidea, and Eehinoidea, the pedicellariae already described,. are used to seize the food and convey it to the mouth. Their ambulaera are perhaps sometimes used in the sanie way. In the Crinoidea, the furrow of the tentacles, aided by the tentacles themselves, serves well to conduct the food from the arms and pinnulae to the mouth.(l) In the Holothurioidea, and Sipunculidae, there are completely retractile tentacles of a special nature. In the first, they are hollow, pinnated or branched, and, arranged in a circle around the mouth, are attached by their base to the osseous circle and to thde elongated vesicles which project into the cavity of the body. These tentacular vesicles contain a liquid, and, in the Asteroidae, where they are upon the 2 Holothurioidea. ventral surface at the end of the furrows, the rays 3 Holothurioidea and Sipunculoidea. bend round to the dorsal surface; and again, 4 Asteroidae. although Tiedemann',1leckel's Deutsch. Arch. 5 Ophiuridae. loc. cit. p. 175) thinks these last can distinguish 6 According to Sharpey (Cyclopoedia, &c., loc. light from darkness, yet it is doubtful if these ani- cit. I. p. 616> and Valentin (Wagneer's Handmals can really see by these organs. They appear, wdrterbuch der Physiol. I. 1842, p. 493), the interlike many other inferior animals, to perceive the nal surface of the stomach and its appendages, of light by its action as an excitant upon their skin, the Asteroidae, has a ciliary movement. Valentin. and in this way can, like plants, seek the sun- (Mlonogr. &c. p. 79) has also found ciliated epithelight. The account which Forbes (Hist. of British lium in the entire digestive canal of Echinsus. Star-fishes, p. 139, and Froriep's neue Not. No. With Phascolosomae where I have found cilia 420, 1841, p. 26) has given of Luidia fragilis- upon the tentacular apparatus, and with Com.asima, which, having made its escape by the loss tula, where Muller (Abhandl. d. Berl. Akad. of an arm, looked with scornful eyes upon its per- 1841, p. 233) has found them in the anus, they secutor, is pleasant to read, but is far from set- extend probably through the intestine. tling this question. 1 Midller, Abhandl. d. Berl. Akad. 1841, p. 2229 1 Asteroidea, Echinoidea, and Sipunculoidea. '~ 84. THE ECHINODERMATA. 85 which, by their contraction, is pressed into the cavity of the tentacles for lubrication. (2) The retraction of the tentacles is due in part to their own contractility, and in part to the numerous muscles, which, arising from the internal surface of the cavity of the body, are inserted into the osseous circle. By these means, it, together with the tentacles, can be retracted into the'body.3l) With the Sipunculidae the tentacular apparatus consists of a:fringed border on the margin of the mouth, which is also provided with vesicles.4) In Sipunculus, and Phascolosoma, there are four long;muscles, which, arising from the internal surface of the body, pass on to the mouth, and are retractors of the tentacular membrane.(0) It is possible that these oral tentacles serve not only as prehensile organs of food, but also as those of locomotion and respiration.( ) ~ 84. The mouth of the Comatulinae presents nothing remarkable; but with the Asteroidae, it is covered with hard papille, projecting from its corners and angles. In the Ophiuridxe, the inverted angles are covered with hard papillae, while the everted ones have calcareous teeth, between which are concealed soft cylindrical tentacles. Immediately behind all of these, the entrance of the stomach is indicated by a membranous sphincter. In the Asteroidae, however, this is wanting, there being a short Esophagus leading directly into the stomach. With the Echinoidea, and Holothurioidea, the mouth has a soft circular lip, between which, with the Echinidae, and with the Clypeastridae, project the points of enamelled teeth. The mouth of the Echinidae, and Clypeastridae, has a very remarkable mnasticatory apparatus. In the first, the calcareous basis which supports the teeth has long been known as Aristotle's lantern. This conical basis is divided into a base and summit; the first being the superior part of the animal itself, while the second is formed by points of teeth projecting from the mouth. It is, moreover, composed of fifteen pieces, five of which are three-sided, hollow pyramids, and so adjusted that they touch each other by their plane surfaces, presenting externally the third surface which is convex. This last has internally a longitudinal furrow, in which is fitted a very long, narrow and slightly-curved tooth. Beside these five principal pieces, which form the jaws of Echinus, there are two other kinds, much 2 These vesicles are found in Holothuria and 3 In Pentacta, there are five large cylindrical Chirodota; see Tiedemann, loc. cit. Tab. II. fig. muscles arising from the subcutaneous longitudinal 4, e. 6, i.; also the Catalogue of the Museum, Lon- ones, and inserted into the osseous chicle;- they don, &c., IV. PI. XLIX. fig. 1, 2 (Holothuria tubu- are special retractors of the tentacles * see ]leckel, losa) i and the Atlas Zool. du Voyage de l'Astrolabe. System d. vergleich, Anat. IV. p. 62. Zoophytes, P1. VIII. fig. 3 (Chirodota fusca). 4 I am inclined to regard as tentacular the two In Pentacta doliolum, I have found only a single vesicles of Poli, in Sipunculus; and of which,cylindrical vesicle fixed to the circle of tentacles. Delle Chiaje (Memor. &c. Tav. I. fig. 6, d.) perIn Synapta Duvernaea (Quatrefages Ann. d. ceived only one, although Grube (Miiler's Arch. Sc. Nat. loc. cit.), these vesicles are entirely want- 1837, p. 251, Taf. XI. fig. 2, P.) has seen them ing. both fixed in a space circumscribed by the tentacCuvier (Anat. Comp. V. p. 454) and other anat- ular membrane. omists (see Grant, Outlines, &c., p. 333) have 5 Grube, Ibid, p. 241, Taf. XI. fig. 1, u. 2, m. m. erroneously taken these parts for salivary organs. and Delle Chiaje, Memor. &c. Tav. I. fig. 3. They do not communicate with the digestive canal, 6 The oral tentacles of Synapta Duvernaea, but connect freely with the circulatory and respir- which, according to Quatrefages (loc. cit. p. 63, atory systems, —a point, therefore, to which we P1. IV. fig. 1), have suckers on their internal surshall further allude hereafter. face, are certainly used as locomotive organs. S 86 ITHE ECHINODERMATA. ~ 85. smaller. Of these, five are elongated quadrilateral plates, placed at the base of the lantern, between each two pyramids. The other five, smaller and longer, are curved upon the first. All these pieces are united by many tendons and muscles to each other, and to the neighboring osseous circle which projects inwards from the shell.. The muscles of mastication are in ten pairs; five of these arise from the' longest processes of the osseous circle, and are inserted on the pyramids below the summit of the lantern. The other five, on the other hand, pass from the shortest processes of this circle to the base of the pyramids. By this arrangement, when the first five contract and separate the summits of the pyramids together with their teeth, the second five, contracting also, carry the points of the teeth again together, by separating the bases, of the pyramids.(') In the Clypeastridae, the masticatory apparatus is more- simple. It is, composed of ten unequal, triangular pieces, joined together, V-form, two, and two. Each of these pieces has in its projecting angle, a furrow in which a tooth is fitted. These five jaws are so arranged around the mouth that their angles and the points of their teeth meet together in its centre.(2. ~ 85. The digestive cavity of the Ophiuridae is only a simple stomachal sac, occupying the centre of the hollow disc of their body. It is divided by walls projecting inwardly, into many caeca, which never extend into the rays.l) There are usually ten of these caeca, which in Astrophyton are subdivided into numerous smaller caeca.(2) With the Asteroidae, the stomach is large and has a similar situation; but it sends off radial caeca into the rays. In those species which have an anus, the digestive canal may be divided into three parts. The stomach is separated into two chambers by a circular, projecting fold. The first of these is the true stomach, and the second sends off the radial caeca. A narrow, short rectum, passing off from the stomach, forms the third part of this canal, and terminates in an anus, situated upon the back of the animal and concealed among points, callosities, &c. This rectum has folds which, of a variable length and sometimes branched, are called the inter-radial caeca, and are situated between instead of in the rays. (3 In the Comatulinae, this canal consists of a coecum situated at the end of a short oesophagus, and which, after a spiral course about the axis of the body, terminates in an anus having the form of a short tube projecting from the ventral surface not far from the mouth.(4) In Comatula europaea, the axis, around which the digestive canal passes 1 This apparatus has been minutely described by 2 Meckel, Syst. d. vergleich, Anat. TV. p. 50. Tiedemann (loc. cit. p. 72, Taf. X. fig. 1, 2), by 3 See also Tiedemann (loc. cit. Taf. VII.), whose Meckel (Syst. d. vergleich, Anat. IV. p. 56), and beautiful figures have been copied everywhere;. by Valentin (MAonogr. &c. p. 63, P1. V.). See and the original designs of the digestive cavity of also the beautiful figure by Rymer Jones (Out- Asteracanthion, Archaster, and Culcita, by M/l-. line of the Anim. King. &c. p. 167, fig. 70, 71). ler and Troschel (loc. cit. Taf. XI. XII.). 2 Agoassiz, Monogr. &c. 2z Livr. Scutelles. p. 4 Upon the digestive canal of Comatula, see: 15, P1. XII. XIII. XIV. &C. Heusinzger, Zeitschr. f. d. organische Physik. III_ 1 Konrad, De Asteriarum fabrica, fig. 5. 1829, p. 3"1, Taf. X. XI. ~ 86. THE ECHINODERMATA. 8T spirally, consists of a spongy substance, from which projects a lamina like the lamina spiralis of the conch of a snail shell.(5) In Spatangus, the toothless mouth opens into a delicate cesophagus which passes insensibly into a long tube of nearly the same size. This last makes two convolutions in its course, and sends off at about its anterior fourth a very long caecum. The digestive canal, situated between the origin of this caecum and the cesophagus, is of a dark color and has transverse plicae, while the remaining portion below is smooth and of an orange hue.(6) In the Clypeastridae, the numerous spiral turns of this canal are supported by many calcareous lamine situated upon the interior of the shell.',) In many species of Clypeaster, this canal has at its commencement, transverse folds, and further on numerous lateral caeca, which are separated from each other by laminse like those just described.(8) In the Echinidae the pharyngx has very thick muscular walls, and is surrounded by masticatory organs. Upon it succeeds a proper oesophagus, which, after a few convolutions, passes to the anus situated in the centre of the back. The digestive canal is a caecum given off by this last, and has many spiral turns in the cavity of the body.(') In the Holothurioidea, the very muscular pharynx is surrounded by the osseous circle. In the Holothurinae, the intestinal canal, which is long and equal throughout, has many turns from behind forwards, ending at last in a large cloaca situated at the posterior part of the body. But in the Synaptinae, it is short and nearly straight, and terminates in an anus having no cloaca.(10) In the Echiuridae m11) this canal closely resembles that of the Synaptinae. In the Sipunculidcae it is long, making its first turn about the middle of the body, and its second near the posterior extremity. The ascending and descending portions of this last pass spirally around each other on their way to the anus which is situated on the ventral surface of the body. (12) ~ 86. As to the glandular appendages of the alimentary canal, the salivary organs are perhaps entirely wanting in these animals. In the Holothurinae alone, are there particular appendages opening into its anterior portion, which could be regarded as organs of this nature. In the different genera, species, and even individuals of this family, these appendages widely vary as to form and number. 5 Miiler, Abhandl. d. Berl. Akad. 1841, p. 230, loc. cit.; afterwards by Quoy and Gaimard (AtTaf. V. las zool. du Voyage de l'Astrolabe. Zoophytes, P1. 6 See Meckel, Syst. d. vergleich, Anat. IV. p. VI. fig. 2, PI. VII. fig. 3). The cloaca is always 65, ar.,f Delle Chiaje, Memor. &c. Tav. XXV. wholly attached to the skin by numerous tendinous fig. 12; also Caruts and Otto, Erliuterungstafeln fibres. In Chirodota fusca the intestine is spiral z. vergleich. Anat. Hft. IV. Tab. I. fig. 25, and (Atlas zool. &c. P1. VIII. fig. 3); but in Synapta Wagner, Icon. zoot. Tab. XXXII. fig. 8. The Duvernaea it is nearly straight (Quatrefages nature of the canal figured by Delle Chiaje is yet Ann. d. Sc. Nat. loc. cit. P1. II.). unknown. It arises from the first portion of the 11 See the remarks of Forbes and Goodsir upon intestine, and returns to it at its middle portion. the Anatomy of Thalassema and Echiurus (FroIt has not been mentioned by Meckel. riep's neue Notizen, No. 392, p. 273, fig. 12). 7 Agassiz, Monogr. des Scutelles, p. 14, P1. III, 12 The alimentary canal of Sipuncsulus nudus, fig. 19, a. and of Echinorhyncus, has been faithfully de8 Ibid. p. 17, P1. XXII. fig. 28 (Laganum and scribed by Delle Chiaje (Memor. &c. I. p. 9, Tar. Mellita). I. fig. 5, 6- p. 126, Tav. X. fig. 11) and Grube 9 See Tiedemann and Valentin, loc. cit. (Muller's Arch. 1837, p. 245, Taf. XI.). I have 10 The digestive canal of the Holothurinae was found a similar intestine in Phascolosoma granufirst figured by Delle Chiaje and by Tiedemann, latum. :88 T1IE ECHINODERMATA. g 86. In Holothuria tubusosa, they are cylindrical, pure white, and very numerous, being united in bundles which are attached to the digestive canal -near the pharynx by short white pedicles.'1) In Pentacta doliolum, there is usually only one of these organs, —a small, white, curved horn, which sends to the pharynx a very tortuous,canal, which is widely removed from the excretory duct of the genital organs. The whiteness of these organs in Holothurinae is due to a reticulated -calcareous skeleton in their walls.t2) The radial caeca of the Asteroidae ought probably to be regarded as'hepatic organs. They are often quite developed, extending as a double canal from the stomach into each ray. Their walls have numerous small botryoidal vesicles, which secrete a yellow liquid. Usually each of these ten liver-like organs arises fiom the stomach by a proper canal; (3) but in some, two of them connect with this organ by a single canal.t4) With those Asteroidae which have an anus, there is another series of glandular appendages, the inter-radial caeca, which pass off from the rectum. Their function is not yet known. They contain a brownish liquid, in which, with Asteracanthion rubenzs, no uric acid has been found. In Astrog'onium, Solaster, and Asteracanthion, these organs are branched, and only two in number.(5) In Archaster, and Culcita, there are five; but in Culcita coriacea, each of these is divided dichotomously into two other long botryoidal caeca, which, separated by a septum, are spread out between the rays.(6) In Astropecten,(7 which is without an anus, there are sometimes found two short, analogous caeca, which open into the base of the stomach by a common orifice. But in Luidia, which is also without an anus, these organs are entirely absent.(8) In the other Echinoderms, which are entirely without these glandular appendages, the walls of the alimentary canal probably secrete the fluid requisite for digestion, and thus supply also the want of the hepatic organ. (9) 1 It has already been shown that the cylindrical Tiedemann (loc. cit. Taf. VII. or, Wa-rner, Icon. vesicles of Holothuria taken by Cuvier and other zoot. Tab. XXXII. fig. 1). It is the same, also, in naturalists for salivary organs do not comlnunicate Archaster, Culcita, and Luidia i see Mller and with the digestive canal, but rather with the tenta- Troschel, loc. cit. p. 132, Taf. XI. fig. 2 Taf.;cles. The white appendages of Holothuria tubu- XII. fig. 1. losa were first described as testicles by Delle 4 Asteracanthion; see Konrad, De AsteriaChicaje (Mlemor. &c. I. p. 97,Tav. VIII. fig. 1. o.), rum fabrica, fig. I; and Mlialler and Trosctel, and Tiedemnann (loc. cit. p. 29, Taf. II. fig. 6, loc. cit. Taf. XI. fig. 2. p.) assigned to them the same function. It is cer- 5 See 3iiler and Troschel, loc. cit. p. 132, Taf. tain that they have no testicular character, although XI. fig. I (Asteracanthiion rubens); an entire I cannot affirm that they are salivary organs. group of these rectal coeca of Asteracanthion'They have been figured, in Holotlhuria atra, by glacialis, has been figured by Konrad, loc. cit..Jaeger in his dissertation: De. Holothuriis, Tab. fig. 1, cl. III. fig. 2, e. e. 6 Mliuller and Troschel, loc. cit. p. 132, Taf. XI. 2 This calcareous tissue has been observed by fig. 2, Taf. XII. fig. 1. Jaeger (loc. cit. p. 38, Tab. III. fig. 7), by Wag- 7 Tiedemann, loc. cit. Taf. VII..eer (Froriep's neue Not. No. 249, 1839, p. 99), 8 Miller and Troschel, loc. cit. p. 132. 1(0X8. THE HELMINTIHES. 113 this canal is simple, straight, and ends posteriorly in an anus.() In many Treimatodes, the intestinal tubes have in all their course simple or ramified caeca, and in some, these caeca are so fully developed that the intestinal canal appears to fill the whole body.(8) The intestinal walls here are very thin, but this does not prevent peristaltic and anti-peristaltic movements, by which their contents move backwards and forwards, and are often rejected; through the mouth.(9) ~ 10s. In the Nematodes, and Gordiacei, the intestinal canal passes straight from the mouth which is at the anterior extremity, through the cavity of the body to the anus, which, in the first, opens front of the cauclal extremity.t") In very many Nematodes, the mouth has nodosities and swellings, but it isseldom that its cavity has horny, tooth-like processes.(i~ From the mouth extends a long and very muscular oesophagus, which is usually dilated claviform at its lower extremity. When the oesophagus is very long, it has one or more constrictions.(3) It is nearly always composed of three longitudinal muscles which are united by longitudinal seams. The. triangular cavity circumscribed by these muscles is lined by a very firm epithelium, which is sometimes horny, and in some species so thickly set in, the clevate dilatation that it resembles a masticatory apparatus.(i The. intestine consists of a straight tube, with thin walls and without dilata-. Gasterostomum; and the species above men- are, moreover, species which have very rudimenttioned I have discovered in the intestinal canal of ary digestive organs. In SlShaerularia bonzbi, Percafluviatilis, and Lucioperca. there is neither mouth nor annus, and in the place 7 See Miram, Owen, and Diesing, loc. cit. The of the intestinal canal there is a row of long sacs opening at the posterior extremity of many Trema- clinging together, and arounld vwhich the genital ortodes, and by many lIelminthologists taken for an gans are coiled (Wiegmann's Arch. 1838, I. p. anus, belongs to a special secretory organ, which 305). In Filaria rigida, living in the intestines will be mentioned hereafter. of Aphodius fimetariuos, I have found no digest8 In many species allied to Monostomum trigo ive canal whatever (/~ialler's Arch. 1836, p. 33). nocephalum, the two intestinal tubes have simple In the various species of Mierni.s, there is a dis — caeca upon both sides of their entire length. In tinct mouth, oesophagus and intestine, but this last. Octobothrium lanceolatum, the structure is the ends in a caecum. I have been unable as yet to same; see Mayer, Beitr. p. 21, Taf. III. fig. 3. positively determine a mouth with Gordius aqua — These lateral caeca are more or less ramified in Oc- ticus s; the anus is certainly wanting, and it might tobothrieum palmatum, sagittatum, Merlangi, be questioned if the two tubes which traverse thePsolystomum appendiculatum, and TristomLum body should be regarded as an intestine; see elongatum (Leuckart, Zool. Bruchstticke, Hft. 3, Wie-mansn's Arch. 1843, II. p. 305. p. 26, 51, Taf. I. fig. 4, c. b. Taf. II. fig. 5, d.; 2 With Strongylhts arma.tus, hlypostomus, den — Nordmann, Microgr. Beitr. Hft. 1, p. 79, 81, Taf. tatus, and tetlracfnthts, the entrance of the mouth, V1i. fig. 2, Taf. V. fig. 6 * and Baer, Nov. Act. is provided with a circle of horny teeth, whichl are Acad. Leop. XIII. pt. 1, p. 665, Taf. XXXII. fig. moved by special muscles; see AMehlis, Isis. 1831,. 2). With Distomum hepaticum., these ramilica- p. 78, Taf. II. fig. 5, 6. With Spiroptera stron — tion;s are very fully developed; see M'ehlis, Observ. gylina, I have seen the entire internal surface of de I3istomate, fig. 1, 2, 7, 8. In the very remark- the mouth provided with a spiral, horny swelling.. able genus Diplozoon, the digestive canal consists In Czucullanus, there is a very complicated appaof a single tube which traverses the whole body ratus for opening and closing the mouth, composed. upon the median line, and sends off laterally of solid, horny pieces. ramified caeca, while at the point of junction of 3 With Ang tilltlla ftueviatilis, Oxyueris vermi — the two bodies of the animal it dilates into a stom- cularis, Ascaris acumzinzta, brevic.audata, dacachal cavity i see Nordmann, loc. cit. lHft. 1, tyluris, oxyura, and vesicularis, tie cesophacus p. 67, Taf. V. fig. 2. The blackish ramifications has this enlargement. But it is divided into two of Polystomum integerrimutn, and which have portions by a prominent constriction with CZuc.ulbeen regarded by Baer (Nov. Act. Acad. Leop. lanus elegans, Physaloptera alata, Spiroptera loc. cit. p. 6S2, Taf. XXXII. fig. 7, 8) and other anthuris, europtera, obvelata, and crassicauauthors as a digestive canal, belong to the subcu- da. In Triclzocephalus, it is very long, andt has taneous pigmentary net-work already mentioned. behind very many constrictions, which are succes9 The digestive canal of Trema;odes is usually slve at short intervals; see Mayer, Beitr. &c. Taf. partly filled with blood which they have absorbedl I. II. With Trichosoma falconum, it is equallyand partly with brown or yellowish chyme e it is long and divided into many sections, which give it therefore evident how, from the thinness of its an articulated aspect. walls, it would, when empty, entirely escape the 4 By many Helminthologists this tube has been observation. called oesophagus, and its dilatation stomachus. 1 Among the Nematodes, and Gordiacei, there 10os 114 THE HELMINTHES. 109. tions, and which terminates in a short muscular rectum. The proper intestine is of a brown, greenish, or dirty yellow color, which is due to its walls being formed of compact cells filled with colored granules. The loose and cellular walls, having very feeble peristaltic movements, are surrounded externally -by a kind of dense peritoneum, and lined internally by a very fine epithelium.~) In some species of Ascaris, the intestine is lengthened into a caecum at its junction with the oesophagus.(6) ~ 109. There are observed, here and there, only traces of appendant organs of the digestive canal. In many Trematodes, there are upon each side of the neck, two more or less developed cords or canals, of a cellular aspect, and of a pale yellow color by direct light. They pass towards the mouth, open perhaps into its cavity, and have a function, probably, like that of salivary organs.(l) In many Nemlatodes, two or four caeca extend fiom the cephalic extremity along the oesophagus, and as they open distinctly into the oral cavity, it is, therefore, the more probable that they should be regarded as salivary organs. (2) The same signification should be given to the coecal appendage found in many species of. A.scaris, which extends from the constriction of the oesophagus to the beginning of the intestine.('3 Hepatic organs have been found nowhere but in the Nematodes; but it may be that the granular cells in the thick walls of the intestinal canal, take their place. 5 This epithelium has sometimes special inequali- cates with it directly, and also with two cords ties, which, with Ascaris osculasta, and spic ulige- accompanying the cesophagus. According to him, ra, form a regular zig-zag series, resembling the there is also a similar disposition with Strong-ylos valves of the intestinal mucous membrane of some hypostomus, and tetracanthuls. vertebrates. With Ascaris aucta, they have the Similar appendages, analogous to salivary orform of long, sharp villosities. gans, occur, according to Owesn, in the new genus 6 This caecal appendage, accompanied usually Gznathosonza, as four caeca surrounding the cesowith a constriction of the posterior end of the phagus, and opening into the mouth (Wiegcesophagus, was first observed by Mlehlis (Isis. mann's Arch. 1838, I. p. 134). With Cheiracan1831, p. 91, Taf. II. fig. 16, 17, 18). It is found thus, and Ancyracanthus, there are four similar with many Ascaris, but its length is very variable. organs, and Diesing is certainly in error in In Ascaris heterura, sem7iteres, and ensicaudata, regarding them as analogous to the ambulacral it is very short, and protrudes scarcely beyond the vesicles of the Echinoderms (Ann. d. Wiener Mus. cesophageal constriction; while in Ascaris depres- II. Abth. 2, p. 224, 226, 2285, Taf. XVII. fig. 85, 9, sa, aocrta, angulata, and nmucronata, it reaches to Taf. XVIII. fig. 3). I am disposed to regard as the middle of the oesophagus, and in Ascaris spi- salivary organs, also, the two long caeca which culigera, osculata, and the species described as pass from the mouth along the cesophagus of Filaria piscium,.it extends nearly to the cephalic Stronsgylus strialus. extremity.* 3 I have discovered a similar cesophageal apI These glandular-like organs are often very penalage in a group of Ascaris known as Filaria distinct in'the cercarian larvae of the Trenmatodes, piscioum (Wiegmann's Arch. 1838, I. p. 309); and in many adults of lIonostomtmo, and Disto- such are, Ascaris m:tcronata, angzulata, oscumum; see WiegmannL's Arch. 1843, If. p. 322. lata, spicssligera, at.cta, acus, and labiata. It is 2 Mehlis (Isis, 1831, p. 81, Tatf. II. fig. 6) has remarkable that with the exception o the last two,,observed with Strongylus armattes, an annular all these have also a caecun upon the intestine. vessel surrounding the mouth, which comlmuni* [ 108, note 6.] See, for the alimentary canal lastomum appendiczulatum, there is this pecu-,of ascaris infecta, Leidy (A Flora and Fauna liarity, that the intestine commences by a broad, within living animals, Smithsonian Contrib. V. Art. deeply sinuate, cordiform dilatation, which rapidly 2, p. 43, P1. VI. fig. 1-7). He divides it into a narrows to a short, cylindroid portion, and then strongly muscular gizzard, a cylindroid intestine sends off a long, capacious, gourd-form receptacle, lined with hexahedral epithelium, and a pyriform or diverticulum, and afterwards proceeds backrectum. wards to the rectum, and in its course, in the viSee also his description of that of Streptoso- cinity of the generative aperture, performs a single mnum, Thelastomum, &c. (Ibid. p. 49). In The- short convolution. - ED. 110. THE HELMINTIIES. 115 CHAPTER VI. CIRCULATORY SYSTEIM. ~ 110. Most of these animals have a vascular system. The circulating liquid is usually wholly colorless, and often contains vesicular or granular corpuscles, which are difficult to perceive from their delicacy and transparency. The circulation is due to the general contractions of the body or of the walls of the vessels. In the Acanthocephali, the vessels have no proper walls, but are spread out, as has already been said (~ 106), in the subcutaneous parenchyma.'There are two larger, lateral canals, which pass from the neck to the caudal extremity, sending off laterally numerous small canals, which anastomose with each other. A similar net-work is found in the proboscis through its whole length.(1) These two canals connect also with the lemnisci, upon each side of the neck. These last, of which there are always two upon the,sides of the proboscis, passing from the neck to the cavity of the body, are usually riband-like, and composed of a finely-granulated parenchyma, which, like the cutaneous one, has a system of vascular canals. (2) In most species of Echinorhynchus, this system consists of a main canal upon the border of the lemniscus, from which are sent off inwardly, numerous small branches. These last form the net-work which fills the parenchyma of the proboscis.(3) In many,(4) the lemnisci are surrounded by muscular fibres, which, converging to the posterior extremity of these organs, form two short muscles, which, in their turn, are blended with those passing obliquely to the proboscideal sheath. The point of junction is at a short distance from the place where they are detached from the subcutaneous muscular layer. Each lemniscus is constricted into a narrow neck at its base, which passes into the skin at the base of the proboscis. The junction of the cutaneous with the lemniscian vascular system occurs at this point, as is indicated by the contained liquid passing backwards and forwardsbetween the two from 1 This vascular system, taken by many Hel- norhynchus claviceps, they are longer than the *minthologists for a digestive canal, has been fig- body, and lie coiled in its cavity. In Echinoured by Westrum.b (De Helminth Acanthocephalis rhynchus gibbosus, hystrix. and strLmosus, Tab. II. fig. 10, III. fig. 10, 12, 21), and Burow they are discoid and very short. (Echinorhynchi strumosi Anat. 1836, fig. 1, 8). 3 Echinorhynchuss anzsustoats, haeruca, polyThe movements of the nutritive liquid may be morphues, proteus, and gibbos-us. As a wide distinctly seen by placing these animals alive and exception, the principal canal occupies the median undilated as natural under the microscope. One line of the lemniscii, and sends off laterally small will then be quickly convinced that the circulation branches, with Echinorh/ynchus g-ig'as. Here is due to the general movements of the body. If and there its course is broken by oval, voluminous, Echinorhynchus is placed in much water, the transparent and apparently vesicular bodies. see absorption distends not only the body, but the WFestrumb loc. cit. Tab. II. fig. 7. Similar bodies canals of the vascular system. are so filled that the in the lemnisci and subcutaneous parenchyma, are subcutaneous parenchyma is swollen, and the found with Ech/inorhynchus claviceps; see l4idlskin is raised here and there into vesicles. ler, Zool. Danica. Tab. LXI. fig. 3. These bodies 2 With E chinorhynchus ac onustatu-s, acus, are, moreover, regular neither as to their number fusiformis, proteus, and poly7noslhust, the two nor position, and I have not learned their nature. lemnisci have a riband-like form. In Echino- 4 Echinorhynclhus acus, angustatus, fusiforrh.ynchus gigas, they are very long; and in Echi- mzis, and proteus. 116 THE HELMINTHES. ~ 111. the peristaltic actions of the body and the alternate retraction and protraction of the proboscis.t)1 In the Gordiacei, and Nematodes, no vascular system has as yet been found. Only in a group of species described as Filaria piscium, has there been found a riband-like organ concealed in the cavity of the body, and traversed by a net-work of canals, which resemble those of the lemnisci of' the Acanthocephali.(6' ~ 111. In the Cystici, Cestodes, and Trematodes, the vascular system is well developed. Its canals have proper walls, the contraction of which produces the circulation. In the first two orders, it consists of two pairs of longitudinal canals, which pass along the sides of the body and head, and intercommunicate occasionally, by transverse canals. These four vessels open, in the head, into an annularring which surrounds the proboscideal sheath; there is here, therefore, a completely isolated system.'' In the Trematodes, this system consists of a contractile net-work spread over the whole body; and in which are two larger trunks, which pass along the sides of the neck and body.(') 5 Mehlis (Isis, 1831, p. 82) affirms to have seen Platner (A~iiller's Arch. 1838, p. 572, Taf. on the neck of Echinorhysnchus gigas two small XIII. fig. 4, 5) affirms to have seen semilunar valves. orifices by which the lemnisci open outwards. But at the orifices of the transverse canals of Taenirt I have been unable to see them in this species, or solium. others of this same genus. If they really exist, The four lateral cervical vessels which I havethey will shed light upon the doubtful functions of observed not only in Taenia, but also in Bothriothese organs. From what we know of their struc- cephalus, and Cysticercus, may be traced with ture, it is not improbable that they belong to the perfect distinctness in Taenia cyathiformnis, and nutritive system, and transude a liquid which serrata, to the vascular ring which surrounds the bathes and nourishes the organs in the cavity of proboscideal sheath. With Caryophyllaeus muthe body.* tabilis, and Taenia ocellata, which are without a 6 With the Nematodes, the liquid appears to proboscis, this vascular ring does not exist any transude through the walls of the intestine into the more than with Bothriocephallus; here also the cavity of the body, and there bathe, without a vas- four lateral vessels widely ramify in the head, and. cular system, all the organs. The riband-like organ form by anastomoses, a distinct net-work. Bothfound in the Filaria piscium. (see Wiegmann's riocephalus claviceps has a similar organization. Arch. 1838, I. p. 310), and which I have also found It should, moreover, be here observed that from in Ascaris osculata, has the same vascular rami- the contraction of its very thin walls the vascular fications as the lemnisci of Echinorhynchus gi- system will easily elude the observer. gas, and the vesicle-like bodies are not wanting 2 The vessels of the Trematodes are remarkable upon the course of the principal canal. Perhaps for their prominent flexures; see Distomum cirthey also transude the nutritive liquid, for I have rigerum, tereticolle, duplicatum, and the various not found any communication between them and species of Diplostomumn (Nordma.zsn Microgr. the intestinal canal. Beitr. lHft. 1, Taf. I1. fig. 8, IV. fig. 5, 6). One The two lateral enlargements also, which, as should not confound with the sanguineous vessels,. already mentioned (~ 102), are extended between as has often been done, the very finely-ramified the longitudinal muscles of the skin, have often canals of the excretory organ, which will hereafter been regarded as sanguineous vessels * but I have be mentioned. Thus I think that the vascular observed with them neither longitudinal nor lateral net-work of Distom.um hepaticumn described by canals.t Bojanus (Isis,1820, p. 305, Taf. IV.) belongs to1 These lateral vessels, regarded by some Hel- this excretory organ. Laurer also (de Amphisminthologists as intestinal tubes, give off in their tome conico. p. 10, fig. 22), has not carefully discourse no lateral branches, except these transverse tinguished them; and Nordmann appears to have canals. With the articulated Cestodes, these last fallen into the same error (loc. cit.). are always situated at the posterior extremity of With Diplostomum, the vessels open each side. the articulations, thus giving a ladder-like aspect into a large reservoir situated at the extremity of to the entire vascular system. They are also the body. Between these two receptacles, the; found, however, in Caryophyllaeus nutabilis, excretory organ passes to the extremity of the which is not articulated. body, and Nordmann has taken its orifice as * [~ 110, note 5.] The observations of West- t [~ 110, note 6.] Berthold (Ueber den Bau rumb and Burow on the circulatory system of the des Wasserkalbes. &c. loc. cit.) has described a Acanthocephali, have recently been thoroughly vascular system with the Gordiaceij but Blanchard verified by Blanchard, who has illustrated it with (Ann. d. Sc. Nat. 1849, XII. p. 7) has failed tco excellent figures; see Ann. d. Sc. Nat. 1849, XII. confirm his statements after very careful research. p. 21, and Rigne animal, nouv. Edit. Zoophytes, -ED. P1. XXXV. fig. 2.- ED. 112. THE HELMINTHES. 117 CHAPTER VII. RESPIRATORY SYSTEM. ~ 112. A respiratory system has not yet been found with certainty in the IHelminthes. The pedunculated vesicles of many Nematodes, situated under the skin, and projecting into the cavity of the body, and which have great absorptive power, have been compared to trachean pouches and branchiae; but their structure is so little known, that any opinion as to their function ought to be deferred.(') A remarkable fact is the presence in some Trematodes of extremely active vibratile lobules, situated intermittingly on the inner surface of the walls of the vessels.(2) It may be questioned if these vessels have a special function, different from that of the others. They somewhat resemble the aquiferous system of the Polyps, Acalephs, and Echinoderms, and like it, belong, perhaps, to the respiratory system. They differ, however, in not having openings which communicate outwardly; but, probably, they receive by endosmosis, water absorbed by the skin.(3) But another objection to this view, is, that in this order there has been found nothing like blood-vessels. belonging to the nutritive vessels. The nutritive I am yet uncertain if the vibratile organs found liquid of the vascular system differs from the in the neck of Distomum globiporum and noducoarsely-granulated excretion of the excretory losuum (Wiegmann's Arch. 1836, I. p. 218), and organ, by its homogeneous and colorless aspect. in the parenchyma of Distomzum duplicatum beIt is remarkable that in Distomum tereticolle hind the ventral sucker, are of the same nature. this liquid has a reddish color, which, in the finest Ehrenberg (Wiegmann's Arch. 1835, II. p. capillaries has a yellowish cast * see Wiegmann's 128) was the first who observed this ciliary moveArch. 1835, I. p. 59. ment in the vessels of Diplozoon. When the H. Meckel, likewise, thinks that the above-de- motions of these lobules are free, there is a rapid scribed vascular system of the Trematodes, is in current of the liquid, as Nordmann has remarked direct communication with the secreting organ (Microgr. Beitr. Hft. I. p. 69). But if an animal peculiar to these Helminthes * see Al'iiller's Arch. is compressed between two plates of glass, and 1846, p. 2, Taf. I. fig. 2.* their motions thus impeded, it will be quickly seen 1 Bojanus (Isis, 1821, p. 187, Taf. III. fig. 51- that these last are the cause of the circulation; in 55) affirms to have observed in Ascaris lumbri- fact, when the lobules cease moving, the colorless, coides these pedunculated vesicles, which are homogeneous, and, without doubt circulatory liquid, found also in Ascaris depressa, and Strongylus is no longer perceived. gigas, in connection with the lateral swellings 3 Burmeister (lIandbuch d. Naturgesch. 1837, but this throws no light upon the nature of these p. 528) compares, not without reason, this system vesicles, for we are yet ignorant of that of these to the trachean system of insects, the first being swellings. The stigmata which he affirms (loc. cit. aqueous, and the second aerial respiratory organs, p. 187, Taf. III. fig. 56) to have observed upon thus confounding this vascular system of Helminthese lines with Ascaris acus, are, according to thes with the excretory organ and duct found in my own observations, only subcutaneous cell-like most Trematodes. There may be, however, a combodies. parison between these two systems, if we except 2 I have quite distinctly seen these vessels with the insects with stigmata, and take those which are Diplozoon paradoxum, Aspidogaster conchi- aquatic and have a completely closed trachean cola, Distomusn echinatum, and an allied species apparatus (see below), admitting no air from withof this last from the intestine of Falco apivorus. out. * [~ 111, note 2.] Van Beneden (Ann. d. Sc. with the Cestodes and Trematodes, but see the Nat. 1852, XVIII. p. 23) has recently expressed beautimul piates of Blanchard, Ann. d. Sc. Nat. doubts upon the presence of a circulatory system 1848, X. Pi. XI. - ED. 118 THE HIELMINTHES. ~ 11[. CHAPTER VIII. ORGANS OF SECRET ION. ~ 113. No orga Is of secretion have been found, except in the Trematodes and: Nematodes, In most of the Trematodes, there is, upon the median line of the posterior part of the body, a contractile sac, which usually opens out — wards,'3) at the caudal extremity, and seldom at the posterior part of the back.(2) This sac is single,(3) bifurcate,(4) or multiramlose. In the last case, its branches are spread usually over the whole body.(t) Its walls are quite: thin, and therefore, it is seen with difficulty when wholly contracted or empty. It contains a colorless liquid filled with numerous granules or vesicles, which, during the contractions, pass up and down, or escape.through the external opening.~() This organ is sometimes so crowded with clear, solid corpuscles, composed apparently of earthy matter, that examined by reflected light, it has a cretaceous aspect.(7' In many Nematodes, there is on the ventral surface and at a variable distance from the head, a small oblique opening surrounded by a sphincter. In some species, two canals pass from it and run backwards on each side of the intestinal canal; and in others, there are also two other canals which extend forwards in the same way. The use of the colorless and homogeneous secretion of these organs is yet unknown.(8) 1 This opening, known as the Foramen caudale 5 Beside Distomnum hepaticum, Holostomumr with Distomum, Holostomuzm, Monostomum., urnigerum, the Distoma also with a spinous Aspidogaster, and Diplostomum, has formerly head, have a widely-ramified excretory organ; see been compared to'an anus by Nardo (Heusin- IlMehlis, Isis,1831, p. 182. ger's Zeitsch. fuir organische Phys. 1827, I. p. 68), 6 With the spinous-headed Distomum militare, and by Baer (Ibid. If. p. 197). Mehlis (Observ. and echinatum, this organ is often so reduced in de Distomate,p. 16) having shown that it belonged, substance, that here and there are perceived only in Distomus., hepaticum, to a particular organ isolated groups of the ramified canals. which is ramified like a vessel, has properly re- 7 The solidity of these corpuscles may have been jected this analogy; see Isis,1831, p. 179. With the reason why Ehrenberg (Symb. Physic. Anim. the larvae of Trematodes, known as Cercaria, Evertebr. Ser. I. Phytozoa entozoa) has taken those Bucephalus, and Distomoum duplicatum, the of Cercaria ephemera for eggs, and the two canals base of the tail is thrust into the excretory opening of the excretory organ for ovaries; and why of this organ, and its contents cannot escape until Nordmann (Microgr. Beitr. lift. 1, p. 54, Taf. I. the animal has lost the tail. fig. )) has regarded their escape from the body 2 Amphistomum. with Distomum annuligerusn, as an'act of ovi3 Monostomsumfaba, Distomum cirrigerum, position. Gasterostomun flimbriatum, and Bucephalus The corpuscles of this kind found in the excretory polymorphus. organ of certain Trematodes, as for instance in a 4 Distomum chilostomum, clavigerum, lima, larva of Monostomum known as Cercaria ephemmaculosuzm, tereticolle, variegatum, and many era, remind one from their aspect, of the small species of Monostomum, - where the two closed calcareous subcutaneous bodies of many'aeniae, ends of the sac often extend to the cephalic ex- and it may be asked if they are not an effete matetremity. With Distomum appendiculatum, the rial, which, not being contained in proper organs, two branches of the excretory organ unite directly is with these H-Ielminthes thus subcutaneously behind the oral sucker. With Aspidogaster con- deposited. chicola, it divides into two canals near the Fora- 8 This organ, to which I first called the attention men caudale, which extend to the anterior ex- in the dissertation of Bagge (De evolutione Strontremity. In Amnphistomum, two similar canals gyli auricularis et Ascaridis acuninatae, 1841, p. wind from the head along each side of the body, to 13), is composed of two canals which run backthe middle of the posterior back, where they open wards in Stlrongylts auric laris, Ascaris brevioutwards, after having formed by reunion a pyri- caudata, and acuminata (Bagge, loc. cit. fig. 30, form reservoir. Laurer (De Amphistomo conico. A. B.); and in Ascaris dactyluris, and paucip. 10, fig. 22) has given a figure of this reservoir, para, mihi (from the intestine of Testudo graeca), in which he has confounded the secretory canals of two anterior and posterior canals, the common. with the nutritive vessels. opening of which is near the middle of the body. ~~ 114, 115. THE HELMINTHES. 119 CHAPTER IX. ORGANS OF GENERATION. ~ 114. Although most of the Helminthes propagate by means of genital organs, 7et there are a few species which multiply by fissuration and gemmation. The fisszration is always transverse, and differs from that of the Protozoa and Zoophytes in the fact that complete individuals are not produced, there being only a separation of certain organs from the perfect animal, as, for instance that of the segments of the body in the Cestodes. This fissuration is complete or incomplete. In the first case, occurring in the Taenia, the segments are detached from the body, and continue to live independently, without, however, ever forming a new individual.(l) Gemmation has been observed inthe sexless Coenurus and Echinococcus. In Coernurus cerebralis, it is incomplete. The buds are formed on the internal surface of the parent-vesicle, and never separate from it, nor become perfect individuals. They have only a head and neck which project outwardly after the complete development. In Echinococcus, however, the gemmation is complete. The buds appear as in Coenurus, but the young animals are sooner or later detached and fall into the liquid of the parent vesicle. When completely developed, this vesicle bursts, and they are set at liberty. That their development occurs in this way is shown by their hanging by a cord, which, like the tail of Cercaria, is inserted into a fossa at the posterior extremity of the body. Like this last, also, this cord subsequently disappears, and the young animal moves freely about, by the aid of its double circle of hooks and its four suckers.(2) ~ 115. In those species which reproduce by male and female genital organs, these last are sometimes upon a single animal, and sometimes upon two separate individuals. The eggs and spermatic particles are formed after very different types. In all, the copulatory organs are extraordinarily developed. The Cestodes and Trematodes are hermaphrodites.11' The structure of 1 The imperfect fissuration with Ligula and 2 See Chemnitz, De Iydatibus Echinococci Triaenopholsrus is limited almost to a constriction hominis commentatio,1834 * fliller, in his Arch. of the lateral borders. With Bothriocephaluls 1836, p. CVII.; and Siebold, in Burdach's Physpunctatus, it is only here and there that a ring is iol. II. 1837, p. 183. detached, and over most of the body the transverse 1 According to Nordmann (Microgr. Beitr. lIft. and opposite sulcations do not extend near to the 2, p. 141), Diesing (Ann. d. Wiener Mus. I. median line. With Bothriocephalus tetr-apterus, Abth. 1, p. 9), aril Miram (Nov. Act. Acad. the fissuration is more complete but even here, XVII. pt. 2, p. 636), the male and female genital there are only some incompletely limited rings organs of the genus Pentastomum, classed by among numerous others which are completely so. many modern Helminthologists among the TremaOf all Helminthes the Taeniae have the most todes, are situated upon different individuals. But complete fissuration; here not only is the separa- Owen affirms to have observed the opposite tion of the rings indicated by a complete furrow, (Trans. of the Zool. Soc. of London, 1835, I. p. but the rings are sometimes detached and live thus 325). The only way to settle this point is by independently. The separated rings of Taenia analyzing accurately the contents of these organs; solium, cucumerina, and others, move freely, and a method pursued by Valentin (Repertorium III are FO individualized, that they resemble some 1837, p. 135), who found filamentoid spermatic Tremitodes. particles in the organs of an apparently female X120 THE HELMINTHES. $ 115. the genital organs of the first is yet imperfectly known; while that of those,of the second is well understood. The female apparatus of the Trematodes consists of a germ-forming organ (ovary), with its excretory duct; then, two others for forming the vitellus, which have also excretory -ducts; and then a simple uterus with its vagina. The male apparatus consists of testicles with their excretory canals, an internal seminal vesicle, a cirrhus-sac, an external seminal vesicle, and a penis.(2) The ovary consists of a round or pyriformn (3) reservoir, situated, usually, upon the median line of the body,(4) from which it is distinguished by its pale color and transparency. It is filled with simple round cells — the Yegg-germs. The nucleus of these cells is the germinative vesicle, and the nucleolus, the germinative dot.(5) The short and small excretory duct of the ovary opens at the commencement of the uterus. The organs which secrete the vitellus are two in num*ber, of variable length, and situated upon each side of the body near the dorsal surface; they occupy either the cervical, the central, or the posterior portion of the animal, and sometimes extend over them all. They are;nearly always composed of ramified caeca filled with white, granular. vitelline corpuscles. By reflected light these caeca appear through the,skin as a white, ramified, botryoidal mass,)6) and from each of them, pass -off inwardly, numerous excretory ducts, which reunite opposite the ovary -into two common canals. These last approach each other transversely, and form a single canal upon the median line, which, after a short course,,opens at the bottom of the uterus by an orifice which is common to it and the ovary.(7) Pentastomum taenioides, organs which are re- representing a vitellus. But in the other Trema-,gard(led by Diesing as caeca for secreting the en- todes it is so thin as scarcely to be perceived. velope of the eggs. 6 With the following Trematodes there is a wide Since all the parts of the genital organs of Pen- deviation from this usual arrangement. In Dis-.tastomum have not been examined with this same tomsum longicolle the organs producing the precision, I can give no opinion as to their use.* vitellus are two simple round caeca located behind 2 See Siebold, in Wiegmann's Arch. 1836, I. p. the ventral sucker * in Distomumocygnoides, 217, Taf. VI., and in MIuller's Arch. 1836, p. 232, they are two very small deeply-fissured bodies; Taf. X. fig. 1. and in Distomum gibbosum, there is one only, 3 The ovary here is always smaller than the which is star-shaped and located at the middle of testicle, and sometimes as to form very closely the body. resembles it, as in Distozoum globiporum, and 7 These organs, until now regarded as ovaries, ilongicolle, mihi (from the urinary bladder of secrete only vitelline cells. With most Trematodes Cottus gobio); consequently it may easily be their nuclei are clear, and have been taken for ~taken for a third testicle. eggs. In eggs recently formed, one can always 4 With Monostomum, it lies wholly at the pos- distinguish these cells from the germs. In passing terior extremity. the excretory canals they are compressed and 5 In Polystomum, Octobothrium and Diplo- elongated, but never run into each other. When zoon, the germs are so large that they may easily these canals are crowded, they have the aspect of'be taken for perfect eggs. white cords, which have often been taken for There is here, moreover, between the cell-wall nerves. But when they are empty, they, as well.and the nucleus (the germinative vesicle), quite a as the vitellus-secreting organs, are almost invis-,thick layer of albuminous substance, somewhat ible.t [~ 115, note 1.] See upon this subject Van studied, you first notice the germs as nucleolated,Beneden (Ann. d. Sc. Nat. XI. 1849, p. 326), who cells, of which the nucleus is the future germinahas described in detail the sexual organs of Lin- tive vesicle and the nucleolus the germinative dot. guatula Diesingii, and has shown the sexes to be These cells increase in size, and as they move:separate. See also my note under ~ 99.- ED. along there appear in the liquid which lies between t [~ 115, note 7.] To say that certain organs the nucleus and the cell-wall minute granules -secrete vitelline cells, is a little obscure, and no which ultimately become cells; in this way the doubt Sicbold intended to convey the meaning vitellus is formed, the formation being enCogenous that they secreted the plastic material out of which and not exogenous. These special organs or these cells are formed. I make this perhaps tubes therefore are vitellus-forming organs, in virseemingly unnecessary reference to the matter, tue of their secreting the formative material out -since it concerns the subject of the development of of which the vitellus is formed within the original,;the ovum. In the Ascaris, where the origin and nucleolated germ-cell. - ED. ~development of the ovum can be satisfactorily Af 115. THE HELMINTHES. 121 The neck of the internal seminal vesicle (Vesicula seminalis interior), discharges its contents at this same place into the uterus, through a special Vas deferens from one of the testicles. The Uterus commences as a narrow'tube, which may be regarded as a Tuba Fallopii. Its dilated portion, which has powerful peristaltic motions notwithstanding its thin walls, is throughout of nearly an equal diameter. It winds through a large portion -of the body and terminates in a narrow, more or less straight, muscular vagina, which always opens externally by the side of the penis.(8) The testicles, of which there are usually two,(9) are generally of a round or oval form,(l) and located in the posterior region of the body, nearly always one before the other.(" They are transparent and colorless, and -the filiform spermatic particles are extremely small and active. (12) The -two Vasa deferentia open into the cirrhus-sac, which is perforated at its'bottoml to communicate with the Vesicula seminalis exterior.(13) From,each testicle there passes off, also, a third Vas deferens which opens into the neck of the lesicula seminalis interior.(141 The cirrhus-sac is pyri~formly elongate, or round,(1) and the Vesicula seminalis exterior is always situated at its base. This last is prolonged, opposite the openings of the vasa deferentia, into usually a very long, tortuous Ductus ejaculatorius, which opens into a tubular penis.(') There is one common genital opening for the penis and vagina which are usually side by side, and out of which the penis often considerably projects.(") In most Trematodes, these two organs are located at the anterior extremity of the body, and only in Holostomunt, and Gasterostomum, are they removed to the other extremity. (1) 8 The length of the uterus varies very much in perceived unless they are quite isolated. When lifferent genera and species, and its coils are put in water they become twisted together, and always irregular. With Monostomum mutabile, assume a loop-like arrangement, - their motions and verrucosum, the oviduct arising in the poste- instantly ceasing. xior extremity, passes in front with numerous For the development of the spermatic particles transverse coils. of the Trematodes, see Kdlliker, Die Bildung du 9 I have found one testicle only, in Amphisto- Saamenfiden in Blischen, loc. cit. p. 44, fig. 31.*:mnu subclavatum, and Aspidogaster conchicola, 13 These two vasa deferentia are sometimes although I have seen three or four in Distomum blended together before reaching their destinazappendiculatum, and cygnoides. tion; this is so in Distomum variegatum, and 10 With Distomumn oatusm, the two testicles are longicolle.:side by side behind the ventral sucker; with Dis- 14 The internal seminal vesicle is so extraordi-.tomum chilostomum, they are on each side of this narily large in Distom.um, variegatum that it sucker, and with Distomumn crassum, mihi (from exceeds that of the ovary and two testicles. the intestine of Hirundo domestica), they are in 15 This cirrhus-sac, together with the penis, is front of it, on each side of the neck. very long with )2istom.um. liza, maculosum, 11 With Distomum longicolle, lanceolatum., variegatum, and ovatum; but it is especially so oxyurum, echinatum, globiporume, and Amphis- with Aspidogaster conchicola, and Monostomum tomnum conicun., the testicles have many depres- verrsscosum. sions; see Bojanus, Isis, 1821, Taf. II. fig. 25-27; 16 Tihe protruding cirrhus or penis of Distomum Burmneister and Siebold, in Wiegmann:s Arch. holostomuzm is provided with small bunches; and 1835, II. Taf. II. 1836, I. Taf. VI.; also Laurer, that of 2lonostomum verrucosum with numDe Amphistomo conico. fig. 21, 24, 25. With berless little warts. Amphistomum. subtriquetrum, gig anteum., and 17 When the penis is protruded, it may then be Distomum hians, the number and depth of these seen how the contents of the vagina are emptied at depressions gives the testicle the aspect of a bundle its base. When the common genital opening is of caeca; see Bojanus, loc. cit. Taf. II. fig. 14-17, closed, the very flexible penis can be turned into the and Diesing Ann. d. Wiener iMus. I. Abth. 2, vagina and there discharge its contents, and in Taf. XXII. this way the self-impregnation of these animals 12 In the testicles of the Trematodes, the devel- may occur. opment of the spermatic particles occurs after the 18 The common genital opening is usually situsual mode. uated on the middle of the neck, and with DisThe bundles which they form are separated in tomum, it is directly in front of the ventral sucker. their passing the vasa deferentia, and they collect With Distomuml clavigerum, and ovatum, it is into irregular masses in the seminal vesicles. upon the sides of the neck, and with Distossum Their extremely active movements cannot be caudale, and holostomum, exceptionably, it is onf * [~ 115, note 12.] Thaer (Miller's Arch. 1850, ured the spermatic particles of Polystomum app. 602, Taf. XXI. fig. 19) has described and fig- pendiculatuLm as Cercaria-form. - ED. 11 122 THE IELMINTIHEIS i. 115. In the terminal, constricted portion of the uterus, egos, vitelline cells,. and spermatic particles are often found mixed together. It is probably here that the eggs are formed, their fecundation occurring without copulation, and by means of the Vesicula seminalis interior. The succeeding folds of the uterus contain already, nicely-defined, oval eggs containining a germ and many vitelline cells. Their recently-formed envelope is still colorless, and so thin and flexible, that the peristaltic contractions of the uterus give it a variety of forms. But in passing from the uterus they lose this flexibility; their envelope becomes more solid, - of a yellow and then a brown color; and the whole, at the same time, undergoes a decrease in size, due probably to a condensation of their substance. The eggs of most of the Trematodes have an opercular opening at one extremity.'l' In the Cestodes, the walls of the genital organs are so very thin, and so intimately blended with the parenchyma of the body, that their structure and relations have not yet been well made out. With the exception of in Caryophyllaeus,(20) these organs are repeated many times one after another, having in the same individual different degrees of development. They are-always most complete in the posterior portion of the body, being only rudimentary near the neck, while in the neck itself they do not exist at all. In the articulated Cestodes, each ring contains both male and female sexual organs; and in their two Groups, the arrangement of these is the same as in the Trematodes. It is probable that the ovaries and the secreting organs of the vitellus are separate. (2) In Ligula, Triaenophorus, and BothriocephaZus, the uterus consists, exactly as in the Trematodes, of a very tortuous tube filled with oval eggs.(22) But in the posterior extremity of the body. Its position ferent form * they are oval and colorless, and at is indicated, even when the penis is not protruded, each extremity have two papillae, which are gradby a small papilla. ually developed into very long, sharp appendages; With Octobothrium, and Polystomum, there see Dujardin, Hist. Nat. d. HIelminth. P1. VIII. is a round muscular sac concealed directly behind fig. G, B. 3.* this opening, which contains a circle of delicate 20 With Caryophyllaeus mttabilis, there is only horny ribs, the lower extremities of which are a single cirrhus-sac upon the ventral surface of the bifid and form a support like a bownet. Mayer posterior body, and from which a delicate long (Beitr. loc. cit. p. 21, Taf. III. fig. 3, 6) has seen penis often protrudes. ten similar ribs with Octobothrisum lanceolatum. 21 I think I have seen an ovary in each of the I have found eight with Polystomzum integerri- segments of Bothriocephaluspunctatus, and Taemcum, and forty with Polystomum ocellatum. nia ocellata. As such, ought, perhaps, to be reTheir use is wholly unknown to me. garded those organs which Eschricht (Nov. Act. 19 The eggs of the Trematodes have apparently Acad. Leop. XIX. Suppl. 2, Tab. I. fig. 2, e, e) only a single envelope. Among the normal eggs in has considered with Bothriocephalus latus to be the uterus may often be found others which are real- ovaries. The organs secreting the vitellus are a formed, also very irregular bodies of a yellowish or mass of irregularly arranged granulations situated brown color, formed almost entirely of the sub- upon both the dorsal and the ventral surfaces, and stance of these envelopes. These bodies were which have very fine excretory ducts. This mass, most probably secreted by the walls of the uterus called by Eschricht (loc. cit. p. 25, Tab. I. fig. 5) (the Tuba Fallopii) at a time when the ovaries and the ventral and dorsal granules, cannot, together the secreting organs of the vitellus were inactive, with its excretory ducts, be made out, except when so that the substance of the envelopes was hard- filled with the vitelline substance. With Taenia ened before receiving their usual contents. With ocellata, the vitelline organs are limited to the Amphistomsum subclavatum, Octobothrium lan- sides of each segment, at the anterior border of ceolatum, Polystomum integverrimum, and ocel- which two main excretory ducts are easily seen; latum, and Diplozoon paradoxum, the eggs are these form a single short canal in the middle of the very large, and in the last-named species their ex- body. In this same place are two transverselytremities are narrowed and lengthened into a spiral placed oval sacs, and which are probably the two filament, wherefore one of these eggs has been taken ovaries. for a testicle and penis * see Nordmann Microgr. 22 The uterine convolutions are generally in the Beitr. Ift. 1, p. 73, Taf. V. VI. fig. 1, h. also Vogt, middle of the body, and when filled with mature in Miller's Arch. 1841, p. 34, Taf. II. fig. 11. eggs, appear through the skin as a brown rosette The eggs of Monostomunsz verrucosum, and see Eschricht loc. cit. Tab. I. II. (Bothriocephasome other species of this genus which live in the l-us lats). intestine of Clielonia esculenta, have a very dif* [~ 115, note 19.] See also for the structure of p. 602, Taf. XX. fig. 17 (Polystomum appendithe genital organs Thaer, Miller's Arch. 1850, culatum). - ED. 115. THE HELMINTHES. 123 Taenia, it is a reservoir, composed of numerous ramified coeca, and intimately blended with the parenchyma of the body.(3) The vagina is a narrow, muscular canal, which usually opens close to the penis by a special orifice (Vulva), or by a common genital opening (Pores genitalis). It is difficult to decide whether the testicles, which always form the middle layer of the body, consist of a collection of inter-opening caeca, or of a single spirally-rolled tube. The cirrhus-sac with the Vas deferens opening at its bottom, is always very distinct. As in the Trematodes, it has a Vesicula seminalis, with a Ductus ejaculatorius and a muscular penis. (24) The contents of the different canals, the seminal vesicle and the ejaculatory duct, are always very active, filiform spermatic particles.t (2 The genital openings are upon the middle of the ventral surface, or on the lateral borders of' the body; but in those species where the sexual openings are separate, they are lateral for the male, and ventral for the female.(t') The eggs of the Cestodes, situated like those of the Trematodes in a spiral, pouch-like uterus, have also a similar structure. Their simple, oval, brownish-yellow envelope, has also, sometimes, an operculum. The eggs of Taenia have a very different structure; the envelope is colorless, and of a very variable, and sometimes quite remarkable form.(2T) 23 With most Taeniae the borders of the cellular gilis, proboscideus, rugosus, and with most Taeuterus are very difficult to distinguish. But its niae, the cirrhus-sac and the vagina open by a lateral caeca with Taenia ocellata, and its arbo- common genital orifice upon the lateral border, rescent divisions with Taenia solium, are very and usually through a papilla. Mith Taenia easily seen; see Delle Chiaje, Compendio di cucumerina, and bifaria, mihi (from the intestine Elmintografia umana, Tav. III. fig. 10. of Anas leucophthalmus), I have found an orifice 24 The cirrhus-sac is either short and pyriform, of this kind upon the two lateral borders of each or very long. With very many Taeniae, as with segment, and behind which were the genital orTaenia amphitrica, lanceolata, multistriata, gans.t scolecina, and setigera, the penis has numerous 27 Although I have not seen either the germinasmall spines pointing backwards see Dujardin, tive vesicle or dot in the eggs of the Cestodes, list. d. Helm. Pl. IX.-XI. That of Taenia probably from their delicacy, yet I do not for a infundibuliformis is surrounded with very large moment doubt their presence there, since Kolliker bristles; and according to Dujardin (loc. cit. P1. (Muller's Arch. 1843, p. 92, Taf. VII. fig. 44) has IX. B. 210) this is also true with Taenia sinuosa. seen them in the eggs of a Both/riocephalus. 25 By very slight pressure, the spermatic parti- Many species of this genus produce oval eggs cles contained in the Vesicula seminalis of the which have a simple brown envelope. Of an oval cirrhus-sac are pressed out through the penis; form, but colorless, are those of Caryophyllaeus, this is so with Bothriocephalus punctatus, latus, Lisula, Triaenophorus, Taenia literata, and Taenia cucumerina, planiceps (from the intes- scolecina. Those of Taenia amphitricha, bifatine of Hirundo urbica), inflata, pectinate, ser- ria, macrorhyncha, serpentulus, and serrata, are pentruaus, and villosus. As with the Trematodes, round, and have two colorless envelopes; this is true the spermatic particles here cease to move when also of the oval eggs of Taenia angulata, villosa, put in water, and are twisted into loops.* e4c. There are three of these envelopes with, the 26 With Ligula, Bothriocephealus nodosous, round or oval eggs of Bosthriocephalus infundibullatus, claviceps, ditremus, punctatus, and te- ifor7nis, probosce'deus, Taenia porosa, lanceotrapterus, the two genital openings are situated lata, ocellata, setigera, and soliumm. With Taeon each side of the ventral surface, while the penis nia infundibuliformis, and planiceps, each exprotrudes from a special opening directly in front tremity of the envelope is lengthened into a long of the vulva ~ see Mehlis in Isis, 1831, Taf. I. fig. and delicate appendage. Two similar but fibril1, 2, and Eschricht, loc. cit. Tab. I. fig. 5. lated appendages exist upon those of Taenia With Bothriocephalus punctatus, there are variabilis. With Taenia cyathiformis, the extwo pairs of these openings upon each segment, ternal pyriform envelope of the eggs has, at its one under the other, but in Bothriocephalus te- attenuated extremity, two round, bladder-like aptrapterus, these are side by side. With Triaeno- pendages. Dujardin (Hist. d. HIelm. P1. IX.phorus, nodulosus, and Taenia ocellata, the vulva XII.) and I (Burdach's Physiol. 1837, II. p. 201) is upon the ventral surface, and the penis upon have seen many other forms with the eggs of the lateral border. With Bothriocephalus fra- Taenia. The round and doubly-enveloped eggs ~ [ 115, note 25.] I have observed the de- years, by Blanchard (Ann. d. Sc. Nat. X. 1848, velopment of the spermatic particles with Taenia. p. 321) and Van Beneden (Hem. Acad. Belgique, They are developed in special cells, and before 15850, XXV.) and the sexual parts pretty clearly they have escaped,are therein coiled up resembling made out. They both agree that, internally, the those of the coleopterous insects. They are simply male and female organs are wholly distinct, and filiform. - E. therefore that impregnation of the ova must be by t [ ~ 115, note 26.] The Cestodes have been the self-copulation. - ED. objects of much careful study during the last few 124 THE HELMINTHES. ~ 116. ~ 116. In the Acanthocephali, the genital organs ccupy a large portion of the cavity of the body. They arise in the posterior portion, and are supported by a Ligamentum suspensorium, which extends from this last to the base of the proboscideal sheath. In the females, there are neither proper ovaries, nor an uterus; but in their place there are numerous oval, or round, flattened bodies of considerable size, which float fireely in the liquid of the cavity of the body; they have nicely-defined borders, and are composed of a vesicular, granular substance, and, as eggs are formed within them, they may be regarded as so many loose ovaries.(') When the eggs have reached a certain size, they fall from the ovaries into the cavity of the body. At this time they are ovo-elongate, have only a single envelope, and contain both a vesicular and a finely-granular substance, but no trace of a germinative vesicle. They continue to increase in size, and two new envelopes are formed about them.(2) The muscular canal which passes off from the simple vulva which is situated at the posterior part of the body, may be regarded as a uterus. At the point where it is attached to the Ligamentum suspensorium, it becomes a campanulate or infundibuliform organ, whose borders float freely in the cavity of the body, and thus the whole is comparable to a Tuba FalIopii. The bottom of this bell-shaped organ communicates with the superior extremity of the uterus by a narrow, valvular opening, which presents a lateral, semilunar fissure. This whole organ is endowed with very active peristaltic motions, by which the loose contents of the cavity of the body are absorbed; and while the larger ovaries are thrown out, the little immature eggs are returned into the cavity of the body by the lateral fissure, - the more mature ones only, reaching the uterus.(3) This uterus, which is of variable length, opens outwardly through a very short and narrow vagina. The males of Echinorhynchus have usually two oval or elongated testicles, one before the other, and attached to the Ligamentunt suspen.sorzum. of Taenia cucumerina (Creplin, Observ. de 2 The long eggs of many Echinorhynchi are Entozois fig. 12, 13) and crateriformis, have the formed bxthe same process. They are all colorless, remarkable arrangement of being grouped in tens and may be distinguished by the peculiar aspect to twenties, and each group is surrounded by a of their middle envelope which at both extremities gelatinous envelope.* is constricted like a neck. But those of Echivno1 The ovaries of Echinorynchus were formerly rhynchus gigas form an exception; for they are taken both for mature eggs, anti for cotyledons; shorter and oval, their middle envelope is yellowish, and to this is due the very inaccurate figures of and, like the two others, has externally numberless them by Westrumb and Cloquet (loc. cit.). Du- small obtuse spines. With Echinorhynchus strujardin, however (Hist. d. Ielm. Pt. VII. fig. D. mosus, hystrix, angustatus, and proteus, the 6), perceived their true nature. external envelope of the eggs presents the peculiar A state of development which I have observed phenomenon that when pressed between two plates with many females of Echinorhynchus gibbosus, of glass, it separates into very fine fibrillae. would appear to throw some light upon the ques- 3 The nature of this campanulate Tuba Fallopii tion as to the part of the body where the ovaries has been wholly mistaken by Bojanus, Westrumb are first formed. Here the Ligamentum suspen- and Cloquet. Burow (Echinorhynchi strumosi sorium had, over most of its extent, large granu- Anat. p. 22, fig. 1. g, fig. 6) was the first to lar globules, while the cavity of the body contained describe it, without however conveying the correct neither ovaries nor eggs. I think, therefore, that idea. See my description (Burdach's Physiol. this ligament is the elementary material from which loc. cit. p. 197), which has been confirmed since the ovaries are developed under the form of glob- by Dujardin (Hist. d. Helm. p. 495, PI. YII. fig. ules, which, being subsequently detached, continue D. 5). their development in the liquid of the cavity of the body. * [~ 115, note 27.] See Van Beneden (loc. cit. composed like those other animals, — with a germinp. 67), who has observed the eggs of the Cestodes ative vesicle, &c.- ED. ~ 117. THE HELMINTHES. 125 They send off two varicose Vasa deferentia to the posterior portion of the body, where, after uniting very probably with the neck of an odd elongated vesicle (Vesicula seminalis?),they are prolonged into a copulatory organ.(4) There are six pyriform bodies,which secrete a finely-granular substance, and are attached behind the testicles to the Vasa deferertia. Their six excretory ducts successively unite, ending finally in two which open into the copulatory organ.(5) The penis is usually folded inward, but when projecting outwardly, it is a muscular, cup-shaped appendage, whose fossa receives the posterior portion of the body of' the female during copulation. (6) The spermnatic particles are developed after the usual mode; they are filiform and very active, and quickly die in water, interlooping and twisting together.(7) The very adhesive, viscous, yellowish-brown wax-like substance, often found about the vulva, is apparently the secretion of the pyrifolrm bodies during copulation.~1) ~ 117. With the Nemiatodes, the genital organs consist of a long, simple or partly double caecal tube, which winds around the straight intestine. In the female it has the following parts: Ovariunm, Tuba Fallopii, Uterus, and Vagina; and in the male, Testes, Vas deferens, Vesicula serninalis, and Ductus ejaculaltorius. With Trichosoma, Trichocephalus, and Sp/haerularia, the genital tube is simple in the females, and usually so in the males. But in Filaria, Ascaris, Strongylus, Spiroptera, OxyzLris, and Anguillula, the ovary, Fallopian tube, and uterus, are double.'1 In the females, the ovary is the posterior portion of this genital tube, and in its terminal portion are small round 4 With Echinorhynchus strumosus, these two and Ascaris paucipara, I have found the female round testicles are side by si(le. Having always organs likewise simple. When these organs are found the odd, long vesicle empty, I cannot decide double, either one uterus with its ovary and oviwhether or not it serves the function of a seminal duct passes in front from the simple vagina, while vesicle. the other passes behind, as is the case with Ascaris 5 These six pyriform bodies were formerly taken brevicacsdata, sig'rovenosa, Oxyssris vermicufor seminal vesicles i see Westru.nb, tde Ielminth. laris, Spiroptera atrthluris, Strosngyls a corictuAcanthocephalis, p. 55, Tab. III. fig. 24; and laris, and striatus; or both pass side1 by si(de Nitzsch, in Ersch and oGruber's Encyclop. TII. behlindl, as in Ascariss aueta, mnystax, sluTbrsi1821, plate for the Acanthocephala, fig. 2, 3, i. coides (Cloquet, A'nat. &c. P1. I. fig. 2) and ausWith Ecninorhynchuss claviceps, I have found cul/tal. With Cucullanus eleOgans, and mssicroonly one of these bodies. cephalus (from the intestine of Ensys Istaria), 6 The copulatory organ, which protruded has the uterus alone is double; one horn terminrlating mostly an oblique direction, has been very exactly posteriorly in a caecum without an ovary or Fallofigured by J)Lujardin (Hist. d. HIelm. p. 493, PI. pian tulbe, while the other, which has these parts, YrII. fig. D, 1, D, 2). passes in front. There are, moreover, species of 7 For the spermatic particles of the Acanthoce- Ascaris into whose vagina open three eo four geniphali, see my observations in Mziller's Airch. tal tubes. Thus with Ascaris soicrocephala, I 1836, p. 232. have seen the uterus divide upon reaschiing the 8 This waxy substance incrusts sometimes the vagina into three tubes, each having an ovsary anti whole caudal extremity of females * this is so with oviduct. Accordling to lVatlhusizts (fVieTmsans's Echinorhynchus gigas, and globocaudatus; see Arch. 1837, I. p. 57), the uterus of F/ilaria labiata, Cloquet (Anat. &c. &c. p. 100, P1. IItI. fig. which is at first simple, divides at its posterior ex4, 5) and Nitzsch (Wiegmann's Arch. 1837, I. tremity into five tulbes. p. 64.* T'he double uterus of Strongylus intfexus has, 1 For the simple genital tube with its various posteriorly, numerous constrictions, giving it a parts of the female of Trichocephalus dispar, see moniliform aspect. Mlayer, Beitr. &c. Taf. IL. With Filaria rigida, * [ 116, note 8.] For some further details on animal nouv. edit. Zoophytes, P1. XXXV. fig. 3b,. the genitalia of the Acanthocephali, see Blanchard 3c, 3,1, 3e, 3f). -ED. (Ann. d. Sc. Nat. 1849, XII. p. 23), and Rhgne 11* 126 THE HELMINTHES. ~ 117. cells; in the anterior portion, these cells are more numerous and begin to be surrounded by a granular vitelline substance, in which the primitive nucleated cells are still seen; these cells therefore, ought perhaps to be regarded as germinative vesicles. In front, these eggs, which are of a discoidal form, are arranged in a row, or are grouped closely around a rachis which traverses the axis of the ovary. In the Fallopian tube, which may be known by its less diameter, the eggs become more mature, and, having been surrounded by a double colorless envelope, pass into the base of the uterus. 21 This last is the largest portion of the genital tube, and is distinguished by its well-makrked power of peristaltic action. The vagina, which is distinguished from. the uterus by its narrowness and its muscular walls, opens at very different points of the body. Generally, as for instance in Ascaris, Spiroptera, Strongylus, Oxyuris, Cucullanus, and Trichocephalus, the Vulva, consisting of a transverse fissure, and often surrounded by a very remarkable fleshy swelling, is situated either a little in front of, or near the middle of the body; but sometimes it opens just in front of the anus.(1) The sperml is usually so accumulated in the bottom of the uterus, that this is probably the locality of fecundation.4) In the males, the posterior portion of this tube is the testicle; another portion of it, which is short and constricted, is the Vas deferens, which passes into a dilated portion,- the Vesiczda seminalis. Usually this last is separated by a constriction from the Duzctus ejaculatorius, which opens into another muscular tube (sheath of the penis).(0) At the anterior portion of this last, is a horny, copulatory apparatus. The simple or double penis is of variable length, and is protruded by the muscular contractions of its sheath through the external opening, which is always situated at the poste2 The formation of eggs in various Nematodes borders of the vulva appear quite swollen. With has been described by Siebold (Burdach's Phys- Trichosoma, this swelling is so attached to the iol. loc. cit. p. 208), by Bag'ge (Dissert. de. Stron- vulva as to resemble a prolapsus of the vagina gylo, &c., fig. 1-5), and Kslliker (AMiiller's Arch. (Dutjardin, Hist. d. Helm. P1. I.). 1843, p. 69, Taf. VI; fig. 20). I have found a With Filaria attenuata, inftexo-caudata, mihi rachis in the ovaries of A4scaris atcta, luanbri- (from the pulmonary cysts of Delphinzus phocoides, mystax, osculata, Ciucullanus elegans, caena), and papillosa (see Leblond, Quelques and Stronzgylus infiecxus. The eggs of these, mat6riaux pour servir a l'histoire des Filaires et while yet immature and flattened, have a point on des Strongles, 1836, P1. II. fig. 1), the vulva is at one of their extremities by which they are attached the side of the mouth. to the rachis. With Strongylus paradoxus, it is swollen to the With those of 4scaris lusmbricoides, this point form of a bladder, and is situated near the caudal is very long during a certain period of develop- extremity; while that of Ascaris paucipara is ment, and the opposite end has many deep sulca- directly upon the anus. tions, giving it a remarkable appearance; see 4 See Bagge, loc. cit. p. 12; and K6lliker, in Hesnle, in MAiiller's Arch. 1835, p. 602, Taf. XIV. Miiler's Arch. 1843, p. 72. fig. 11. 5 For the male genital tube, see Mayer, Beitr. In the mature eggs, which are nearly always oval, Taf. I., and Cloqsuet, Anat. &c. P1. I. fig. 5, P1. it is rare that the double colorless envelope can be II. fig. 8. As yet I have observed only a few clearly perceived. With Trichosoma, and Tri- exceptions to this typical form with male Nemachocephalus, there is a short diverticulum at each todes. extremity of the egg. But in Ascaris dentata, With Filaria attenuata, the posterior portion there is at this same place a long fibrillated filament; of the testicle is bifulcate, and with Ascaris vesisee Mayer, Beitr. Taf. II. fig. 8, and Kol/liker, cularis, there are two moderately large caecal proin Miiller's Arch. 1843, Taf. YI. fig. 16-19'.* longations which arise from the Vesicula seni3 With Ascaris dactyluris, Cucullansus ele- halis at the place where it empties into the Vas gans, Strongylus nodularis, and striatus, the deferens. * [~ 117, note 2.] Primitively, the ova of Asca- become developed into cells, and in this way the ris consist of nucleolated cells, which are polyhe- mature ova are formed. Probably no better opdral from mutual pressure. These increase in size portunity is afforded to perceive that morphologigradually, in their passage down towards the ovi- cally the ovum is at first only a nucleolated or duct, and the granules of the liquid lying between nucleated cell; see Leidy, loc. cit. p. 43, P1. VII. the nucleus or germinative vesicle and the cell-wall fig. 14, c. — ED. 117. THE HELMINTIIES 127 rior portion of the body.G) It has a great variety of forms, and from its iioeatlh arise two antagonistic muscles, which are inserted at its base.7 The -,psoaitic particles, which are always motionless, have usually a cell-form, or,( t least, are never filiform corpuscles.(8) For aiding the union of the;S'xe s during copulation, the males have lobular appendages, papillae. and suckers, situated about the genital opening. Without doubt, the spiral posterior extremity also of the animal, is often used for the same purpose. Moreover, in many instances, there is secreted a wax-like substance intended to fasten the two sexes together."~i 6 According to Leblond (loc. cit. p. 20, PI. III. nuclei with their nucleoli are first formed; afterfig. 1), both the male and femnale genital openings wards these nuclei are surrounded by a finelywith Filaria papillosa are quite near the oral ori- granular substance around which the cell-memfice. I have been unable to confirml this observa- brane is formed. tion, at least with Filaria attesnuaft, iqlexo-cau- In this state the testicle exactly resembles an data, and another species found in the thoracic ovary filled with germinative vesicles and eggs. cavity of Sturnus vulgcaris. Still later, the parent-cell membrane increases more 7 With Trichocephoiaits, and Trichososma, the and more. and the granular substance is found penis is simple and very long, and, beside the mus- only upon the internal surface of the cell. During.cular sheath, has anotlier which is membranous, these changes, the nucleus which resembles a gerand sometimes covered with small spines pointing minative vesicle, is transformed into a long, solid, backwartds. This sheath, being folded outwards and neatly-circumscribed corpuscle. With Strohzwhen the penis is protruded, is comparable to a gdtlus ausricularis, the spermatozoal [daughter?] Praeputium; see lAfayer, Beitr. loc. cit. Taf. I., cells are pyriform; and with Oxtyuris amobipita and Dujardin, Hist. cl. Helmn. P1. I.-III. With their form is similar (Kollikcer, loc. cit. p. 73, Taf. nearly all the other Nematodes the penis is double. YII. fig. 26). It is very long with Ascaris acuminata, brevi- It is very probable that Mayer's assertion (Neue eaudata, depressa, spiculigera, and Strongylus Untersuch. aus dem Gebiete der Anat. u. Physiol. paradsoxes; but is very short with Ascaris ensi- 1842, p. 9) that he had seen thread-like spermatic eaudata, semiteres, Cucullanues elebans, Fila- particles with OxyuLris vermicularis, has leci ria attenuata, insfexo-caudata, Spiroptera an- Kolliker to regard. these pyriform cells as so mar r tihuris, and Stronzgylus iiflexous. With Spirop- bundles of filanmentoid spermatic particles. But tera, the two penises are of unequal length, and never have I seen filaments of this kind in the Newith Ascarispaucipara, brevicaudata, and StroA- matodes. gylees, there is an additional horny piece like a The pyriform spermatic particles of Strongylius third penis. auricularis, which have a short peduncle, as well With most Nematodes, the penises are sulcated, as the round, cell-like, and nucleated ones of Asand those of Strongglus have a singular form due caris aczeuminata, have been figured by Reichert to the presence of numerous appendages. The two (Beitr. zur Entwickel. der Saamenkl rp. bei den delicate, retractor muscles of this organ, arise from Nematoden). This same naturalist has shown that the internal surface of the cavity of the body, and these spermatic particles arise by endogenous genwhen the penis is double there are two pairs. eration, by fours in each cell; see Ml/ller's Arch. With Ascaris osceulata, veszcularis, and spicu- 1847, p. 88, Taf. VI.* li-era, I have found these four muscles very long. 9 The large caudal valve of the irmale Stron gyus, See upon the penis of the Nematodes, lMayer, and the spiral tail of the male Spiroptera, may be B3eitr. Taf. I., and Dujardin, -Hist. d. Helm. P1. here instanced. With very imeany male Ascaris, I.-VI. there are two rows of papillae upon the sides of hle 8 For the spermatic particles of the Nematodes, genital opening, and with iscaris vesicularis,,see Bagge, Dissert. de Strongylo, &c., p. 12, and isflexoa, I have found a copulatory sucker fig. 27, 28. The development of these cell-like directly in front of this opening. The male of spermatic particles may be easily observed with Hedrluris ansdrophora winds himself about the Ascaris paucipara, where the parent-cells are female during copulition, and the caludal valve of very large. In the posterior end of the testicle the the male Strongylus trachealis glues itself so * [~ 117, note 8.j The statement here made that daughter-cell (see my Memoir, The Origin, DeReiceert has observed the development of the velopment, and Nature of the Spermatic Particles.spermatic particles of an Ascaris by fours in each in the four classes of Vertebrata, in the Mene. cell, deserves attention from its histological relation. Amer. Acad. of Arts and Sc. V. 1853). The view According to my own observations,the histological of Reichert, therefore, that four spermatic partiformative conditions of the development of the cles are here formed in one cell, does not appear to spermatic particle are exactly analogous to those me admissible, although I have no observations of the development of the embryo. The nucleus upon the instance in question. It appears to me of the sperm-cell divides or segments like the vitel- explicable in this way: the nucleus of the parent lus of the ovum, and this process continues until sperm-cell underwent here only a second segmentthe sperm-cell which has now attained a large size, ation, thereby only four daughter-cells being prois filled with numerous small nucleated cells duced. The nucleus of each of these became a (daughter-cells); and the nucleus of these last is spermatic particle, and these four particles passed changed into the spermatic particle. into the cavity of the parent-cell. Reichert thereI think, therefore, that, invariably,the spermatic fore, probably saw four spermatic particles in a.:particle is only a metamorphosed nucleus of a parent and not in a daughter cell. -ED. 128 THE HELMINTHES. ~ 118 The few observations hitherto made upon the genital organs of the Gordiacei have shown that they are wholly tubular as in the Nematodes. But their intimate structure, and the development of their spermnatic particles are so strikingly different, that this point alone would justify their separation from the Nematodes.(10) ~ 118. With the exception of the Nematodes, and Gordiacei, the development of all Helminthes, which reproduce by means of genital organs and eggs, is metamorphotic. A complete series, from beginning to end of these metamorphoses has yet never been observed with any species. From the separate, parts of it here and there which have been observed, there appears the remarkable fact, that the embryos after escaping the egg, are not always. changed at the end of the metamorphosis, into individuals like the parent, but appear as larva-like animals, capable in their turn of producing other larvae.. These last larvae alone, change into individuals, which are like the parent.. This particular kind of transformation and development which is quite common among the Trematodes, has received the name of Alternate Generation..() Whether it occurs among the Cestodes and Acanthocephali, cannot now be stated positively, for as yet we are unacquainted with the first.period of their metamorphosis,- the embryo as it escapes from tile egg. (2 In many Cestodes and Trematodes, the embryos are developed before the eggs are cast, and in some of the last order, they make their escape while the eggs are in the uterus. The development of the Cestodes occurs as follows: After the disappearance of the germinative vesicle, large, transparent embryonic cells appear in the midst of the vitellus, which undergoes fissuration. These multiply by division, increasing at the expense of the vitellus, which in the tightly to the vulva of the female in this act, that opening is always at the posterior extremity of the they cannot disengage themselves (Siebold and body. The testicular tubes of Gordius aquatic us Nathusius, in Wieg'mann's Arch. 1836, I. p. 105, contain anteriorly, cell-like bodies; but posteriorly Taf. III. 1837, I. p. 60, 66). With many other there are others, staff-like, and which, being found species of Strongylsts, and Ascaris, it is not rare among the egg-s in the uterine tube, I have regardedl to find a brownish gum about the vulva, and in as perfect spermatic particles. The genital openwhich there is, sometimes, the very distinct impress ing of the male Gordiius is between the two more of the male caudal valve (Mehlis, Isis,1831, p. 87).* or less prominent lobes of the caudal extremity,. 10 In the genus Mermis formed by Dujardin, and is without copulatory organsl. The simple, the tubular uterus, the muscular vagina, and the round, colorless eggs, are bound together at the vulva situated far from the caudal extremity, - all posterior part of the uterus by all albuminous sub — remind one much of the Nematodes. The eggs of stance, and are deposited in a very long row. It Mermis nig'rescens, like those of Ascaris den- is this row of eggs which Lons DOtifour hastata, have long fibrillated appendages (Dujardin described as Filariafilariae (Ann. d. So. Nat. Ann. d. Sc. Nat. 1842, XVIII. p. 133, P1. VI., and XIV. 1828, p. 222, PI. XI. fig. 4). Siebold, in Wiegmann's Arch. 1843, II. p. 309); 1 See Steenstrup, Ueber den Generationswechand at the caudal extremity of the males of Mermis sel, &c., 1842. albicans, mihi (Entom. Zeit. 1843, p. 79), there 2 In various marine fish there is a trematode are, as in most Nematodes, two horny penises. larva of a Tetrarhynchus (l'Iiescher, Bericut But with Gordius, the structure of the genital ueber die Verhandl. d. Naturforsch. Gesellsch. in organs is very different (see Siebold, and Dujar- Basel. 1840, p. 29, and in Wiegsoann.'s Arch. din, loc. cit.). In both sexes the cavity of the 1841, II. p. 302), which would lead one to conbody is completely filled with a double genital elude that alternate generation exists also with the tube, straight, and simple posteriorly, the sides Cestodes.t of which ale formed of large cells. The genital * [~ 117, note 9.] For many details of the re the alternating generation of the Cestodes, has productive organs of Ascaris infecta, with beauti- recently been confirmed most thoroughly by Sieful illustrative figures, see Leidy, A Flora and bold, who has treated the subject in a most comFauna, &c., loc. cit. 4 B. P1. VII. 14, 16, b. 19.- prehensive manner, in a Memoir in Siebold andl lD. Kolliker's Zeitsch. II. 1850, p. 198. - D. t [~ 118, note 2.] The view here suggested of 118. THE HELAIDNT'IES. 129 end they completely replace. When this has taken place, there is a mass of extremely small cells, which, being covered with a delicate epithelium, form a round or oval embryo, upon one extremity of which there are gradually formed six small horny hooks.(3) The embryos of the Acanthocephali are perhaps developed in the same manner, but they have only four hooks.(4" The Trematodes are developed exactly like the Cestodes, excepting that their oval embryos have usually ciliated epithelium, and there is an oral: sucker in place of the hooks.t5) Beside this first period of development, or embryonic state, there are, other more advanced or larval states, during which many Helminthes have been described and figured as separate species in the science. () Among these may be especially noticed two forms of the Trematodes - the cylindrical and the cercarian larvae. The first (the germinative tubes of Baer), form one of the phases of the alternate generation, and have a more or less complete organization. In the cavity of their body, germinative corpuscles are formed; these consist of a vesicular, granular substance, and resemble eggs neither by their structure nor mode of development. These corpuscles produce larvae of a cylindrical or cercarian form, which, deprived of their tail, are changed into perfect animals which have genital organs; and thus the series of metamorphoses is terminated.t7) 3 For the embryonic development of Bothrioce- Those of Distomum, longicolle, cygnoides, Monphalus, and Taenia, see Siebold (Burdacl's ostosusnsm mnutabile, and Aspidooaster conchi — Phys. loc. cit. p. 200), Dujardizn (Ann. d. Sc. cola, have an oral sucker. In this last species,. Nat. X. 1838, p. 29, P1. I. fig. 10, also XX. 1843, there is another sucker also, at the posterior exp. 341, P1. XV., and his Hist. d. Helm. P1. IX.- trellity of the body (Dujardin, Hist. d. Helm. p. XII.), and Kolliker (Muller's Arch. 1843, p. 91, 325). Taf. VII. fig. 44-56). 6 In this category are the genera Cercaria,. The small hooks which the cestoid embryos so Histrionella, Bucephalu.s and others, which as actively protrude and retract, somewhat resemble yet have been founded only upon liftrerent species those which are circularly arranged with the adult of Trematode larvae. The -Ielminth described by Taenia.* Leblond (Ann. d. Sc; Nat. VI. 1836, p. 289, P1. 4 As yet, with Echinorhynchus gigas alone XYI. fig. 3) as Amphistomum ropaloides, is only have I succeeded in liberating the embryos from a larva of a Tetrarhynchus. The species forming the egg by compression. The four hooks of these the genus Scolex are certainly only imperfect. embryos resemble, by their form and position, those Bothriocephallts; and the Gryporhynchus puof the Cestoid embryos. It does not appear, how- silltes of NordmaLnnz (Micr. Beitr. Itft. I. p. 101,, ever, that the embryos of all Echinsorhyn chus s Taf. VIII. fig. 6, 7), is probably only a young have them 5 at least Dujardin has not found them Taenia. There may also be a doubt here, if thewith those of Echinorhynchus transversus, and Cystici can be considered as real species. globocaudatus (Hist. d. Helm. P1. VII.). It is very probable that they are imperfect Ces — 5 For the embryonic development of Msonosto- todes whose genital organs are to be afterwards mum, and Distomum, see Siebold (Burdach's developed, as with Cysticercus fasciolatus, while Phys. loc. cit. p. 206), and Kslliker (Miiller's the Rodents in which it lives are devoured by car Arch. loc. cit. p. 99). The embryos which swim nivorous animals. Tsenia crassicollis is, perabout like Infusoria by means of ciliated epithelium, haps, to Cystic ercus fasciolaris, what Bothrioc eand which escape the egg while yet in the uterus, phalus nodosus is to Bothriocephalus solidus; have been observed of Distomum hians, by Meh/- see Creplin, Nov. Observ. &c. p. 90. lis (Isis 1831, p. 190); of Distom'um nodilosimnz 7 The cylindric larvae of the Trematodes have and globiporum, by Nordmann and Creplin been termed by Steenstraup (loc. cit. p. 50) nursesr (Microgr. Beitr. HIft. 2, p. 139, and in Ersch and (Ammen). They are yet known only as living Gruber's Encyclop. XXIX. 1837, p. 324); of parasitically upon Mollusks, as for instance, upon Distomum cygnoides, longicolle, Amphisto- Pal/dina, Lymnaeuts, Planorbis, Ancyl/es, Sacmzn subclavatum, and Monostom um mt tabile, cinea, AnodonLta, and Unio; also upon Hel/i by myself (Wlegmann's Arch. 1835, I. p. 66, Taf. pomnatia, and Tellina baltica, according to -Boia1.). See also Dujardin, in the Ann. d. Sc. Nat. nus, Baer, Carsus, Steenstlruap, and myself. Thle VIII. 1837, p. 303, PI. IX. fig. 3. I have seen the cylindric larvae of Bucephalus poly7molrpus, alre embryos of Distomum tereticolle, and Aspido- very long tubes, varicose here and there, somegaster conchicola, without the ciliated epithelium. times ramified, and which do not exhibit any * [ ~ 118, note 3.] The history of all our best development is not from true eggs but rather from embryological studies shows that the segmentation buds, a view which is the more worthy of attention of the vitellus is the invariable preface to the be- from the recent developments made by Sieboldo gimnning of development with all true ova. In the with Gyrodactyluss; see below, my note under case of the Cestodes, if, as above mentioned, there ~ 118, note 7.- ED. is no such process, it is highly probable that such 130 THE HELMINTHES. ~ 119. ~ 119. With the Nematodes, of which very many are viviparous, the embryos are developed within the egg in two different ways: Either the embryomovements (Baer, in the Nov. Act. Acad. Leop. aquatic, as of Libellula. Agrion, iEphesmera, and XIII. pt. 2, p. 570, Tab. XXX.). Those of Dis- Phrygoanea, I have never met with one whose tomum duplicatum have simple, oval, and rigid genital organs were in a state of advanced developgerminative utricles (Baer, Ibid. p. 558, Tab. ment. XXIX.). Those of Cercaria ephemera, are also The full development of these organs, the delivery simple, but of a cylindrical form (Siebold, in cate contours of which may be seen while the parBurdach's Phys. loc. cit. p. 187, and Steenstrtlp, asites are in the bodies of these animals, is not loc. cit. p. 78, Taf. III. fig. 1-6). Those of Cer- perhaps attained, until the insects have been cariafurcata are simple and cylindrical, but very swallowed by birds and other animals, - being long and endowed with quite active peristaltic thereby furnished with more proper conditions for motions (Baer, loc. cit. p. 626, Tab. XXXI. fig. 6). their complete formation. The curious animal, Leucochloridium paradox- Some Cercariae lose their tail and are surrounded oum, consisting of only a cylindrical sac with a with a capsule without leaving the Mollusks which tail, is only a trematode larva (Carus, in the Nov. are their first habitat. This is probably so, beAct. Acad. Leop. XVII. pt. 1, p. 85, Tab. VII.). cause these Mollusks are liable to be eaten by N'ith the slow-moving, cylindrical, orange-colored aquatic birds, in which these parasites may propnurses of Cercaria ephemera, there may be easily erly reach their final development. It should, seen a mouth, a pharynx, and a simple coecal however, be remarked that when these larvae beintestine (Siebold, in Burdach's Phys. loc. cit. p. come chrysalides, their investing capsule or cyst, 187). Those of Cercaria echinata, are similar, is a secretion from their bodies, and not a product but they have also two short oblique prolongations of the animals in which they live. It is probable in front of the obtuse caudal extremity (Baer, loc. that very many of these larvae never attain a percit. p. 629, Tab. 31, fig. 7, and Steenstrup, loc. cit., feet state, for, in their migrations, they fail to reach -. 51, Taf. II. fig. 2-4). The germinative bodies their destined and final habitat. from which Cercaria is developed, have nothing These migrations undoubtedly occur with many comparable to a chorion or germinative vesicle. Cestodes while young; at least Miescher (loc. cit.) Their larvae have always a tail, which is simple has observed it with Tetrarhyncheus. But although (Cercaria armata, ephemera, Distomum dupli- we have followed these in their migrations, and the catum), or bifurcated (Cercaria jurcata), or transformation of many of them into Monostomum d;aouble (Bucephalus polymorphus). The move- and Distomum has been observed, and therefore ments of this tail are very slow with Distomeum the completion of their metamorphoses, yet we are dusplicatum, but extremely lively and vortical but slightly informed as to their beginning by the with Cercaria. With Bucephaluzs, the two fili- alternation of generation. form tails lengthen and shorten considerably, at the There is yet little known as to the manner in same time jerking all about. which these embryos are changed into the cylinWhen the larvae are developed, they leave the dric nurses. There are now only two isolated facts corpuscles and pass into other animals to complete throwing light upon this point. According to my -their final metamorphoses. Many Cercariae appear own observations (Wiegmann's Arch. 1835, I. to prefer the larvae of insects whose bodies they en- p. 75, Taf. I.), each embryo of AMonostomum ter by means of their cephalic hooks. In this way mutabile contains a germinative tube, which, at I have seen the Cerearia armata easily enter the the death of the embryo, is freed and quite resemlarvae of Ephemera, Nemiura, and Perla. By the bles the nurse of Cercaria echinata. I have also aid of its sting it can perceive the intersegmental observed in the embryos of Amphistomum submembrane of these larvae. Frequently it loses its clavatum a tubular body, but I could not satisfy tail in passing through a narrow opening it has myself of its germinative nature. According to made. Steenstrup (loc. cit. p. 98), there is an animal like Immediately upon reaching the cavity of the a Paramaecium, and probably an embryo of a body of the larva, it is surrounded by a vesicular D)istomum, living in Muscles, and which. finally membrane, in which the sting is rejected, and the is deprived of its epithelium, and changed into the animal enters upon its final metamorphosis. But rigid, germinative tube of Distomuno duplicatum; I have a doubt whether it is there completed, for see upon this, my Jahresbericht in WYiegmann's among the numerous similar parasites which I have Arch. 1843, II. p. 300.* found in the most different insects whose larvae are [~ 118, note 7.] In this connection should be recently investigated; and I believe this mode of noticed the remarkable phenomena of reproduction reproduction to be only a peculiar form of gemmiwith Gyrodactylus as recently observed by Sie- parity or budding suited to some ulterior, econombold (Siebold and KzIlliker's Zeitsch. I. 1849, p. ical purpose of the animal's life. On a future page 345). Individuals are here developed viviparously I shall speak more fully on this point and attempt as in the so-called alternating generations, and to show that the whole set of phenomena known Siebold has observed a mother in which was a under the name of "Alternation of Generations" daughter and in this last a grand-daughter, the is, when divested of its paraphernalia, only a kind series being therefore three-fold. These viviparous of Gemiuiparity. individuals contain no sexual organs proper, but See also for further details on that curious ani..the new individual is developed out of a group of mal Leuc~ochloridizum paradoxum, Piper, in:cells situated within the body. The whole repro- Wiegmann's Arch. 1851, I. p. 313, but especially ductive conditions which Siebold has'detailed with Siebold, in Siebold and Kslliker's Zeitsch. IV. his usual care appear to me to closely resemble 1853, p. 425, Taf. XVI. B. This last-named obthose of the viviparous Aphides which I have server has shown that this animal form is only a. 119. THE HELMINTHES. 131 nic cells present the same successive phases as in the Cestodes and Trematodes, without the appropriated vitellus undergoing any segmentation; or, the whole vitellus after a complete segmentation, is changed into an embryo. ('1 In both cases, the embryo has the parent's form. A muscular cesophagus and straight intestine appear in its body in the midst of the refuse vitelline granules; and thus the young animal attains its perfect state by simple increase and by the development of its genital organs, but without any metamorphosis.(2) From the few observations hitherto made upon the development of the Gordiacei, it appears that the embryos exactly resemble the parents.(3) 1 Kslliker was the first to call the attention to their genital organs or their bodies in general, -these two types of development with the Nema- except through a transplantation upon other anitodes (Miiller's Arch. 1843, p. 68, Taf. VI. VII.). mals; exactly as occurs with the trematodal larvae. With Ascaris dentata, Oxyuris amb.igzta, and (See the observations of Creplin and myself upon Cucullanus elegans, free embryonic cells are the sexless Trematodes, in Wiegmann's Arch. formed in the vitellus without its fissuration. But 1838, I. p. 302, 373.) there is a complete segmentation with Ascaris The Trichina spiralis of man is undoubtedly an bnigrovenosa, acumninata, succisa, osculata, encysted and imperfect form of one of the Nemalabiata, and brevicaudata, Strongylus auricu- todes, and in which one may seek in vain for gen-.laris, dentatus, Filaria inJlexo-caudata, rigida, ital organs. Some of these Nematodes appear to and Sphaerularia bombi. After I had already increase in their cysts without their genital organs noticed this vitelline segmentation with the Ne- being developed in the same proportion. Thus, the matodes (Burdach's Phys. loc. cit. p. 211), which Filaria piscium are sometimes found very large, Bagge (Dissert. loc. cit.) described very fully, while their genital organs are very little developed; Kulliker (loc. cit.) attempted to reconcile it with and these last do not probably attain their perfect the cell-theory, by regarding the cells which state, until, as with Bothriocephalus solidus, appear in the segmented, vitelline globules, as the these worms have passed into other animals. For.embryonic cells, and in the multiplication of the same reason, I agree with Steenstrup (loc. cit. which by segmentation, the enveloping vitellus p. 113), who doubts that the Filaria piscium participates. become, as Aliescher has affirmed (loc. cit. p. 26), 2 It appears that, as with the Trematodes, so in a globular capsule out of which there afterward the Nematodes, a migration of the young precedes appears an animal at first resembling a Trematheir complete development. tode, but which finally becomes a TetrarhynIn the tissues of the most different insects and chus.* vertebrates, there are found small Nematodes 3 See Dujardin (Ann. d. Sc. Nat. XVII. loc. without genital organs, and contained in a cyst. cit. Pl..VI. fig. 15, 16) upon Mermis nigrescens, They could not get there except by a migration, researches which I have been able thoroughly to Sand they cannot attain the full development of confirm.t kind of nurse of a Distomum, containing peculiar kin, Lect. on Morbid Anat. of Serous and Mucous -germ-bodies which are developed into Dzslomum. Membranes, I. p. 212; Curling, London Med. But the most important result obtained is that all Gaz. February, 1836; Bowditch, Boston Med. and Distomum are not developed by means of a cer- Surg. Jour. April, 1842; Luschka, Siebold and carian, larval stage,-the economy of some making K61liker's Zeitsch. III. 1851, p. 69, Taf. III., and it seemingly requisite that the developmental pro- Gairdner, Edinb. Monthly Jour. of Sc. May, cess should be more direct. - ED. 1853. The subject'is one that deserves especial * [~ 119, note 2.] In regard to Trichina spi- attention from IHelminthologists. - Eo. ralis, the various researches upon its structure, t [~ 119, note 3.] Grube (Wiegmann's Arch. -made in England and America, would show that it fuir Naturgesch. 1849, p. 358) and Leidy (Proc. is a true animal having genital organs. The fol- Acad. Sc. Philad. V 1850, p. 98) have observed lowing are some of the references upon this sub- the development of Gordius. It corresponds ject: Owen, London Med. Gaz. April and Decem- pretty closely with that of Ascaris as described by'ber, 1835, or Transact. Zool. Soc. London, IV., or Bagge; but the embryo on escaping from the egg Cyclop. Anat. and Phys. Art. Entozoa; Wood, is annulose and tentaculated, and differs much London Med. Gaz. May, 1835; Farre, Ibid. De- from the adult form. Nothing is known of the cember, 1835; Harrison, Report of the Brit. history of the animal between these two conditions, Assoc. for the Advancem. of Sc. 1835; Knox, Edinb. - ED. Med. and Surg. Jour. 1836, XLVI. p. 86; Hodg BOOK SIXutJ. TURBELLARIA. CLASSIFICATION. ~ 120. THE TURBELLARIA receive their name from the ciliated epithelium, which covers their whole body. Their flattened, or cylindrical, non-articulated body, is formed of a loose parenchyma, in which lie hid the viscera. The nervous system appears very little developed, and when visible, consists only of a cervical ganglion, from which there never extends a ventral cord.. The multiramose intestinal canal is always without an anus. The genital organs are either very much developed, or entirely absent.(l) In the first case, these animals are always hermaphrodites, and have copulatory organs. The Turbellaria have been shifted from one zoological system to another, but their organization has sufficient peculiarities to entitle them to a special class by themselves. Ehrenberg was the first to found the group Turbellaria; but he has ino cluded therein many different animals; and we are, therefore, indebted to Orsted, for a late revision of this group. ORDER I. RHABDOCOELI. The alimentary canal is simple and cylindrical; the osophagus, nonprotractile; locomotion, mostly natatory. Genera: Vortex, Derosto2num, Gyratrix, Strongylostonzum, Mesostomum, Typhloplana, Macrostomuni, Microstomurn. ORDER II. DENDROCOELI. Intestinal canal dendritically ramified; cesophagus completely protractile; locomotion reptatory. 1 I cannot here omit the question, if these small era, and if they are not rather the larvae of other sexless Turbellaria, as for example, Derostomum, inferior animals. and Microstomum, really constitute distinct gen ~ 121. THE TURBELLARIA. 133 Genera: PolyceZis, Monocelis, Planaria, Leptoplana. Eurylepta, Planocera, Thysanozoon. BIBLIOGRAP HY. Baer. Ueber Planarien, in the Nov. Act. Acad. Leop. XIII. 1826, p. 691. Duges. Recherches sur l'organisation et les moeurs des Planariees, in the Ann. d. Sc. Nat. XV. 1828, p. 139; and XXI. 1830, p. 72. See Isis 1830, p. 169, or Froriep's, Not. 1829, No. 501. Mertens. Ueber den Bau verschiedener in der See lebender Planarien, in the Mem. de l'Acad. de St. Petersbourg, 6eme Ser. Tom. II. 1833, p. 1. Ehrenberg. Phytozoa turbellaria, in the Symbolae physicae, Ser. I. 1831. Focke. Ueber Planaria Ehrenbergii. in the Ann. des Wiener Mus. I. Abth. 2, 1836, p. 193. F. F. Schulze. De Planariarum vivendi ratione et structura penitiori nonnulla. Dissertatio. Berolini, 1836. A. S. Orsted. Entwurf einer systematischen Eintheilung und speciellen Beschreibung der Plattwiirmer. Copenhagen, 1844. ADDITIONAL BIBLIOGRAPHY. Beside the writings referred to in my notes, see the following: Schmidt. Die rhabdocoelen Strudelwiirmer des siissen Wassers. Jena, 1848. Neue Beitrige zur Naturgesch. der Wiirmer. Jena, 1848. Erster Abschnitt, Turbellarien. Handbuch d. vergleich. Anatomie, 1849, p. 294. lM. S. Schultze. Ueber die Microstomeen, eine Familie der Turbellarian, in Wiegmann's Arch. 1849, p. 280, Taf. VI. Beitraige zur Naturgeschichte der Turbellarien. 1851.- ED. CHAPTER I. CUTANEOUS SYSTEM. ~ 121. The whole body of the Turbellaria is covered with ciliated epithelium, under which lies a loose cellular parenchyma. In this parenchyma, and directly beneath the epithelium, there are found, in many species, particular cell-like bodies, which sometimes remind one of the nettling organs of certain zoophytes, and sometimes exactly resemble the prehensile organs 12 1.34 THE TURBELLARIA. ~ 122. of the arms of Polyps. l) These bodies contain six or eight, or even more;. staff-like, colorless corpuscles, which are parallelly arranged side by side,. or curved a little spirally. With their further development, the envelope disappears, and they then remain free under the skin, but sometimes pro — jecting through it.'2 CHAPTER II. MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS. ~ 122. Although their parenchyma is extremely contractile, yet the Turbellaria have only a very feebly-developed muscular system. In many small species of the Rhabdocoeli, the parenchymal muscles may be made out; and in the larger Planariae, when the muscles are visible, their fibres appear unstriated. The small Rhabdocodli swim by means of their ciliated epithelium, like many Infusoria, their bodies revolving on its longitudinal axis; while the flattened Dendrocoeli crawl along like the Gasteropoda.l1) Many larger species of the first order,(2) appear to float from place to place by means of their epithelium, thus really neither creeping nor swimming. 1 With Microstomum lineare, brsted, these hystrix, are probably of the same nature, as may prehensile organs so closely resemble those of also be said of the delicate short bristles found Hydra that they need not be described. According everywhere under the skin of Derostomum leuto Orsted they are urn-shaped glands in the centre cops, Duges. of which are parabolic bodies which are constantly Quatrefages, in his monograph on marine in motion (loc. cit. p. 73, Taf. II. fig. 18). But Planariae (Ann. d. Sc. Nat. IV. 1845, p. 146, P1. had he pressed these organs between two plates of VIII. fig. 9, 10), also mentions various formations glass, he would have seen the protruding filament, which, partly as spines, partly as nettling ortogether with its double hooks. gans, are found in the skin of certain Dendrocodli. 2 I have seen these corpuscles protruding through 1 The mode of locomotion by which these animals the lateral border of the body of Planaria lactea. mote over solid bodies, or upon the surface of the In the dorsal papillae-of Thysanozoon Diesingii, water, has not yet been satisfactorily explained. a part of these corpuscles are contained in cells i The ciliated epithelium cannot here be the principal but the others are free and often protrude through agent. According to Schulze, loc. cit. p. 32, the the skin. With Mesostomum Ehrenbergii, and staff-like corpuscles projecting from the back of rostratum, they are arranged in rows in the these animals, and which he terms bristles, are used anterior half of the body, forming striae, which as oars. quickly catch the attention. Orsted has taken According to Mertens (Mom. de l'Acad. de St. these corpuscles for as many muscular columns Petersbourg, 6eme, sfr. II. 1833, p. 5), Planaria (loc. cit. p. 70, Taf. II. fig. 26, 37). The spines lichenoides moves by means of the protruded which, according to him (loc. cit. p. 72, Taf. II. fig. lobes of its pharyngx. 29, 34) cover the entire surface of 2lacrostomum 2 For example, Mesostomum. O, 123, 124. THE TURBELLARIA. 135 CHAPTERS III. AND IV. NERVOUS SYSTEM AND ORGANS OF SENSE. ~ 123. The nervous system with the Turbellaria, is quite indistinct, for it has not yet been observed in the small species, and in the larger ones its disposition is yet doubtful. A double ganglion in the cervical region appears to form its central part, and from this nerves pass off in different directions. (1) ~ 124. Among the organs of sense, those of vision are the most developed with very many species. The red, brown, or black spots on the anterior extremity, two or more in number, are not always simple pigment cells,(') but may be regarded as eyes, for they have a cornea,- a light-refracting body surrounded with pigment, and a nerve-bulb. (2) As to the sense of touch, no special tactile organs have yet been found, but the whole surface reiacts sensitively from the lightest contact; and-this sensibility appears particularly prominent at the anterior extremity, which, with many Dendrocoeli, is furnished with lobular and other appendages.(3) 1 Ehrenberg has seen two disconnected ganglia p. 37. With Monocelis, these organs are very with Planaria lactea (Abhand. d. Berl. Akad. remarkable, being composed of two eyes blended 1835, p. 243). With other Dendrocodli, as with into one, and the simple and spherical ball of the Planocera sargassicola, and pellucida, these two eye is filled, according to Orsted, with a transpaganglia are blended into one; at least, the organ rent vitreous body, in which two conical crystalline which Mertens has here described as a heart, has lenses are buried with their apices pointing inexactly the appearance of two united ganglia (loc. wards (loc. cit. p. 6, 56, Taf. I. fig. 1, 2, and in cit. Taf. I. fig. 6, Taf. II. fig. 3, m. or Isis 1836, Taf. the text, fig. 10). Orsted has distinctly seen two IX. fig. 3, c. m.). The light pulsations which this optic nerves passing laterally to this organ. It is author affirms to have here observed, are perhaps, quite remarkable that with one of the three known as Ehrenberg has supposed (loc. cit. p. 244), due to species, the Monocelis unipunctata, the eye is the contractions of neighboring organs. According entirely without pigment. Ehrenberg affirms that to Schulze (loc. cit. p. 39), with Planlaria torva, he has observed with Polycelis, many star-like the double central ganglion gives off two nerves, ganglia in the middle of the anterior part of the which pass backwards on both sides of the intes- body, which are for the long row of eye-dots (loc. tine. cit. p. 2.43). This double ganglion, situated in the cervical re- For the eyes of the marine Planariae, see also gion, and the nervous filaments which it gives off, Quatrefages, loc. cit. p. 178, P1. III. The organ have been demonstrated by Qastrefoges (loc. cit. which with Monocoelis has been taken for an eye p. 172, P1. IV.-VI.). by 7r-sted, appears to be, according to the re1 Most commonly there are two eye-dots. With searches of Frey and Leuckart (Beitr. p. 83, Taf. Planocera, and Leptoplana, there arc many which I. fig. 18), an auditory organ. That which Orsted are grouped together, and with Polycelis nigra, regarded a vitreous body, is an otolite, and his two the whole anterior part of the body is covered with crystalline lenses, are two semicircular prolongathem. In many small species, they appear to be tions attached loop-like to the otolite. Frey and of a simple pigmentary nature. Leuckart are also convinced that Convoluta par2 With Planaria lactea, there is, between the adoxa Orst., has a single auditive capsule, situated cornea-like bulging of the skin, and a semilunar, on the median line of the cervical region, and conpigment layer, a small, conical, transparent body, taining an otolite which floats in a lilac-colored corresponding exactly to a crystalline lens; see fluid * see Beitr. loc. cit. p. 82, Taf. I. fig. 17.* Ehrenberg, loc. cit. p. 243, and Schulze, loc. cit. 3 There are contractile and antenniform append* [~ 124, note 2.] See also Leidy (Proc. Acad. question as visual organs. Schmidt has often Nat. Sc. Philad. III. 1848, p. 248) on the eye-specks failed to find anything like an otolite; but, on the of Phagocata gracilis, a sub-genus made by him other hand, has often found with various Derostofrom Planaria, and Schmidt (Die Rhabdocoelen mum a complete visual apparatus. This point, Strudelwdrmer,&c., p. 7, and Neue Beitrfige Zur therefore, is still unsettled, unless, as Schmidt inNaturgesch, der WSrmer, &c., p. 11). Both of geniously suggests, it may be that one organ serves these observers agree in considering these parts in the functions of two separate senses. - ED. 136 THE TURBELLARIA. ~ 125. CHAPTER V. DIGESTIVE APPARATUS. ~ 125. With the two orders of Turbellaria, this apparatus is formed upon very,different types. But in both orders, the location of the mouth varies so much, that it serves as the basis of genera, according as it is at the anterior extrem-ity, or a little behind it, -or, at the middle of the belly, or a little behind that also. The walls of the intestinal canal are always intimately blended'with the parenchyma of the body. WTith the Rhabdocoeli, the mouth leads to a muscular oesophagus, which is either an annular sphincter, or a longer or shorter tube, but which, in no case, can be everted firom the mouth. The intestinal canal is a simple cae-;cum extending from the Esophagus to the posterior extremity; but with those species which have the mouth situated more or less posteriorly, it:stretches forward as a coecum to the anterior portion of the body.(l) With -the Dendrocodli the mouth opens into a large throat, containing a protractile and very movable deglutitory organ (Pharynx). This organ, which can be protruded entirely out of the throat while the animal is eating, is either a tube composed of longitudinal and transverse muscles, or a collection of lobular and ramified tentacles circularly arTanged about the mouth. Its base is prolonged into the proper intestine, whose dendritic ramifications extend over the whole body. (2) Scarcely a trace of salivary or hepatic organs have here been found with these animals. (3) ages on the anterior part of the body of Planaria 716, Tab. XXXIII. fig. 8-11, and Dugbs, loc. cit..tentaculata, and Eurylepta cornuta, and upon XV. p. 152, P1. IV. fig. 18, 19). the neck of Planocera. With the last, they sup- The large and plicated cesophagus of Planaria port a part of the eye dots. tremellaris, constitutes the transition to the ten1 The mouth and cylindrical oesophagus of Gy- tacular form of the deglutitory organs (Dugds, loc. ratrix hermaphroditus, and Vortex treuncata, are cit. XV. P1. IV. fig. 20, 21). Fully ramified ten-:at the cephalic extremity (Ehrenberg, Abhandl. tacles are found with Planocera sargassicola,,d. Berl. Akad. 1835, p. 178, Taf. I. fig. 2, 3). But pelltecida, and Leptoplana lichenoides. When the mouth and annular csophagus of Derosto- collefted in the throat, they present exactly the asmLum is situated just back of this extremity, into pect of a ramified intestine (Mertens, loc. cit. Taf. which, however, the coeeal intestine extends. The I. fig. 2, 3, 6, Taf. II. fig. 3, 4, and the Isis, 1836, uesophagus is also annular with ltfesostomum, Taf. IX. fig. 3, b. 3, c.). The ramified intestine of:and Typhloplana. In the first, the mouth is at the many Dendroco~li has been figured by Baer, Du-middle of the ventral surface; and in the last, a gis, and lMertens, in their works already cited.* little behind this point, while the intestine projects 3 Focke (loc. cit. p. 196, Taf. XVII. fig. 11, c. scoecally far into the anterior extremity (Orsted, f.) is inclined to regard as salivary and hepatic orloc. cit. Taf. II. fig. 26, 31, and Fockle, loc. cit. gans, two large lateral vessels, and a glandular or-'iaf. XVII.). gan which he has discovered near the cesophagus 2 Tile genus Planearia has become fsamous for its and intestine of Mesostomum Ehrenbergii l but movable organ of deglutition, which, being sepa- he himself admits that this view is not yet well rated from the body, still continues for a while to founded.t sswallow all presented to its mouth (Baer, loc. cit. p. * [ 6 125, note 2.] With Phagocata (Planaria) [ ~ 125, note 3.] Will (3Miiller's Arch. 1848,.gracilis, Leidy (Proceed. Acad. Nat. Sc. Phil. III. p. 508) has shown that the brownish layer covering 1848, p. 248) found, instead of a single sucker, the whole extent of the intestine of Planaria is;twenty-three, n the full-grown animal. These are composed of hepatic glands (Dendrocoelum lacall protruded when the animal feeds, but when teum, Planaria torva, and nigra). —. ED. not in use, are closely packed together within the:animal. They all connect separately with portions of the dendritic alimentary cavity. - ED. Y 126. THE TURBELLARIA. 137 CHAPTERS VI. AND VII. CIRCULATORY AND RESPIRATORY SYSTEMS. ~ 126. As yet, only a very imperfect vascular system has been observed in the'parenchyma of these animals. With the Dendrocoeli, there are constantly two principal vessels, extending along each side of the body, which give off many lateral branches and anastomose together at their two extremities. This system has no central heart-like organ, and the walls of the vessels not being contractile, the circulation is probably effected through the general contractions of the body.(t) The contained homogeneous and colorless liquid ought therefore to be considered as a nutritive fluid. With the Rhabdocoili, the disposition is different. In many there are,one or two vessels which traverse the body and loop at its extremities, without either giving off branches or diminishing in size. The movement,of their colorless liquid is due to isolated vibratile lobules situated here and there in the vessels. This organization reminds one more of an aquiferous than a sanguineous system. (2) Special respiratory organs are here wholly absent, if we do not regard as such the aquiferous system just mentioned. There remains, therefore, only the Iconjecture that the ciliary epithelium upon the entire surface of the body is:subservient to a general cutaneous respiration, by constantly bringing the water in contact with the skin. 1 Dugds has described and figured very corn- dal extremity, they approach so near to the cuta-,pletely the vascular system of Planaria (loc. cit. neous surface that it is impossible to decide whether XV. p 160, Pl. Y. fig. 1, 2, XXI. p. 85, P1. II. fig. they terminate there by a loop, or open externally. 224, 25). The cordiform organ which Mertens (loc. Ehrenberg (Abhandl. d. Berl. Akad. loc. cit. p. acit. p. 12, Taf. I. fig. 6, Taf. II. fig. 3) refers to the 178, Taf. I. fig. 2) has figured two pairs of such vascular system of Planocera sargassicola and vessels with Gyratrix hermaphroditus, and which pellucida, is probably, as seen above, the central loop at the posterior extremity, but in front termipart of the nervous system. DuRgs is the only nate indistinctly. The trembling in the interior of observer who affirms to have seen with the Den- these vessels observed by Ehrenberg, indicates droco~li proper movements of the vessels; while certainly the presence of vibratile lobules, and Mlertens, Ehrenberg (Abhandl. d. Berl. Akad. which Orsted (loc. cit. p. 17, Taf. III. fig. 48) has Joc. cit. p. 243), Schulze (loc. cit. p. 18), and Ors- distinctly found in the vessels of Mesostomum ted (loc. cit. p. 16), have observed only the con- Ehrenbergii, while Focke (loc. cit. p. 200) could trary. see only their effects. These are the very vessels 2 With Derostomum leucops, Dug., I have which this author supposes connect with the phaseen two intertwined vessels of equal size through- rynx; but this is not so according to my own obout, extending from the caudal extremity to the servations.* hlead where they form a simple loop. At the cau* [;126, note 2.] See for these two systems, Neue Beitr. zur Naturgesch. d. Waiirmer, &c.,. Schmidt, Die Rhabdoc, Strudelw. &c., p. 11, and p. 15..ED. 12* 138 THE TURBELLARIA. ~ 127, 128. CHAPTER VIII. ORGANS OF SECRETION. ~ 127. No special organs of secretion have yet been found with the Turbellaria, although these animals, and especially the Dendrocodli, secrete from their cutaneous surface an extraordinary quantity of mucus.(1) CHAPTER IX. ORGANS OF GENERATION. ~ 128. The Turbellaria propagate by transverse fissuration, and by the means of genital organs. In the smaller Rhabdocoeli, which have no trace of genital organs, the transverse fissuration is the rule.(') It is, however, probable that at certain epochs of their lives, genital organs are developed, and therefore, that they multiply also by eggs.(2) With both the larger Rhabdococli, and the Dendroco/li, the genital and copulatory organs of' both sexes are situated upon one and the same individual, so that they are capable of self-impregnation; but there is generally a reciprocal copulation.(3) This genital apparatus is very complex, and as the contents of its various parts have not yet been subjected to a careful analysis, it is not positively certain that the right interpretation of them is given. 1 It is yet undecided whether the subcutaneous and which can be multiplied artificially by divisions cell-like bodies of the Dendrocoeli have any relation in all directions, would lead us to infer that they to this secretion. propagate also from accidental divisions, to which 1 Dugds (Ann. d. Sc. Nat. XV. p. 169, P1. V. fig. their vulnerable nature is constantly exposed.* 15) has observed a voluntary transverse fissuration 2 Orsted (loc. cit. p. 21, Taf. III. fig. 53) and with Derostomum leucops. I have been able to Ehrenberg (Abhandl. d. Berl. Akad. loc. cit. p. follow the very regular fissuration of Microsto- 178, Taf. I. fig. 2, 3) affirm to have seen ovaries, mum lineare, where each unseparated half of the testicles, copulatory organs, and eggs with JMIicrobody began to halve again, and then these four pieces stomum lineare, and many other allied Rhabdoalso each divided, and so finally the body appeared c6ili, such as Gyratrim, Vortex, and Strongyloworked by seven transverse furrows, into eight stomum; but the details they have given are too divisions. imperfect to allow definite opinions upon this orI must here remark, to prevent an error, that I, ganization. I must here ask if these animals have contrary to Orsted (loc. cit. p. 73), regard these not been confounded with the sexless larvae which two mentioned species as distinct; for Derosto- multiply by fissuration like those of Medusae. mum leucops, Dug., is without the reddish brown 3 Coition has often been observed with Planaria eye-dots and the prehensile organs, which are found and Mesostomum, and has been figured by Baer, with Microstomum lineare, Orst. The wonder- Dughs, and Focke. ful reproductive power of the sexless Planariae., * [ ~ 128, note 1.] See Leidy (loc. cit.); he this subdivision could not be carried successfully found that with Phagocata (Planaria) gracilis, beyond three or four parts.- ED. ~129. THE TURBELLARIA. 189 The following are the parts usually found: an ovary or organ of vitelline secretion, which is double, and, extending into the parenchyma of the body, opens by a common excretory duct into a large cavity, - a vagina or oviduct; a double testicle sends its seminal liquid, full of filamentoid and motionless spermatic particles, into the seminal vesicle through two tortuous vasa deferentia; to this seminal vesicle is attached a very erectile penis, situated by the side of the vagina. There is a common genital opening, situated always behind the mouth, for the protrusion of this penis and the escape of the eggs. With Flanaria, there are, beside, two special, hollow organs, with narrow excretory ducts, which open into the vagina. Of these, one very probably secretes the envelope of the egg, while the other serves as a Receptaculum seminis. (4) ~ 129. The embryonic development of the Turbellaria is yet unknown except with the Planariae. It differs wholly from anything yet known with other Invertebrates. Many of these embryos are developed, always simultaneously, in one large egg; but it is impossible at first to determine their number, since 4 See, for the genital organs of Mesostomum Eh- the vulva. As I have found many spermatic parrenbergzi, Focke (loc. cit.); for those of Plano- tidles in the first of these, I am led to regard it as cera, and Leptoplana, Mertens (loc. cit.); and for a Receptaculum seminis. But in the other, those of I)Derostomum, and Planaria, Duges, which Baer (loc. cit. Tab. XXXIIi. fig. 18, e.) has Baer, and Orsted (loc. cit.). But the interpretation taken for a penis, I have never found either eggs here given of the different parts of these organs or germs, but always only a granular substance must be much changed. For, to speak here only from tiss I am inclined to think that this organ seof the genus Planaria, what Baer has regarded cretes the material which envelops the vitelline as the ovaries and oviducts, are certainly the two cells grouped in the vulva. With the Planariae, testicles with their vasa deferentia, since I have one egg at a time is always formed in the round always found them filled with spermatic particles Vagina; this is very large, and when it is de(loc. cit. Tab. XXIII. fig. 18, a. b.). The two sem- posited others succeed it in the same way. This is inal canals open into a hollow, flask-shaped body not true, however, with Mesostomum Ehrenlike a Vesicula seminalis or a Ductus ejacu- bergii; here the vagina is short and narrow, latorius, the neck of which is continuous with a and receives various organs whose nature is very contractile and erectile tube (Penis). This not yet well determined. One of these contains, penis is in a cavity separated by a septum from according to my own researches, a confused mass the large vulva, with which, however, it communi- of active, filamentoid spermatic particles, and may cates by a special orifice, and consequently can be therefore be regarded as a Receptaculum semprotracted through the common genital opening. inis. Two canals which pass off right and left There is, beside the intestinal canal, another rami- from the vagina, bifurcate into two simple coeca, fled organ in the body of Planaria, and which one of which passes forwards, and the other backvery probably is an ovary, or at least a vitellus- wards, and in wJhich very large eggs remain for a; secreting organ. But its caeca contain only simple long time. This therefore may be regarded as an! vesicular bodies, which have no germinative vesi- uterus. See Focke, Taf. XVII. fig. 1, 11, g.g. cles. The canal which Dugis (loc. cit. XV. P1. v. According to the very minute researches of fig. 4, b.) has taken for an oviduct, belongs prob- Quatrefages (loc. cit. p. 163, P1. IV.-vIII.) made ably to the ramifications of this organ. The other upon various marine Planariae, both the male and: two organs which this author (Ibid. P1. v. fig. 4, the female organs of these Dendrcceli have two 8, c.) has described as Visicule copulatrice ou distinct orifices situated in the ventral region, one reservoir du sperme et des oeufs, do not appear behind the other. The posterior is a vulva and to me to exist in all Planariae. They consist of two opens into a more or less long coecum (vagina or hollow, pyriform organs, not blended together as copulatory pouch) upon which are laterally inserted: Dugds has figured them, hut distinct; one opens two oviducts. The anterior orifice is for the proby a long, and the other by a shlorter canal, into trusion of the protractile penis.* * [ ~ 128, note 4.] See, for many details on the spermatic particles of the Planariae is littleundersexual organs of the Turbellaria, and illustrated stood. They probably have not a hair-like form as with figures, Schmidt, loc. cit. (Protostomum, mentioned in the preceding note, but are CercariaVortex, IHypostomum, Derostomum, Meso. like; see KSlliker, loc. cit., Quatrefages, loc. cit. stomrum, Opzstomum, Macrostomum, Microsto- P1. VIII. fig. 5-9, and Schmidt, Die Rhabdoc. mum, Stenostomum, Schizostomum, Typhlo- Strudelwirmer, &c., p. 16; this author, however, plana; according to this author, Dinophilus vor- describes those of Opistomum pallidsum as someticoides is separate-sexed, —the exceptional in- what different, there being a filament, beyond the stance among the Rhabdocoeli. The subject of the head (Taf. v. fig. 14b). - E,. 140 THE TURBELLARIA. ~ 129. their chorion contains only loosely-arranged vitelline cells, among which there is seen no trace of one or more germinative vesicles. The vitelline cells always contain, beside a finely-granular albuminous substance, a round nucleus which has a nucleolus. Both the nucleus and the granular substance are shifted from one side to the other of the cell by the very remnarkable peristaltic movements of the cell-membrane. After a time, these movements cease, the cell-membrane disappears, and the contents mix with those of other cells which have been affected in the same way: by these means, little collections of vitelline substance here and there are formed, which increase by the addition of other cells, - and finally are transformed into roundish, nicely-defined embryos which become covered with ciliated epithelium. From this time the embryos do not increase as before by the external fusion of cells, but there is a muscular, discoid oesophagus formed upon their periphery, and through this the remaining cells are ingested and assimilated within the animal. Still later, the embryo, hitherto spherical, becomes flat and elongated at two opposite points; — ultimately, and upon the appearance of the eyespecks, it assumes exactly the form of the adult Planariae. The size of the young Planariae depends upon the number of embryos developed in the same egg, for the smaller this number, the larger the embryos at the time of their hatching, and vice versa. The cause regulating the number of embryos in an egg is yet unknown.* (1) i See my details upon this subject in the Bericht. The remarkable movements of the vitelline cells neber die Verhandl. d. Berl. Akad. 1841, p. 83. in the eggs of the Planariae, andwhich I was the During the development of Planaria, one can, first to observe, have since been confirmed by K/lafter a while, ascertain the number of vitelline cells liker, with Planaria lactea; see Wiegmann's assimilated by fusion and deglutition, by counting Arch. 1846, I. p. 291, Taf. X. I am unable to say their nuclei which are easily seen in the parenchy- whether or not the spontaneous movements observed ama of the body. According to Focke (loc. cit. p. by Quatrefages (loc. cit. p. 169, PI. VII. fig. 6-9) 201), the eye-specks, and the cesophagus are de- upon the larger portions of the vitellus of Polycelis veloped very early in the young Mesostomum pallidus while in the oviducts, are of the same naEkhrenbergii;-a species with which each egg ture; this naturalist himself supposes that these contains a single embryo only, and which is devel- portions were the embryos of this Planaria.t oped while the egg is in the uterus. * {End of ~ 129.] Recent embryological studies doec. Strudelwfirmer, &c., p. 17; by Agassiz (Proc. have thrown some light upon this point —the Amer. Assoc. Advancem. of Sc. 2 id meeting, 1849, alleged plurality of embryos in a single egg. The p. 438), who made the interesting observation that so-called egg in these cases is almost undoubtedly the Infusoria-genera, Kolpoda and Paramaecium, an ovarian sac. in which are developed many germs; are onlk larvae of Planaria; by Girard (Ibid. p. some of these germs may perish, and the fewness 398), and by liiller (Miiller's Arch. 1850, p. of those remaining would give the appearance of 485). Miller has here some interesting remarks on an egg with many germs. -ED. the relations of the study of these forms to the t [ ~ 129, note 1.] The development of Plana- class Infusoria. - ED. r-a has been also observed by Schmidt. Die Rhab ' 130. ITHE ROTATORIA. 141 BOOK SEVENTH. R OT AT O RIA. CLASSIFICATION. ~ 130. THE body of the ROTATORIA is covered with a smooth, hard epidermis, and, from transverse incisions, at least at its posterior portion, usually appears articulated; while its anterior portion has vibratory retractile partsthe so-called rotatory organs. The very indistinct nervous system is almost wholly comprised in a cervical ganglionic mass. The fully-developed digestive canal lies in the large cavity of the body, and its anterior portion is provided with masticatory organs, while posteriorly, it terminates in an anus. Female genital organs alone have as yet been found with certainty. No one would deny that the Rotatoria, whose organization is so high, ought to be separated from the Infusoria, whose structure is scarcely advanced above that of a simple cell-nature. One can be in doubt only as to their other and proper place in the animal kingdom; - whether, with Burzneister, they are to be placed among the Crustacea; or with Wiegmann, Wagner, Milne Edwards, Berthold, and others, among the Worms. But the choice here between these two classes will not be difficult, for, as will soon be shown, they differ widely from the Crustacea. Aside from the absence of a ventral cord and of striated muscular fibres, these animals have vibratile organs upon the surface of their body, as well as upon their respiratory and digestive organs - a structure not found with the Crustacea, nor with the Arthropoda in general. Their development is non-metamorphotic, and they do not have articulated feet when they escape from the egg; while the Crustacea, and even those which, from a retrograde metamorphosis, become veruifornm, have at least three pairs of articulated legs when hatched. On the other hand, they have, in common with most worms, an articulated body, internal and external vibratile organs, absence of a ventral cord, and, with all, the want of articulated feet. Although the uniformity of their organization does not admit of these animals being divided into orders, they can at least be considered as a separate class in the great section of Worms. 142 THE ROTATORIA. $ 131. FAMILY: MONOTROCHA. Genera: Ptygura, Ichthydiunm, Chaetonotus, Oecistes, Conochilus. FAMILY: SCIIIZOTROCHA. Genera: Megalotrocha, Tubicolaria, Stephanoceros, Lacinularia, l'elicerta,, Floscularia. FAMILY: POLYTROCIIA. Genera: Enteroplea, Pleurotrocha, Hydatina, Notommata, Synchaeta, -Polyarthra, Diglena, Triarthra, Eosphora, Cycloglena, Theorus, Miastigocerca, Euchlanis, Salpina, Stephanops, Squarnella. FAMILY: ZYGOTROCITA. Genera: Rotifer, Actinurus, Philodina, Noteus, Anuraea, Brachionus. BIBLIO G RAPH Y'. See the works already cited under Infusoria. ADDITIONAL BIBLIOGRAPHY. Besides the writings of Brightwell, Huxley, Leydig, and others, quoted in my notes, see the following: 0. Schmidt. Versuch einer Darstellung der Organisation der Raderthiere, in Wiegmann's Arch. 1846. Frey. Ueber die Bedeckungen der wirbellosen Thiere. Gottingen, 1848. D'Udekem. Bull. de'l'Acad. Roy. des Sc. de Belgique, XVIII. 1, 1851. See also the new edition of Pritchard's Infusoria, given under Book first.- ED. CHAPTER I. CUTANEOUS SYSTEM. ~ 131. Nearly all the Rotatoria are covered with a smooth,hard skin,el) which is thrown into folds by the contractions of the subcutaneous parenchyma; at the anterior extremity only, it is very delicate, and covered with vibratile organs, which also move to and fro with the parenchyma. With many, 1 With Chaetonotus, and Philodzna aculeata, spines. With Noteus, and Anuraea, there are the structure of the skin is quite different from species whose faceted skin is roughened by innumerthis; for its surface bristles with stiff points and able granulations. -~ 132, 133. THE ROTATORIA. 143 the annular sulcations of the skin, partial, or over its whole extent, give the body an articulated aspect. (2 Many others have a skin so hard and stiff as to be like a carapace.(3) CHAPTER II. MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS. ~ 132. The muscular system of the Rotatoria is quite distinct in many parts of the body. There can at once be observed, distinctly separated from the general parenchyma, unstriated muscles, of which some are transversely annular, and many others narrow and longitudinal.(1) The first, subcutaneous and widely separated from each other, are usually upon the borders of the segments of the body. The second, divisible into dorsal, ventral and lateral portions, arise from the internal surface of the skin, and are inserted at the cephalic or opposite extremity.(2) The posterior extremity of those species which move freely, has two stiff points of variable length, which are moved as tentacles by two cylindrical, or clavate, caudal muscles. Some have long, movable bristles or pedicles,.by which they row along or move by quick leaps.(3) ~ 133. The prominent characteristic of the Rotatoria is the retractile, vibratile apparatus at their cephalic extremity, known as the rotatory organs. By these, they swim freely about, revolving upon their axis, or, when at rest, produce vortex-like motions of the water. The form, number, and arrangement of these organs varies much according to the genera, and may be used even to characterize families. The rotatory organ is either single, double, or multiple. Often it consists of a disc, supported by a pedicle of variable length, upon whose borders are successive rows of regularly-arranged cilia, the motion of which gives the appearance of rotation to the disc itself. This apparent motion 2 With Conochilus, Megalotrocha, Lacinula- cles of Euchlanis triquetra are transversely stri-.ria, Brachionus, Noteus, Squamella, PNotom- ated like those of the higher animals (Die Infusmata, and Stephanops, the tail is transversely ionsthierchen, p. 462, Taf. LVII. fig. 8). marked or articulated. With many species of Hy- 2 For the muscles of the Rotatoria in general, see datina, Rotifer, Philodina, Actinurus, and Eos- Ehbrenberg, loc. cit. and his description of the Hyphhora, not only the caudal extremity, but the whole datina senta, in the Abhandl. d. Berl. Akad. 1830, body, is regularly segmented., and capable, espe- p. 47. cially at the posterior extremity, of being intussus- 3 Many Rotatoria use their caudal pincers as a cepted or drawn out, like a telescope. fulcrum when creeping along. Philodina moves 3 A solid carapace, like the shell of Daphnia, is along in a leech-like manner, using its mouth and found with Brachionus, Anuraea, NToteus, Salpi- tail as suckers. Polyarthra has many bundles of na and Esuchlanis. bristles upon the sides of its body, which it uses as 1 The muscles are smooth when at rest, but when oars. Triarthra has under the throat and at the Contracted, they appear more or less distinctly pli- posterior extremiiy of the body, long stiff bristles, cated transversely. The assertion of E'hrenberg articulated with the body, and by which these aniis therefore remarkable, that the longitudinal mus- mals can leap like a flea. 144 THE ROTATORIIA. ~ 134 is quite remarkable with those species whose single or double disc is not. crenulate, but entire.(1) With those whose organs are more numerous, but, smaller, this appearance is not observed.(2) With Floscslaria, and Stephanoceros, the rotatory organs have quite a, different form. With the first, there are five or six button-like processesabout the mouth, covered with very long bristles; these bristles produce usually but very feeble motions, and rarely give rise to vortexes. But Stephanoceros reminds one much of the Bryozoa, for its rotatory apparatus consists of five tentacle-like processes covered with vibratile cilia(3) The rotatory organs differ, moreover, from the ordinary vibratile cilia of epithelium,, in being under the animal's control, —that is, moved or kept at rest, at will. (4) CHAPTERS III. AND IV. NERVOUS SYSTEM AND ORGANS OF SENSE. ~ 134. Notwithstanding the transparency of the Rotatoria, and the distinctness with which their organs are separated from each other, yet their nervous system has not yet been made out with certainty, for their bodies are so small that their peripheric nerves elude the microscope, and their principal nerves and ganglia cannot be distinguished from the muscular fasciculi, the ligaments, and the contractile parenchyma of the body. It appears certain, however, that in all, there is, as a nervous centre, a group of cervical ganglia, from which pass off threads in various directions. (1) 1 Conochilus, Philodina, and Actinurus. uliform body found upon most Rotatoria, and in 2 Hydatina, Notommata, Synchaeta, and Dig- the neck of Hydatina senta, and Notommata col-. lena. laris (Abhandl. d. Berl. Akad. 1830, p. 52, Taf. 3 See Ehrenberg, Die Infusionsthierchen, Taf. VIII. 1833, p. 189, Taf. IX., and, Die InfusionsthierXLV. chen, p. 386, &c.). Besides this ganglion, he has 4 According to Ehrenberg, there are, at the base mentioned with Hydatina, Synchaeta, and Digof each cilium of the rotatory organs, many striated lena, many others scattered through the anterior muscles, which, acting antagonistically, produce the part of the body, and connecting with the cerebral motion (Abhandl. d. Berl. Akad. 1831, p. 34). one by nervous filaments. Likewise, with EnterBut neither Dsejardin (Infusoires, loc. cit. p. oplea, Hydatina, Notommata, and Diglena, he 579), nor Rymer,.ones (Compar. Anat. &c. p. has regarded as a nervous loop, the two filaments 120), has been able to perceive this apparatus. which pass off from the cerebral ganglion, and go to The contractile parenchyma on which the virbra- the cervical respiratory orifice. Finally, he refers tile discs are situated, appears to be destined only to the sensitive system, a white sacculus, single or for the protrusion and retraction of the rotatory double, and situated behind the cerebral ganglion, organs.* with Notommata, Diglena, and Theorus (Die 1 Ehrenberg, to whom we are indebted for our Infusionsthierchen, p. 425). Grant's description of chief information upon the nervous system of these the nervous system of the Hydatina, as being animals, first took for a cerebral ganglion the gland- composed of many ganglia and a ventral cord, * [ ~ 133, note 4.] Dobie (Ann. of Nat. Ilist. 1848) long and filiform, of uniform thickness, and not speaks of two kinds of cilia with Floscularia; " one vibratile under ordinary circumstances." They are of the usual short vibratile kind, covering the inte- slowly moved, being spread out by the contractile rior of the alimentary tube; the other extremely substance of the lobes of the rotatory organ. - EDo 9~ 135, 136. THE ROTATORIA. 145 ~ 135. Beside the sense of touch, apparently located chiefly in the rotatory organs and their tentaculiform processes,(1 ) these animals have also an organ of vision. Usually this consists of a single or double eye-speck upon the neck; and sometimes, though rarely, of three or four red specks; upon the forehead. (2) These specks are usually very small, but nicely defined, and covered by a kind of cornea. They are situated immediately upon the cerebral ganglion, or are directly connected with it, by nervous filaments.0( " CHAPTER V. DIGESTIYE APPARATUS. ~ 136. The digestive apparatus is well developed with the Rotatoria, and has the following parts: The mouth opens into a muscular pharynx which has two horny, masticatory organs, which move laterally upon each other. Succeeding this pharynx is a narrow osophagus of variable length, which leads to a stomachal. (Outlines, &c., p. 88, fig. 82, B.), is founded, un- regretted since Dujardin has not regarded them, doubtedly, upon supposition, and not upon real ob- as visual organs (Infusoires, p. 591). IIe supservation.* ports this view by the fact that they disappear with 1 The vibratile disc of Conochilus has upon its the adult individual; but this objection will appear' centre,four cylindrical processes, terminating usu- valueless when it is remembered that this is also ally by a bristle, and quite resembling antennae. true of certain parasitic Crustacea. At all events,. The two or four styles projecting from the front of the small ocular dots of Conochilus, Rotifer, and Synchaeta, are probably of the same nature. Philodina, are nicely-defined organs surrounded. 2 The eye-speck is simple with Euchlanis, No- with a solid capsule, and appear to me wholly dif — tommata, Synchaeta, Cyclo-lena, and Brachio- ferent from the dffused masses of red pigment nus; double with Conochilus, Mleegalotrocha, which Elhrenberg has erroneously taken for eyes Diglena, Rotifer, and Philodina; with Eosphora, with the Infusolria. The disproportionate size of' there are three, and with Squamella, four; while the red dots which Ehrenberg (Die InfusionsthierHydatina, Enteroplea, Ptygura, Tubicolaria, chen, Taf. LI. LIIIJ.LVI.) has figured with Nfotomand the adult Flosculariae, have none at all. mataforcipata, Synchaeta baltica, Cycloglena,. 3 Ehrenberg, who was the first to regard these and Eosphora, lead one to suppose that they arered dots as eyes, has given their intimate structure only collections of pigmentary granules. in none of his writings; this is the more to be * [ ~ 134, note 1.] Gosse (Ann. Nat. IIist. 1850, p. of four bipolar cells with their processes. 2. A gan21) describes the nervous system of Asplanchna glion at the beginning of the caudal prolongation, priodonta as follows: "Each of the three eyes rests similarly composed of four larger ganglionic cells'n a mass that appears ganglionic; the clubbed and their processes." But, that these parts belong masses at the lateral apertures are probably of the to the nervous system, appears by no means posisame character; and the interior of the body con- tive i for, as, this observer candidly observes, and tains a number of very delicate threads, floating it is, I think, a capital comment on this whole freely in the contained fluid, which have thickened class of study: " That these cells, with their radiatknobs here and there, especially where they anas- ing processes, are ganglion globules and nerves, istomose." a conclusion drawn simply from the histological Leydig (Zur Anat. und Entwickelungsgeschichte constitution of the parts, and from the impossibility der Lacinularia socialis, in Siebold and Kolliker's of making anything else out of them, unless inZeitsch. Feb'y, 1852, p. 457) describes a very pecu deed, organs are to be named according to oiw liar nervous system with Lacinularia, consisting mere will and pleasure." - ED. of: "' 1. A ganglion behifd the pharynx, composed 13 146 THE ROTATORIA. ~ 136. dilatation. This dilatation is continuous into an intestine which opens externally by an anus. The mouth is always between the rotatory organs, so that it receives what is drawn in by their vortical action, - the animal swallowing or rejecting the particles at will.(') The pharyngeal masticatory apparatus is round, and composed of two jaws having one or several teeth, which are brought together laterally by the action of special muscles.(2) Usually these jaws are formed of two knee-shaped divisions (Processus anterior and posterior). The posterior division gives insertion to the masticatory muscles, but the anterior terminates with a tooth,(3) or as a multidentate apophysis.() WVith some which have this last arrangement,(5) the two jaws are formed of three horny arches, and noted for their stirrup-like form. Two of these arches (Arcus superior and inferior), form the arched portion of the stirrup, pointing inwards, while its base is formed by the third arch (Arcus externus), pointing outwards. The masticatory muscles are inserted upon the inferior arch, and move against each other - the transversely-arranged teeth passing over the other two. With the multidentate Monotrocha, and Zygotrocha, the pharynx rests always in the same locality; but with the unidentate Polytrocha, it can move up and down, and even be protruded through the mouth. In this last case, the teeth serve as pincers for the seizure of food. The intestine usually traverses the cavity of the body in a straight line, rarely looping,() and is lined throughout with ciliated epithelium. From the stomachal dilatation to a point near the anus, its walls are very thick. The walls of the stomach and intestine are formed of large cells with a colorless nucleus, and which, as they contain a brownish or,greenish granular substance, are of an hepatic nature. With most species, two caeca, rarely more, with thick walls and lined with ciliated epithelium, open on the right and left of the beginning of the stomach. Their walls are also composed of large cells, which, as they differ widely from the hepatic ones by their colorless contents, may perhaps serve the function of salivary glands or pancreas.(7) The term Rectum has been given to a short and terminal portion of the intestine, which has thin walls, capable of being widely distended by feces. Its orifice is excretory not only of the fseces, but also of the contents of the genital organs and of the aquiferous system - and may therefore be regarded as a cloacal as well as an anal opening. It is nearly always at the base of the caudal extremity. 1 The tentaculiform, rotatory organs of Stephano- size throughout, except the rectum which is dilated. eeros, are also used for the seizure of foodi see But it is coiled, especially with those which are Ehrenberg, Abhandl. d. Berl. Akad. 1832, Taf. enclosed in a carapace, as with Tubicolaria, and XI. fig. 1, e., also, Die Infusionsthierchen, Taf. Melicerta, since here the anus is far in front. XLV. fig. II. 5. 7 These two pancreatic caeca are nearly always 2 For the structure of the teeth, see Ehrenberg, present, being wanting only with some species of Abhand. d. Berl. Akad. 1831, p. 46, Taf. III. IV. Ichthydisum. MWith Notonmmata claets.lata, and 3 Pleurotrocha, Furcularia, and many species Diglena lacsstris, there are, besides these caeca of Notommata, and Diglena. which are long, attached to the stomach many 4 Hydatina, Euchlanis, Salpina, Anuraea, smaller sacs, which are colorless and perhaps of Brachionus, and many species of Notommata, the same nature. and Diglena. With Megalotroc/ea albo-flavicanLs, there are b Philodina, Lacinularia, Melicerta, and also two like caecal appendages entering the base Conochilus. of the stomach, and which are independent of the 6 With Euchlanis, and Brachionus, the stom- short pancreatic ones of the same locality i see ach is separated from the intestine by a constric- Ehrenberg, Abhsandl. d. Berl. Akad. 1831, Taf. *ion, and with Philodina, the intestine is of equal III. and, Die Infusionsthierchen, Taf. L. LIV. .Qt~~ 137, 138. THE ROTATORIA. 147 CHAPTERS VI. AND VII. CIRCULATORY AND RESPIRATORY SYSTEMS. ~ 37. As no sanguineous system has yet been found with the Rotatoria, it must be admitted that all the organs are bathed directly by the nutritive liquid which transudes through the intestine.(l) ~ 138. The vessels observed with the Rotatoria belong probably to the aquiferous,system, which, from its structure and limited distribution, must be regarded as of a respiratory nature. In most species, a straight and riband-like organ is seen upon each side of the body, which contains a stiff, tortuous, vasculiform canal. At the anterior extremity of these two lateral bands, their canals connect with many short lateral vessels which open into the cavity of the body, - their orifices being furnished each with a very active, vibratile lobule. (1) These lateral orifices have the appearance of pyriform, or oval corpu'scles, in the interior of which, the vibratile lobule, produces the aspect, when *its motions are diminished by pressure between plates of glass, of a small, flickering flame. The number of these organs varies with the species, and also, it would appear, even with different individuals of the same species. Usually there 1 The sanguineous vessels which Ehrenberg has tions, or muscles. From their extreme tenuity, it frequently described and figured, have not ap- is difficult to determine the nature of the other filipeared as such to Dujardin (Infusoires, p. 589), form organs in the body of the Rotatoria, and which Rymer Jones (Comp. Anat. p. 125), Doy~re Ehrenberg has also referred to the sanguineous (Ann. d. Sc. Nat. XVII. 1842, p. 201), and my- system. But, equally well might they be taken for self. muscular fasciculi, ligaments or nerves.* The so-called annular vessels encircling the body 1 Ehrenberg was the first to point out these,of many species at regular and wide distances, and vibratile organs, and designated them as the interwhich, as he himself avows (Die Infusionsthier- nal gill-like respiratory organs (Abhandl. d. Berl. lchen, p. 415), are not connected by longitudinal Akad. 1833, p. 183). vessels, are undoubtedly only the transverse sulca* [~ 137, note 1.] Dalrynsple (Phil. Trans. or appendices, whose free extremities are directed 1849, p. 334) has described with Asplanchna towards the interior of the animal, and are affected Brightwellii what he regards as a peculiar cir- by a tremulous, apparently spiral motion, like the,culatory system. It " consists of a double series threads of a screw. This is undoubtedly due to of transparent filaments (for there is no proof of cilia arranged round these minute appendices. their being tubes or vessels), arranged, from above The tags are from eight to twelve, or even twenty, downwards, in curved or semicircular form; sym- in number, varying in different specimens." I:le nlletrical when viewed in firont. These filaments, thinks these organs fulfil their function by the cilabove and below, are interlaced loop-like; while iated tags producing currents in the fluid which another fine filament passes in a straight line, like fills the body of the animal. the chord of an arc, uniting the two looped extrem- These observations are curious and deserve furIties. To this delicate filament are attached tags, ther attention. - ED. 148 THE ROTATORIA. 139, are two or three on each side, and sometimes there;,re from five to eight pairs,(2) but rarely more.(3) The lateral bands approach each other at the posterior extremity, and their canals join in a common, highly-contractile vesicle with thin walls, which empties externally its aqueous contents through the cloacal opening. (4) An orifice, situated usually upon the neck, and sometimes pedunculated,. serves probably to introduce the water into the cavity of the body. This. water enters the aquiferous system through the lateral vessels which float free in this cavity, and at last is expelled through the contractile vesicle. In this way, a constant renewal of water can occur, and the opening upon the neck may therefore be properly termed a respiratory orifice or tube.(5) There can be but little doubt that the rotatory organs also, have a respiratory function, for their surface is covered with thin epithelium, and their cilia produce a constant change of the water. CHAPTER VIII. ORGANS OF SECRETION. ~ 139. Some of the Rotatoria secrete a gelatinous substance, which, hardening forms the cells and tubes into which they can partly or wholly withdraw themselves. The -organ of this secretion is yet unknown; but the secretion appears to be derived from the posterior extremity, and especially from the, cloacal opening. a) 2 Notommata copeus, and syrinx. Brachionus, and some species of Salpina, Esuch3 With Notommata clavulata, and m.yrmeleo, lanis, and Notommata, it is replaced by a tube. the number of these organs is remarkable; each With Actinuruts, exceptionably, a simple reslateral band has thirty-six to forty-eight see piratory tube is placed under the throat; and with Ehrenberg, Die Infusionsthierchen, Taf. XLIX. L. Tuubicolaria, and Melicerta, there are two in the 4 Ehrenberg was the first to direct the atten- same region. tion of naturalists to these two lateral bands and iWith Conochilus, and Lacinularia, where their contractile vesicles5 but he regarded them several individuals are attached by their tails as two testicles with their vesiculae seminales around a comnlon centre, the nucleus of one of (Abhandl. d. Berl. Akad. 1830, p. 51). The incor- these colonies is formed by a loose, gelatinous subrectness of this opiiion, and which he has main- stance, in the cells of which these animals can partained in his grand work, cannot be doubted, if it tially withdraw themselves. With Oecistes, Tu is considered that these two bands with their bicolaria, Stephanoceros, Floscitlaria, and Lim appendages are already developed and in activity nias, each individual occupies an isolated andt with the young animals, and this even before they more or less hard gelatinous tube (Ehrenlberg, Die have escaped the cavity of the parental body. Infusionsthierchen). The tubes of Aflelicerta, of In all Ehrenberg's published figures, one no- which Schalffer has given an excellent figure (Die tices nothing of the flexuous canals of these or- Blumlen-polypen der sdissen Wasser 1755, Taf. I. gans, and which, therefore, he does not appear to II.), are very remarkable, and according to Elren - have observed. berg, are composed of blown polygonal cells which 5 The respiratory orifice is cervical with Entero- are excreted through the cloacal opening and plea, Hydatina, Diglena, and many species glued together (Die Infusionlsthierchen, p. 406). of Noftommata; but, with Rotifer, P/hilodinea, 4 140. THE ROTATORIA. 149 CHAPTER IX. ORGANS OF GENERATION. ~ 140. Althcugh it is certain that the Rotatoria propagate only by genital organs, yet the female organs only are yet well known. These consist of a fingle or double ovarian tube of variable length, situated upon the sides of the intestinal canal at the posterior part of the cavity of the body, and ~opening into the cloacal cavity through a short oviduct. These ovaries never develop but a few eggs at a time. The mature eggs are always,oval and surrounded by a simple, solid, colorless envelope. They contain a finely granular and usually colorless vitellus, in which there is a distinct germinative vesicle. Many species are ovigerous, but a few only are viviparous. (1) It would be naturally supposed that these animals, which have such distinct female organs, would have also those of the other sex. But as yet the most minute researches have failed to detect them. It is therefore doubtful whether these animals are hermaphrodites or of separate sexes.t (2) 1 For the various forms of the ovaries see the ing to Ehrenberg (Die Infusionsthierchen p. 483), classical works of Ehrenberg. With Philodina always surrounded with an extensible membrane roseola, Brachionus rubens, and Mastigocerca of the ovary (uterus). But it has always appeared carinata, the vitellus of the eggs as well as the to me that the mature eggs of the viviparous Phiparenchyma of the body is of a reddish color. lodinae, are detached from the ovaries and fall into With those, species which live in the tubes, the the cavity of the body, where afterwards the eggs are usually deposited in the cavity of these hatched young move about. Perhaps oviducts are last. But with Triarthra, Polyarthra, and here wanting and the young escape from their Brachionus, they remain glued to the cloacal parent through an orifice near the cloacal openopening. ing.* With Philodina, the young are often hatched 2 Admitting that there are here male genital in the cavity of the parental body, and are, accord- organs, the respiratory tube upon the neck of * [ ~ 140, note 1.] The view here expressed that thinks also that he observed a well-defined introthe young of the viviparous Philodinae may find mittent organ confected with the testis, and a their escape from the body of the parent through passage for its extension from the body of the an opening near the anus —the oviducts being animal. perhaps wanting - is probably correct, since, in the In verification of this observation it may be menviviparous Aphides, where the processes of repro- tioned that Brightwell observed the actual coitus duction occur likewise by a kind of gemmiparity, between the sexes, and Gosse (loc. cit. p. 22) has there are, according to my observations, no ovi- witnessed the development of the males from the ducts proper, but the young, having fallen into the ovum. abdominal cavity, thence escape through a Porus Huxley, on the other hand (Quat. Jour. Mic. genitalis situated near the anus.- ED. Sc. No. I. Oct. 1852, p. 1), has found with Lacint [End of ~ 140.] The discovery of distinct ularia no trace of a male individual, but in some males with the Rotatoria is due to Brightwell specimens he observed singular bodies which (Ann. Nat. Hist. Sept. 1848) who has positively answered precisely to Kblliker's description of the determined it with.splanchna. Here it is about spermatic particles of Megalotrocha. Hie says, half the size of the female, being also of a different 6" They had a pyriform head about 1-1000 in. in form; it is exceedingly transparent and easily eludes diameter by which they were attached to the parietes observation. The testis appeared as a round ves- of the body, and an appendage four times as long eel situated at the bottom of the body on one side, which underwent the most extraordinary contorand filled with ef ermatic particles. This author tions, resembling however a vibrating membrane 135 150 THIE ROTATORIA. ~ 141. ~ 141. Their embryonic development occurs, as in most invertebrate animals, through a complete segmentation of the vitellus; and the embryonic cells then appear in the segmented portions. The newly-hatched embryo has already rotatory and masticatory organs, eye-specks, &c., and the general form of the adult animal.t (1) many species was formerly taken for a penis. But animals (Froriep's neue Not. No. 28, 1843, p. the incorrectness of this view has since been seen, 17). But this whole observation is somewhat susfor no one has here observed the copulatory act. picious, for Kolliker has very probably confounded According to Ehrenberg, who regards these ani- the vibratile lobules of the aquiferous system with mals as hermaphrodites, certain parts of the aquif- the spermatic particles, and of which there are four erous system represent the male organs. Hie with Megalotrocha in the anterior extremity. regards the two lateral bands as testicles, and The observation of R. Wagner (Isis, 1832, p. 386, their inferior extremities as vasa deferentia, while Taf. IV. fig. 1, 7) is particularly worthy of attenthe contractile vesicle is the vesicula seminalis. tion, for followed out, it might lead to the discovery But these organs contain only an homogeneous here of male genital organs. HIe has described aqueous fluid, in which there is at no time anything peculiar eggs, found frequently by him with Hylike spermatic particles moreover they are fully datina senta, and whose whole surface is covered. developed in the young individuals which then with very fine, thickly-set hairs. Ile has regarded have no trace of female organs. these as in their first stages of development,. It would be wholly anomalous that these ani- although Ehrenberg (Abhandl. d. Berl. Akad. mals should constantly secrete sperm during their 1835, p. 154, and, Die Infusionsthierchen p. 415), whole life. One would therefore wholly assent to has taken this villous envelope for an alga of the the doubts of Dujardin (Infusoires, p. 587), upon genus Hygrocrocis. But these villous envelopes this view of Ehrenberg, and some contradictions have always reminded me of the masses of sperm-i into which this last has fallen upon this subject, atic particles in the testicles of leeches and which have been noticed by Doydre (Ann. d. Sc. Nat. have been figured by Henle as whitish felt-like XVII. 1842, p. 199). K61liker has also thought globules (Miiller's Arch. 1835, p. 584, Taf. XIY. this view unfounded, and has sought to remove fig. 6. a). the doubts by a search after the spermatic parti- [Additional jNote.] Kdlliker (Neue Schweiz. cles. tie regards as such, with Megalotrocha Denkschr. VIII. Taf. II. fig. 31, a.) having since albo-ftavicans, the peculiar trembling bodies which figured the spermatic particles of Ilegalotrocha he has seen in the cavity of the body, since they albo-flavicans, my former view that he had conare composed of a pryiform body, to which is founded these with vibratile organs, is incorrect.* attached a movable tail. These bodies he affirms 1 K6lliker was the first to observe the complete are developed in round cells, often nucleated, and segmentation of the eggs, with Megalotrocha~ he has often counted ten to twenty in the same (Froriep's neue Not. loc. cit.). It wholly escaped individual. As he also asserts to have seen eggs the observation of Ehrenberg amid his numerousl at this time in the same individual, this would cer- researches upon the eggs of these animals; see tainly be a proof of the hermaphroditism of these Abhandl. d. Berl. Akad. 1835, p. 152.4 more than the tail of a spermatozoon." He very 452) and to Huxley (loc. cit. p. 11-15), for extendjustly concludes that they cannot at present be ing our knowledge in this direction. They have definitely regitrded as spermatic particles. - ED. carefully observed the development of Lacinu* [~ 140, note 2.] The subject of the form and laria, and the phases correspond exactly with character of the spermatic particles of the Rotatoria those of Megalotrocha as described by Kolliker. is quite interesting, as it may perhaps throw some But beside this ordinary mode. of reproduction,. light on the position of these animals in the animal they have observed another which is a sexual and kingdom. As yet, however, we have very few analogous if not identical with what has been observations, and even these are not fully defi- observed with some of the lower Crustacea (see nite. infra ~ 292), - propagation by the so-called hiberSchmidt (Vergleich. Anat. &c. p. 268, note) nating eggs. Their observations throw light on the speaks of the spermatic particles of Euchlanis whole of this interesting subject, and have fully macrura, as being cercaria-form. confirmed me in my previous conjectures that these Leydig (Siebold and Kblliker's Zeitsch. III. " Ova " are only genmae having their exact reprelift. 4, p. 471) has given those of Lacinularia as sentative in the bud-like eggs of the viviparous composed of a nuclear body from which radiate Aphides. - ED. many tails, like these particles with the Decapods. i [ ~ 141, note 1.] K6lliker's observation aboveSee Taf. XVII. fig. 2. -ED.. mentioned on Megalotrocha, has since been cont [End of ~ 141.] We are indebted to Leydig firmed by Leydig (Isis, 1848, p. 170) who has (Zur Anat. u. Entwickelungsgesch. d. Lacinularia observed it likewise with Notommata and Euchsocialis, in Siebold and K6lliker's Zeitsch. III. p. lanss.- ED. BOOK EIGHTH. ANNELIDES. CLASSIFICATION. ~ 142. THE ANNELIDES are distinguished from all other worms by their ventral, ganglionic cord, and by their annulated body, at the two extremities of which there is a mouth and anus. They resemble the Arthropoda, but at the same time differ from them in having a completely closed vascular system, and in wanting articulated, locomotive organs. The epithelium of their body is not ciliated except where it covers the external branchiae. The Nemertini, which have hitherto been classed among the Turbellaria, belong more properly to the Annelides, since their body is more or less distinctly articulated, and its parenchyma closely resembles that of the Hirudinei. Moreover, the power which many of them have to divide spontaneously into many segments, is another affinity with various Annelides. It will therefore appear proper to unite the Nemertini with the other Annelides in the following manner: (1 ORDER I. APODES. Body without bristles. S UB-ORDER I. NEMERTINI. Posterior extremity of body without a sucker; cephalic extremity often provided with lateral respiratory fossre. 1 Since K6lliker (Verhandl. d. Schweiz. naturf. visit at Trieste in 1847, been convinced that Gesellsch. zu Chur. 1844, p. 89) and Quatre- these animals should be classed among the Turfages (Ann. d. Sc. Nat. VI. 1846, p. 113) have bellaria, and that they especially deserve this name published their researches on the anatomy of since their entire body is covered with very -disthe Nemertini, I have, also, during my last tinct vibratile cilia. -A dditional note. 152 THE ANNELIDES. g 142. Genera: Tetrastemma, Polystemma, Micrura, Notospermus, Mleckelia, Polia, Nemertes, Borlasia. sUB-ORDER IL. HIRUDINREI. Posterior extremity of body provided with a sucker. Genera: Branchiobdella, Piscicola, Clepsine, Nephelis, Haernopis, Aulaco. stornum, Sanguisuga, Pontobdella. ORDER II. CHAETOPODES. Body provided with tL;b+1ts. SUB-ORDER ZIi. IJ7MBRICINI (ABRANCHIATI.) Body without feet. Genera: Chaetogaster, E.?chytraeus, Nais, Lumbriculus, Euaxes, Saenu. ris, Lu-obhricus, Sternaspis. SUB-ORDER IV. CAPITIBRANCHIATI. Body provided with feet; branchiae situated upon the cephalic ex. tremity. 4Genera: Siphonostomum, Chloraema, Amphicora, Serpula, Sabella, Amphitrite, Terebella. SUB- ORDER V. D ORSIBRANCHIA TI. Body provided with feet; branchiae situated upon its segments. Genera: Arenicola, Ammotrypane, Chaetopterus, Aricia, Aricinella, Cirratulus, Peripatus, Glycera, Goniada, Nephtys, Alciopa, Syllis, Phyllodoce, Hesione, Lycastis, Nere's, Oenone, Aglaura, Lumbrinereis, Eunice, Amphinome, Sigalion, Polyno', Aphrodite. BIBLIOGRAPHY. Pallas. Miscellanea zoologica. Hague, 1766, p. 72. O. F. Midiler. Von den Wiirmen des siissen und salzigen Wassers. Copenhagen, 1771. Savigny. Description de 1'Egypte. Histoire Naturelle. Tom. XXI. 1826. Annelides. Also, Isis, 1832, p. 937. Moquin-Tandon. Monographie de la famnille des Hi-Irudinees. Paris, 1827. MIorren. De lumbrici terrestris historia naturali, nec non Anatomia. Bruxelles, 1829. ~ 142. THE ANNELIDES. 153 Andouin et Milne Edwards. Classification des Annelides, et descriplion des especes qui habitent les cotes de la France, in the Annales des Sciences. Tom. XXVII.-XXX. 1832-33, but published separately under the title, Recherches pour servir d i'histoire naturelle du littoral de la France. Tom. II. Paris, 1834. Ehrenberg. Symbolae physicae. Phytozoa turbellaria. Milne Edwards. Cyclopaedia of Anatomy and Physiology, vol. 1, 1836. Art. Annelida. Grube. Zur Anatomie und Physiologie der Kiemenwiirmer. K6nigsberg, 1838; also, Aktinien, Echinodermen und Wiirmer des Adriatischen,und Mittelmeers. Konigsberg, 1840. Orsted. Gr6nlands Annulata dorsibranchiata. Kj6benhaven, 1843. Annulatorum Danicorum conspectus. Fasc. I. Maricolae. Hafniae, 1843. Entwurf einer systematischen Eintheilung und speciellen Beschreibung der Plattwiirmer. Copenhagen, 1844. Hoffmeister. De vermibus quibusdam ad genus lumbricorum pertinen-tibus. Berolini, 1842. RathkL. Zur Fauna der Krim. St. Petersbourg, 1836, p. 117. De Bopyro et Nereide. Rigae, 1837. Beitrige zur vergleichenden Anatomie und Physiologie; in the Neuesten Schriften der Naturforschenden Gesell-,schaft in Danzig, III. Hft. 4, 1842, p. 56. Beitrage zur Fauna Norwe-,gens; in the Nov. Act. Acad. Nat. Cur. XX. pt. 1. 1843, p. 149. ADDITIONAL BIBLIOGRAPHY. Besides the references in my notes, see the following writings: Moquin-Tandon. Monographie de la Familie des Hirudinees. Nouv. Ed. revue et augmentee, accompagn~e d'un Atlas de 14 planches gravees et coloriees. Paris, 1846. Schmidt. Neue Beitrage zur Naturgeschichte der Wiirmer. Jena. 1848. (zweiter Abschnitt, Ringelwfirmer). Quatrefages. Etudes sur les types inf6rieurs de l'embranchement des Anneles, containing: Memoire sur la Familie des Hermelliens, Ann. d. Sc. Nat. 1848, X. p. 1.; Sur la Circulation des Annelides, Ibid. XIV. 1850, p. 281; Sur la Respiration des Annelides, Ibid. XIV. 1850, p. 290; Memoire sur le Systeme Nerveux des Annelides, Ibid. XIV. 1850, p. 329; Me3moire sur le Systime Nerveux, et les affinities et les analogies des Lombries et des Sangsues, Ibid. XVIII. 1852, p. 167; Memoire sur le Branchellion de D'Orbigny, Ibid. XVIII. 1852, p. 279. Note sur le Systeme Nerveux et sur quelques autres points de l'Anatomie des Albiones, Ibid. XVIII. 1852, p. 328. Meimoire sur l'Embryogenie des Annelides. Ibid. X. 1848, p. 153. Leydig. Zur Anatomie von Piscicola geometrica mit theilweiser Vergleichung anderer einheimischer Hirudineen, in Siebold and Kclliker's Zeitsch. I. 1849, p. 103. Anatomisches iiber Branchellion und Pontobdella. Ibid. III. 1851, p. 315. Leidy. Descriptions of some American Annelida abranchiata, in the Jour. Acad. Nat. Sc. Philad. 1850, II. p. 43 [contains many anatomical details]. - ED. 154 THE ANNELIDES. ~~ 143, 144. CHAPTER I. CUTANEOUS SYSTEM. ~ 143. The skin of the Annelides consists of a very thin, non-ciliated epidermis,(') and a more or less compact dermis composed of solid, but delicate fibres obliquely intertwisted. The iridescence and often splendid colors of many of the Chaetopodes, are not due to a pigment, but to an optical effect produced by the reticulated union of the dermic fibres. But the Apodes, on the other hand, owe their many colors to a pigment net-work and cells. Usually the epidermis is separated with difficulty from the dermis, but with many Capitibranchiati, and Dorsibranchiati, the opposite is true. With the Apodes, the skin is closely united with the subjacent muscular layer. With many Dorsibranchiati, the skin has filiform or lamellar appendages sometimes so much developed that they overlap each other like scales.(2' With some Chaetopodes, there are, beside the bundles of locomotive bristles and hairs, numerous appendages of this kind covering most of the body. (3 CHAPTER II. MUSCULAR SYSTEM AND LOCOMOTIVE ORGANS. ~ 144. The muscles of the Annelides, although highly developed, are never striated. The whole body is enveloped by a subcutaneous muscular layer divisible into three sheets: an external, of circular fibres; an internal, of longitudinal fibres; these are the most developed. Then a middle one composed of obliquely intertwisted fibres; this is less distinct, and sometimes entirely wanting.t1) 1 The external respiratory organs alone are 3 The back of Aphrodite hystrix has numerous covered with ciliated epithelium. Orsted (Beschreib. bristles and hairs; with Aphrodite aculeata, these d. Plattwiirmer, loc. cit. p. 77) however, affirms hairs are so thickly set that they conceal the back that the body of the Nemertini is provided with by a kind of felt. vibratile cilia. But this is to me improbable at 1 The middle muscular sheet is found with the least with the large species of Borlasia, NVemertes, Hirudinei and Lumbricini; see Brandt and Ratand Polia. zeburg, Med. Zool. II. p. 244, Taf. XXIX. fig. 1, At all events this statement of his requires new 2, and Morren, loc. cit. p. 83. proof. See additional note under ~ 142. But with the Nemertini it is wanting; see 2 Scaly appendages of this kind cover the back RathkW, Neueste Schrift. d. naturf. Gesellschaft, in of Aphrodite, Polynoe, and Sigalion. With Danzig. loc. cit. p. 95. Polynoe squamata, they are very easily detached. 145. THE ANNELIDES. 155 With the Apodes, this muscular envelope so closely embraces the viscera,, that the cavity of the body is made very small. But with the Chaetopodes, this cavity is larger. With many of the Branchiati, the muscular fibres form distinct fasciculi - so that instead of a common muscular envelope there are longitudinal and annular muscles distinct from each other.(2) With many Chaetopodes, the internal surface of this envelope sends off annular muscular septa into the cavity of the body, at the junction of the, segments, — thus dividing this last into as many chambers as there are segments; sometimes these septa bind the intestinal canal so closely, as tu( regularly constrict it.(3' ~ 145. Besides the common subcutaneous muscles, which produce- the1 vermecular motions of the body, there are other groups: 1st. Flor the auxiliary locomotive organs, and 2nd, for many other organs. 1. The Hirudinei are distinguished, as is well known,. by, a sucker sictu ated at their posterior extremity, which contains both circular and. radiating muscular fibres. This sucker serves both to move and to attach, the body. All the Chaetopodes have short, horny stings (acicuZi),. and long bristles, (setae), united in fasciculi of various forms, which they use: as fulcra. when they creep, or as oars when they swim. With the Branchiati, these organs are most fully developed,and are nearly always situated laterally upon a double row of fleshy knobs;, and those of the two inferior rows may be regarded as rudimentary feet. The Lumbricini have short and usually S-shaped stings which are atrranged in many rows upon the belly, and may be wholly withdrawn into the abdominal cavity. Beside these last, Nais has also a row of bristles each side of the, body.(1l 2 These separate muscles are found in Aphro- The number of these organs may therefore varydite, Polynoe, and Nereis, with which the longi- very much upon the different segments of the same tudinal ones especially, are seen separated into individual. It is remarkable that with the Lum dorsal, ventral and lateral layers. See for the bricini the stings are often detached interiorly, and:' subcutaneous muscles of the Branchiati in gen- falling into the cavity of the body form there tough eral, Rathki, De Bopyro et Nereide, p. 29, Tab. masses which are glued together by a viscous subIL., and in the Danzig. Schrift. loc. cit. p. 62, Taf. stance lodged in the posterior chambers of the IV. fig. 6; also Grube, Zur Anat. und Physiol. d. body; see Hoffmeister, De vermibus quibusdam, Kiemenwiurmer, p. 4. et seq. loc. cit. Tab. II. fig. 3, and in Wiegmann's Arch. 3 When these septa are largely developed, and 1843, I. p. 196. These agglutinated masses inr embrace closely the digestive canal, as in Lum- which are lodged usually various kinds of vibrioid; bricus, Sabella, Serpula, and Eunice, there are parasites, have been taken by Montigre (Observ_ always foramina in these diaphragms or septa, sur les Lombries, in the Mdm. du Museum I. p.. through which the contents of the cavity of the 246, fig. 5, 6, g) for the eggs and foetuses of thebody can pass from one chamber into another.* Lumbricini. lMotrren (loc. cit. p. 195, Tab. XXV.1 The stings and bristles of the Abranchiati, XXIX.) has gone even further, by taking theseupon whose various forms see Orsted (Conspectus stings for the chrysalids, and their enclosed vibriose; generum specierumque Naidum, in Kroyer's for the embryos of these animals. Naturhistor. Tidskrift. IV. 1842, p. 128, Pl. III.), are easily lost from use, but are as easily reproduced. *[ [ 144, note 3.; The development and inti- of these elementary parts. The fibre is not trans-. mate structure of the muscles of the Annelides has versely striated, and is composed, of a structureless; been carefully studied by Leydig (Siebold and envelope or sheath which is filled with a fineKilliker's Zeitsch. I. 1849, p. 103) upon Pisci- granular substance; see loc. cit. Taf. VIIL g.cola, Clepsine, Nephelis, and other Hirudinei. 13-23. The muscular fibre is here developed as in the See also Hoist, De struct. 3Muscul. in genere eg higher animals out of large nucleated cells arranged annulat. musculis in specie, Diss. Dorpate: 1846z in rows, and the adult fibre often shows the relics - ED. 156 TIHE ANNELIDES. ~ 146. With the Branchiati, these organs are often of a cultrate, lanceolate, or sagittate form. Often too, they are denticulated, or barbed upon one or both of their sides, and sometimes they appear articulated.(2) These stings and bristles are moved by a special, muscular apparatus, consisting of many short muscles which arise from the internal surface of the cavity of the body and pass obliquely front and behind to the bases of these organs. These bases project into the cavity of the body, and as their fasciculi are surrounded by a common membranous sheath, when all the muscles contract at once, these organs are thrust out; but they move in various ways, when the muscles contract separately. The other transverse muscles which pass either from the median line of the b'elly, or from the anterior and posterior parts of the body, and are inserted at the base of these organs, retract them anew into the cavity of the body.-3) 2. With many Branchiati, there is a group of longitudinal muscles at the cephalic extremity, which, arising from the internal wall of the anterior segments, act as elevators and depressors of the oesophagus,(41 as well as retractors and protractors of the fasciculi of the cephalic bristles and tentacles. (15 CHAPTER III. NERVOUS SYSTEM. ~ 146. The nervous system is highly developed in all the Annelides excepting the Nemertini. The central is distinctly separated from the peripheric portion. The first is usually composed of a row of ganglia, joined together by nervous cords upon the median line of the body. The most anterior ganglion, and which in some respects may be considered analogous to the brain of the higher animals, rests upon the cesophagus, although the rest of the ganglionic chain which is situated on the median line under the digestive canal, may be regarded as a ventral cord. This cerebral ganglion differs from the others in its larger volume, and appears to be the product of a fusion of two or more symmetrically-arranged unequal-sized ganglia. These ventral ganglia are of uniform size, although not always of the same number with the segments of the body. Strictly, each of them is composed of two ganglia blended together either very perfectly, or very incompletely. The cerebral ganglion is joined to the first of the ventral chain by two cords which surround the oesophagus 2 For the nearly inexhaustible variety of form 3 See Rathkd, De Bopyro et Nereide, p. 31, Tab. of these horny locomotive organs, which, when II. fig. 7, 12 * Grube, Zur Anat. d. KiemenwUrmer cultrate, or lanceolate, are used as weapons of de- p. 5; and Gruithuisen, Anat. d. geziingelten fence, see Audouin and Milne Edwards, Classifi- Naide, in the Nov. Act. Acad. XI. p. 240, Tab. cation des Annelides, loc. cit. XXVII. p. 370, and XXXV. Orsted, Gronllands Annulata und Annulatorum 4 Aphrodite, Nerets, and Arenicola. nanicorum Conspectus, fasc. I. P1. I. 5 Amphitrite, and Siphonostomum. ~~ 147, 148. THE ANNELIDES. 157 laterally, thus forming a ring (the osophageal ring) through which the csophagus passes. ~ 147. The histological elements of the nervous system of these ani ials, are arranged in the following manner: (1) The central mass of the nervous system is enveloped by a fibrous tissue (Neurilemma), of longitudinal and transverse fibres which are often covered with special pigment cells. The nervous cords and filaments are composed of extremely fine, primitive fibres, between which in the ganglia are situated various-sized cell-like ganglionic globules.(2) Some of these primitive fibres pass from the cerebral ganglion through all the ventral ganglia, while others pass off from the central ganglia to the peripheric nerves. Many of the ganglionic globules of the brain and abdominal cord are remarkable for their longer or shorter prolongations which may be traced even into the roots of the nerves. (3) ~ 148. The nerves are given off usually from the ganglia, and rarely from the interganglionic cord. The cerebral ganglion sends off nerves to the organs of sense in the head, and to the labial, proboscideal, and masticatory organs about the mouth. Its development therefore corresponds exactly to the more or less complicated condition of the cephalic extremity. The ventral ganglia send off from each side usually two or three symr metrically-arranged main nerves to the muscles and skin. It is with the Annelides that there have been found the first traces of a vegetative or splanchnic nerve (Nervus splanchnicus). This consists of delicate filaments which are distributed upon the intestinal canal, with here and there enlargements, and which anastomose, some directly with the oesophageal 1 Our knowledge of the intimate structure of the and ventral ganglia of the leech so regular and nervous system of the Annelides is as yet based symmetrical an arrangement of the ganglionic upon researches of that of the Hirudinei only; see globules, that those of the two lateral halves corfelmlholtz, De fabrica systematis nervosi everte- responded exactly as to number, volume and posibratorum dissertatio. Berol. 1842, p. 12; IHanno- tion; see Vaslentin, loc. cit. p. 208, Tab. VIII. fig. ver, Recherches microscopiques sur le systIme 62, &c. This symmetry must appear highly astonnerveux, Copenhague, 1844, p. 72; Will, Vorlhliu- ishing. fige Mittheilung Uber die Struktur der Ganglien 3 These prolongations give the ganglionic globund den Ursprung der Nerven bei wirbellosen ules a clavate aspect, as already seen and figured Thieren, in 2Miiller's Arch. 1844, p. 82; Ehren- by Ehsrenberg (loc. cit. Tab. VI. fig. 7, and fig. berg, Beobachtung einer auffallenden, bisher uner- 7.11., 7.1'2.). kannten Struktur des Seelenorgans bei Menschen Further researches must decide if these prolonund Thieren, in the Ahhandl. d. Berl. Akad. 1831, gations are really continuous with the primitive p. 720, Tab. VI. fig. 7; and Valentin, Ueber den nervous fibres, as Helmholtz (loc. cit. p. 15), and Verlauf und die letzten Enden der Nerven, in the Hannover (loc. cit. p. 73, Tab. VI. fig. 78), affirm Nov. Act. Acad. XVIII. 1836, p. 202, Tab. to be the case; for, Valentin in his apparently so YIII. careful reesearches, has never seen any trace of a 2 Valentin declares that he has seen in the brain clavated or pedunculated ganglionic globule.* *[~ 147, note 3.] This alleged relation of the Leydig, an excellent observer, confirms the genelements of the nervous tissue is a point of no little eral view here advanced of the direct connection histological importance and I shall give it a special of the ganglionic globule with the nerve-tube i see consideration in noticing the minute structure of loc. cit. p. 130, Taf. X. fig. 67 (Piscicola). See this tissue with the higher animals. I have made also Bruzch, Siebold and K61liker's Zeitsch. 1849, no observations on the animals in question, but p. 175, Taf. XII. fig. 7, 8, 9.- ED. 14 158 THE ANNELIDES. ~ 148. sing, and others with the cerebral ganglion by means of other small gan-;lia near the cephalic extremity.(') With the different orders and sub-orders of the Annelides, the nervous system has the following modifications: 1. The Nemertini differ remarkably from the other Annelides in this respect; for their ventral cord is without ganglionic enlargements, and,eomposed of two separated cords, one on each side of the body, which:send off, right and left, lateral. branches along their course. These two cords arise at the anterior extremity in two ganglia blended together above the oesophagus, which represent the cerebral ganglion, and send off many nervous branches in front. (2) 2. With the Hirudinei, the ventral ganglia are much fewer than the segments of the body, and are bound together by two contiguous cords. The first and last of these ganglia are remarkable for their size. The first sends filaments to the lips, the second to the caudal sucker. ( rT,'~e Splanc/nic system is composed of a small ganglion situated in front of the cerebral one, and with which it is connected by two filaments. By its side are two others, which are also small and connect with the cerebral by delicate threads. All three send branches to the oral parts, while a deli-,cate filament goes to the inferior surface of the intestinal canal, and repre-.sents an inner splanchnic nerve.(4):3. The ventral medulla of the Lumbricini consists of two nervous cords 1 Brandt, Bemerkungen fiber die Mundmagen- 3 See Brandt and Ratzeburg, Med. Zool. II. p. roder Eingeweide-nerven der Evertebraten. Leipzig 250, Tab. XXIX. B. (Sanguistuga medicinalis), 1835, p. 37. and Leoe, in Muiiller's Arch. 1835, p. 422, Taf. XI. 2 Rathke:(Danzig. Schrift. loc. cit. p. 100, Taf. fig. 10 (Piscicolageometra). Wagner has found'VI. fig. 10), 10;) has thus described the nervous an arrangement quite different from the above, in:system. of Borlasiat s triata. Pontobdella muricata (Isis, 1834, p. 131, He has seen particularly two pairs of cephalic Taf. I. fig. 3). He saw here the ventral ganmelrves arise from the cerebral ganglion. One and glia united by a single cord which sends off;the larger of these is principally distributed to the from each side only a single nerve. This nerve, xespiratory fossae of the head, while the other, the after a short course, has a ganglion, and then:smaller, passes directly in front, probably for the divides into lateral branches. According to Stan-:vermiform organ upon the cephalic extremity. nises, these lateral branches are not united together sbrsted,!(Beschreib. d. Plattwvrrmer loc. cit. p. 5, by longitudinal cords as is the case with the Am&18), appears to be wrong in suspecting that Rathkd phinome.*'has taken the vascular for the nervous system, for 4 See Brandt, Med. Zool. II. p. 251, Tab. XXIX.,Quatrsefagles ((Icon. du ROgne anim. de Cuvier. B. fig. 7, and, Bemerk. fiber die Mundmagennerven Zoophytes, P1. XXXIV. fig. 1) has figured by the loc. cit. p. 39 (Sangseisuga medicinalis).t,side of the vascular systeni, the nervous system of Vem ertes CasstiSlae, exactly as it is described by ~athket. 1* 4[ I8, notes3.s Leydig (loc. cit. p. 129) has t [~ 148, note 4.] See, for some further remarks ffoundthe struct'xe of the cerebral nervous centre on the Splanchnic system of the IIirudinei and,of Piscicola, qu-ite different from that as described Lumbricini, Quatref ag es, Ann. d. Sc. Nat. VIII. Iby Lee.,The cerebral mass is composed of cap- 1847, p. 36. According to him that of the Hiru-:sules containing ganglionic globules; these cap- dinei resembles that of the Insects, and is com-,sules are symmtetrically situated on each side of posed of a chain of ganglia from which pass off ithe median line, but are connected by a well- filaments, some to the abdominal chain, others to gnarked transverse commissure composed of nerve- the jaws, and others still to the walls of the cesoph-,fibres:; see Taf. X. 67, 68, 69. See also upon the agus. There is also a frontal ganglionic chain nervous System of the Leeches, Bruch (Ueber which forms in front a real arcade, and from which,das.Nervensystesem des Blutegels: Ein Beitrag zur filaments are given off anteriorly.,toaogrstphiechen Histioloaie des Nervensystenms, With the Lumbricini it is considerably different, inl Siebold and Kolliker's Zeitsch. 1849, p. 164). and he thinks unlike that which has yet been This memoir is principally histological, and bears described of all the other Annelides. aspon that disputed point, - the alleged direct con See further, Ann. cl. Sc. Nat. XIV. 1850, p. 282. nection -between the ganglion-corpuscles and the and XVIII. 1852, p. 167. eorve-fibres. It has, however, some topographical See also Leydig, Siebold and Kislliker's Zeitsch. anatomical details, and the accompanying figures III. Hft. 3, p. 315, and Quatrcfages, Ann. d. Sc. could make the whole subject very clear. - En. Nat. XVIII. 1852, p. 316 (Branchellion). -ED. $ 148. TIHE ANNELIDES. 159 which are nearly blended together into one, and whose closely-successive ganglia correspond numerically with the segments of the body.5) 4. With those Chaetopodes which have external branchiae, the nervous system is most highly developed, but has wide variations as to its whole or its details, according to the more or less complicated structure of the cephalic extremity and segments of the body. With those species which are without antennae and eyes, the ventral medulla is composed of two contiguous cords the enlargements of which are indistinct and not sharply defined. 6) These two cords are separated at the cephalic extremity, and terminate either, by a ganglion on each side without apparently forming, by a commissure an osophageal ring,(7) or by encompassing the esophagus, and forming a ring through a ganglion lying upon it.(8) With some, the two parallel cords are without ganglia but are reunited at each segment of the body by two transverse threads.(9) With others, this connection occurs through transverse threads and ganglia.(tl) There are many Branchiati with which the two cords are so closely contiguous that they are separated only by a longitudinal furrow. Their round or elongated ganglia are then common, and succeed each other at longer or shorter intervals.~(l) With an entire series of the Dorsibranchiati, the ventral ganglia are so closely approximated that the interganglionic cords appear wholly wanting.(l2) The brain is composed of only two ganglia, which are more or less blended into one with the Capitibranchiati, and with those Dorsibranchiati whose:head is very slightly developed; (1) while with the other Dorsibranchiati whose head is distinct and the eyes and tentacles very much developed, it is the product of the fusion of many ganglia.(14) 5 See Grutithuisen, in the Nov. Act. Acad. phonostomum, the ventral ganglia are very long; XIV. 1828, p. 412, Tab. XXV. fig. 3-5 (Chaeto- see Rathke, Danzig. Schrift. loc. cit. p. 90, Taf. VI. gaster diaphanus); Henle, in Miiller's Arch. fig. 3. Here, the peripheric nerves are given off 1837, p. 85, Taf. VI. fig. 2, 3, 8, x, y (Enchi- from the interganglionic cords and not from the.traeus); Roth, De Animalium invertebratorum ganglia themselves. systemate nervoso. Wirceburg, 1825, fig. 3; and With Amphitrite, the ventral ganglia are long Alorren, loc. cit. p. 117, Tab. XIX.-XXIII. also, but from the fifth segment of the body they (Lumbricus terrestris). alternate with others that are round, so that each In the common Lurnbricus, two pairs of nerves segment has two ganglia. Both of these ganglia (Nervi annulares) pass off laterally from the cen- furnish exclusively the peripheric nerves, but in tre of the gasnglionic enlargements; and between front where the round ganglia are wanting, they every two ganglia, exceptionally, there passes off are furnished also by the interganglionic cords another pair (Nervi interansnuloares) which are see RathLke, loc. cit. p. 75, Taf. V. fig. 7, 15. With distributed to the transverse muscular septa; see Aricinella (Qs.atrefages, loc. cit. p. 96, P1. II. Morren loc. cit. The nervous system of Sternas- fig. 5), and Astsphi/some (Treviranus, Beobacht. yis thalassemoides is quite different, and appears aus d. Zoot. u.'hysiol. 1839, p. 83, Taf. XI. figr. retrograded to the type of that of the Sipunculidae, 72), the ganglia are very closely set together. With for the ventral medulla consists only of a simple AptoroEdite, and Polynsoe, the number of ventral cord which is enlarged at the caudal extremity i ganglia exceeds that of the segments of the body - see Will, in MiUller's Arch. 1842, p. 427. see G mrube, loc. cit. p. 66. 6 Arenicola, Am.motrypane, and Terebella. 12 Nereis, Eunice, Glycera; see Wacanner, in 7 Arenicola; see Grube, Zur. Anat. d. Kiemien- Isis, 1834, p. 133, Taf. I. fig. 11; Maller, in the wuirmer, p. 17, Tab. I. fig. 7; and StannLius, in Ann. d. Sc. Nat. XXII. 1831, p. 22, P1. IV. fig. 10 Adlitler's Arch. 1840, p. 379, Taf. XI. fig. 15. Rath/k, De Bopyro et Nereide p. 41, Tab. II. fig. 8 Ammotrypane e; see Rathk/e, in the Nov. Act. 13; Grube, Zul. Anat. di. Kiemenwvirmer, p. 43, Acad. XX. p. 197, Tab. X. fig. 14, 19. Taf. II. fig. 9; and Quatrefages, Ann. d. Sc. 9 Sabella; see Warner, Isis, 1832, p. 657, Taf. Nat. loc. cit. PI. I. fig. 1, 2, 3. X. fig. 14; and Grube, Zur. Anat. d. Kiemenewur- 13 sAmphitrite, Siphonostomum (Rathke', Danmer, p. 30, Teaf. I. fig. 16. zig. Schrift. loc. cit. Taf. V. fig. 7, 14, Taf. VI. fig. 10 Phyllodoce. Here, the transverse threads 3), and Glycera (Quatrefages, Anm. d. Sc. Nat. commence only at the border of the 7tl or 9th gan- loc. cit. p. 96, P1. I. fig. 3).* glion. They alternate regularly with these and 14 Nereis, Eunice, and Phyllodoce; seeMiildisappear towards the last segments of the body i ler, Ann. d. Sc. Nat. loc. cit. P1. IV. fig. 10; see Quatrefages, Ann. d. Sc. Nat. II. 1844, p. 95, Rathke, De Bopyro et Nereide, p. 43, Tab. II. fig. PI. II. fig. 2, 3. 4, 5, 13; and Quatrefages, loc. cit. p. 81, P1. I. 11 Siphonostomum, AmpLitrite, Ampphinome, fig. 1, 2, P1. II. fig. 1. Aricinella, Polynoe, and Aphrodite. With Si*[ ~ 148, note 13.] See Quatrefages, Ann. d. Sc. Nat. X. 1848, p. 47 (Hermella), and XIL. 1849, p. 300 (Chloraema). - ED. 160 THE ANN]LIDES. ~ 149.With the Dorsibranchiati, the many delicate threads which arise from the cerebral ganglion by special roots and pass to the different portions of the digestive canal with a ganglion here and there upon their course, may be regarded as splanchnic nerves.(15) With the Amphinomae, Euniceae, Nereidcleae and Ariciae, there arise from the posterior border of the cerebral ganglion two roots which may be regarded as Nervi pharyngei superiores, and which unite near their origin into a Ganglion pharyngeum superius. From this last pass off posteriorly delicate threads which form many ganglia upon the cesophagus, and afterwards spread over probably many other parts of the digestive canal. Beside this Plexus splanchnicus superior, there is sometimes a Plexzs.. splanchnicus inferior —formed by other roots which pass off inferiorly from the brain; part of these form under the cesophagus a Ganglion pharyngeum inferius, while others, passing backwards, constitute Nervi pha-. ryngei and (esophagei. (3) The Amphinomae have on each side of the abdomen a very remarkable ganglionic chain. Their ganglia intercommunicate, not only by longitudinal, but also by transverse anastomoses, with the central mass of the nervous system. Among these last, those which are given off from the anterior lateral ganglia, join the connecting filaments of the cesophageal ring; while the others, arising from the posterior lateral ganglia, go to the various ganglionic enlargements of the ventral cord. (17) It has not yet been possible to ascertain the signification of these lateral. ganglionic chains. CHAPTER IV. ORGANS OF SENSE. I. Organs of Touch. ~ 149. With the Annelicles, the sense of touch is particularly developed at the cephalic extremity.() With some Lunmbticini, this extremity is prolonged into a kind of tentacular proboscis.(2) The Branchiati have special and 15 Cuvier (Lee. d'Anat. Comp. II. 337) has no- 17 These two ganglionic chains were first deticed with Aphrodite two nerves passing back- scribed by Stannius with Amphinome rostrata wards which ought to be regarded as of a splanch- (Isis, 1831, p. 986, Taf. VI. fig. 4). He saw three nic nature;,but Grube (Zur. Anat. d. Kiemene- ganglia connect with the cesophageal ring on each wtirnmer, p. 58) has been unable to find them even side. But Grube (De Pleione carunculata, p. 10, in the same species. fig. 5) has seen six on each side with Amplhinome 16 Stannsius (Isis, 1831, p. 986, Taf. VI. fl. 8, r. carunculata. These lateral ganglia, moreover, r.), and Greube (De Pieione carunculata, 1837, p 9,. remind one of those described by Wagner, as alfig. 5, r.), have seen with certain speeies of -Amphi- ready noticed with Pontobdella muricata. nome the two roots of the Plexus splanchnicus 1 According to Rathled (Danzig. Schrift. loc. cit. superior, but were unable to trace them further. p. 94, 100), the two cephalic and respiratory fossae However, with Eunice Harassii, Grube (Zur. with the Nemertini, are the seat, of a most delicate Anat. d. Kiemcenwfirmer, p. 43, Taf. II. fig. 9, i.) has sense of touch; and their white, long and protracfound beside these two roots, the Ganglion pharyn- tile proboscis is also a tactile organ. But other geum superiors which they form, and the nervous naturalists attribute wholly different functions to filaments which pass off from thlis last. Quite lately, these organs. Quatrefage. has given very exact and detailed 2 The proboscis is non-articulated with NaYs prodescriptions and figures of the expansions of the boscidea, and Euaxes filiformis (Grube, WiegPlexus splanchnicus superior and inferior, with nanzn's Arch. 1844, I. p. 204, Taf. VII. fig..1). Eunice Nereis, Glycera, Phyllodoce, and Arici- But it is articulated with Rhynchelenis (Hodffnella; see Ann. d. Sc. Nat. 1844, II. p. 81, P1. 1. II. meistcr, Ibid. 1843, I. p. 192, Taf. IX. fig. 8). 150. THE ANNELIDES. 161 often very prominent tactile organs, in the form of processes of variable number and shape, which are situated principally though not entirely upon. the cephalic extremity of the body. Those upon the head have been named Antennae, and the others Cirri. These last are often very numerous upon the first segment of the body. Both are contractile and usually unarticulated, though sometimes having very distinct joints.(3) The antennae receive their nerves directly from the cerebral ganglion,4) while those of the cirri of the first segment, are given off from the base of the two lateral cords of the esophageal ring, and from the first ventral ganglion. () II. Organs of Vision. ~ 150. With nearly all the Capitibranchiati,') and with many Nemertini, and' Lumbricini, the eyes are wanting. But, as visual organs, have been reagarded the brown or black dots, which are two in number with many Nais,, four with Tetrastemma, but are innumerable and arranged irregularly or in rows upon the neck, with Polystemma and 2Nemertes. But these are scarcely more than simple pigment dots.(9) ( - With the two to ten eye-specks of the Hirudinei,~3) however, the structureis quite different. Here the eye~4 is composed of a transparent cylindrical body, a little attenuated and rounded at its inferior extremnity, while the opposite one causes the skin to bulge out like a cornea. Its remaining portion is3 The antennae of the Annelides have been dis- appear, two eyes not only at the cephalic extremity, tinguished from those of insects by being termed but at the opposite one also.* Tentacula; for they are non-articulated, while 2 Gruithuisen (Nov. Act. Acad. Nat. Cur. XI. p.. those of insects are articulated. But this distinc- 242) has described the two eyes of Nai's proboscition is not valid, for, with the Branchiati, there are dea as particles of pigment enveloped by a sensi.insensible transitions from the non-articulated ten- tive parenchyma. But this is not based upon obtacula to the articulated antennae. But another servation, and is an hypothesis only, as Miiller and more essential difference is, that those of the has very judiciously remarked (Ann. d. Sc. Nat. Annelides are contractile, while those of insects are XXII. 1831, p. 20). The assertion of Quatrefa?'es: not. These organs are articulated with Ezunicer is of more weight (Comp. rend. XIX. 1844, p. 195). Peripatus, and Syllis. In this last it is true of iHe athrms that the pigmenlt specks of many Ne — the cirri also. The modifications and varieties of mertini and of a marine species allied toNVais, con — the antennae and cirri belong, however, to the tain really light-refracting bodies, and connect province of Zoology. with the nervous cenltre by particular nerves.. 4 With Nereis, four nerves pass off from the The last of these Annelides has similar pigment anterior portion of the brain to the four antennae a specks also upon each side of the segments of thethe two external as gustatory nerves and which go body, which receive each a distinct neleve from the to the larger antennae, are largely swollen at their ventral marrow. Is not this species identical with. extremity; see Rathkl, De Bopyro et Nereide, p. the Nais picta described by Dstjardin (Ann. d.. 43, Tab. II. fig. 4, 5. Sc. Nat. 1839, XI. p. 293, P1. VII. fig. 9)? t 5 See Rathkel, Ibid. Taf. II. fig. 18, d. d. and in 3 Clepsine has two, foulr or six eyes; Nephelis, the Danzig. Schrift. loc. cit. p. 76, Taf. V. fig. 14, eigiht; and Haem.opis and Sanguisu -a, tenll d. d. while with Branzchiobdella, they are wanting.. 1 A remarkable exception to this occurs witlh With this family (the Hirudinei), these organs are Amphicora Sabella as described by Eihrenberg always symmetrically arranged upon the neck. (Mittheil. aus d. Verhandl. d. Gesellsch. naturf. 4 Atleast with Sanooeisouga qfifcinalis. Freunde zu Berlin, 1836, p. 2). It has, it would * [ ~ 150, note 1.1 Qzuatrefages (Ann. d. Se. Dec. 31, 1849) has found very perfect eyes with. Nat. X. 1848, p. 48, P1. II. fig. 10, y.) describes Torrea vitrea, consisting of a crystalline lens, a, two colored points situated on the miliddle of the choroiMl coat, a vitreous humor, a transparent corbrain of Hermella, as eyes. They are composed nea, &c. lie thinks also that he has discovered, of pigment and rest directly on the nervous sub- with Sabella eyes situated on the branchiae t stance. —ED. ED. t [ 150, note 2.1 Quatrefages (Compt. rend. 1 4HaX 162 THE ANNELIDES. ~ 151. enveloped with a layer of black pigment.() Each of these bodies receives a nervous filament firom the cerebral ganglion. Undoubtedly, these filaments are optic nerves, and the cylindrical bodies are light-refracting and light-eoncentrating organs.(6) Many of the Dorsibranchiati are entirely without eyes, having only the eye-specks; but others, belonging to the Amphinomae, Nereideae, Euniceae,.and Aphroditae, have two to four very distinct eyes.(7) In these, there is an eye-ball invested with a black or brown pigment layer: and this layer often has, above, a very distinct round pupillary opening, covered by the:skin, which bulges out like a cornea. At the central portion of this layer, there is concealed a transparent body, which is very probably surrounded by a retina-like expansion of the optic nerve. The optic nerves which are given off usually from the upper surface of the brain have, after.a short course, and before entering the pigment layer of the eye, an enlargement. It is said that with some the light-refracting body and the pupillary opening are wanting. In such cases, the eyes could only distinguish light from darkness. () III. Organs of Hearing. ~ 151. Although it has never been doubted that the Annelides can perceive sounds, yet it is of late only that the attention has been directed to the locality of the auditory organs. The two vesicles, which, with some Chaetopodes, are situated near the cesophageal ring, and contain crystalline bodies, may be regarded as simple Vestibula, containing many otolites.(l) 5 Weber was the first to show that the black ner (Lehrb. d. Physiol. p. 383, and Icon. physiol. *specks of Sanguisuga osficinalis were really eyes Tab. XXVIII, fig. 15). Wagner, who, formerly I(Meckel's Arch. 1827, p. 301, Taf. III. fig. 24). (Zur vergleich. Physiol. d. Blutes, 1833, p. 55), This has been confirmed by Brantdt (Med. Zool. I. could not, any more than )Miiller, perceive the p. 251, Taf. XXIX. A. fig. 10-12), and more re- light-refracting body, has at last seen it distinctly..cently, Wagner has discovered in the interior of For my own part, I can confirm its presence in the the pigment layer, a transparent body, composed, two eyes of Eunice gigantea, which have a circuhe thinks, of two parts, a crystalline lens and a vit- lar pupil. According to RathkI (De Bopyro et reous portion; see Wagner, Lehrbuch, d. ver- Nereide, p. 44, Tab. II. fig. 4, 5) the eyes of Negleich. Anat. 1835, p. 428; also Lehrb. d. speziellen reis pulsatoria and lobulata want the pupil, Phys. 1843, p. 383, and, Icon. physiol. 1839, Tab. although it is present with those of Nereis DumerXXVIII. fig,. 16. i/ii. According to Wagner, the pupil is wanting 6 Brandt has been able to trace the ten optic with the two posterior eyes, but is present with the nerves of Sanguisu-a oficinalis from the brain two anterior ones, with most of the Nereideae. even to the eyes (Med. Zool. loc. cit. p. 250, Taf. 1 SIhave compared the swellings noticed upon the XXIX. B. fig. 2).* cesophageal ring of Areslicola, by Grube and Stan7 With Glycera, Aricia, Arenicola, and Cir- nius (see Wiegsmann's Arch. 1841, I. 166), to the ratulus, the eyes are wanting. With Goniada, auditory vesicles of Mollusks, and their contents to and Nephtys, there are only simple pigment specks otolites; since then, Qusatrefages has recognized upon the head. With Eunice, Phyllodoce, and the presence of similar auditory organs containing I4ciopa. there are two eyes; and four with Nereis, many otolites with two species allied to Amphicora,Syllis, Hesione, and Amphinonse. The genus Al- (Compt. rend. XIX. 1844, p. 195, and Ann. d. sc. ciopa is well suited, from its large size, for the dissec- N at. 1844, II. p. 94). Frey and Leuckart (Beitr. tion of these organs. &c. p. 81), after a very careful examination of the 8 For a most detailed description of the eyes of organs of Arenzicola, which I have regarded as aulVereis. we are indebted to AIiiller (Ann. d. Sc. ditive, have confirmed this opinion. Nat. XXII. 1831, p. 22, Pl. IV. fig. 6 10), and Wag* [ ~ 150, note 6.] For further details on the ocu- with Piscicola: "They receive no nerve, neither lar organs of the Hirudinei, see Itoquzqin-Tandon, do they contain a light-refriacting body. I regard loc. cit. Ed. 1846, p. 80, PI. VIII. fig. 11. Accord- them as simple ornaments, wholly analogous to the ing to him, they contain neither a lens nor a vitre- corresponding pigment dots on the pedal shield, ous humor, and are only light-perceiving organs. with which they also correspond in color and disSee also Leydig (loc. cit. p. 129) who makes the tribution." —ED. ollowing statement upon the nature of these bodies ~ 152, 153. THE ANNELIDES. 163 CHAPTER V. DIGESTIVE APPARATUS. ~ 152. The digestive canal of the Annelides, which is organized after very different types, opens always at the anterior part of the body by a nmouth, and at the posterior part by an anus. It is situated upon the axis of the body, and is usually straight, rarely having convolutions. Often it is divided into many sections, to which the names of pharynx, cesophagus, stomach, and intestine,may be given. The mouth is usually surrounded with thicl lips, and, with many Capitibranchiati, it has very erectile tentacles and cirri, which may be not only tactile but prehensile organs.(l) With others of this group, the food is taken in by the action in the water of the ciliated branchial rays which surround the mouth in an infundibuliform or spiral manner.(2) But usually the food, both soft and solid, is seized by the protuberant lips, and swallowed by the very muscular pharynx. Many Annelides can,also suck in liquid food through their organs of deglutition.~31 The stomach and intestine is lined with ciliated epithelium. The intestinal canal, whose walls are in general very thin, is either closely embraced by the parenchyma of the body,(4) or, when there is a cavity of the body, is supported and constricted by numerous muscular septa.'5) I. Organs of Deglutition and Mastication. ~ 153. The mouth of the Nemertini is situated upon the ventral surface, and iusually at some distance from the cephalic extremity. It is a longitudinal orifice opening into a long, muscular and very spacious pharyngeal tube.(1) This tube is intimately united with the parenchyma of the body, and after passing a short distance backward, joins directly with the intestinal canal.(2) With many Hirudinei, the mouth is at the anterior extremity. Its anterior border projects so as to form a kind of lip, which the animal can vol-antarily change into a sucker. Other species have a complete oral sucker, 1 Terebella, Amph,;rite, and Siphonostomum. Thus Du gds, with Polystemma (Prostoma) arma2 Sabella, and'Serpula. trnm (Ann. d. Sc. Nat. XXI. 1830, p. 74, P1. II. 3 Many H-Iirudinei. fig. 5), and Quatrefages, with Nemertes man4 This is true of the Hirudinei, and many Nemer- dilla (Icon. du ERgne anim. de Cuvier, Zooph. P1.',tini. XXXIV. fig. 2), regard the long canal which opens 5 With the Chaetopodes. at the cephalic extremity, as the pharyngeal tube, 1 See Delle Chiaje, Memorie loc. cit. Tav. and the spines at its base as masticatory organs; LXXVIII. fi. 8. b. (Polia -enicaLlata); H.aschl/e, while Orsted (Beschreib. d.. Plattvfirmer, p. 22, Isis, 1830, Taf. VII. fig. 2 (lvotospermus drepa- Taf. III. fig. 41, 49, 50) regards this wrhole appamensis); Gr'ube, Aktinien, [Echinod. und WUirller, ratus with Tetrastesnma as a copulatory organ &c., loc. cit. fig. 7, a. (Al1eckelia annulata); Rath- (see below). In my opinion, the animals here cited ie, Danzig. Schrift. loc. cit. Taf. VI. fig. 8. ). (Bor- do not belong even to the Nemertini. lasia striate); and Ehrenberg, Symbol. Physic. 2 Borlasia (Rathke, loc. cit. p. 96, Taf. VI. fig. Phytozoa Turbellaria, Tab. IV. fig. 4. g. (Msicrura 10, 11) and Polia (Delle Chiaje, loee. cit. II. p. fasciolata). Ehrenberg, moreover, wvas deceived 407, Tar. XXVIII. fig. 3, j., or isis, 1832, p. 648, in regarding this mouth as the opening of the gen- Taf. X. fig. II. 3, j.). Withl Meckelia anntulata, I ital organs, and ih taking the proboscideal organ of have found the pharyngeal tube arranged in the this species, for the true mouth. There is yet in same way. this respect much contradiction among natulalists. 164 THE ANNELIDES. ~ 154. entirely distinct from the rest of the body. () These suckers serve not only as locomotive organs, as the one, for instance, which is situated at the posterior end of the body, but also for the drawing in of liquid food, and particularly blood. For this purpose, many Hirudinei have a short and spacious pharynx, possessed of muscular walls, which are blended with the parenchyma of the body, and which are armed with horny teeth, by which they cause the wounds necessary for sucking the blood. With Branchiobdella, the pharynx has horny upper and lower jaws, of a pyramidal form.J(4) With Sang'wisuga, and Haernopis, on the contrary, the base of the pharynx has three fleshy swellings, the projecting arciform border of which is edged with bicuspicd teeth.( In this respect, Clepsine is quite different. The pharyngeal tube is very long, and front its base a movable fleshy tube can be protruded out of the mouth, and which the animal can use as a proboscis.(6) Wit the Abranehiati, and Capitibranchiati, the pharynx is simple, short and muscular, and presents nothing remarkable. With the Dorsibranchiati, it is very muscular, of variable length, and stretches freely into the cavity of the body. By the aid of' special muscles, it may be folded upon itself, and project far out of the mouth.(7) With many Annelides, the pharynx has a. horny, masticatory apparatus of sometimes a very complicated structure, and which, when the pharynx is protruded, often extends out beyond it, and serves as a prehensile organ.(8) These two, four, seven,'eight or nine jaws always move laterally upon each other. They are usually curved like hooks, and denticulated upon their concave side. When numerous, they are of dissimilar forms with the same individual.(9' IL. IntestinaZ Canal. ~ 154. The intestinal canal of the Nemertini passes directly from the mouth to the anus, without forming a stomachal dilatation. Its walls are closely united with the parenchyma of the body, and its internal surface throughout is thickly set with annular folds, which, projecting far into the canal, formn there pouch-like divisions.(') 3 Piscicola, and Pontobdella. tus Qf this organ are against this view, and quite irn 4 See Henle, Mlller's Arch. 1835, p. 575, Taf. favor of its being a pharynsx. XIV. fig. 1. 8 The jaws are wanting with Amphinome, Phyl5 See Jloquin-Tandon, Monog. des HIirud. p. lodoce, Aricia, Chaetopterus, and Arenicola. 43, P1. I. fig. 2. 11, P1. IV. V.; Brandt, Mted. Zool. 9 There are two strongly-curved jaws with YeII. p. 245, Taf. XXIX. A. fig. 13-18, 21, Taf. reis, Lycastis, and Peripatus e four with Polynoe, XXIX. B. fig. 13-17. The swellings of these Aphrodite, and Glycera; and eight with Lumbrileeches are carried in front during suction, so as nereis. Of the seven with Eunice, there are to resemble a three-rayed star —the form of the four, one on one side, and three on the other. The wound which they produce. same asymmetry exists with those of Ag laura and 6 See Moqsuin-Tdndoez, loc. cit. P1. IV. This Oenonze; see Ausdoulin and lilne EdwLards, Rieproboscis quite reminds one of the phalryngeal tube cherches, &c., loc. cit. of the Planariae, which also can be protruded from 1 According to Rathki (Danzig. Schrift. loc. cit. p. the:mouth, but without being reversed. 96), these transverse folds do not exist with Borlasia 7 This pharyngeal tube is short with Amphi- striata, except when the body is shortened by connome, Nereis, Etcnice, and Peripatus; but very traction, and they disappear when it is again extendlong with Aphrodite, Polyenoe, Hesione, Phyllo- ed. But it did not appear thus to me with the nudoce, Glycera, and Goniada; see Audosuin and merously folded intestine of Meckelia anonulata. Milne Edwards, Recherches, &c., loc. cit. That of Delle Chiaje had already observed these folds Aphrodite, Polynoe~, Amp/ehinome, alnd others, with Polia sipuLnculues, but figured them as isohas been regarded as.a stomach; see Treviranus. lated pouches (Memorie, loc. cit. II. p. 407, Tav. in Tiedemann's Zeitsch. f. Phys. III. p. 161, Taf. XXV!III. fig. 3, 6, or Isis, 1832, Taf. X. fig. II. 3, XII. fig. 9. 10, k; Grube, Zur Anat. d. Kienmen- 4). According to Qusatrefages (Ann. d. Sc. Nat. wormer p. 54, et seq. and Stannius, Isis, p. 982. VI. 1846, p. 243), the intestinal canal of theBut the position, structure and muscular appara- Nemertini, which occupies the axis of the body, 154. TIlE ANNELIDES. 165 With the Hirudinei, the intestinal canal varies very much, especially as to the number and volume of its appended coeca.(~) Its very narrow anal opening is upon the back directly above the pedal sucker.(3) With Nephelis, the canal is simple and gradually enlarges from before backwards, but has no coeca. With Branchiobdella, it is deeply constricted in several places.(4) With Pontobdella, it is simple with its two anterior thirds, but there is a caecum on each side of its remaining portion.(5) This last is also true of its posterior third with Haemopis, Clepsine, and Sanguisuga.(6) With this last genus, the other portions of the canal are divided by ten or eleven constrictions into as many parts which send off on each side short caeca; (7) while that,of Clepsine has on each side five or six coeca, all of which may'be ramlified. There is a kind of valve directly behind the last two caeca, and so the part of the intestinal canal in front of this may be regarded as a stomach and a small intestine, while the remaining portion behind it, represents the rectum.~(' With the Abranchiati, the intestinal canal is short, and its osophagus which is usually narrow passes into a muscular pharynx, which leads into a stomachal dilatation. Upon these parts follow the remaining portions of the intestine which are separated from each other by the transverse septa of the body and often resemble the stomach. With a few species only, the stomach is remarkable for its thick, muscular walls.(9) With some of the Capitibranchiati, the digestive canal arises directly behind the esophagus and has bulging portions like those of the colon,(10 assuming, posteriorly, sometimes a spiral form..m) With others, the oesophagus is continuous directly into the intestinal canal, which, free and unattached by diaphragmatic septa, makes many turns in the cavity of the body, and by constrictions is divided into a stomach, small intestine, and rectum. (12) With many Dorsibranchiati, the intestine follows directly upon the (esophagus, and is either straight and divided by constrictions,(t) or assumes a spiral form (14) or is without constrictions and irregularly tortuous.(1) With others, the portion of intestinal canal between the pharynx and in. forms with the buccal orifice, a cavity distinct from 10 Terebella, and Sabella; see Grube, Zur that of the abdomen, and its anus has a kind of Anat. d. Kiemenwtirmer, p. 20, 27, Taf. II. fig. sphincter. But this is certainly an erroneous view 12, and Milne Edacards, Ann. d. Sc. Nat. X. of the organization of these worms: the contents 1838, P1. X. XI. of the cavity are sufficient alone to confute it. 11 Sabella; see Carus and Otto, Erlauterungs2 Moquin-Tandon, loc. cit. P1. I.-IV. taf. Hift. IV. Taf;. III. fig. 4, 6, and Wa/gner, Icon. 3 With Piscicola, exceptionally, the anus is up- zoot. Tab. XXVII. fig. 21. on the ventral surface of the last segment of the 12 Amphitrite, and Siphonostomum. With the body; see Leo, in Miiller's Arch. 1835, p. 420. first, the stomach is long, spiral, andl divided into 4 Henle, Miiller's Arch. 1835, Taf. XIV. fig. 1. an ascending and a descending portion; see Rath5 Wagner, Isis, 1834, p. 130, Taf. I. fig. 1, 2. ki, Danzig. Schrift. loc. cit. p. 64, 86, Taf. V. VI. 6 Brandt and Ratzeburg, Med. Zool. II. p. 246, 13 m.mphinomne, Arenicola, Eunice, and NephTaf. XXIX. B. fig. 12. tys; see Stannius, Isis, 1831, Taf. VI. fig. 10 7 Ibid. Taf. XXIX. A. fig. 19, 20, 55. Milne Edwards, Ann. d. Sc. Nat. X. 1838, Pl. 8 With Clepsine marginata, this rectum has XII. XIII. i Grube, Zur Anat. d. Kiemenwvirmer, coecal appendages also; see F. iler, in Wieg- Taf. I. mann's Arch. 1844, I. p. 371, Taf. X. fig. 14.* 14 According to Greebe (Ibid. p. 34), the intes9 With Lumobriculs, the stomach is very muscu- tine of Cirratuluzs is spiral like that of Sabella. lar * see Morren, loc. cit. Tab. XI.-XIY. This is 15 Ammotrypane (according to Grube, see also true of Nais proboscidea, but not with Lum- Rathki, Nov. Act. Acad. Nat. Cur. XX. p. 197, lbriculus, and Enchitraeus. Tab. X. fig. 13). * [~ 154, note 8.] For many special details Clepsine, Nephelis), see Leydig, loc. cit. p. 110, illustrating as well the histology as the anatomy of Taf. VIII. IX. fig. 24-37. -ED, the intestinal canal of the Hirudinei (Piscicola, 166 THE ANNELIDES. ~ 155, testine, receives the excretory duets of glandular appendages and is therefore, more properly a stomach than an oesophagus.(16) WTith many, the stomach and its appendages are wanting, but then the entire canal stretching directly across the cavity of the body has on both sides long analogous appendages which sometimes consist of dilated sacs, so that these appendages have wholly the aspect of caeca."7) IIi. Glandular Appendages. ~ 155. The glands appended to the digestive canal of the Annelides may be divided into the salivary and hepatic organs. The first of these are sometimes absent, but the last are never wanting. The organs regarded as salivary glands are attached either to the pharynx or to the beginning of the intestinal canal. With the Nemertini, they are absent. But with Sanguisuga, as abdominal salivary glands, may be regarded the many groups of round corpuscles which surround the commencement of the intestine, and whose excretory ducts open into it by many orifices, after anastomosing together.(l) With Lumbricus, there is a long lobular body on each side of the pharyngeal tube which secretes a whitish liquid, and which is analogous perhaps to an oral salivary gland.(2) The four pairs of transparent vesicles, which, with Enchytraeus, open at the inferior extremity of the oesophagus, are possibly of the same nature.)(3 With Siphonostomnum, there are two riband-like caeca which pass along the cesophagus and open separately into the oral cavity.(4) With many Dorsibranchiati, the commencement of the intestine has two glands of probably a pancreatic nature.(5) It is difficult to decide as to the hepatic or salivary nature of the numerous and usually white appendages, which belong: to both sides of'the whole alimentary canal of the Aphroditae. With Polynoe, these consist of six cylindrical, caecal, and sometimes bifid tubes, lying between the muscles of the walls of the body.(') With Aphrodite hystrix, there are twenty of these tubes on each side 16 Nereis; see Rathikd, De Bopyro et Nereide p. 4 Rathke, Danzig. Schrift. loc. cit. p. 87, Taf. V. 35, Taf. II. fig. 7, 8. fig. 5, c. c. 17 With Aphrodite hystrix, and aculeata, the 5 With Nereis, these two salivary glands comintestine has on each side twenty glandular append- municate by two narrow duects with that portion of ages with long peduncles. In this last species, the intestinal canal which should be regarded as a these appendages are caeca also, for they have at stomach; see RathkC, De Bopyro et Nereide, p. their extremities saccular dilatations filled with 38, Tab. II. fig. 7, g. 8. Grube has found these chyme; see Pallas, Miscell. Zool. p. 85, Tab. VII. two appendages at the beginning of the intestinal fig. 11; Treviranus, in his Zeitsch. f. Physiol. canal with Arenicola (Zur Anat. d. KiemenwdirIII. p. 162, Taf. XII. fig. 9, 10; and Milne Ed- mer, p. 6, Taf. I. fig. 1, 5, h.), and with Ammotryo warls, in Cyclop. Anat. and Phys. I.-p. 169, fig. pane (Nov. Act. Acad. XX. p. 197, Tab. X. fig. 70. 13, 19, h.). See also Mflilne Edwards, in the Ann. 1 Brandt, MIediz. Zool. II. p. 247. Taf. XXIX. d. Sc. Nat. X. 1838, P1. XII. fig. 1, j. (Nereis), and A. fig. 22, 23.* P1. XIII. fig. 1, e. e. (Arenicola); and Wagner, 2 Morrez, loc. cit. p. 129, Tab. X. XI. (Lum- Icon. zoot. Tab. XXVII. fig. 18, g. g. (Nereis).t bricus terrestris). 6 Grube, Zur. Anat. d. Kiemenwiirmer, p. 62, 3 Henle, in Miuller's Arch. 1837, p. 79, Taf. VI. Taf. II. fig. 13 (Polynoe squamata). fig. 6, d. d. * [ ~ 155, note 1.] For the salivary glands of t [ 155, note 5.] For the salivary glands of Hirndinei, see Moqsuin-Tardon, loc. cit. Edit. Branchellion, see Leydig, Siebold and Kltliker's 1846, p. 108, P1. X. fig. 4 (Hirudo medicinalis), Zeitsch. III. IIft. 3, p. 315, and Quatrefages, Ann. P1. VI. fig. 11 (Ilaemopis), P1. I. fig. 5 (Branch- d. Sc. Nat. XVIII. 1852, p. 296, P1. VI. fig. 3, a. ellion). - ED. c. - ED. ~ 156. T-IE ANNELIDES. 167 of the intestinal canal; these are narrow and their botryoidal extremities lie in the interstices of the dorsal wall of the body. With Aphrodite aculeata, the structure is analogous but differs in that these appendages have more the aspect of coeca with thin walls, and have not the ramified diverticula except in their central part and between the already-mentioned saccular dilatations.(7) As an hepatic organ may be regarded with more certainty a particular tissue colored in part brownish yellow, and partly greenish yellow, which closely surrounds the whole intestinal canal of most Annelides. Carefully examined, this tissue is found composed of closely-aggregated glandular sacs which empty their contents into the intestine either direc;ly', or by many common excretory ducts. ) This contained liquid is, with most species a transparent fluid in which are suspended brown granules, and it resembles the bile of the higher animals. CHAPTER VI. CIRCULATORY SYSTEM. ~ 156. This system is highly developed with the Annelides. The blood is usually colored, and the vascular system, remarkable for many peculiarities, is complete and closed. This system may be divided into a central and a peripheric part. The first consists of large contractile vessels taking the place of a Heart. There are also various heart-like organs in the shape of varicose dilatations upon the course of the contractile vessels. The principal vessels have a longitudinal course, occupying the whole length of the median line of the body, - one as a dorsal, and the other as a ventral vessel. With many Hirudinei, there are also lateral vessels. The dorsal and ventral vessels unite at both extremities, beside anastpmosing by transverse branches in the separate segments. When there are lateral vessels, these also connect with the median ves7 See Pallas, Treviranus, Miln.e Edwards, XXIX. A. fig. 28, 29. With many, this hepatic loc. cit., and Grube, loc. cit. p. 54. layer envelops also the blood-vessel upon the dorsal 8 According to Henle (Aiiller's Arch. 1837, p. surface of the intestine. It is possible that the 81, Taf. VI. fig. 2), this glandular envelope forms a yellow canal described by Morren, with Lumbrivillous envelope about the intestine. This is also cus terrestris as Chloragogena, is only this hepattrue of Lumbricuzs, Lumbriculus, Nais, and ic mass (loc. cit. p. 142, Tab. Xv. XVI.). Another Chaetogaster. The glandular sacs are greenish canal which is traversed by blood-vessels and closext with Branchiobdella (Henle, loc. cit. 1835, p. 575), at both extremities, and which is contained in a yellowish with Amesphitrite (RathkeS, Danzig. longitudinal enlargement upon the internal surSchrift. loc. cit. p. 65). With Sanguisuga, the ex- face of the intestinal canal, and is called by Morcretory ducts of the hepatic sacs inter-anastomose ren, Typhlosolis (loc. cit. p. 138, Tab. XI. XII. and form a kind of net-work around the stomach XVI. XVII.) may perhaps be regarded as a recepand its coeca i see Brandt, Med. Zool. p. 247, Taf. tacle of chyle.* * [~ 155, note 8.] The hepatic organs with the (Lumbricus, Nais), and the long, thread-like and Annelides have been successfully studied by Will coecal glands (Hirudo, Haemopis, Aulacostoma, (Miiller's Arch. 1848, p. 508), who has used chem- Helluo, Piscicola, Clepsine) which surround the ical tests. IIe has found the glandular layer intestinal canal, to be organs of this nature. -ED. 168 THE ANNELIDES. ~ 157.,sel by transverse anastomoses. The peripheric vessels arise by means of a capillary net-work,.from the most various points of the longitudinal and:transverse vessels. The circulation has on the whole a determinate direction, -the dorsal vessels force by a kind of peristaltic movement the blood from behind forwards into the ventral vessel, which returns it into the dorsal vessel. The blood can, however, pass from the dorsal to the ventral vessel by a much shorter way, - by traversing the capillaries, or directly through the transverse anastomoses. It is, moreover, very probable that the course of the blood in the transverse vessels is not always in the same direction, and that it mnay under certain circumstances pass fiom the ventral into the dorsal vessel. This makes it difficult to decide which of these vessels are arteries, and which veins. The respiratory organs, which usually form the limit between the venous and arterial systems, are, with most Annelides connected with the transverse vessels, and therefore throw no light upon this doubtful point. From the multitude of these transverse anastomoses, it must appear impossible to distinguish the arterial from the venous blood, and the distinction of veins from arteries with most Annelides must be wholly arbitrary. The blood of the Annelides, although red like that of the vertebrates,:is, however, quite different. It is composed of a liquid containing globules. These last, which are always colorless, of unequal size, and of a spherical form, are granulated on their surface.(l) The blood liquid is either colorless, or contains a coloring matter, which is usually red, but,sometimres yellow or green. ~ 157. With the Nemertini, whose blood is red (1) but as yet imperfectly known, the circulation appears to be due to two cardiac dilatations concealed in the cephalic extremity.(2) The Hirudinei have, beside the two median vessels, two lateral ones also, which intercommunicate by very numerous transverse vessels.t3) From the contractions of these vessels, the blood is driven sometimes forwards, and 1 For the blood-globules of the Annelides, see hearts are divided into two chambers, the anterior Wagner, Zur vergleich. Physiol. d. Blutes, lift. I. having deep-colored blood, while that of the posterior p. 23, ift. II. p. 39. According to him, those of one is more clear. This arrangement has led this Terebella (Ibid. lift. I. fig. 8) are pale red, circu- naturAlist to regard as hearts the bodies described lar discs. Here the exception is remarkable, sup- by Rathkf. with Borlasia striata, as cerebral ganposing there was not an error of observation. It glia, and as blood-vessels, the nerves which are given appears that beside the blood which circulates in off from them laterally (see above, ~ 148, note 2). the vessels the fluid contained in the visceral cav- But if Quatrefages' figures of the nervous and ity of the Chaetopodes plays also an important vascular systems of Nemertes mandilla are exampart in the act of nutrition, for the eggs and the ined (Regne anim. de Cuvier 6d. illustr. Zoophytes. spermatic particles which with these animals are Pl. XXXIV. fig. 1), it will be seen that there are often detached from the ovaries and testicles at here three main trunks, a median and two lateral. a time when still quite imperfect, attain their com- These last accompany the lateral nerves, while a plete development while remaining in the visceral bifurcating vessel which passes from the median to cavity, probably by means of this nutritive fluid. the two lateral trunks, embraces closely, in a loopSee Quatrefages, Ann. d. Sc. Nat. V. 1846, p. 379. like manner, the two cerebral ganglia, so that they 1 According to Milne Edwards (Ann. d. Sc. Nat. easily escape observation. This is perhaps true X. 1838, p. 197), the blood of the Nemertini is color- also of Borlasia. less. 3 The sanguineous system of San-uismuga has 2 The vascular system of Polystemma has been been very carefully described by Brandt (Med. distinctly seen by Dugds (Ann. d. Sc. Nat. XXI. Zool. II. p. 247, Taf. XXIX. B.) * see also Boja1830, p. 75, P1. II. fig. 6), and by Orsted (Bes- nus, in the Isis, 1818, p. 2089, Taf. XXVI. fig. 3. 4. chreib. d. Plattwdrmer, p. 17). It is composed of With Nephelis, there are only two lateral vessels many longitudinal vessels, which intercommunicate and an abdominal one, lying along the ventral menot by transverse ones, but by arcuate anastomo- dulla; see Muller, in Meckel's Arch. 1828, p. 24, -ses at the cephalic extremity, and by two hearts in Taf. I. fig. 1. the cervical region. According to Orsted, these 4 157. THE ATNNELIDES. 169 sometimes backwards and oscillates from one side to the other, through the transverse vessels.t' With most genera, the blood is red, being colorless -with a few only, and it is always pool in corpuscles. (d The Chaetopodes have no lateral vessels. Their circulation is often due to pulsatory organs, and there is a great variety in the disposition of their vascular trunks and sinuses. With the Abranchiati, the dorsal vessel lies close upon the intestinal vcanal, and is almost wholly enveloped in the hepatic tissue. At the anterior extremity, it divides in many bifurcating branches, which, after encompassing the pharynx, utite below it, and form the ventral vessel.6) This vessel accompanies theentfi;al cord to the posterior extremity, and connects with the dorsal vessel by bifurcating branches, as before.(' The transverse anastomoses connecting the dorsal and ventral vessel, form at each segment simple, or torose canals. (8) With the small Lumbricini, these are usually 4 The irregularity of the blood-currents has, un- vascular system communicates directly through ~doubtedly, given rise to the numerous different small canals with the coeca of the digestive canal, opinions upon the circulation of these animals * see so that the contents of this last may pass into the.Dug/s, Ann. d. Sc. Nat. XV. 1828, p. 308; Weber, blood without being changed.t in Meckel's Arch. 1828, p. 399; Miiller, Ibid. p. 6 See Henle, in lui/ller's Arch. 1837, p. 83, Taf. r24; and in Burdach's Physiol. IV. 1832, p. 143; VI. fig. 5 (Enchytr/aeus), and Hofffmfeister, De;and WYagner, Isis, 1832, p. 635. If the valves vermibus quibusdamn, &c., loc. cit. p. 14, Taf. II. fig. -wNhich Leo (Miiller's Arch. 1825, p. 421, Taf. XI. 4 (Saenuris variegata). fig. 9) has found in the dorsal and ventral vessels 7 With Luzmbricus, there are, beside the princiof Piscicola, should be found also with other Hiru- pal ventral vessel, three others smaller, and in didinei, it would throw some light upon the real course rect connection with the ventral cord. Two of these of the circulation.* pass off laterally, and the third underneath; see 5 With Sanguisuga, Haemopis, Pontobdella, Leo, De Structura Iumbrici terrestris, p. 27; Dugds IVephelis, Piscicola, and others, the blood is red * Ann. d. Sc. Nat. XV. 1828, p. 295; and Morren, it is colorless with some Clepsine, according to Fi- loc. cit. p. 152, Tab. XXI.-XXIV. fig. 5, who /lippi (Lettera sopra l'Anat. e lo sviluppo delle Clep- especially has carefully described the vascular sys-sine, 1839, Pavia, p. 11); it is also brown, violet or tem of Lumbricus terrestris.,red, according to the species.,He also declares (loc. 8 The transverse anastomoses are simple with,cit. p. 8), that with Clepsine and Piscicola, which Lumbricus, but torose with Saenuris; see Ho.flive wholly upon the blood of the lower animals, the meister, loc. cit. * [~ 157, note 4.1 The memoir of Gratiolet the two lateral vessels. The consequences of this t(Mem. sur. l'Organisation du syst/me vasculaire de form of structure may be easily summed up. The laSangsue m6dicinale et de l'Aulostome vorace, pour blood oscillates from the alternate contractions,servir A l'histoire des mouvements du sang dans les from one pulmonary net-work to another. It circuMirudinues bdelliennes, in extract in the Comp. lates in the principal organ of the intestinal abtend. 1850, XXXI. p. 699), is worthy of a special sorption, in the testicles, and in the muciparous reference in this connection. HIe says: "The lat- glands. eral vessels, whose walls are very muscular. are "This circulation, very different from that which:the principal organs for the movement of the blood; D)ug/s admits in the alleged pulmonary vesicles, they contract alternately, as has been well observed shows how various are the means employed by na-'by Dugis, Weber and Misller, and their contained ture. Here she determines the course of the blood,blood moves in a circular manner, sometimes one by means of valves and stoppers; while elsewhere,way, sometimes the opposite. she accomplishes the same end by causing certain "The branches given off by these lateral vessels blood-currents to prevail over others.":are of two kinds: The valvular structure of the vessels with Pisci"A. Those destined for the skin, and which are cola, as mentioned by Leo, has since been conramified in the respiratory net-works; they never finned by Leydig (loc. cit.), who has found it also.anastomose with those of the opposite side. Before with Clepsine. Leydig calls the attention to their final and minute ramifications, they form a another kind of circulatory system in Piscicola i large varicose net-work under the skin, which hith see loc. cit. p. 116. But this point has not yet been erto has been regarded as a plexus of hepatic ves- well made out; see also soqLuin-Tandon, loc. cit. sels, but which is positively an interlacement of p. 133, P1. X. fig. 10, 15, 16, and P1. XII, fig. 13. Vblood-vessels. -ED. "B. The other branches are destined for the t [ ~157, note 5.] The recent observations of s.mall intestine, and its spiral valve for the testicles, Leydig (loc. cit. p. 119), have shown the blood of the copulatory apparatus, to the loops and to the Piscicola to be always colorless. This view is proba-muciparous vesicles. bly the correct one, since it better accords with the "All these branches arise from the branches or the histological relations of the blood of these aninals. Large arches which form a free anastomosis between - ED. 15 170 THE ANNELIDES. ~ 157. only in the anterior segments of the body.t9) With the genus Lumbricus, the cardiac organs consist of five to nine pairs of moniliform, transverse canals, situated above the stomach, and whose pulsations are very distinct.(l)0 With all the Abranehiati yet examined, the blood is red. With the Capitibranchiati, there are often two dorsal vessels, one immediately subcutaneous, the other lying, as usual, on the intestine.(l" This duplicity of' the dorsal vessel is observed particularly with those species which have a coiled intestinal canal.t() In this case, there is also a second ventral vessel accompanying the coils of the intestine. All these longitudinal vessels interanastomose very frequently, and send many transverse branches to the intestine and the walls of the body, where they blend with the capillary system. Not unfrequently, the dorso-intestinal vessel is dilated at its anterior extremity, above the pharynx, into a large, pulsatory, heartlike canal, which sometimes has two lateral arcuate, sinuses situated at the commencement of the intestine.(3) The extremity of this vessel sends off, right and left, many branches to the branchiae, which are situated in this region. Leaving these organs, these vessels are distributed, some in front to the tentacles, and to the other organs surrounding the mouth; while others pass below to unite with the ventral vessel. As the blood is thrown from behind forwards in the dorsal vessel, and thence passes into the branchiae, this vessel may be called a dorsal vein, and its dilatation a branchial heart; while the ventral vessel, which receives the returning blood from the branchiae, would be an abdominal aorta. But there are other reasons for this view. The dorso-intestinal vessel, from its intimate connection with the liver, might well serve the function of a Vena portarum, while the close union of the ventral vessel to the ventral cord, is undoubtedly for the purpose that the latter, as a central nervous mass, may receive arterialized blood directly from the branchiae. With these animals (the Capitibranchiati), the blood is red in some, and green in others.(14) The Dorsibranchiati often have double dorsal and ventral vessels, two of which belong to the intestinal canal, and two to the walls of the body.t(1) With some, these longitudinal vessels are divided into two or three branches.1l6) The principal dorsal vessel is sometimes dilated at its anterior extremity, above the pharyngeal tube, into a cardiac sinus, to which, at the beginning of the intestine, there are added two lateral, arcuate dilatations.('l) 9 Enchytraeus, Chaetogaster, and Nai's. The constriction at its posterior part * see Rathkd, loc. vascular system of Euaxes and Lsumbriculus is cit. p. 89, Taf. VI. fig. 5, f. g. very remarkable in this respect. Instead of trans- 14 With Terebella, Amphitrite, and Serpula, verse anastomoses, there are, in each segment of the the blood is red; with Siphonostomsum, Chiloraebody, two vessels which pass off from the dorsal ma, and some species of Sabella and Serpula, it is trunk, and divide into many coecal branches i see green. Treviranus, Beobacht. aus d. Zoot. loc. cit. p. 60; 15 We are indebted to Milne Edwards for very and Grube, in Wiegmann's Arch. 1844, I. p. 205, detailed accounts of the vascular systsm of the DorTaf. VII, fig. 1, 2, d. sibranchiati; see Ann. d. Sc. Nat. loc. cit. P1. XII. 10 See Dauges, loc. cit. P1. VIII. fig. 1, and Mor- XIII.i see also, for that of Areniccla, Stannius, rest, loc. cit. p. 162, Tab. XX.-XXIII., XXI.- in Miiller's Arch. 1840, p. 357. XXIV. fig. 1. 16 With Eunice sangeain'ea, there is a double 11 linthe Edwards has made very beautiful re- dorso-intestinal vessel (A'ilne Edwards, loc. cit. searches upon the vascular system of the Capiti- P1. XII. fig. 2, 3't ) and a double ventral one branchiati; see Ann. d. Sc. Nat. X. 1838, p. 193, with Nephtys Hombergi. With Arenicola, there P1. X. XI. are three ventral vessels accompanying the ventral 12 Am.plhitrite and Siphonostomum; see Rath- cord (Maller, in Burdach's Phys. loc. cit. p. 147). kd. Danzig. Schrift. loc. cit. p. 76, 88, Taf. V. fig. 4,5. and with Amplhinome, Grube has found three 13 With Terebsella, there is a vascular heart and dorsal ones beside, all widely separated from each two lateral sinuses - see Miln e Ed'wards, loc. cit. P1. other. X. XI. fig. 1. With Siphonostomum, there is a 17 Eunice; see Milne Edwards, loc. cit. P1. similar cardiac dilatation upon the pharynx, and it XII. fig. 2. The vascular system here resembles is divided into two chambers by a well-marked that of Terebella. $ 158. THiE ANNELIDES. 171 These last are sometimes found alone.(18) With many of these Annelides, the transverse vessels are dilated, before branching, into real branchial hearts. (19) As their branchiae are variously situated among the transverse anastomoses, the distinction between the arterial and venous blood is not as marked as with the Capitibranchiati; it must be arbitrary, as with the Hirudinei and Abranchiati. The blood is usually red, but sometimes is yellow or nearly colorless. (01 CHAPTER VIL. RESPIRATORY SYSTEM. ~ 158. With the various families of the Annelides, the respiratory organs are formed after wholly dissimilar types. With the Nemertini, they are least developed, for, excepting two longitudinal fossae upon the sides of the cephalic extremity,(l) there are no organs which can be regarded as of this nature. These two respiratory cavities are of variable depth, and their lateral borders are so approximated as to have the aspect of a longitudinal opening, and with some they are situated so far out on the cephalic extremity as to be blended together.('2 They are lined with a delicate ciliated epithelium, quite different from that covering the rest of the body,(3) and by the vortex actions of which, fresh water is brought constantly in connection with the blood.(4) Considering the smallness of these organs, it is very probable that the whole skin has also a respiratory function. 18 A4renicola; see Milne Edwards, loc. cit. P1. Micrura fasciolata (Ehrenberg, Symb. phys. XIII. Phytozoa Tab. IV. fig. 4. e. i. g.). 19 Eunice; Ibid. PI. XII. fig. 2. 3 See Quatrefrges, Rigne anim. illustr. Zooph. 20 With Eunice, NYephtys,Glycera, and Areni- PI. XXXIV. fig. 1, b. b. (Nemertes Camillae). cola, the blood is red; with Phyllodoce, it is yel- 4 Rathkd (see above, ~ 149, note 1) is of the opinlow; and it is nearly colorless with Aphrodite, ion that these two cephalic fossae are the seat of Polynoe, and Sigalion; see MIilne Edwards, loc. touch; but the view of Orsted (Beschreib. d. Plattcit. p. 196.* wormer, p. 18, 77), who thinks them of a respira1 See italler, Zool. Danica. Tab. LXVIII. fig. tory nature, is, perhaps, the more correct. In sup1-4 (T'etrastemma (Planaria) viride); Delle port of this last, is the fact of the presence of ciliChiLaje, Memor. loc. cit. Tav. LXXVIII. fig. 8, a ated epithelium, and of a very large blood-vessel (Polia geniculata); Quoy and Gaimard, Atlas directly beneath them (see Quatrefages, loc. cit. Zool. de l'Astrolabe Zooph. P1. XXIV. fig. 10 (Bor- P1. XXXIV. fig. 1, g. g. (Nemertes Camillae)) lasia viridis); and the Diet. d. Sc. Nat. LVII. Art. and which, in many Nemertini, is clearly seen Vers, p. 574, P1. Parentomozoaires, Nemertds, fig. through the thin epithelium; see Muller, Zool. 1, 2 (Borlasia Angliae, and Cerebratulus biline- Dan. Tab. LXVIII. (Tetrastemma vivire); Delle atus); also Huschke, Isis, 1830, Taf. VII. fig. 1-3. Chiaje, Memor. Tav. LXXVIII. fig. 8 (Polit Niotospermus drepanensis. geniculata), and Isis, 1830, Taf. VII. (Notosper2 Tetrastenzma vi; ide, Polia geniculata, and mus drepanensis). *~ 157, note 20.] See also for the blood of the Annelides, Quatrefages, Ann. d. Sc. Nat. XIV 1850, p. 287. -ED. PI 72 TiHE AXNNELDES. ~ 159. ~ 159. With the Hirudinei, and Lumbricini, the peculiar canals found in the abdominal cavity may be regarded as internal branchiae, or as aquiferous vessels. The intimate structure of this aquiferous system is difficult to unravel with the Hirudinei. It is most easily observed with the Branchiobdella; here there are only two pairs of curved canals whose inner surface is ciliated. One of these pairs opens upon the ventral surface at the beginning of the second third of the body, while the other opens at the extremity near the median line. Each of these four canals is dilated just before its external opening into a round, yellow cavity, from which pass off many loop-like vessels.(l) With the other Hirudinei, these organs in pairs are more numerous, and situated one after another from the second third to the extremity of the body. It is remarkable that the ciliated epithelium lining these canals with Branchiobdella, is absent in all the other species.("2 The structure of the respiratory system of the Lumbricini is not less.difficult to be understood. With all the genera there are, at the commencement and on each side of the intestine, very tortuous canals which open upon the ventral surface, by a narrow orifice near the median line. These canals are lined with long cilia which have an undulatory movement; (3) they also are colorless and sometimes have dilatations before opening externally, but they never contain air, so that the terms tracheae or pulmonary cells, have been erroneously applied.(4) Often they float loosely in the cavity of the body, and their free extremity has an orifice surrounded by long vibratory cilia.(5) With some, however, they terminate by thickly1 See Henle, in Miiller's Arch. 1835, p. 576, colorless, non-ciliated canals connecting with a fTaf. XIV. fig. 1. This epithelium would undoubt- vesicular pouch which is filled with red blood * so eXlly favor the constant renewal of water in these that in the posterior two-thirds of the body there canals. is a double row of seventeen sanguineous sinuses, 2 With Sanguisuga, there are seventeen pairs inside the lateral vessels. These sinuses, already of these organs. They have been taken by Brandti carefully described by Miller (Meckel's Arch. (Med. Zool. II. p. 251, Taf. XXIX. A. fig. 55-58) 1828, Taf. I. fig. 1), take no part in the pulsations for organs of special secretion, since he has seen a of the main vessels, and are not alternately empwhitish liquid escape from their ventral orifices. tied and filled during the transverse circulation of The riband-like organ of these Annelides is not, these animals. moreover, as is usually supposed, a simple canal, A very interesting fact to me, is the existence but is composed of numerous interwoven and fre- with this Nfphelis, of a multi-lobulate, rosetted, lquently interanastomosing canals, having no trace ciliated, colorless organ in the interior of these of ciliated epithelium. sanguineous sinuses.* Fr)m Duges' remark (Ann. d. Sc. Nat. XV. 3 See Henle, in Miiller's Arch. 1837, p. 84, Taf. 1828, p. 308, P1. VIII. fig. 2), I think it probable VI. fig. 7; 8, v. w (Enchytraeus); and Gruithuitllat this net-work is formed of blood-vessels which sen, Nov. Act. Acad. Nat. Cur. XI. 1823, p. 238, are occasionally empty, for I have always found Tab. XXXV. fig. 1, i., XIV. 1828, Tab. XXV. fig. them colorless. 5 (Nais and Chaetogaster). In this case, the real aquiferous canals are prob- 4 An aqueous respiratory fluid circulates in ably concealed in the net-work, and from their want these canals undoubtedly by the aid of cilia. The of ciliated epithelium not easily seen. terrestrial Lumbricini which live only in the damp With Nephelis vulgaris, I have seen the same earth obtain this fluid therefrom. number of internal branchiae as with Sanguisuga. 5 I have observed this with Saenuris varieHtere, the aquiferous system appears as a knot of gata, Lumnbriculus variegatus, Naios elingu.is, ~ [6159, note 2.] See, upon the circulatory sys- lie also states as conclusions: tenm of Branchellion, Quatrefages (Ann. d. Sc. 1. The non-communication of the abdominal vesNat. XVIII. 1852, p. 314). According to him, the sels with the branchiae. general cavity of the body here, is represented by 2. The existence of a subcutaneous lymphatic a collection of canals which are lacunae. This vessel. forms a vascular lymphatic system which circulates 3. The origin from this vessel of trunks which chyle to the branchiae i these last are, therefore, go to the branchiae. - ED. " branchies lymphatiques." c 160. THE ANNELIDES. 17;3 arranged loops.(6) With Lumbricus, these aquiferous canals are surrounded by a very distinct vascular net-work, which has a botryoidal aspect from its numerous pedunculated, vesicular dilatations which are filled with blood.(7) ~ 160. With most of the Capitibranchiati, and Dorsibranchiati, the respiratory organs consist of external branchiae, which are very apparent, although having variations in their development. They always consist of lobules or filaments covered with ciliated epithelium, and in which are very considerable vessels as branchial arteries and veins.() The branchiae are here always situated between the venous and arterial systems, so that a portion only of the whole blood is made to pass through the respiratory organs. It is possible that the two bundles of tentacles which are found with many Capitibranchiati, as infundibuliform,() or spiral(3) tufts, are also respiratory; for their vibratory organs not only draw in food, but also produce a constant change of the water. Other Capitibranchiati have distinct and exclusively respiratory organs in the cervical region, which are either dendritic,~4) or senmi-pinnate.(5 With the Dorsibranchiati, nearly every segment of the body has branchiae upon both sides of its dorsal suriface. These are so simple and rudimentary with the Ariceae, and Nereideae, that they consist only of simple lobules, exactly resembling the cirri of the feet.~6j Enchytraeus albidus, and others. Those canals 7 These vesicular dilatations do not pulsate, and( thus situated remind one of the trembling orgfans are undoubtedly analogues of the simple sinuses of Rotatoria, connecting the two lateral canals which conlmunicate with the aquiferous canals of with the cavity of the body; see above, ~ 138. Nephelis vulgaris.* 6 With Lumbricus terrestris, and its allied 1 These respiratory organs may be taken as species, I have as yet been unable to find any ori- analogous to the aquiferous vessels of the Luimbrifices of the aquiferous canals. Henle also (M3iil- cini,which can be everted so that the internal ciller's Arch. 1835, p. 580) hals always found theml -iated surface becomes external, and the external looped upon themselves. They may however exist, blood-vessels internal. although they have eluded the notice of Henle and 2 Serpt.la, and Proteula. myself, for the respiratory organs of Lumbrictis 3 Sabella. are so difficult to study that there is yet no de- 4'Terebella; see Delle Chiaje, M1em. loc. cit. scription or figure giving ally idea of their coIn- Tav. XLIII. fig. 1-5, Tav. XLV. fig. 2, 10 and plexity; see the poor figures of Lssmbricus ter- lMilne Edwsacrds, Ann. d. Sc. Nat. X. 1S38, p. 200, restris by Leo (Loc. cit. p. 25, Tab. I. fig. 4), and P. X. X.. fig. 1. There are here on eacth side of I'sorren (loc. cit. p. 53, 14S, Tab. XIV. XV.). the neck three multiramose, contractile branlchiae Those of Iioffns eister, although more detailed, are which are placedclose together. Into these a scarcely less unsatisfactory (loc. cit. p. 15, Tab. I. large tlortion of the blood of the mnedian dorsal vesfig. 35, 36). It now remains to inquire as to the sel enters by six lateral branches, while the rerelations existing between tllese aquiferous canals maining portion passes on through the dorsal vesand the glandcls at their base which have been sel to the tentacles and the borders of the lips. taken by many for mucous pouches. I cannot, for In each branchial tuft there are a simple artery my own part, perceive that these glands with the and a vein placed side by side, which anlastomnose Lumbricits terrestris, excrete any liquid -vwhat- at its extremity in an arcuate manner. ever upon the ventral surface. On the other hand, The returning blood from the six branclhiae I have often seen escape from the back of this passes by as many veins into the mediau dorsal animal, a watery liquid which was only the con- vessel, and the frequent strong contractionls alnd tents of the cavity of the body, issuing through dilatations of the branlchiae, certainly very mucht small orifices upon each side of the median line aid the current. between the segments of the body. Although I do 5 Amphitrite; see Pallas, MIiscell. zool. p. 120, not know, yet I suppose, that similar orifices exist Tab. IX. fig. 1, 5, 6, 8, e, e Racthll, Danzig. with the other Lulmbricini, aid thus, by these ori- Schrift. loc. cit. p. 59, Tarf. fig. 1, 3. Here the fices and by those of the internal branchiae, the four semi-pinnate branchiae are upon both sides of necessary renewal of water for these last, can take the second and third rings of the body, and each place. This hypothesis appears adumissible since lamella contains a tightly-closed vascular netthe cilia of the aquiferous canals always move in work. the same way. G The filaments of these branchiae are very short * [~ 159, note 7.] See, for many details on Respirationsorgane d. Regenwvurms, in Siebold these parts, Gegenbaur (Ueber d. sogenannten and Kolliker's Zeitsch. IV. p. 221). ED. 1 Aff 174 THE ANNELIDES. ~ 160. It is remarkable that the branchiae are perhaps entirely wanting, with the Aphroditae,171 while they are often' highly developed, partly in a pectinate and partly in a fascieulate manner, with the Eunieeae, Amphinomae, and Arenieoiae.(8) with Glycera, Nere's, Lycastis, Nephtys, and the Asteroidae, the respiration occurs by water others; but with Cirratuluss, they are very long. entering the cavity of the body and bathing the With Phyllodoce, a:d Alciopa, there are flat- intestine. tened lobules. But with LumDsbrinereis, Aglaura, 8 With Onuophis, and Ezunice, the branchiae and some other allied genera, these are wholly are pectinate or semi-pinnate; see Milne Edwanting; see Milsne Edwlards, Classif. loc. cit. woards, Classific. loc. cit. With Diospatra, and The question here arises if the Dorsibranchiati Chloeia, each branchia consists of a single ramified which have atrophied branchiae, have not there- fasciculus; but with the Amphinomae, and Arenifore internal respiratory organs. It is at least colae, there are several fasciculi see Milne Edprobable that the two pairs of remarkable net- weards, loc. cit. and his plates annexed to R/gne works surrounding the pharynx of Nereis and anim. de Cuvier, Annelides; also Stannius, Isis, which have given rise to various interpretations 1831, Taf. VI. With Eunzice, the blood of the (see Rathk/, De Bopyro et Nereide, p. 48, Tab. II. median dorsal vessel passes first into the inferior dig. 5, bb, fig. 8, f, g, h, and Tab. III. fig. 14; lateral vessels which have the form of cardiac also Milne Edwards, Ann. d. Sc. Nat. X. 1838, sinuses, and by the pulsations of which it passes p. 210, PI. XII. fig. 1, o, p) are properly internal into the bronchial vessels, whence it returns into branchiae. They receive the blood from the dorsal the other two dorsal vessels by the superior latvessel through two lateral vessels, and it is returned eral ones; see Milne Edowards, Ann. d. Sc. Nat. to the median ventral vessel by two others which X. 1838, p. 207, PI. XII. fig. 2. are also lateral. rMoreover, according to RathLke With Amphinome, there is at the base' of each (loc. cit. p. 40), there is, between every two feet branchial fasciculus, in the cavity of the body, a upon both sides of the segments of the body, a small Plexus branchialis, closely resembling the'wonorifice opening into the cavity of the body and derful net-works of Nere/s, and from which the through which water for respiration can pass. blood passes into two lateral vessels which here 7 Different observers have equally different exist; see Catal. of the Physiol. Ser. &c. II. PI. opinions upon the branchiae of these animals. For XIV. fig. 10, or Rymer Jones, Outlines, &c., p. my own part, I have found no trace of these 218, fig. 93. organs, either internal or external with Aphrodite With Arenicola piscatorum,'only the thirteen aculeata, and hystrix. I suppose, therefore, that middle segments of the body have bronchial faswater enters the cavity of the body by orifices ciculi. These communicate with the ventral and which are very small and difficult to be seen, and dorsal vessels by simple lateral vessels. comes in contact with the entire vascular system. As there exist here at the extremity of the body Milne Edweards (Rlgne anim. illustr. Annm- between the two dorsal and ventral vessels, two lides, PI. XVIII. fig. 2a, c) has figured rudiment- cardiac sinuses, it is probable that these force the ary bronchial lobules with Aphrodite aculatea, blood from before backward into the ventral vessel, which are crenulated and concealed between the and thence by the lateral vessels into the branchiae; scales, and are, perhaps, invisible, when the animal so that these inferior lateral vessels would be is in a fresh state. Moreover, Sharpey (Cyclop. called arteries, and the superior lateral vessels Anat. and Phys. I. p. 618), having observed with which return the blood to the dorsal vessel, veins; the same species a very active ciliary motion espe- see Milne Edwards, Ann. d. Sc. Nat. loc. cit. p. cially upon the external surface of the intestine 215, PI. XIII.* and its coeca, it is very probable that here, as with *[ ~ 160, note 8.] The respiratory organs of the ized by the formation of a canal which communicates Annelides have been much studied by Quatreyf- with the more or less spacious lacunae. ges (Ann. d. Sc. Nat. XIV. 1850, p. 290), and the " 6. These true branchiae may be distributed all following is his r6sume: along the body (Eunice sanguinea). "1. The respiration is at first general and en- "7. They may be concentrated upon a certain tirely cutaneous (Lumbrinereis, Lysidice, He- number of rings situated near the middle of the body sionle, &c). (Eunice Bellii, Arenicola, Herrnella, Polydora). " 2. It is stillcutaneous, but is confined or concen- " 8. They may be concentrated towards the antetrated upon particular rings of the body (Chae- rior extremity of the animal, and occupy only a few topterus). rings (Terebella, Pectenaria). "3. It is localized upon certain points of each " 9. Finally, they may be located wholly at the ring, without the structure of these points being extremity of the body, and form only a double tuft sensibly modified (Nereis). (Sabella, Serpula). " 4. The first degree of the specialization of the "10. In considering sometimes the entire body, respiratory organ appears under the form of a sim- sometimes each ring separately, a real distinction pile cul-de-sac, or an ampulla into which the blood between the venous and the arterial system may flows (Glycera). nearly always be made out."- ED. " 5. The branchiae become gradually character - 161, 162. THE ANNELIDES. 175 CHAPTER VIII. ORGANS OF SECRETION. ~ 161. Many Annelides are covered with a mucus which is secreted by small,:simple follicles situated in the skin.(1) The calcareous tubes of the Serpulini, appear to be secreted by a collar surrounding the first segment of the body.(2) It is not yet decided that the leathery tube in which many other Branchiati are concealed,(3) is -secreted by an analogous organ. Those Capitibranchiati which form tubes with grains of sand, bits of shells, &c., have, perhaps all, an opening close behind the mouth upon the ventral surface. This opening is in connection with many glands situated at the anterior extremity of the body, which probably secrete a substance for the gluing together of the materials of these tubes.(4) CHAPTER IX. ORGANS OF GENERATION. ~ 162. The Annelides reproduce partly by a transverse fissuration, and partly by a sexual apparatus. 1 Similar muciparous follicles are arranged in with Amphitrite, upon the ventral surface of the curved rows with the Hirudinei, upon both the yven- first and second segment of the body, and tral and dorsal surfaces, giving the skin a granu- opening by a common canal at the first seglated aspect; see Bra'ndt, Med. Zool. II. p. 244. I ment; see Danzig. Schrift. loc. cit. p. 71, Taf. V.'have seen similar groups of follicles with the larger fig. 6, aa. fig. 2, d. With Terebella, and SaLumbricini.* ~ bella, the two glands near the cephalic extremity, 2 The secretion of the calcareous matter occurs are perhaps of the same nature. Grube, however, here probably as upon- the border of the mantle of thinks them male genital organs i see, Zur Anat. d. 1iollusks. Kiemenwiirmer, p. 31, Taf. II. fig. 12, y.; and 3 Sabella, Onuphis, and Chaetopterus. Mlilne Edwards, Ann. cl. Sc. Nat. X. 1838, P1. X. 4 As secreting organs of this glue, Rathkt has n. P1. XI. fig. 1, h. fig. 2, f. correctly described four yellowish glands situated, *[ ~ 161, note 1.] Leydig (Siebold and K;lli- With Piscicola, these are situated in the cephalic ker's Zeitsch. 1849, p. 109) has described with Pis- and pedal shield, but in Clepsinze, and Nephelis, cicola, Clepsine, Nephelis, and other Hirudinei, they are also present in the skin throughout; see.cutaneous glands. These consist of an infundibu- loc. cit. Taf. VIII. fig. 23. This structure is reliform sac, which exactly resembles a nucleated markable from its resemblance to some of the cuta-,cell, from which passes off a long, tortuous duct. neous glands of the higher animals. - ED. 176 THE ANNELIDES. ~ 163H. Spontaneous transverse fissuration occurs particularly with the Abranehiati,(l3 but has also been observed with the Nemertini,(2 and Branchiati.(;> It occurs usually at the middle portion or at the border between the second and third segments of the body. Very often there may be perceived at this point, when this process has somewhat advanced, the place where, with the two future individuals, there will be a new fissuration. If the animal has a proboscis, tentacles, or eyes, these organs are developed with the posterior individual before its final separation.(') ~ These animals have no trace of genital organs, while this process of division lasts. The individuals thus produced, re-divide, and this division continues until a certain time of the year. It then ceases, and genital organs being developed, reproduction takes place by eggs. The extreme vulnerability and reproductive power of many Chaetopodes, give rise to their frequent multiplication by artificial and accidental division. The fragments thus produced are finally developed, and the mautilated animal ultimately regains its lost parts.(5) Some have the power of voluntary division from the least handling of their body,~6). and these sepoarated parts are probably developed to new individuals. ~ 163. Most of the Annelides reproduce by sexual organs, and the few Lumbricini which, as just observed, multiply by fissuration, have probably, like their allied species, genital organs at certain seasons of the year.(l) The eggs of the Annelides present nothing remarkable; they are always spherical, and have a chorion and thin vitelline membrane containing a finely-granular vitellus with a germinative vesicle and dot.t2) This 1 Lumbriculus, Nais, Chaetogaster and Aeolo- gle individual of Myrianida.fasciata, which is alsoma. lied to Phyllodoce, produces six young by as many 2 See Johnston, in the Mag. of Zool. and Bot. I. successively disposed divisions. According to Frey' 1837, p. 534. and Leucieart (Beitr. &c. p. 94, Taf. II. fig. 1). 3 With the Nereideae. there are with Syllis prolifera also, several young 4 Fissuration with many species of Nais, has developed simultaneously, one after the other, at already been noticed by 0. F. Miiller (Naturgesch. the caudal extremity.* einiger Wurm-Arten des sfissen und salzigen Was- 5 See the experiments upon this subject with the sers. Taf. II. &c.). For that of Naisproboscidea Lumbricini by Reaesnsur, Bonnet, Trembley, and. and Chaetogaster diaphanus, see Gruithuisen, Roesel. Dalyell (Froriep's neue Not. No. 331,. Nov. Act. Acad. Nat. Cur. XI. p. 213, Tab. XXXV. 1810, p. 1) has observed a similar mode of reprofig. 1, 3; XIV. p. 412, Tab. XXV. fig. 2. For that duction with Sabella. of Aeolosoma, see Orsted in Kr6yer's Naturhist. 6 This has been observed by Grube, with Polia: Tidskrift. IV. Pl. III. fig. 7; and for that of Ne- delintata (Zur Anat. d. Kiemenwiirmler, p. 58)> reis prolifera, see Jliiller, Zool. Dan. II. p. 16, Meckelia annozulata has also the same property. Tab. LII. fig. 6. This last species is a very young 1 Aeolosoma. Nereis. It is probable that many other Branchi-? See Wagner, Prod. 1list. gener. loc. cit. Tab. I, ati multiply in the same way. Quatrefafges (Fro- fig. 9, 10 (Sanszs isuga and YVephelis); Stannius,. riep's neue Not. No. 726, 1845, W344) has recently in Mliiller's Arlch. 1840, Taf. II. fig. 1, 2 (Arenirecognised a Syllis in JNere is prolifera. cola piscatorusm); AMilmne Edwards, Ann. d. Sce Sars (Faun. litt. &c. p. 87, Taf. X. fig. 18, 19) Nat. III, 1845, PI. V. fig. 2, 3, P1. IX. fig. 43, 44has observed multiplication by transverse division (Terebella and Protula); and Sars, in [Wiegwith Filogranas irmplexa, a young animal detach- mann's Arch. 1845, 1. Taf. I. fig. 13 (Polsynoe ciring itself from the caudal end of this Serpula. I have rata). If the bodies which H. 7-Iec/cel has figured observed a like division with a Protula, a genus (sIiiller's Arch. 1844, p. 481, Taf. XIII, fig. 13allied to Serpula. According to Mlilne Edwards 23) as the elggs of Lumbricsus terrestris, are really (Ann. d. Sc. Nat. III. 1845, p. 180, P1. XI.) a sin- such, which I think is doubtful, they differ much * [ ( 162, note 4.] See in this connection, Schultze ther Lesuckart, I[eber die ungeschlechtlichte Ver(Ueber die Fortpflanzung durch Theilung bei Nais mehrung bei Nais proboscidea, in Wyiegmann'e proboscidea, in Wiegmann's ArcIm. 1850, p. 293). Arch. 1851, p. 134, Taf. II. fig. I.-III. and Krohn,. Hie has carefully described this form of multiplica- Ueber die Erscheinungen bei der Fortpflanzung vom tion with this animal, and according to hlim it is a Syllis prolifera und Autolytus prolifer. Ibid. 1852, truefissuration, and not a gemmnation, as that of p. 66. -lED. ~yllis, described by Frey and Leuckart. See fur ~ 164. THE ANNELIDES. 177T vitellus is usually whitish or yellowish, but rarely of a more marked color.() With the Hirudinei and Lumbricini, the spermatic particles are filamen-. toid and very active, while with the other Annelides they have the form of Cercariae. (4) ~ 164. With the Hirudinei, and Lumbricini, the two sexes are always united ire the same individual. The sexual organs consist of testicles, vasa deferentia, and vesiculae seminales; then, ovaries, oviducts, and the male and: female copulatory organs. The female copulatory organs are upon the ventral surface of the anterior part of the body and behind the male organs- so that two individuals by placing together their anterior ventral surfaces in an inverse position, can be mutually impregnated.a) The excretory ducts of both sexes are often lined with a very delicate ciliated epithelium. from the eggs of other Annelides, in containing be- veloped like those of the tirudinei and Lumbricini. tween the vitellus and vitelline membrane a layer While in the excretory ducts of the sperm, the of caudate cells. These cells, of variable number spermatic particles are found in bundles * and when, and size, but always of uniform size in the same as at the procreative period, many of these bundles egg, have often been compared, from their form, to are collected together, their very active, undulaNaviculacae; see Henle, in AIieller's Arch. 1835, tory movements give a most wonderful appearance p. 591, note, and Hoffmeister, De vermibus qui- beneath the'microscope; see Morien, loc. cit. p. busdam, &c., Tab. II. fig. 14-17. 178, Tab. XXIV.-XXVIII., and myself in iMuller's 3 The vitellus is rose-colored, or greenish, with Arch. 1836, p. 42. Among the filamentoid spermClepsine, and violet with Polynoe. atic particles of Hirudinei, those of Branchiob4 The development of the spermatic particles of della are worthy of special mention. One of their the Hirudinei and Lumbricini is very remarkable. extremities is delicate and spirally turned (see my The cell-membrane of the parent cells, in which the observations, Miiller's Arch. 1836, p. 42, Taf. II. spermatic particles are usually developed, disap- fig. 8), and terminates, according to Kolliker, by a pears before these last are developed. There are then small vesicle (loc. cit. p. 18, Taf. II. fig. 16, f.). small cells grouped around a discoid nucleus. These With the Branchiati, the cercarian-form predomicells lengthen out, and finally become spermatic nates, according to Quatrefages (Comp. Rend. particles, and they remain attached to the disc until XVII. 1843, p. 424). With the Nemertini, they are fully developed. If a bundle of these is placed either simply filamentoid (Notospermus, accordin water, they separate and become intertwisted in ing to Orsted, Entwurf. einer Einth. d. Plattwiirm. the usual manner; ee Henle, in Miller's Arch. loc. cit. Taf. III. fig. 54) or more cercarian-form. 1835, p. 584, Taf. XIV. fig. 4, 6, 7, 9; K61liker, (Nemertes, according to Quatreffates, RsgneBeitr. zur Kennrtn. d. GeschlechtsverhAltnisse, p. anim. illustr. Zooph. PI. XXXIV. fig. 6 i and Kil — 17, Taf. II. fig. 16, 18, 19; H. Meckei, Miller's liker, Verhandl. d. schweiz. naturf. Gesellsch. bei. Arch. 1844, p. 477, Taf. XIII. fig. 2-10 (Sangui- ihrer Versammlung zu Chur. 1844, p. 91). suga, Pontobdella, and Branchiobdella)* and For the spermatic particles of the Annelides, see Hoffmeister, De vermibus quibusdam, &c., Tab. especially K6lliker in the N eue schweiz. Denkschr.. II. fig. 6-10. From Stannius' description and fig- vIII. p. 33.* ures of the sperm of Arenicola (Miiller's Arch. 1 See Bojanus, Isis, 1818, Taf. XXVI. fig. 1;; 1840, p. 375, Taf. XI. fig. 3-6); and Rathkd of that Brandt, Med. Zool. II. Taf. XXX. fig. 25 (Sanguiof Amphitrite auriconma (Danzig. Schrift. loc. cit. suga medicinalis); Leo, Miiller's Arch. 1835,, p. 67, Taf. V. fig. 13); and Quatrefages, of that Taf. XI. fig. 3 (Piscicola geometra); Morren, of Nemertes mandilla (Rsgne anim. illustr. Zooph. loc. cit. Tab. XXVII.-XXXI.; and: Hoffseister, PI. XXXIV. fig. 3-5), we can conclude that the De vermibus quibusdam, &c., Tab. I. fig. 29, 30G spermatic particles of the other Annelides are de- (Lumbricus and Enchytraeus).t * [ ~163, note 4.] For the spermatic particles ance because they are then just escaping from the of the Hermella, see Quatrefages (Ann. d. Sc. daughter-cells, and the more or less adherence of' Nat. X. 1848, p. 167); he describes them as being of the membrane of these last to the particles, gives a cercaria-form. My own results on the spermatic the appearances above mentioned in the note. I particles of the Annelides and their development, have observed the same appearances with some of do not agree with the view above expressed. Here, the Coleopterous insects, where the development as elsewhere, I have found them to be the metamor- occurs unmistakably in special cells. These parphosed nucleus of the daughter-cells. It is true tides are, according to my own observation, hairthat with the Lumbricini they present some pecu- like with the Hirudinei, and Lumbricini, but are liarities, but these are apparent only. The mul- pin-shaped with some of the Capitibranchiati.-ED. berry-like mass to which they are here found ad- t l ~ 164, note 1.] See also Leydig, Siebol dand herent, is composed of the remains of the develop- KElliker's Zeitsch. III. lift. 3, p. 318, and Quatrement, and the spermatic particles which seem to ra- fages, Ann. d. Sc. Nat. XVIII. 18652, p. 299 diate from it in all directions present this appear- (Branchellion).-ED. 178 THE ANNELIDES. 9 165, 166. With the Nemertini, and Branchiati, the sexes are upon separate individuals, and the genital organs are composed simply of testicles and ovaries. ~ 165. The structure of the genital organs of the Nemertini is yet quite obscure. Tk- few researches hitherto made only furnish the general result that the sexes are separate. There are numerous glandular follicles situated laterally in the parenchyma of the body between the skin and the intestinal canal, which are closely aggregated and serially arranged. With some individuals, these follicles contain eggs, and with others, sperm. They ought, therefore, to be regarded as ovaries and testicles. Each follicle opens separately upon the surface of the body.(1) There are very contradictory statements as to whether these animals have, or have not, copulatory organs. According to some Naturalists, the worm-like organ, concealed in a canal extending along the back, and which, with both sexes, is often protruded and moved actively about, ought to be regarded as an excitatory organ,although no connection between it and the testicles or ovaries, has as yet been found. According to others, it is a proboscis unconnected with the genital organs.(2) ~ 166. The disposition of the genital organs of the fHirudinei and Lumbricini, is essentially different. The first have only two simple genital openings, -one male, the other female, both situated, one after the other, upon the median line of the ven1 See Dug~s, Ann. d. Sc. Nat. XXI. 1830, p. 76, Polystemma armatum (Duges, Ann. d. Sc. Nat. P1. II. fig. 5 (Polystemm.a (Prostomum) arma- loc. cit. p. 75, P1. II. fig. 5) Tetrastemma vari. tum.); Johnston, Mag. of Zool. I. p. 532, P1. XVII. color (Orsted, Entwurf. &c. p. 23, Taf. III. fig. fig. 2', 6", I. XVIII. fig. 3' (Nemertes and 41), and Nemertes (Johnston, Mag. of Zool. I. p.' Borlasia); Orsted, Entwurf. einer Beschreib. d. 530, fig. 2; Quatrefages, RIgne anim. illustr. loc. PlattwUirm. p. 22, Taf. III. fig. 41 (Tetrastemm.a cit. P1. XXXIV. fig. 2, and K6lliker, Verhandl. d. varicolor); Kolliker, Verhandl. d. schweiz. na- schweiz. &c.) there is at the centre of this organ a turf. Versamml: zu Chur. p. 91 (Nemertes); and dart pointing forward; which is horny, accordRathkd, Danzig. Schrift. loc. cit. p. 98 (Borlasia ing to Dug~s, and calcareous, according to Orsted..striata). this last author has not seen the orifices On each side of this dart, there is a reservoir of of the genital organs. Quatrefages (Rhgne anim. many others, smaller and yet imperfect, destined, illustr. loc. cit. PI. XXXIV. fig. 1, n. n.) did not probably, to replace the former when lost. Dugis, see them with Nemertes Camilla, and Johnston Johnston, and QuatreJfages, who regard this or. is also silent on this subject. According to Orsted gan as an intestinal canal, and Killiker, who con(Entwurf. &c. loc. cit. p. 25, Taf. III. fig. 47, of siders it prehensile, all regard these darts as a kind Notospermus flaccidus) the Nemertini secrete of teeth but Orsted thinks they serve to excite from the whole surface of their body, a gelatinous the genital organs. For my part, they involunta-mucus, which surrounds the eggs, and thus forms rily remind me of the darts of the Helicina. an envelope into which they can draw their bodies. [Additional Note.] - I have now satisfied myself.Something similar to this occurs with the Lumbri- upon living individuals of Tetrastemma, that the cini and Hirudinei. See below. eggs can escape from the visceral cavity through 2 The Nemertini being of distinct sexes, this or- numerous lateral openings in the wall of the body gan can be regarded neither as a penis, nor as an I am also satisfied that with the Nemertini, the everted spermatic vessel, as Huschke has done walls of the digestive canal (the middle body-cavity.(Isis, 1830, p. 682, Taf. VII. fig. 5). More prop- according to Quatrefages) are not the points of erly could it be considered, with Orsted (Entwurf. departure of the genital organs, as Quatrefages &c. p. 25), as an excitatory organ; although Rathkd thinks, and who also would regard as a digestive (Danzig. Schrift. loc. cit. p. 100, and Nov.Act. Acad. tube the snout of these animals, an organ which is Nat. Cur. XX. p. 233) regards it as of a tactile, yet enigmatical. The very detailed figures which:and K6lliker of a prehensile nature (Verhandl. d. this naturalist has given (loc. cit.) of the walls of schweiz. p. 90). Other observers agree with the digestive canal of these animals, present nothing Ehrenberg (Symb. phys. loc. cit.) that it is an in- like an ovary, and show no trace of the presence testine and an everted oesophagus, its orifice being of germs. a mouth; but this is undoubtedly erroneous. With .f 166. THE ANNELIDES. 179 tral surface. The posterior opening connects with a short muscular canal which may be regarded as a reservoir of eggs. From the base of this reservoir, a narrow spiral canal passes off, and bifurcating into two oviducts, terminates with two round ovaries.l) From the anterior opening, a long filiform penis may be protruded, which, when not erected, lies spirally concealed in a bulbous muscular sheath. A Ductus ejaculatorius extending from the seminal vesicles, opens into each side of this sheath. These seminal vesicles are formed each by a kind of continuation of the vas deferens into a varicose tortuous canal, which lies in the midst of a dense cellular tissue. The Vasa deferentia are narrow,;and passing backwards along the sides of the body, receive upon their finternal surface the short excretory ducts of the five, nine, or twelve pairs,of round isolated testicles, which form a double row near the ventral,cord.(2) With many Hirudinei, a portion of the skin is connected with the sexual -function. Such is the case with Nephelis, with which numerous cutaneous glands are developed upon the back and belly near the female genital opening. The skin soon has a bloated, transparent appearance, so that the animal appears to have a girdle about its anterior extremity. Before the deposition of the eggs, these glands secrete a substance which hardens in water, and surrounds the body of the animal like a horny belt. This belt is filled with a greater or less quantity of eggs; the animal then withdraws, or- slips out from it, while its two extremities are closed up by its own elasticity; but the enibryos developed in this egg-capsule are not thereby prevented from making their escape.(3) The Sanguisugae form cocoons in a similar manner; but they are surrounded with a very thick, spongy substance.(4) The various species of Clepsine form sac-like capsules for their eggs, and which they usually carry about with them, attached under their belly, shielding them with their body at the approach of danger.(5) I See Brandt, Mediz. Zool. II. p. 252, Taf. XXIX. five pairs of these organs; with Haemopis, eight; A. fig. 45, 46; Aloquin-Tandon, Monogr. loc. and with Aulacostomum, twelve (Moquin-Tan~cit. p. 80, P1. I.-III.; Leo, Muller's Arch. 1835, don, ilonogr. loc. cit. PI. III. fig. 8 5 PI. I. fig. 3, p. 424, Taf. XI. fig. 10 (Sanguisuga, Aulacosto- P1. II. fig. 10). With Nephelis, the arrangement unum, Nephelis, Pontobdella, and Piscicola. is different, there being on each side of the posteAccording to the careful researches of Filippi rior part of the body, numerous testicular vesicles (Lettera sopra l'anat. e lo sviluppo delle Clepsine, united in a botryoidal manner; see Moquin-Tanp. 16. Tav. I. fig. 5), Grube (Untersuch. fib. d. Ent- don, Monogr. loc. citsPl. III. fig. 4.* wickl. d. Clepsinen. p. 6, Taf. III. fig. 3), and Fr. 3 See Rayer, Ann. d. Sc..Nat. IV. 1824, P1. X. Miiller (Muller's Arch. 1846, p. 138, Taf. VIII.), fig. 1-6, and AMoquirn-Tandon, loc. cit. PI. VI. fig. the two ovaries of Clepsine and Nephelis, consist 4, e-h. These cocoons are often found as brown of long flexuous cords surrounded by two more or scales, glued to aquatic plants. Piscicola forms less long muscular sheaths, which are uninterrupt- similar cocoons, but they never have more than one Redly continuous into the oviducts; they receive the egg each; see Leo, loc. cit. p. 425, Taf. XI. fig. 6 -.eggs as they are detached from the ovaries, and pass and Brightwell, Ann. of Nat. Hist. IX. 1842, p. them along by peristaltic movements. 11.t 2 Sanguisuga has nine pairs of testicles (Brandt 4 See Rayer, loc. cit. PI. X. fig. 10, and MoquinMed. Zool. II. p. 252, Taf. XXIX. A. fig. 32-44). Tandon, loc. cit. P1. V. According to Wedeke The Vasa deferentia of the seven pairs with Pis- (Froriep's neue Not. No. 452, 1842, p. 183). the,cicola are dilated before reaching the two seminal medicinal leech ejects from the mouth as a scum, vesicles into two long and very fiexuous tubes (Epi- the spongy envelope of these cocoons. didymis, according to Leo, loc. cit. 1835, p. 423, 5 See Grube, Untersuch. iiber die Entwick. d. Taf. XI. fig. 10). With Pontobdella, there are Clepsinen, 1844, p. i. * [ 166, note 2.] For many valuable details on t [ ~ 166, note 3.] See, for an histological examin the genitalia of the Hirudinei, see the often-quoted nation of these genital glands in Piscicola, Leyand valuable works of Leydig, loc. cit. p. 120. It dig, loc. cit. p. 122, Taf. IX. fig. 43, e. 49, a. b. c. acontains histological, as well as anatomical results. - ED. according to him, Piscicola has six, and not seven (Leo) pairs of testicles. -ED. 180 THE ANNELIDES.; 167. ~ 167. The genital organs of the Lumbricini are very difficult of dissection: for often those of both sexes are intimately united together into a common mass. It is certain, however, that the male and female orifices are always in pairs and situated at the anterior extremity of the body, near the ventral median line. (1) These orifices communicate with more or less numerous glands, sacs, and pyriform or cylindrical vesicles. Their nature as testicles, ovaries or sperm-receptacles, is known only by their contents. As yet it has been possible to trace only very imperfectly their excretory ducts. With some, two of these caecal organs have been observed intersuscepted in each other. The internal one contained spermatic particles, and should therefore be regarded as a testicle; while thee outer one contained at its base, eggs and egg-germs, and ought therefore to be taken for an ovary.(2) The larger Lumbricini appear to be without copulatory organs, the collar situated back of the genital orifices, taking their place.''Withmany, it is situated chiefly on the back, but terminates on the belly with two long lateral swellings, which, during coition, seize those of the -other individual.(3) This collar, moreover, is compdsed of a mass of glandular follicles, which copiously secrete, during the sexual period, a white, viscous liquidIt is then very fully developed, but at other periods it is scarcely visible. The belt which is developed near the genital openings of the smaller LumI With Lumbricus terrestris, the two anterior bundles of spermatic particles, but never their cells genital openings are male, and the two posterior, of development. Duges has made a similar obserfemale. These have been figured by Montdgre vation with his Nais ofiliformis (Ann. d. Sc. Nat.. (loc. cit. fig. 2, a. c.), Leo,(De Struct. Lumbr. ter- loc. cit. p. 320, P1i. VII. fig. 2), only he does not restr. Tab. I. fig. 2), and by Morren (loc. cit. specify the contents of the organs. Menge, also, Tab. III. fig. 2). Withi Saenuris, and Nats, I has observed these two caeca with Euaxes. but he have also found these two pairs of genital openings. unhesitatingly regards them as testicles (Wieg2 This invagination of the testicle in the ovary mann's Arch. 1845, I. p. 32, Taf. III. fig. 2, aa. has been distinctly observed by me with Saenuris fig. 3). Never having seen any connection between variegata, and eYais proboscidea. From HF. these caeca and the testicles behind them, I am Nlieckel's late researches upon the very compli- disposed to think that the two posterior genital cated genital apparatus of Lumbricus terrestris, it openings of some Lumbricini, are the common oriappears that there are three pairs of seminal vesi- ffces of the invaghinated testicles and ovaries, while cles and testicles; these last being intimately joined the anterior caeca, which are filled at certain times with as many ovaries (Miller's Arch. 1844, p. with sperm, are two isolated Receptacula seminis. 480, Taf. XIII. fig. 12). It is probable that here During the mutual copulation, the sperm will pass the testicles and ovaries are also invaginated, and from the testicles into these reservoirs, in order to that the vesicles which have usually been taken for be used during the subsequent deposition of the' testicles are only vesiculae seminales; see Mor- eggs. ren, loc. cit. p. 175, Tab. VII'.-X. and Treviranus, From Hojffmeister's description (Die bis jetzt: in his Zeitsch. f. Physiol. V. p. 154, Taf. VII. How- bekannt. Arten aus der Familie der'Regenwiirmer, ever, as yet I have been unable to trace to their ter- 1845, p. 15) of the copulatory act with Lumbricuse mination, the excretory ducts of the testicles and agricola, it would appear that the sperm remains ovaries which are invaginated together. - equally distant from the female organs, being reThis point is all the more difficult, for, as Dugds ceived into special fossae, which correspond per — appears to represent (Ann. d. Sc. Nat. XV. 1828, haps to the Receptacula seminis. N- ais probosp. 328, PI. IX. fig. 2, or Isis, 1830, Taf. III. cidea, although having a pair of genital'openings,. Tab. 9, fig. 2), the vas deferens is probably has only one testiculo-ovarian canal, both of which invaginated in the oviduct. Many observers have although invaginated, have a very active and indegone so far as to think that the eggs having escaped pendent peristaltic action.. They are bifurcated anfrom the ovary, and fallen into the cavity of the teriorly. See Gruithuisen (Nov. Act. Acad. Nat. body, pass gradually to its posterior portion, and Cur. XI. p. 246, Tab. XXXV. fig. 4, 5), who hats are there evacuated through invisible openings. very correctly perceived the eggs in the bottom of Ons this account, several of them have taken for the ovarian sac, but not the nature of the invagieggs and embryos, the collections of horny spines, nated testicular canal. and vibrios, which are often found, in these ~animals. 3 With Lumbricu.s olidus,. he two copulating' See above, ~ 145, note 1'- and E. Home, Lect. on individuals seize each other so;ightly oy their colComp. Anat. IV. 1823, P1. CXLIX. lars, that each of these animals completely envelI have always been astonished that, at the epoch ops the other by this organ; see HoJfmeister, in of procreation with Saenuris, Euaxes, and Nais, Wiegmann's Arch. 1843, I. p. 190, and, De verthe two anterior genital openings should communi- mibus quibusdam, Tab. I. fig. 30. cate with two caeca which contain sperm and long , 168. THE ANNELIDES. 181 bricini at this period, is of an analogous nature. It is also composed of numerous cutaneous glands, closely aggregated, and extending completely over many segments of the body.(4) The secretion of this collar is like that observed with the Hirudinei, probably for the formation of cocoons. But these cocoons differ from those of the Hirudinei in having the place of their opening prolonged into a long, narrow neck.'5' ~ 168s. The Branchiati resemble the Arthropoda in their annulated body, their distinct head endowed with organs of sense, the structure of their nervous system, and the development of their locomotive organs; but, from the simplicity of their locomotive apparatus, and the complete absence of copualatory organs, they would be carried towards the Zoophytes. Here the sexes are separate, and the genital organs of both the Capitibranchiati, and Dorsibranchiati, appear as simple glandular bodies, ovaries or testicles, which project from the ventral surface into the cavity of the body between the fasciculi of the cutaneous muscle.i') At the sexual period, they are filled with eggs, or spermatic particles, although at other times they can scarcely be seen.(2) Neither the testicles nor the ovaries have excretory ducts which open upon the surface of the body. The sperm and eggs escape into the cavity of the body, which, during this period is thereby filled throughout.(3) It is possible that the scarcely visible orifices said to be concealed be4 Saenuris, Nais, &c. i see Gruithuisen, loc. cit. of the opinion that the Branchiati, like the Lumbri-'Tab. XXXV. fig. 5, b.b. cini, are hermaphrodites. But Quatrefages, from 5 With the large species of Lumbricus, each co- his knowledge of the development of the spermatic coon has from one to six eggs (L. Dufour, Ann. d. particles, has recognized separate sexes with the Sc. Nat. XIV. 1828, p. 216, P1. XII. B. or, Froriep's most different species, thus: Terebella, Sabella, Notiz. No. 472, 1828,-p. 149, fig. 13-16; and Hoff- Aricinella, Nephtys, Syllis, Glycera, Eunice, mneister, De vermibus quibusdam', Tab. I. and Die Sigalion, Phyllodoce, Nlere's, and -Aphrodite; Arten aus der Familie, &c., p. 16, 25, 42). With see Comp. Rend. XVII. 1843, p. 423. But before the smaller Lumbricini, as with Saenuris, Euaxes, this, Stannius had concluded that the sexes were Ntais, &c., the cocoons contain nearly always five separate with Arenicola, from a difference in the to eight eggs (Dugis, loc. cit. XV. P1. VII. fig. 5, contents of the cavity of the bodies of different inNais). Most of these cocoons have appendages dividuals (Miller's Arch. 1840, p. 375). The by which they are attached to vegetables and other glands at the cephalic extremity of the Branchiati bodies. Hoffmeister (Die Arten aus der Fam. &c. which live in cases, and which Grube has regarded p. 42, fig. 9, c.) has figured a very remarkable as male genital organs, are certainly not such, for husk-shaped cocoon of a new species, Criodrilus they occur with both sexes, and do not change in size lacuum. during the procreative season. (See ~ 161, note 4.) * 1 See Treviranus, Zeitsch. f. Physiol. III. 1827, 3 According to Quatrefages (Compt. rend. p. 165, Taf. XIII. fig. 17, 18 (Aphrodite) Rathki, XVII. 1843, loc. cit.), the parent sperm-cells De Bopyro et Nereide, p. 39, Tab. II. fig. 12, 1. leave the testicle before the formation of the (Nere is), and Danzig. Schrift. loc. cit. p. 66, Taf. V. spermatic particles, which occurs in the cavity of fig. 6, hh. fig. 11, aa. (Amphitrite); Grube, the body. This is confirmed with Arenicola, by Zur Anat. d. KiemenwOrmer, p. 16, Taf. I. fig. 1, Stannius (Miiller's Arch. 1840, loc. cit.). Ac2, m. (Arenicola), p. 44, Taf. II. fig. 6, y. z. (Eu- cording'to Krohn (Wiegmann's Arch. 1845, I. p. nice); also, Nov. Act. Acad. XX. p. 201, Tab. X. 182); the eggs and the spesatic particles, with Alfig. 13, 15, m. (Ammotrypane). RathkC's and ciopa, are developed fro"in the visceral cavity, Grube's opinion upon the presence of both male without the intervention of special organs, ovaries and female organs with the same individual is only and testicles. Frey and Leuckart (Beitr. &c. p. an uncertain supposition, founded upon no histo- 88) think they have observed the same fact with logical examination of the parts. Perets, Syllis, Phyllodoce, Aonis, Ammotry2 This condition of the genital glands after the pro- pane, Ephesia, Hlermella, Vermilia, Fabricia, creative season, is the reason why, as yet, we pose and Spirorbis; they speak of the presence of ovasess so few facts as to their structure. Most ob- ries and testicles in certain Annelides (Aphrodite, servers, and among them Rathk/ and Grube, are Arenicola) as the exception. * [~ 168, note 2.] According to Quatrefages porary, for they are not found in many individuals, (Ann. d. Sc. Nat. X. 1848, p. 46) the sexes are sep- having, probably, quite disappeared from atrophy arate with the Hersmella. Both the testicle and the after the procreative period. This fact should be ovary consist of a delicate areolar tissue adherent to remembered in the study of the genitalia of other the inferior internal surface of the general cavity of Annelides. - ED. the body. These genital organs are evidently tem16 182 THE ANNELIDES. 169. tween the feet of many Branchiati, serve for the escape of the sperm and eggs.(41 With others, the cavity of the body opens outwardly, probably by a loss of the last segment, especially with those which are viviparous.t35 The water is undoubtedly the medium of fecundation, and receives the sperm from the males, probably through orifices like those which serve for the escape of eggs with the female. With the viviparous Branchiati, water filled with sperm can enter the body and fecundate the eggs through these same openings. ~ 169. The development of the Annelides as far as yet known, occurs after two different types; but it always commences with a complete segmentation of the vitellus. I. With the Hirudinei, after the vitellus has divided into many large cells, a central one becomes distinguished from the others by its still further division; this becomes the digestive tube. The others, still dividing, form, a primitive embryonic part in which appears the future ventral and nervous portion. The embryo is atfirst spherical, and ultimately is covered with a delicate ciliary epithelium. A kind of sucker is then developed upon a certain point of its surface; this connects with the stomach, and through it is received, for fobod, the albumen surrounding the embryo. It then gradually lengthens, and, losing its ciliary epithelium before the escape from the egg, a sucker appears upon the posterior extremity, and it finally becomes fully developed without a Metamorphosis.() II. With the Branchiati, there is a complete metamorphosis. The segmentation of the vitellus is uniform throughout, and this last is finally changed into a round embryo -which, escaping from the egg, swims freely about like an Infusorium, by means of the ciliated epithelium which covers its whole body. The embryo then lengthens, and the epithelium disappears 4 According to 2Mlilne Edwards' observations nelides has recently appeared in the Neue Schweiz. upon several Capitibranchiati, as Terebella, Ser- Denkschr. VIII.* pula, Protula, &c., the eggs are glued together in 5 According to my friend H. Koch of Trieste (in masses by an albuminous substance, and attached the MS. just indicated), the eggs of a species allied to the stones of the anterior border of their cases; to Eunice sanguinea, are developed in the cavity see Ann. d. Sc. Nat. III 1845, p. 148, 161, PI. V. of the female body, whence the young escape fig. 1, P1. VII. fig. 28, P1. IX. fig. 42. With Poly- through a rupture of its posterior extremity. snoe cirrata, on the other hand, masses of eggs are 1 Bee F. de Filippi, Lettera sopra 1'Anatomia, e attached and borne about on the scales of their lo sviluppo delle Clepsine, Pavia, 1839, Tav. II.; body; see Sars, in Wiegmnann's Arch. 1845, I. p. Grube, Untersuch. iiber die Entwick. d. Clepsine, 13, Taf. I. fig. 12. With the females of Exogone p. 15, Taf. I., and Frey, Zur Entwickel. von. Nepheand Cystonereos, the eggs are situated in longi- lis vulgaris, in Froriep's neue Not. No. 807, tudinal rows upon the ventral surface; see Orsted, 1846, p. 228. The old observations of E. H. Wein Wiegmann's Arch. 1845, I. p. 21, Taf. II. fig. ber (Meckel's Arch. 1828, p. 366, Taf. X. XI.) 4, and Kslliker, in an as yet unpublished memoir and R. Wagner (Isis, 1832, p. 398, Taf. IV.) agree for the Helvetic Society, titled: Einige Worte zur very well with those of Filippi Entwickelungsgeschichte von Eunice, von H. Koch As yet, we possess nothing upon the developin Trieste, mit einem Nachwort von K6lliker. ment of Lumbricini, whose young, as is known, like [Additional note.] The often-quoted memoir of those of the Hirudinei, leave their cocoons without. Koch and Kolliker on the development of the An- undergoing any metamorphosis.t * [~ 168, note 4.]. According to Felilx Dujar- servation, from its singularity, requires confirmdin (Ann. d. Sc. Nat. XV. 1851, p. 298) Exogone ation. - ED. pusilla is androgynous. Beside the well-known t [L 169, note 1.] For the embryology of Nepediculated ovarian sacs on the ventral surface, mertes, see Desor, Boston Jour. Nat. Hist. VI. p. each segment of the body, except the first two, 1. The general facts accord with those mentioned has, with this species, a dorsal, fusiform cirrus, in in the text. - ED. which are developed spermatic particles. This ob ~ 169. THE ANNELIDES. 183: except upon the belt-like parts of the two extremities. The future anterior extremity is directed in front during the motions of the animal, and eyes appear upon it; while the other extremity is gradually divided into segments upon which bristles and feet appear.(2) While the embryos are thus acquiring the adult form, there appear upon the cephalic extremity and upon the sides of the body, tentacles, cirri, and branchiae, of forms which vary according to families, genera and species. The development of the digestive and circulatory organs occurs also with equal pace.(3) 2 See Lovin in Wiegmann's Arch. 1842, I. p. fig. 6), is only a larval Terebella, as will be seen 302, Taf. VII. (Nereos); Sars, Ibid. 1845, I. p. by referring to Milne Edwards' figures of the de12, Taf I. fig. 1-21 (Polynoe); Orsted, Ibid. velopment of Terebella nebulosa (Ann. d. Sc. p. 20. Taf. II. (Exogone); and Milne Edwards, Nat. loc. cit. P1. VII. fig. 24, 25). A4nisomelus Ann. d. Sc. Nat. III. 1845, p. 145, P1. V.-IX., luteus, of Templeton (Transact. Zool. Soc. II. or, Froriep's neue Not. No. 721, p. 257 (Tere- 1841, p. 27, P1. XV. fig. 9-14), is perhaps only a bella, Protula, and Nereis). KOlliker (in MS. young Serpula. already cited) has also observed the development of The absence of branchiae and blood-vessels an Exogone, and of a Cystonereos, an allied ge- which Quatrefages has noticed with many small nus. Here the embryo is not formed through a lBranchiati of which he has made new genera complete and uniform segmentation of the vitellus, (asuAphlebine, and Doyeria, &c.), would lead one but, as with the Hirudinei, the formation is preced- to suspect that they are only larvae * see Ann. d. ed by an irregular division of that portion to be the Sc. Nat. I. 1844, p. 18, or Froriep's neue Not. No. ventral and nervous parts. He, at the same time, 726, p. 341. H. Koch (see above, ~ 168, note 5) calls the attention to a figure of Milne Edwards, has lately observed that the young individuals representing the development of Protula, fromu found in the body of Eunice are identical with which it would appear that other Branchiati also are the Lumbrinereis of De Blainville. developed like the Hirudinei; see Ann. d. Sc. Nat. The new animal described:by Miller and Busch loc. cit. P1. IX. fig. 47?* (Muller's Arch. 1846, p. 104, Taf. V. fig. 3-5, and 3 One ought therefore to be careful about form- 1847, p. 187, Taf. VIII. fig. 1-3) under the name ing distinct genera from these larval Brar.:hiati. of Mesotrocha sexoculata, appears likewise to Thus, Sabellina brachycera, described by Du- be only a young larva of an Annelid.t.ardin (Ann. d. Sc. Nat. XI. 1839, p. 291, P1. VII. *[ ~ 169, note 2.] For the embryology of Poly- t [ ~ 169, note 3.] See Quatrefages (Sur l'Emnoe, see Desor, loc. cit. p. 12. It agrees closely bryogenie des Annelides, in Ann. d. Sc. Nat. X. with that of Nemertes; see also Max Muller, in 1848, p. 153). - ED. tiiller's Arch. 1851, p. 323. - ED. BOOK NINTH. AC E P H AL A. CLASSIFICATION. ~ 170. THE ACEPrHILA are principally characterized in having a headless body, and a very large mantle, which so envelops the body, that there is a spacious and more or less closed cavity in which the oral and anal orifices are,often entirely concealed. Their body is either wholly asymmetrical, or divided into a right and a left side. In this last case, the organs, excepting the digestive canal, are in pairs; and the two sides are perfectly symmetrical, or one is developed at the expense of the other. All Acephala are aquatic; many are permanently attached during life; others creep about, and a few only can swim freely. Copulatory organs are wanting throughout. ORDER I. TUNICATA. Body wholly asymmetrical and so enclosed in the mantle, that there are only two narrow openings. FAMILY: ASCIDIAE. Genera: A. Compositae. Didemnum, Diazona, Aplidium, Botryllus, Botryllo'des, Leptoclinum, Eucoelium, Synoecium, Polyclinum, Sigillina, Perophora, Pyrosomna. B. Simplices. Clavelina, Phallusia, Rhopalaea, Boltenia, Cynthia, Chelyosoma. FAMILY: SALPINAE. Genus: Salpa. ORDER II. BRACHIOPODA. Animals which are symmetrical and bivalved, and whose widely-open mantle encloses two fringed, arm-like, protractile tentacles. $170. THE ACEPHALA. 185 Genera: Orbicula, Terebratula, Lingula. ORDER III. LAMELLIBRANCHIA. Animals which are symmetrical and bivalved, and whose more or less closed mantle encloses two pairs of lamelliform tentacles and branchiae. SUB-ORDER I. MONOMYA. FAMILY: OSTRACEA. Genera: Ostrea, Anomia. "FAMILY: PECTINEA. Genera: Pecten, Spondylus, Lima. FAMILY: MALLEACEA. Genera: Malleus, Perna, Crenatula. SlUB-ORDER II. DIMYA. FAMILY: AVICULACEA. Genera: Avicula, Meleagrina, Pinna. FAMILY: ARCACEA. GCenera': Arca, Pect unculus, Trigonia, Nucula.'FAMILY: NAIADES. Genera: Anodonta, Unio. FAMILY: MYTILACEA. Genera: Mytilus, Modiola, Lithodomus, Tichogonia. FAMILY: CI3AMACEA. Genera: Chama, Isocardia. FAMILY: CARDIACEA. G-enera: Cardium, Lucina, Hiatella, Cyclas, Piscidium, Tellina, Psam-' mnobia, Venus, Cytherea, Tenerupis, Mactra, Lutraria, UnguZlina. FAMILY: PYLORIDAE. Genera: Mya, Solen, Solenomya, Panoplaea. SUB-ORDE1R II. INOCLUSA. FAMIrLY: TEREDINA. Genera:; Pholas, Teredo. 16-* 186 THE ACEPHALA.. 170T FAMILY: ASPERGILLINA. Genera: Aspergillum, Clavagella. BIBLIOGRAPHY. Poli. Testacea utriusque Siciliae eorumque historia et anatome. 1791-95. J. Rathke. Om IDammuslingen, in the Skrivter af Naturhistorie-Selskabet, IV. Kij6benhavn, 1797, p. 139. Cuvier. Memoire sur l'animal de la Lingule, in the Ann. du Mus. d'Hist. Nat. I. 1802, p. 69. Memoire sur les Thalides et sur les Biphores, Ibid. IV. 1804, p. 360. Both of these are included in his Mem.l pour servir a l'histoire et a l'anatomie des mollusques. Paris, 1817. Schalk. De Ascidiarum structura, Dissert. Hal. 1814. Savigny. Memoires sur les animaux sans vertebres, Pt. II. 1816. Recherches anatomiques sur les Ascidies composdes et sur les Ascidies simples. Also, Isis, 1820, lit. Anz. p. 659, Taf. XI.-XXIL Carus. Beitriige zur Anatomie und Physiologie du Seescheiden (Ascidiae), in Meckel's deutsch. Arch. 1816, p. 569, and Nov. Act. Acad. Leop. Carol. X. 1821, p. 423, Tab. XXXVI. XXXVII. Cuvier. Memoires sur les Ascidies et sur leur Anatomie; in the MWm. du Mus. d'hist. Nat. II. 1815, p. 10; also Isis, 1820, p. 387, Taf. 8, 9. Chamisso. De animalibus quibusdam e classe vermium Linnaeana. Fase. I. De Salpis. 1819. Bojanus. Ueber die Athem-und Kreislaufwerkzeuge der zweischaligen Muscheln. Isis, 1819, p. 42, Taf. I. II., 1820, p. 404, and 1827, p. 752, Taf. IX. Eysenhardt. Ueber einige merkwiirdige Lebenserscheinungen an Ascidien, in the Nov. Act. Acad. Leop. XI. 1823, p. 250, Tab. XXXVI. XXXVII. Pfeiffer. Naturgeschichte deutscher Land-und Siisswasser-Mollusken. Abth. II. 1825. bUnger. De Anodonta anatina. Dissert. Vindobon 1827. Carus. Neue Untersuchungen iiber die Entwickelungsgeschichte unserer Flussmuschel, in the Nov. Act. Acad. Leop. XVI. 1832, pt. I. Tab. I.-IV. VMeyen. Beitrige zur Zoologie. Abhandl. I.; Ueber die Salpen. Ibid. p. 363, Tab. XXVII.-XXIX. Owen. On the Anatomy of the Brachiopoda, in the Trans. Zool. Soc. I. 1835, p. 145, P1. XXII. XXIII.; also, in Isis, 1835. p. 143, and Ann. d. Se. Nat. IlI. 1835, p. 52. Deshayes. Conchifera. Cyclop. Anat. Phys. I. p. 694. London, 1836. Eschricht. Anatomisk-physiologiske Undersogelser over Salperne. Kj6benhavn, 1840; also, in Isis, 1842, p. 467, Taf. II. III., and: Anatomisk Beskrivelse af Chelyosoma Mac-Leayanum. Kj6benhavn, 1841. Milne Edwards. Observations sur les Ascidies composees. Paris, 1841. Garner. On the Anatomy of the Lamellibranchiate Conchifera, in the Trans. Zool. Soc. of London, II. 1841, p. 87, P1. XVIII.-XX. Neuwyler. Die Generationsorgane von Unio und Anodonta, in the Neuen Denkschrift. der allg. schweizerischen Gesellsch. f. die gesammten Naturwissensch. VI. 1842, p. 1, Taf. I.-III. 171. THE ACEPHALA. 187 Vogt. Anatomie der Lingula anatina. Ibid. VII. 1843, p. 1, Taf. I. II. Van Beneden. Memoire sur l'Embryog6nie, l'Anatomie et la Physiologie des Ascidies simples, &c., in the Bullet. de l'Acad. royale de Belgique, XIII. No. 2. ADDITIONAL BIBLIOGRR APIIY. K'lziker. Ueber das Vorkom. d. Holzfas. im Thierreich., in the Ann. d. Sc. Nat. 1846, p. 193, P1. V.-VII. Van Beneden. Recherches sur l'Embryogenie, l'Anatomie, etla Physiologie des Ascidies simples, in the Mem. de l'Acad. Roy. de Belgique, XX. 1847. Frey and Leuckart. Beitragen zur Kenntniss der wirbellosen Thiere mit besonderer Berucksichtigung der Fauna des Norddentschen Meeres. Braunschweig, 1847, p. 46, Anatomie des Pfahlwurmes (Teredo navalis). Deshayes. Exploration scientifique de l'Alg6rie, pendant les annees 1840, 1841, 1842. Histoire naturelle des Mollusques, avec un Atlas de 117 Planches. Paris, 1847. Ed. Forbes and Hanley. A History of British Mollusca and their Shells. 4 vol. London, 1853. [Contains many anatomical details.] Dalyell, T. G. Rare and remarkable animals of Scotland, represented from living subjects, with practical observations on their nature. Vol. II. London, 1848, p. 138-173, P1. XXXIV.-XLIII. (Ascidiae). LoJen. Om utvecklingen af Mollusca acephala, Oversigt af k. Vet. Akad. F6rhandl. 5te Arg/ingen, Dec. 1848. Stockholm, 1849, p. 233-257; or, its translation in Miiler's Arch. 1848, p. 531; or, in Wiegmann's Arch. 1849, p. 312. Quatrefages. Memoire sur le Genre Taret (Teredo Lin.), in the Ann. d. Sc. Nat. XI. 1849, p. 19. M6emoire sur l'embryogenie des Tarets. Ibid. p. 102. T. Rupert Jones. Cyclop. Anat. and Physiol. IV. p. 1185, Art. Tunicata. G. A. F. Keber. Beitrage zur Anatomie und Physiologie der Weichtheire, Kinigsberg, 1851. [Devoted to the nervous, circulatory, and respiratory systems of the fresh-water Bivalvia.] -ED. CHAPTER I. CUTANEOUS SYSTEM. ~ 171. The body of the Acephala is enveloped in a special mantle, which, with the Tunicata, is composed of a leathery, cartilaginous, or gelatinous substance, scarcely at all irritable.(l) But with the Lamellibranchia, and Brachiopoda, it is composed of a contractile, fleshy membrane. With the Tunicata, it com1 The mactle is leathery with Cynthia. cartilagi- soft with Salpa, and gelatinous with Clavelina, Di mous and hard with Phallusia, cartilaginous and azona, Aplidium, Botryllus, and Pyrosoma. 188 THE ACEPHALA. Q 172. pletely surrounds the body and has only an oral and anal opening; (2) and with the compound species, it is continuous with the common substance which contains the individuals and binds them into more or less regular groups, and is, therefore, analogous to a corallum. With the Lamellibranchia, and Brachiopoda, it is more or less open, or even may be wholly divided into halves; (3) it has here the property, especially upon its borders, of secreting calcareous matter for the formation of the shell. ~ 172. With the Tunicata, the mantle is remarkable both for its histological structure, and its chemical composition. Recent investigations have shown that, with the Ascidiae and Salpinae, it is composed of Cellulose and therefore of a non-azotized substance.(') Its anatomical structure is quite complicated. Usually it can easily be separated into two or three layers, the internal one of which is composed, in some species, of a lamellated epithelium formed of a single layer of polygonal nucleated cells.(2) Its principal mass in both the compound and simple forms of- this order, is formed of a single, or a double confluent layer of a homogeneous transparent substance, through which are scattered granules, nuclei, groups of pigment' molecules, cells, fibres, and crystals of carbonate of lime,- all varying according to genera and species, and often differently arranged in one.and the same species.(3) But in each species, they are variously arranged in the inner portion of this mantle-substance.14) In some species 2 These openings are properly only simple ori- 3 This basement substance is homogeneous, and fices of the cavity of the body, and correspond to the has the same chemical properties as cellulose. respiratory tubes of certain Lamellibranchia * see 4 Kolliker has made very detailed investigabelow, ~ 190. tions upon the structure of this mantle. RIe has 3 With Mya, Panopaea, Pholas, Teredo, As- kindly allowed me to communicate his results, and pergillum, the mantle is almost entirely closed, authorized me to make use of them without waiting but it has two long fissures at each extrem- for the publication of his work in common with ity with Solen, Cyclas, Tellina, Mytilus, Litho- Lswig (Ueber das Vorkommen von Eolzfaser im domus and others; with the Ostracea, Pectinea, Thierreich). According to them, the middle layer Arcacea, Naiades, and Brachiopoda, it is entirely, of the mantle of Phallusia monachus, and sulopen. cata, Clavelina lepadiformis, and Aplidium 1 This important fact was first stated by Cart gibbulosum, contains numerous nuclei and starSchmidt (Zur. vergleich. Physiol. d. wirbellosen like crystals lodged in a transparent structureless Thiere. 1845, p.'61), with Cynthia mamillaris, substance. But the external layer of this organ is.and has subsequently been confirmed by Lowig filled with very large round cells with very thin.and Kolliker, after the most careful investigations walls, containing no nucleus, but filled with a upon the entire order of Tunicata (Compt. rend. transparent liquid. With Clavelina lepadifor1846, p. 38). These two authors found this non- mis, the peduncle and branches of the whole manazotized substance, particularly in the different spe- tie are so crowded with non-nucleated cells, some cies of Phalltsia, Cynthia, Clavelina, Diazona, round and others elongated, that the basementBotryllus, Didemnum, Aplidium, Salpa, and Py. substance is apparently absent.'It has therefore rosoma; but not with the other MIollusca, nor quite the aspect of a vegetable tissue. With with the Annelides, the Helminthes, the Echino- Aplidium gibbulosum, and Botryllus violaceus, dermata, the Acalephae, and the Polypi. It is thecells of the external layer contain carbonate of certainly wanting in the true Infusoria, for Frus- lime which ultimately so increases that it gives Lulia salina, which Carl Schmidt cites as be- them a petrified aspect. With Didemnum candilonging to this order and as containing cellulose, dum, these petrified cells have calcigerous rays is evidently a vegetable. Lswig and K.illiker and are so numerous that the whole mass of this justly fear, moreover, that this discovery will be compound Ascidian appears filled with white starquickly seized by those who deny that there is any like corpuscles. limit between the animal and vegetable kingdom According to Milne Edwards, this is true also (see loc. cit. p. 8). They seek, therefore, to oppose of Leptoclinum maculosum (Observ. sur les Asthis view by insisting upon the circumstance that cidies composkes, p. 81, PI. VIII. fig. 2,). this cellulose is never found in a pure state in the With Diazona violaceum, Pyrosoma giganmantle of the Tunicata, but always combined with teum, Batryllus p6lycyclus, Salpa maxima, and other substances, and that, moreover, no animal bicaudata, the mantle is without these elegant cells, has as yet been found entirely composed of this and in the basement-substance are found only substance. granules and nuclei, and with Diazona, in addi2 Phallusia mamillarzs, sulcata, Cynthiapapil- tion, are pigment-granules, and srystalline points, or Vata, pomaria, and Salpa bicaudata. calcareous concretions. 172. THE ACEPHALA. 189 of th2is order, the mantle receives, moreover, numerous blood-vessels, or ramified prolongations of the body of the animal.(5 These last are spherical or star-like, with Salpa are peculiar and filled with yellow corpuscles; and maxima, and dendritic with Salpa bicaudata; finally, a third variety arising from the transformwith these species they are not soluble in hydro- ation of the pigment-cells, whose walls are graduchloric acid, and are therefore probably composed ally thickened and ultimately split up into filaof silex. In the mantle of Botryllus, there are, ments, forming concentric layers around the cellin certain places, peculiar flexuous fibres running cavity. When subjected to potassa, these cellin all directions. If these are treated with potassa membranes are decomposed, -like the principal khey will appear evidently composed of cellulose. fibres, into an insoluble, non-azotized substance, According to KSlliker, the structure of the man- while all the other elements of the mantle entirely tle of Cynthia papillata is still more complicated. disappear under the action of this agent. Its middle layer is composed of longitudinal and The researches of K6lliker and Loswig upcircular flexuous non-azotized fibres. Between on the mantle of the Tunicata, have been rethese lie granules, nuclei, crystals and cells; these cently published in the Ann. d. Sc. Nat. V. 1846, cells are nucleated, and contain, sometimes pigment p. 193, P1. V.-VII.* granules, and sometimes daughter-cells which gives 5 Blood-vessels are found in the mantle of varithem the appearance of those of cartilage. ous Phallusiae * they are spread out in a reticuKilliker was unable to determine the structure lated manner, especially in the external layerof the th rd and external layer which is horny, for See Cuvier, Mum. sur les Ascidids, &c., p. 16, PI. he had at his disposal only alcoholic specimens III. fig. 1 (Phallusia mamillaris); Savigny, of this Cynthia. He saw however that it united MIm. &c. p. 102, P1. IX. fig. 1. B. (Phallusia with the middle layer to form the spines which pro- sulcata); and Delle Chiaje, Descrizione e'notoject from the surface of the skin. mia degli animali invertebrati della Sicilia citeriore In the mantle of Cynthia pomaria, the longitu- Tom. III. 1841, p. 33, Tav. LXXXIV. fig. 2 (Phaldinal fibres predominate, and between them lie lusia monachus). crystals, round pigment-cells, and other cells which * ~ 172, note 4.] The presence of cellulose in lose, covers the inner surface of the three Ascidiae animal tissues is a fact of no inconsiderable import- which I examined; the outer surface of the manance in animal and vegetable physiology. The tle of Phallusia appears to have a similar epithesubject has recently received much attention from lium. Schacht (Miiller's Arch. 1851, p. 176), and his " 6. There are two essential points of difference conclusions are sufficiently interesting to be pre- between the modes in which cellulose occurs in the sented in full. Ascidiae and in the vegetable kingdom: "1. In the mantle'of the Ascidiae there is a "(1.) In Phallusia, the cellulose constitutes the substance insoluble in caustic potass, but soluble in inter-cellular substance, but does not, as in plants sulphuric acid, which is turned to a beautiful blue form an integral part of the cell-wall itself. by iodine and sulphuric acid, and which therefore "(2.) In Cynthia and other species, the cellulose consists entirely of cellulose. This substance con- forms free fibres, a form in which it is never obstitutes the interstitial substance of the cells; in served in the vegetable kingdom. the mantle of Phallusia it is homogeneous, but in " 7. The substance of the mantle of the Ascidiae Cynthia it occurs for the most part in a fibrous is not disintegrated by boiling with caustic potass form. and nitric acid, like the vegetable cellular tissue, "2. The mantle of the Ascidiae contains beside into its elementary parts; there is in it none of the this cellulose, another material which is soluble in' inter-cellular substance universally present in veg caustic potass, but insoluble in sulphuric acid, and e6table tissues, and by which the cells are connected not colored blue by iodine and sulphuric acid, and but which inter-cellular material is never composed which consequently is not cellulose; in the mantle of cellulose, as it resists sulphuric acid, but is soluof Phallusia it is only sparingly present, but in ble in caustic potass, as well as by maceration' Cynthia and the new Chilian Ascidian, it is much see loc. cit. -p. 197, 198. This valuable paper is more abundant and alone constitutes the corneous accompanied with three colored, plates representing epidermis of their mantle, sections, &c., of the mantle-tissues, drawn by the " 3. The membrane of the cells in the mantle of camera lucida. Phallusia does not consist of cellulose, it is colored From this it is clear that this discovery of cellubrown by iodine and sulphuric acid; it is soluble lose in animals is very far from confounding the in caustic potass, and behaves exactly like an ani- animal and vegetable kingdoms, for whatever else mal membrane as do the nuclei and vessels. may be said, the previously established law that "' 4. In the mantle of Phallusia, cells abound in the animal cell-membrane always contains nitrogen, a homogeneous, interstitial substance composed of retains its force. cellulose i it is only at the inner margin of the mantle See, also, the report of Payen on Kolliker and that fibres composed of cellulose, with nuclei among Lswig's paper, before the Institute, in the Compt. them, make their appearance. In Cynthia, &c., Rend. 1846, XXII. p. 581. there are scarcely any traces of cells, while the But see for some dissenting views on this subject, nuclei and cellulose fibres abound. Huxley (Quarterly Jour. of Microscop. Sc. Noo. " 5. A tessellated epithelium, containing no cellu- 1, Oct. 1852, p. 22).- ED. 190 THE ACEPHALA. 4 173, 174. 173. With the Bivalvia, the mantle exhibits (especially near its free borders), contractile motions upon the slightest touch. These are due to numerous muscular fibres which traverse in every direction its granular parenchyma, but are most abundant in the borders. It contains here, moreover, nerves, blood and aquiferous vessels, and in some.species, even genital organs. The borders of the mantle of the Lamellibranchia are often provided with very sensitive contractile tentacles; (1) these are rarely wanting around the anal opening, - an orifice which serves also for the respiration.(2) In many, this anal opening is divided by a septum into a round, superior and inferior orifice.(3) The borders of these two orifices are often prolonged eaich into a longer or shorter fleshy tube (Sipho). These two tubes, \which are often blended together, project considerably out beyond the mantle and shell, but usually can be wholly withdrawn.(4) With the Brachiopoda, the border of the mantle has, instead of retractile tentacles, - hyaline, radiating filaments, which are hollow and deeply inserted in the substance of the mantle.(5) With the Lamellibranchia, and Brachiopoda, the internal surface of the mantle is covered with ciliated epithelium, which extends also upon the abdomen, foot, oral tentacles, and branchial lamellae. This epithelium is of great importance, since it constantly directs currents of water into the mantle, and thereby food is brought to the mouth, fresh water to the branchiae, the eggs and sperm are carried away from the genital openings, and the faeces are rejected outwardly. The existence of this epithelium makes it clear how these animals can continue to live when buried in wood or stone. ~ 174. The mantle of the Bivalvia is covered by two shells, whose infinite variety of form serves for their zoological classification into genera and species. These shells are composed for the most part of carbonate of lime so closely With many of the compound Ascidiae, the body siphon is double and very protractile. With Cy-. sends fleshy ramified prolongations into the man- clas, and Teredo, the two respiratory tubes are tie. These have been regarded as blood-vessels by more or less blended together at their base; and Savigny (M4im. &-c. p. 47, (Diazona and Botryl- they are united so as to appear as a single organ, lus)), and Delle Chiaje (Descriz. &c. III. p. 34, with AMlctra, Mya, Panopaea, Solen, Pholas, LuTav. LXXXIII. fig. 13, 15 (Polyclinum viride)); traria, Clavagella, and Aspergillum. but M1filne Edwards (loc. cit. p. 41, P1. VII. fig. 1, In these two last genera, the mantle is prolonged lb. l~. 5d.) has regarded them with Botryllus directly into a siphon without any appreciable line rotifera, and Didemnum gelatinosum, as hollow of separation. It is almost entirely closed, and prolongations,- a view entirely assented to by Kol- beside the siphon and the narrow anterior open — l.iker. ing, there is in the middle of its ventral border, a 1 With 2Avicula, Anomia, Pecten, and Sfpon- very small aperture, whose nature is yet with me dylus, there are two or three rows of cylindrical doubtful; see Riippell and Leuckart, Neue wirbeltentacles along the border of the mantle; with lose Thiere des rothen Meeres. p. 41, Taf. XII. Lima, these tentacles are highly developed, and fig. 4, a i and Owen, On the Anatomy of Clavaare situated upon the convex edge of the fold of the gella, in the Transact. of the Zool. Soc. London, I. mantle. With Mytilus edulis, they are peculiar, p. 270, P1. XXX. fig. 13, 14, or the Isis, 1836, p. being flattened and digitiform. 440, 1837, Tab. II. fig. 13, 14. 2 With the Na'iades (Un-io and Anodonta), there 5 These filaments appear to be composed of a are no tentacles around the anal fissure, while the horny substance. They are smooth and very principal mantle-orifice which is separated from small with Terebratula, and very long and jointed this last by only a narrow isthmus, has them quite with Orbicula and Lingula. numerously upon its borders; see Pfeiffer, Nat- With Orbicula, each article of the filament is urg. deutsch. Land-und Saisswasser Mollusken, surrounded with short bristles; see Owen, Trans. Abth. II. Taf. I. fig. 2, 5, 9, p. h. These Naiades Zool. Soc. p. 147, 154, PI. XXII. XXIII. * or the have also a third fissure, which is dorsal and situ- Isis 1835, p. 144, 151, Taf. V. VI.; or in the ated quite distant from the anal one; it was first Ann. d. Sc. Nat. III 1835, p. 55, 66, P1. I. II.; pointed out by Bojanus. I am yet unsettled as to and Vogt, Neue Denkschriften der allg. schweizer-'fs nature. See Pfeiffer, loc. cit. Taf. I. fig. 5, t. ischen Gesellschaft fuir du gesammten Naturwis8 Isocardia, Tridacna, and Chama. senschaften, loc. cit. p. 3, Taf. I. t With Psammobia, Tellina and Venus the - 174. THE ACEPHALA. 191 blended in a homogeneous organic base, that this last is not apparent ex-,cept by the aid of acids. In a few only, does this organic base predomi-.nate over the calcareous matter.(l) The intimate structure of shells is quite varied,(2) but nearly always an external fibrous, and an internal lamellated layer may be distinguished by aid of a simple lens. The external layer appears to have a crystalline texture, being composed of thickly-set, calcareous prisms, attached perpendicularly or obliquely upon the internal layer. These prisms, however, are not the result of a crystallization, but, as is shown from their development,(3) are only cells filled with lime, and if dissolved in acid, delicate prismatic cells remain as the organic base. The internal layer is made up of numerous superposed, non-cellular lamellae composed of the organic base, and arranged intricately in various ways. To the plicae thus formed, and between which the carbonate of lime is deposited, is due the pearly aspect of this internal layer. The relative thickness of these layers varies, sometimes one, and sometimes the other, being the greater.(4)- The external layer is undoubtedly secreted by the borders of the mantle, while the internal is formed by a secretion of its external surface. The growth of the shell is not continuous, but occurs only at certain periods of the year; hence the formation of concentric lines and furrows upon its surface, analogous to the yearly rings of trees. The external layer is often colored, either uniformly throughout, or only in spots; while the internal one rarely contains any pigment. By examining the cicatrized wounds which these animals accidentally present, it will appear plain that this pigment is secreted by the borders of the mantle. For, if these wounds are situated at a distance from, these borders, the shell is never filled except by a layer of colorless matter.()) In the shells of some Bivalvia there are, moreover, special, narrow canals, which are either simple- and traverse the shell obliquely from within -outwards, or branched in a reticulated manner throughout its whole extent. (6) The shells are not attached to, the animal except by muscular insertions along their borders, and by an epidermis belonging to the borders of the mantle. This epidermis, composed of a horny, yellowish-brown substance, stretches from the borders of the shell over its whole external surface,(7) and 1 The shells of Lingula contain very little lime, and Cardiacea, and with Anoemia, the fibrous and there is even still less in the flexible valves of layer appears to be wholly absent. Orbicula. 5 The formation of pearl occurs only upon the 2 The microscopic structure of shells has of late inner surface of the mantle. It has, therefore, the been studied by several naturalists * see Deshayes, same lamellated structure and iridescent property, Cyclop. of Anat. &c. I. p. 707; Shuttlewzorth, as the natural layer of shells. ueber den Bau d. Schalen, &c., in the Mittheil. d. 6 With Terebratula, these canals are quite disnaturforsch. Gesellsch. in Bern 1843, p. 43; and tinct —occupying the whole thickness of the shell. Carpenter, Annals of Nat. Hist. XII. 1843, p. I have observed the same arrangement with Cy373, P1. XIII. XIV. and especially the Rep. of the clas, while with Lingula, they are confined to the Brit. Assoc. 1844, p. 1, with many figures.* internal layer. By direct light they appear black. 3 Mya arena7ia forms an exception to this; the I am yet uncertain whether this color is due to tooth of its shell contains true prismatic crystals their extreme tenuity, or to calcareous matter in bound together in a star-like manner i see Car- their interior. If the first, they would be comparjpentem Annals of Nat. Hist. loc. cit. P1. XIV. able to the canaliculi of the dentine of teeth; but if fig. 8. the second, to the corpuscles of bone. Carpenter 4 These two layers, of which the outer one quite (Annals of Nat. Hist. loc. cit. p. 384, P1. XIII. fig. resembles the enamel of the teeth, are very dis- 5), has observed that in the shells of Lima rudis, tinctly seen with Malleus, Perna, Crenatula, those canals are divided and form a kind of net. Avicula, Meleagrina, Pinna, Anodonta, Unio, work. 2&c. With Osirea, and Chama, they alternate 7 See Mytilus, Anodonta, Unio, Solen, Lutrawith each other several times. In many Pectinea, ria and Mya. * [~ 174, note 2.] For the complete labors of Physiol. Art. Shell, IV. p. 556. It is replete witfh Carpenter in this direction, see Cyclop. Anat. and figures. - ED. 192 THE ACEPHALA. ~ 175, 176 in some species covers even the whole of the siphon. ) Very often, how — ever, this epidermis is worn away upon old portions of the shell, which is quite striking with those which have lamelliform or pilous prolongations, around the borders of the shell. (9 The two shells are joined together partly by a' hinge (Cardo), and partly by an elastic tissue (Ligamentum).(10) This last, either external or internal, is antagonistic to the adductor muscles of the shell. It is composed of elastic fibres, the internal of which, when the shell is closed, are compressed between the borders of the hinge, while those which are external are lengthened out. In both cases, their natural action is to open the two, shells. (11) ~ 175. The Terebratulae have a very remarkable internal calcareous support situated upon the inner surface of the two shells. It consists, first of two delicate outwardly curved peduncles, which arise from the sides of the two cardinal teeth situated upon the non-perforated valve; then there are two other peduncles which are shorter, and arise from a longitudinal ridge upon the. centre of the same valve; these pass in front and unite in an arcuate manner. The two branches thus formed are abruptly recurved after a short course, and unite, forming a common arc behind the centre of the shell.('> With many, this structure Is much more simple, consisting only of a median apophysis, from which pass off two alar prolongations which are curved at. their extremity.(2) This structure serves principally for the insertion of the tentacles. ('3') CHAPTER II. MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION. ~ 176. The muscles of the Acephala are composed of simple, smooth fibres. 8 With Mya, and Lutraria, the epidermis forms reous formation which constitutes, with the tws a complete sheath around the siphon. united valves, the singular tube of these animals. 9 Mytilus hirsutus, Arca barbata, lacerata, 11 The ligament is internal with Pecten, Sponand ovata. dylus, Mya, Lutraria, and Pholas; but externaL 10 I must omit a description of the various forms with the Chamacea, Cardiacea, Arcacea, and Nalof the hinge and ligament, for they belong properly ades. It is half external and half internal with: to the department of Zoology. The hinge is wholly Malleus, and many other species. wanting with the Inclusa, and the ligament is ab- 1 Terebratula chilensis, dorsata, dentata, and sent with the Brachiopoda i and with Orbicula, Souwerbyi; see Owen, loc. cit. P1. I. fig. 4. and Lingula, both are absent. 2 Terebratula rubicunda, and psittacea. The Aspergillina are distinguished from all the 3 According to Owen, in those species'which other Acephala, by a singular disposition of their have this apparatus highly developed and bent valves. Their mantle ceases early to secrete the backwards, these arches, notwithstanding their calmnatter for the shell-formation. The two valves are careous nature, are somewhat elastic; and when then joined at a point, where, most probably, they the valves are closed, they are slightly depressed, would have been articulated, while the mantle and thus may serve in the absence of the elastica which has only two small openings, and its long ligament, for the opening of the shell. siphon with a double canal, is covered with a calca 177. THE ACEPHIALA. 193 ]But Salpa presents a remarkable exception to this, for here the fibres are striated. (1) With the Tunicata, the muscular system is most simple, being limited to a subcutaneous layer, which, with the Ascidiae, envelops like a sac the' body of each individual, and is attached to the skin only at the two openings of the cavity of the body. It is formed of numerous circular and lon-* gitudinal interlaced muscles, among which there are, here and there,. oblique fasciculi.i2) With Salpa, this cutaneous muscle consists only of a few isolated bands bound together by a thin, homogeneous membrane. These bands, which vary much in number, distance apart, and direction, surround the cavity of thebody, usually in a belt-like manner. They are sometimes straight, some — times curved, and their extremities never meet upon the ventral surface so, as to form a complete belt, but terminate loosely, or are blended by anastomoses with adjoining bands. Around the two openings of the body, they form real sphincters.(3) By means of this muscle, the Tunicata can enlarge or diminish the cavity of the body, and thus cause the necessary renewal of water for nutrition and respiration, beside ejecting the faeces and products of generation. The Salpa, by rhythmical contractions of their body (its anterior superior opening, being closed by a membranous valve), eject water through its posterior opening, and thus are propelled along. ~ 177. With the Bivalvia, the muscular system is much more complicated. Not only are muscular fibres scattered through nearly the whole body, but in certain points, they are so aggregated as to form distinct isolated muscles. The largest of these muscles are the Adductores of the valves. With the Lamellibranchia, these consist of a single or a double mass of thicklyset, parallel fibres, the ends of which are inserted at opposite points of the: two valves. Those species which have two of these muscles are called, Dimya; here one of these muscles is anterior, and the other, larger, posterior. With the Mononiya, there is one muscle alone; this is large and situated near the centre of the valves. With Brachiopoda, these muscles are more complicated, there being four pairs. Part of these, only, are doubly inserted to the valves,(') while the rest, which arise from one of the valves, are inserted upon the peduncle. 1 See Eschricht, Over Salperne, &c., p. 64, Tab. Salpa cylindrica has ten or eleven of these girIII. fig. 16. These striae are due to a zig-zag pli- dies, the anterior of which converge upon the back. cation, as I have satisfied myself from a specimen and are curved from before backwards; see Cuvier, of Salpa zonaria preserved in alcohol. Will has Mim. sur les Thalides. loc. cit. fig. 9; and Savigny, observed the same in the muscles of other inverte- Mim. loc. cit. P1. XXIV. fig. 1. Mith Salpa mubrates (ltuiller's Arch. 1843, p. 359). The mus- cronata, and maxima, these girdles are blended cular fibrillae of Salpa are bound together in prim- together upon the back; see Aleyen, LUeber die itive riband-like fasciculi which are plicated during Salpen, loc. cit. Tab. XXVIII. fig. 5, Tab. XXIX. contraction like the frill of a shirt; this is easily fig. 2. Salpa pinnata (cristata) is remarkable seen when one of these fasciculi is observed in an for having numerous anastomoses uniting the giredgewise position. dies upon the sides of the body and presenting a 2 See Savigny, Mhm. &c. PI. V. fig. 1, 2 (Bol- trellis-like aspect see Chamisso, De Salpa, fig. 1, tenia and Cynthia); Delle Chiaje, Descr;iz. &c., G. It., and Cuvier, loc. cit. fig. 1, 2. III. p. 23, Tav. LXXXIV. fig. 3, 5 (Phallusia); 1 Several of these muscles do not always arise and the Catal. of the physiol. Series, &c., I. P1. V. directly from the shell, but from the visceral sac;. (Phallusia). so that here their action is not solely for displacing 3 Salpa cordiformis and zonaria have from the viscera, but also for the movement of the valves, five to seven isolated and equi-distant muscular to which this sac is attached. girdles; see Eschricht, loc. cit. Tab. I. III. 17 194 THE ACEPHALA. ~ 178. As the points of the insertion of these muscles do not always correspond with the two valves,(2) their direction is often oblique, or, they sometimes even cross each other.c3) Orbicula and Lingula, which want both the ligament and hinge, have this disposition of the adductors which terminate usually by a delicate tendon, and the contraction of either of -these muscles alone, produces the lateral movements of their valves. The spirally-pointed tentacles of the Brachiopoda are moved by a particular apparatus. The fringes of these organs are inserted upon a cartilaginous tubular prolongation which tapers to a point. This is closed at both extremities and contains a liquid, which, by the contractions of the circular muscular fibres, is propelled from the base to the extremity, thereby unrolling the spiral turns.(4) These tentacles here certainly take the place of the elastic ligament of the bivalves, for their extension probably tends to slightly open the valves. With the Lamellibranchia, the tentacles which are not rolled, are ar'ranged quite differently. Like their branchiae, they are scarcely at all irritable, - this being due to the fewness of their muscular fibres. But in the mantle these fibres are very abundant, and especially near their free borders. This is true also of the Siphon, in which both longitudinal and circular fibres can be easily seen; here, two very distinct flattened muscles arise from the base of the siphon and are inserted upon the two valves, external to the posterior adductor muscle: these serve as a Retractor siphonis. ~ 178. Very many of the Lamellibranchia have a highly-developed organ of locomotion, - the foot. () This is a muscular prolongation from the ventral surface, which passes obliquely forward to be inserted upon the internal surface of the back of the shell, by four, rarely more, tendinous cords.(2) These cords surround the abdominal viscera, and becoming gradually thicker and more muscular, finally blend with numerous, interlaced muscular fasciculi which compose the foot. This last varies considerably as to its size and form, and can be protruded a long way out through the open shells, but may also be wholly withdrawn.(') 2 Lingula forms an exception. Here the prin- visceral sac to the valves. With Lingula, there cipal adductor is a short, solid muscle, which are, beside the principal adductor, four pairs of instretches straight across from one shell to the terlaobed muscles, which pass obliquely through the other, at their posterior extremity. centre of the cavity of the valves, and are attached'This muscular apparatus has been particularly by their two ends to the visceral sac. described and figured by Oeven, and Vog't (loc. 4 Owen, loc. cit.; and Vogt, Anat. d. Lingula, cit.) with Terebratula, Orbicula, and Lin-gtla. p. 8, Tab. II. fig. 16-18. With the Terebratula, two pairs of muscles 1 The foot is absent, particularly with'those molarise from each valve. The two anterior ones lusks which are fixed to rocks and other solid alrising from the imperforate valve, are the longer, bodies, by a calcareous cement.,and have their origin back of its centre. After the 2 Usually one pair of these delicate cords passes crossing of their delicate tendons, they pass above, and another below, and are inserted upon through h the opening of the valve and terminate in the valves, quite near the four points of insertion'the pedancle, together with the two posterior ones of the two adductor muscles.'I'his is so with Anowhich are short and fleshy, and which arise at the donta, Unio, Cardiunz, &c. With Isocardia, I base of the hinge. Of those of the perforated have found a third pair of cords inserted upon the valve, the two posterior ones only pass to the posterior extremity of the summits of the shell. peduncle - the two anterior- being attached to the These serve not only as Retractores of the foot, base of the other valve. With Orbicula, there but when this last is fixed to some point, draw the are two posterior, and two anterior fleshy muscles, animal towards it. all of which ipass obliquely from one valve to 3 The laterally-compressed foot of Anodonta, and the other, while the anterior ones sometimes send Unio, arises, by a large base, from the abdomen, off fibres to the short peduncle. In the space cir- and has carinated borders. That of Pectunculus cumscribed by these four muscles, lie four others, and Venus, is quite similar, but its free border is which are small and interlaced, and extend from the hollowed by a furrow, and is therefore bi-carinated. ~ 179, 180. THE ACEPHALA. 195 Most of these animals use this organ to dig in the sand, or to creep along,on soft surfaces. For this purpose, they reach it out in front, and then by alternate contractions and elongations, drag their body after it. Some spe-.cies can in this way glide freely along like the Gasteropoda, or even seize hold of aquatic plants.(4) Sometimes this foot is truncate and hollow at its extremity, and probably, therefore, acts like a sucker.5' ~ 179. With many of the Lamellibranchia,(>) the foot appears imperfectly developed, and has a secretory organ of the Byssus, a part by which these animals are attached to wood, stone, and other bodies. In this case the foot is a delicate, protractile, tongue-like body,(2) capable of a stiffness suf-:ficient for creeping, but used chiefly as a feeler to find the points of attachment by the byssus.(3 It always points towards the oral extremity, and upon its inferior surface there is a longitudinal furrow which has a cavity.at its base. The walls of this furrow and cavity secrete the byssus. From their glandular aspect, they differ much from the rest of the organ, which is formed of numerous interlaced muscular fibres.(4) The bottom of this cavity from which the furrow arises, is regularly divided by numerous delicate, parallel lamellae, from which arises the compact root of the byssus.(5) This byssus is, therefore, inserted into the base of the cavity as are our finger-nails into their matrix. Its base has a fibrous, or lamellated structure, and passes into a longer or shorter trunk composed of numerous cylindrical, or flattened filaments,(6) whose extremities are sometimes discoid.171 ~ 180. Many Bivalvia. which are likewise wanting in locomotive organs, and have, moreover, no organs of the byssus, attach themselves to bodies in another and peculiar way. Thus, with Anomia, one of the valves is marked by a deep fissure, across which, like a short peduncle, a portion of the ad~With Tellina, Donax, and Cyclas, it is very long 4 I do not yet clearly understand the true nature.and more or less ridged, and often quite small at of the walls which secrete the byssus. A. Miiller its base. has designated them as Glandula byssipara, cornWith Cardium, NVucula, Trigonia, Mactra, posed of round cells. He affirms to have seen at wand Isocardia, it is curved like a hook or knee the base of the furrow of Mytiluts edulis, orifices from behind in front. With Solen, it is very long, of the excretory ducts of this gland; see Wiegstraight and nearly cylindrical. mann's Arch. loc. cit. Taf. I. fig. 6. On the other 4 Cyclas and Pisidium. It is probable that those hanld, neither J..lIiiller (De glandul. structura, p. species whose foot is furrowed upon its inferior bor- 39), with Tridacna; nor R. Wag-ner (Lehrb. d. der (Pectunculus), or bent in front (Nucula and vergleich. Anat. 1835, p. 271), with Arca, and Trigonia), can also creep like the Gasteropoda. Pinna, has been able to find these glands. 5 Pholas. 5 See A. 1Muller, in Wiegmann's Arch. loc. cit. 1 The Malleacea, Aviculacea, Mytilacea, with Taf. I. fig. 5, c. (Tichogonia), and Polh, loc. cit. _Pecten, Lima, Arca, Tridacna, &c. II. p. 132, Tab. XXIV. fig. 5-7 (Arca). Quite singularly there exists with Anodlonta, 6 For the intimate structure of the byssus see Unio, and Cyclas, when hatched, a secretory the Memoir of A. Muller, loc. cit. With Arca, its organ of the byssus; see below, ~ 197, note 13. form is very remarkable, consisting of a solid, lat2 For the byssus-forming organ, see Deshayes, erally-compressed trunk, carinated above and beCyclop. of Anat. &c. I. p. 702; and especially A. low, and having filaments upon no portion. With MI4cller, De Bysso Acephalorum, Dissert. Berolini. that of Pinna, on the contrary, its filaments remain 1836 i or, his Memoir in Wiegmann's Arch. 1837, ununited even to the very root. I. p. 1, Taf. I. II. 7 Avicularia and llytilus; see Poli, loc. cit. 3 The manner in which Mytilms and Tichogo- Tab. XXXI. (Mytilus edulis), and Tab. XXXiV. ssia act in spinning their byssus has been described fig. 2 (Pilnna?tltericata). by Marion de Procd in the Ann. d. Sc. Nat. XVIII. 1842, p. 59; and by A. Muller, loc. cit. 196 THE ACEPIALA. % 181, 182, 183& ductor muscle of the other valve() passes, in order to be attached to foreign bodies by its smooth, calcareous extremity. With the Brachiopoda, there is a real peduncle which constantly projects through an opening near the hinge. It is a soft tendinous or muscular tube, which is, perhaps, only a prolongation of the mantle.(2) CHAPTER III. NERVOUS SYSTEM. ~ 181. The nervous system, which has been observed in all the orders of the Acephala, consists of a central and a peripheric portion. The first is composed of one, or several (usually three) ganglia; the second consists of nervous trunks of variable size, which pass off in the most different directions. When the number of these ganglia is considerable, they are arranged in pairs which are situated more or less near the median line, according to the different regions of the body. The ganglia of each pair intercommunicate by a transverse commissure of variable length. They connect, moreover, with others, which are even far removed. by anastomosing filaments. It is difficult to decide which of these ganglia is the brain. Many species want a complete ganglionic ring surrounding the buccal cavity. ~ 182. From its extreme softness, the internal structure of the nervous system of the Acephala is very difficult of study. Its primitive fibres are very delicate, and are surrounded, in the nervous trunks, by a distinct and very thin neurilemma. In the ganglia, through which orange-colored granules are usually scattered,(') these fibres pass into a very loose tissue composed of small transparent vesicles, which probably take the place of the ganglionic globules which are so distinct with pther invertebrates.(2) ~ 183. 1. The nervous system is most simple with the Tunicata. It here consists of a single ganglionic mass, which is subcutaneous, and situated between the two respiratory tubes. I Carefully examined, Anomia will be found to the very short, sucker-like one of Orbicula. Exhave three unequal adductor muscles arising from ternally, it is composed of a thick cartilaginous tisthe imperforate valve. The largest of these, together sue, while its interior is occupied by a hlollow, with one of the others, passes into the fissure of the muscular cord, composed of longitudinal filaments other valve; while the third is inserted upon the see Owen, loc. cit. (Terebratula), and Vogt, loc. samLe valve. cit. Tab. I. fig. 1-6 (Lingula). 2 It has already been remarked ( 177), that with 1 These orange-colored ganglia are quite distinct the Brachiopoda the peduncle receives mus- with Unio, and Anodonta. cles both from the body and from the valves. It 2 Although the Naiades have very large ganglia, has, moreover, muscles of its own, and ought, yet their microscopic examination has furnished no therefore, to be contractile. This contractility is further results, for neither by the compressorium, quite prominent with the very large and long pe- nor by chemical means, can these globules be sepo duncle of Lingula, especially in comparison with arated from the intervening tissue. 5 183. THE ACEPHALA. 197 With the Salpinae, the central nervous mass is upon the dorsal surface in front of the middle of the body. It consists of many closely-aggregated, yellowish ganglia, from which nerves pass off in all directions.ii) With the Ascidiae, it consists of a single large ganglion, which is easily found within the muscular envelope, in an angle formed by the oral and anal tubes. The nerves which pass off in different directions from this ganglion, belong chiefly to the muscular envelope. Some of them, however, pass to the organs of sense situated near the two respiratory tubes, and form:around the orifice of that one of them which is buccal also, a complete cir-,cle which corresponds perhaps to an cesophageal ring.(2) 2. The nervous system of the Brachiopoda is as yet little known. However, from the presence, in some species, of two or three ganglia about the cesophagus, it may be concluded that it is analogous to that of the Lamellibranchia. (3) 3. With the Lamellibranchia, the nervous system is the most distinct.(4) Its very symmetrical arrangement is prominent, except in the unequivalved Species. 1 Meyen was the first to describe with care this regards as the brain; while he has given the name nervous mass with Salpa; for, before him, many of Ganglion sympathicum to a principal ganlgliother parts of the animal had been erroneously onic mass, lying near the anal tube. taken by Savigny (Mim. &c. II. p. 127), and 3 Cuvier (Sur la Lingula, loc. cit. p. 8) thinks Chamisso (De Salpa, &c., p. 5), for the nerves and he has observed two ganglia at the base of the ganglia; see Meyen, Nov. Act. Acad. Leop. loc. arms, but which give off no nerves. Owen (loc. cit. p. 394, Tab. XXVII. fig. 5, d. 18 (Salpa pin- cit.) has found two ganglia in front of the cesophanata), Tab. XXVIII. fig. 5, h k. 12 (Salpa mnucro- gus of Orbicula, and one behind it; and also two nata). Quoy and Gaimard have also observed a nerves arising from the two anterior ganglia atcentral nervous system in the dorsal region of sev- tended with two arteries which go to the two hearts. eral Salpa; see Voyage de l'Astrolabe, Zool. III. 4 The nervous system of the Lamellibranchia p. 559, and the Atlas zoologique of the same, Mol- was discovered by J. Ratehk. In 1797, he had lusques, PI. LXXXVI.; or Isis, 1836, p. 113, Tab. well represented the anterior pair of ganglia of AnVI. odonta (loc. cit. p. 162, Tab. IX. fig. 10, 11). Poli, Eschricht's description is still more minute; but it is true, had already figured the nervous system he has taken for the ventral surface that portion of of several species of this order (loc. cit. Tab. the body in which this lobulated ganglionic mass is XXXVI. fig. 1, n. (Pinnoa); Tab. VIII. fig. 1, i. situated; see his Memoir, Over Salperne, &c., p. (Pholas); Tab. IX. fig. 10, a. (Unio); Tab. X. fig. 12, Tab. II. fig. 8, 10, u, v. (Salpa cordiformis), 15, Tab. XI. fig. 1, Tab. XIII. fig. 6, (Solen); Tab. and Tab. III. fig. 22 (Salpa zonaria). See, also, XXV. fig. 1, (Arca); Tab. XXXII. fig. 18, r. (MyDelle Chiaje, Descriz. &c. III. p. 45, Tav. tilus)). But he erroneously took it for a lymphatic LXXVIII. fig. 3, n. 12 (Salpa maximna). I am system. yet undecided whether the nervous ring, which, The following works may be consulted upon this accordingto Eschricht, is formed by the junction of system: Mangili, Nuove ricerche zoot. sopra the two nerves surrounding the anterior respiratory alcune specie di conchiglie bivalvi. Mlilano, 1804: orifice, really corresponds to the cesophageal ring. (translated in Reil's Arch. IX. 1809, p. 213, Taf. 2 A very detailed description accompanied with xb. (Anodonta)); Brandt, Medizin.Zool. II. p. 310, figures of the nervous system of the simple Asci- Taf. XXXYTI. fig. 10,-12 (of the Oyster); Garner. diae, may be found in the works of Cuvier (Sur On the Nervous System of Molluscous Animals, in les Ascidi6s, &c., loc. cit. p. 24, P1. II. fig. 2 c. 5, the Trans. of the Linn. Soc. XVII. 1837, p. 485, g. III. fig. 2, 3 c. (Cynthia and Phallusia)); P1. XXIV. (Ostrea, Pecten, Modiola, Mictra, Eschricht (Beskrivelse af Chelyosoma, loc. cit. p..lSlya, and Pholas); and, On the Anatomy of the 8, fig. 4, c.); Delle Chiaje (Descriz. &c. III. p. Lamellibranch. loc. cit. p. 89, P1. XIX. fig. 5 (Ve28, Tav. LXXXII. fig. 2, and LXXXIV. fig. 3, 5, nerupis); Keber, De Nervis Concharum, Diss. (Phallusia)); and Savigny, who has included also Berolini, 1837; Duvernoy, Sur l'animal de lFOnthe compound Ascidiae (Mim. &c. p. 32, P1. IX. guline, in the Ann. des. Sc. Nat. XVIII. 1842, p. fig. 22. XI. fig. 11. D'. (Phallusia); also P1. 118, Pi. V. B. fig. 8; and, Sur le Systime nerveux XXI. fig. 15. XXII. fig. 14. XXIII. fig. 18. DI. d*. des Mollusques Acephales bivalves, in the Comp. (Botryllus and Pyrosoma)). rend. 1844, Nos. 22, 25, 1845, No. 8; or in Froriep's The principal ganglionic mass is always nearer neue Not. 1845, No. 731 i Blanchard, Observ. sur the anal than the oral tube, and does not give off le Systime nerveux des Mollusques Acephales testabranches except at its extremities. The nervous cis ou Lamellibranches, in the Ann. des Sc. Nat. -ring of the Ascidiae, has been observed by both III. 1844, p. 321, P1. XII. and in Froriep's neue Cuveier, and Delle Chiaje. Not. No. 741 (Solen, lIactra, and Pecten); and The last of these authors has also mentioned a John Anderson,. Art. Nervous System, in the Cyparticular ganglion which he has observed with clop. of Anat. III. p. 604.* Pihallusia mamillaris, in this ring, and which he * [~ 183, note 4.] See, also, Duvernoy (suite) p. 46; Deshayes, loc. cit. p. 69, PI. VIII. IX.; Compt. Rend. XXXIV. 1852, p. 665, and XXXV. and Quatrefages, loc. cit. p. 63, PI. I. fig. 3, 6 1852, p. 119 i also, Frey and Leuckart, loc. cit. (Teredo). —ED. 17* 198 THE ACEPHALA. ~ 183. A. The central nervous mass is composed of three pairs of principal ganglia, as follows: Par anterius or lahiale, Par posterius, and Par inferius or abdominale. This last pair is extraordinarily developed with. those species which have a foot, and has, therefore, received also the name of Par pedale. The ganglia of the Par anterius are situated one on each side of the digestive canal, and are connected by a filament which extends arcuately over the circumference of the oral cavity.(5) They send off two long; nerves, which pass along the back to the Par posterius, which is the largest of all and usually situated upon the anterior surface of the posterior adductor muscle. Its two ganglia are either blended together, or connected by a transverse commissure.~6) In this way, the anterior and posterior pairs with their commissures form a kind of oesophageal ring which surrounds the base of the abdomen. The inferior or pedal pair is situated at the point where the base of the foot is joined to the abdomen. Its ganglia are contiguous upon the median line, or are blended together into one.(7) They connect also with the labial ganglia by two nerves, thus forming a second oesophageal ring.(8) Besides these principal ganglia, there are others, smaller, and situated in various parts of the body. But these are not constant. for their presence is always due to an unusual development of the muscular system. B. The peripheric nerves arise almost exclusively from the three pair of principal ganglia, for the nerves of connection do not usually give off branches. The few and very delicate filaments which sometimes pass off from these last, belong, probably, to the splanchnic system, for the principal ganglia appear to furnish only sensitive and motory nerves; these are usually distributed in the following manner: The Par anterius sends nerves to the anterior part of the mantle,(') to the anterior adductor muscle, and to the tentacles of the mouth and its circumference. The Par posterius sends two very large trunks to the branchiae; also, other nerves to the lateral and posterior part of the mantle,(1) to the posterior adductor muscle, and delicate filaments to the heart and rectum. 5 The length of the are of this filament of con- ler's Arch. 1840, p. 33, Taf. III. fig. 3, g.; and nection depends upon the position of the two labial Blanchard, loc. cit. p. 336, P1. XII. fig. 3, a. b.),. ganglia. Thus with Pecten, where these ganglia between these ganglia with which it is in connecare situated unusually in the rear, itis very long tion by commissures. and very arched i while with Pholas, and Solen, 8 Of these three ganglia, the Par anterius has; where they are close upon the oral opening, it is often been regarded as the brain. But others have short. With Venus, and Mactra, these ganglia lie rather taken the Par posterius for the principal so close to each other, that this anastomotic fila- nervous mass. For my own part I think that all ment is replaced by a very short, transverse com- three, together with their commissures, correspond missure. to the pharyngeal system of Gasteropoda. 6 The Par posterius, which, from its relations 9 The anterior nerves of the mantle of Solen, to the branchiae, is also called the Par branchiale, which is prolonged far beyond the oral opening, is blended into a single ganglion in those species and is strengthened by a muscular mass —have whose branchiae are united at their lower part 5 as ten to twelve ganglia lying along the border of the Unio, Anodonta, Mactra, Mya, Solen, and Pho- mantle. With Pecten, the mantle-nerve has also las. On the other hand these ganglia are separate, a small ganglion upon the muscular mass which is and connected simply by a transverse commissure, found upon each side of the anterior border of this with those whose branchiae are isolated i as Os- organ i see Blanchard, loc. cit. p. 333, P1. XII. trea, Pecten, Avicula, lMytilus, Lithodomus, fig. 1, f. (Solen), fig. 3, c. (Pecten). Modiola, and Arca. 10 In the mantle of Ostrea, Spondylus, Pecten, 7 According to the earlier Zootomists, the Par Lima, and in general those species in which its pedale was wanting in those species which have borders have numerous sensitive organs, the no foot, although careful investigation has shown branches of the anterior and posterior mantlethat there is a pair corresponding to the Par infe- nerves unite and form a common marginal nerve rius. I refer to that found with Ostrea (Brandt, whose size depends upon the number of the sensiloc. cit. Tab. XXXVI. fig. 11, a. o.), directly behind tive organs to which it sends filaments. the labial ganglia, and with Perten (Grube, Ml 18~ 4 18 185. THE ACEPHALA. 199 The siphon and its muscular apparatus receive their nerves also from this same pair. (1) The nerves of the Par inferius being destined chiefly for the foot, correspond in number and size with the degree of development of this organ. This number, however, varies between two and six for each side. ~ 184. The Acephala have, certainly, a Splanchnic nervous system, but as yet it has been found only with the Lamellibranchia;(l) and even here it is seen with difficulty and imperfectly on account of the extreme tenuity of its filaments. With some species, delicate, lateral filaments pass off from the nerves of communication, which connect the Par gan gliorum inferius and posterius with the Par anterius; these may be properly termed sympathetic nerves, for they are distributed partly to the walls of the digestive canal, and the heart, and partly to the liver, the gland of Bojanus, and the genital organs.(2) CHAPTER IV. ORGANS OF SENSE. ~ 185. Of the organs of sense with the Acephala, those of Touch are the most highly developed. They usually consist of conical, or flattened, protractile prolongations of the skin, which are extremely irritable, covered with ciliated epithelium, and often of a deep color. 11 When the two retractor muscles of the siphon Lamellibranchia. Ue has observed (loc. cit. p. are large, as is the case with Solen, 3Iactra, Ve- 15) that the commissural filaments, which pass nus, and Cytherea, their two nervous trunks have into the Par posterius, give off branches to the several ganglionic enlargements along their intestinal canal, to the liver, and gland of Bojanus; course, connected by transverse filaments; see and that those of the Par pedale give off similar Blanchard, loc. cit. p. 333, P1. XII. fig. 1, 2, d. branches to the genital organs; and also, that (Solen and Mactra).* these nerves form several Plexus between these 1 With the simple Ascidiae, as a sympathetic organs, and from which are given off filaments to system may perhaps be considered the ganglion, the heart. From this disposition, he ought to conwhich, according to Schalk (loc. cit. p. 9, fig. 4, g. elude that these are real organic nerves. q.) is concealed between the intestinal convolutions, If this is so, the same signification would be at the posterior extremity of the body of Phallu- given to the nervous filaments which Blanchard sia, and send off filaments in various directions. (loc. cit. p. 335, P1. XII. fig. 1, e.) has seen arise But, as yet, the existence of this ganglion needs with an Area, and a Solen, from the two small confirmation. ganglia which belong to the commissures of the 2 Garner, Duvernoy, and Blanchard have seen Par posterius. More profound researches upon the filaments, which issue from the principal ganglia, the destination of their nerves, must determine enter the vegetative organs; but as they could not whether the two ganglia situated between the labial further trace them, they hesitate to regard-them as ganglia, with the apodal Lamellibranchia (see above organic nerves. Keber is more positive-in favor of ~ 183 note 7), really correspond to the Par pedalc, the existence of a sympathetic system with the or do not rather belong to the sympathetic system. * [[ 183, note 11.] See Quatrefages (M~m. 63, P1. I.), who has described in detail this system sur le genre Taret. ill Ann. d. Sc. Nat. 1849, XI. p. with the Teredina. - ED. 200 THE ACEPHALA. ~ 185. With both the simple and the compound Ascidiae, there are, at the base of the oral tube and at the entrance of the respiratory cavity, numerous filiform and sometimes fiinged tentacles inserted upon a kind of ring.(') With the Lamellibranchia, there are often conical tentacles around the respiratory and anal openings of the mantle,(2) and the orifice of the siphon.(3) Among those which have an open mantle, there are many the borders of whose mantle, either wholly, or only posteriorly,(4) are provided with thickly-set conical tentacles.(5) These receive all their nerves from those of the mantle. Instead of these retractile tentacles, the Brachiopoda have long radi-,ating bristles upon the borders of their mantle.(') These project a considerable way beyond the borders of the valves, and having perhaps sensitive nerves at their base, they are thus tactile organs like the vibrissae of some Mammalia. The oral opening of all the Lamellibranchia is provided, moreover, with two pairs of contractile, foliated lobes, pointing backwards, which are perhaps oral tentacles.(7) Each pair is composed of two lobules, an internal and an external, which are united at their base, and whose surfaces lie against each other. Behind, the border of these four lobes is somewhat thinned, while in front, the two on the same side usually pass into each other, the external being above, and the internal below, the oral opening.(8) The free surfaces of the lobules are smooth and covered with a very thin epithelium, while the other and opposite surfaces are furrowed transversely throughout, and the borders of these furrows are fringed with very large vibratile cilia.(9) As tactile organs, may be mentioned the two remarkable arms which, with the Brachiopoda, are spirally rolled up near the oral opening. The long, pectinate fringes upon their borders are united at their base by a soft, hollow membrane which is probably contractile, and is provided with vibratile cilia.tl~ I See the figures in Savigny, MIm. &c. loc. cit. Pectunculus, Mactra, Anodonta, Aspergillum, 2 Cardium, Chama, Tridacna, and Isocardia. &c. But Spondylus and Pecten form, in this re3 Solen, Pholas, Aspergillum, Mactra, Venus, spect, an exception. Here, thelobes upon each side Donax, &c. With Donax trunculus, the respir- instead of being continuous, are separated by nuatory tube is remarkable for its ramified tentacles; merous curiously-branched tentacles which sur-see Poli, loc. cit. Tab. XIX. fig. 15-20. round the oral orifice and strikingly resemble those 4 Unio, Anodonta. surrounding the mouth of certain }IolothurioYdae 5 With Donax, Mact/a, and Tellina, this row when contracted; see Poli, loc. cit. Tab. XXII. fig. ~of tentacles is single; but it is multiple with Avic- 8, 13'14, XXVII. fig. 6, 10. ula, Anomia, Ostrea, Pecten, Spondylus, and 9 The branchial lamellae of the Lamellibranchia Lima. have these furrows upon all their surfaces, and 6 See Owen, and Vogt, loc. cit. in their outward aspect closely resemble these tac7 As to the oblong organ which, with Salpa cordi- tile lobes. It is therefore probable that, like the formis. projects into the cavity of the body as oral tentacles of the Polyps and Holothurians, they two parallel cutaneous folds between the anterior have a varied function. Thus, they could serve not respiratory opening and the central mass of the only as gustatory organs for the food entering the nervous system, I am yet undetermined whether or mouth, but also as those of ingestion, beside taking not it corresponds to the tactile lobes of the Lamel- a part also in the respiration. libranchia. It appears smooth upon its free 10 The researches of Cuvier, Owen, and Yogt border, and receives, at its transversely striated (loc. cit.) upon the arms of the Brachiopoda, were base, two nerves from the principal ganglia. With made upon specimens preserved in alcohol. Salpa zonaria, a similar organ lies directly in The relations, therefore, of these organs and front of the central nervous mass; see Eschricht, their fringes during life are not known. Miiler Over Saiperne, loc. cit. p. 14, fig. 8, 10, 22, t. With also (Zool. Danica,I. p. 4), and Poli (loc. cit. II. p. Salpa nzucronata, this singular organ is situated 190, Tab. XXX. fig. 22, 23), say nothing upon the in front of the nervous centre, and has been taken motions of the fringes of Orbicula and Terebraby Meyen for a male genital organ; see Ueber die tula. If they are really contractile and ciliated, Salpen, &c., p. 397, Tab. XX~III. fig. 5-10. the whole apparatus is quite analogous to that of & Avicularia, Isocardia, Pinna, Cardium, the Alcyonellae. t~ 186, 187. THE ACEPHALA. 201 ~ 186. As yet, organs of hearing with the Acephala have been found only among "the Lamellibranchia. They are here feebly developed, consisting only of two simple round capsules filled with a transparent liquid. Their very thick and somewhat solid walls are homogeneous and transparent; they enclose a vitreous spherical otolite, of a crystalline structure,(") and composed of carbonate of lime. These otolites constantly keep up very singular swinging and rotatory motions, which instantly cease, however, when the capsule is ruptured.(2) These auditory capsules when present, are situated in the foot *in front of the pedal ganglia with which they always communicate,(3) either,contiguously, or by two auditory nerves which they receive.t4) ~ 187. Organs of vision are very common with the Acephala, and always many in number. With some, they occupy a large portion of the borders of the mnantle; with others, they are confined to the external orifices of the longer >or shorter mantle-tubes.(l) 1 These organs were first noticed by me with the ity of the septa lying between the pericardium and Naiades, Cardiacea, and the Pyloridae; but were the elevator of the anus, and upon which the ante-:regarded as of a doubtful nature. Since then, after rior extremity of the branchiae is inserted; see,comparing them with the auditory organs of the Comp. rend. 1846, XXII. No. 7; or Froriep's embryos of fish, I am satisfied that they are really neue Not. No. 813, p. 323. very simple organs of hearing; see MliUller's Arch. 4 With Cyclas, and Tellina, the auditory cap1838, p. 49, and WYiegma'nn's Arch. 1841, I. p. 148, sules are contiguous with the ganglia of the Par'Taf. VI. fig. 1, 2 (Cyclas cornea); or, the Ann. d. pedale. With Anodonta, Unic, Cardiu7n, and Sc. Nat. X. 1838, p. 319, XIX. 1843, p. 193, P1. Mya, they are a little removed. II. B. It appears, moreover, that similar corpus- It is remarkable that these organs appear very tcles are found in other orders of these animals. early in the embryos of certain Lamellibranchia Thus, Delle Chiaje mentions with Salpa neapoli- (Cyclas), while in others (Anodonta and Unio), Lana, an organ situated above the nervous centre no trace of them is seen during the embryonic ~ which exactly resembles the auditory capsules I life. have discovered in the foot of Cyclas. Unfortu- 1 Poli (loc. cit. II. p. 153, 107, Tab. XXIL. fig. nately he has neither figured nor carefully described 1, 4; and Tab. XXVII. fig. 5, 14, 15), was the:this organ (Descriz. &c. III. p. 45, Tav. LXXVI. first to compare to human eyes these remarkable.fig. 1, 1.). Eschricht (Anat. Beskriv. af Chelyo- bodies, which, brilliant as diamonds, lie upon the -soma Macleayanum, p. 9, fig. 4, 6, d. y. and fig. 5) borders of the mantle of Pecten and Spondylus, has also regarded as an auditory organ a remarka- with this expression: Ocelli smaragdino colore ble apparatus which he found near the nervous cen- coruscantes. Nevertheless, it is only of late that ~tre of a simple Ascidian. This consists of a pyri- these organs have received much attention. Garform vesicle filled with whitish matter, and of a ner (On the Anat. of the Lamellibr. Conchifer. &c. clavate body which has, upon its large end, a fis P1. XIX. fig. 1, c. 3) was the first to notice anew sure and two lateral depressions. the Ocelli of Pecten. Grant (Outlines, &c., p. Delle Chiaje's figure (Descriz. &c. III. Tav. 258) has described those of Pecten and Spondylus ILXXXII. fig. 4.), of the principal ganglionic mass as organs long known. Grube (Miiller's Arch. of Cynthia papillata, reminds me of the cla- 1840, p. 24, Taf. III. fig. 1, 2), and Krohn (Ibid. vate body of Chelyosoma and leads me to think p. 381, Taf. IX. fig. 16) have described the structhat this author has confounded it with the nervous ture of these organs, and, quite recently. Will (Fro-,centre. I think that this organ exists generally riep's neue Not. 1844, No. 622, 623) has treated with both the simple and compound Ascidiae, for this subject most profoundly. Seavgny has noticed with Cynthia, Phallusia, Deshayes is not satisfied of the existence of orAplidium., Polyclinum, Botryllus, Eucoeliunz,- gans of vision with the Pectinea, while Duvernoy Synoecium, Pyrosoma, &c., two tubercles near the regards as such the bodies situated on the border nervous ring which surrounds the respiratory tube of their mantle (Instit. 1845, p. 52, 88). It is astonish(Tubercule anterieur et postCrieur). And. to ing that Deshayes should have denied eyes to the judge from his figure (Mim. &c. P1. VI. fig. 12, 2, Pectinea, where they are so complete. Ile could have 4'-, h. P1. VII. fig. 21), of one of these tubercles, with better denied them to Phallusia, Arca, Ostrea, and. Cynthia, these organs appear analogous to the cla- other Acephala. During my last visit at Venice vate body just mentioned. At all events, these and at Trieste, I examined living individuals of the tubercles deserve, with Zootomists, more attention genera Area, Ostrea, Pinna, as well as other Lamthan has hitherto been given them. ellibranchia and various Ascidiae; but with all 2 These motions are probably due to the ciliated possible care, I was unable to verify Will's descrip.epithelium lining the cavity of the capsules i see, tion (loc. cit.) of the eyes of these animals. In below, the auditory organs of the Gasteropoda. most cases, the bodies which he has described as 3 I have been unable as yet to find these capsules eyes, have appeared to me only as simple excreswith the apodal Lamellibranchia, —at least, with cences of the mantle, which are variously colored, T1ichogonia, and Mytilus. They appear to exist, but are wholly without the indispensable optic aphowever, for recently Deshayes has found them both paratus for a visual organ. in Teredo. Here they were situated at the extrem 20'2 THE ACEPHALA. ~ 187 Each eye is composed of a ball formed of a fibrous Sclerotica, which i: situated upon a small eminence, or is sunken in a contractile prolongation of the mantle from which projects a cornea, covered by the general skin. Within the sclerotica there is a reddish-brown pigment which is continuous in front into a brownish or bluish-green Iris which has a circular pupil; while behind, at the base of the eye, it has the appearance of a kind of Tapetum. This is composed of staff-like corpuscles, which produce that beautiful emeraldgreen appearance of the eyes of certain species. The Retina surrounds a vitreous body, composed of non-nucleated cells, and which receives in front a very flattened crystalline lens. The optic nerves which enter the eye-ball at its posterior part, are, together with those of the tentacles, received from those of the mantle, and especially from the marginal branches. () The following are the modifications which have already been observed with the eyes of these animals: With the Ascidiae, there are eight eyes at the entrance of the respiratory tube, and six of a deep-yellow color at the entrance of the anal tube. They are situated in the special fissures around the openings, and in the midst of a mass of orange-colored pigment.(3) With Pholas, Solen, Venus, and Mactra, these organs are very numerous and non-pedunculated, and are situated at the base of the tentacles surrounding the two orifices of the siphon. With Cardieum, the borders of the orifices of the short siphons have an extraordinary number of protractile tentacles which can be protruded through the open valves, each of which bears an eye of diamnond brilliancy.(4) With Tellina, the two borders of the mantle have small, reddish-yellow, pedunculated eyes, which are quite numerous at the posterior portions. With Pinna, the anterior part of the mantle near the adductor muscle has, on each side, about forty brownish-yellow eyes situated upon short peduncles. But with Arca, and Pectunculus, the numerous reddish-brown eyes, usually sessile, are scattered irregularly over the borders of the mantle. Anomia has about twenty brownish-yellow sessile eyes concealed among the tentacles, upon each border of the mantle. With Ostrea, the number is still larger; for, for more than a third of the length of the mantle, there is a very small short-pedunculated yellowish-brown eye between every second tentacle. But the beautiful emerald-green eyes of the Pectinea are the most remarkable. They are pedunculate and situated between the tentacles of the marginal fold of the mantle, being very much more numerous upon the side of the plane, than upon that of the convex valve.(6' 2 See Garner, loc. cit. fig. 3i Krohn, loc. cit. the very numerous eyes are partly isolated, and fig. 16, and Grube, loc. cit. fig. 2. partly grouped in twenties and thirties. 3 Phallusia, Cynthia, and Clavellina, accord- 6 Beside the figures already cited, all of which ing to Will, loc. cit. No. 623, p. 102. Grant (Out- belong to Pecten and Spondylus, see also those lines, &c., p. 361) has seen, at least with Phallusia, which Delle Chiaje (Descriz. &c. Tav. LXXV. these fourteen eyes. LXXVI.) has given of the eyes of Pecten. In this 4 See Will, loc. cit. p. 100. The color of the eyes same genus, Will has seen sixteen to twenty-four appears reddish blue with ltlactra, and of a of these organs upon the convex portion of the yellowish brown with others. mantle, and thirty-five to forty-five upon the plane 5 See Will, loc. cit. The pupil is an elongated portion; and with Spondylus gaederopus, sixty oval with Pinna. With Pectunculus pilosus, upon the convex, and ninety upon the plane side. ~f 188, 189. THE ACEPHALA. 203 CHAPTER V. DIGESTIVIE APPARATUS. ~ 188. The digestive canal of the Acephala is formed, throughout the class,upon a single plan. It always consists of irregular convolutions which are separated with difficulty, for their walls are generally not covered by a peritoneal envelope, but are intimately blended with contiguous organs and especially the liver and genital gland. The oral and anal openings, which are always present, are not upon the surface of the body, but are situated in a cavity circumscribed by the mantle.(1) The mouth has always tumid lips and often tentacular appendages. Its cavity has neither distinct muscular walls, nor any trace of a masticatory apparatus. It passes either directly, or by a short esophagus, into a kind of stomach which gradually contracts into a longer or shorter intestine, scarcely different from it in its intimate structure. The extremity of the intestine often projects into the cavity of the body, as a kind of papilla, upon the end of which the anus is situated. Internally, this canal is lined throughout with a very distinct, ciliated epithelium.. The food of these animals, which consists of slime and small organized bodies, is taken into the cavity of the body with the water, and is conducted to the mouth by the ciliated epithelium which lines this last. In a similar manner the faeces are rejected with the refuse water. ~ 189. The very feebly-developed digestive canal of Salpa consists only of a small knob (Nucleus) situated in the posterior part of the cavity of the body. It connects with a furrow formed by two narrow folds situated along the ventral median line. This furrow may become a canal by the joining of its borders, and its posterior extremity, which is a little lateral, opens directly at the entrance of the intestinal canal which is surrounded with a lip, and ought therefore to be regarded as a mouth. The folds of this furrow arise directly behind the anterior respiratory orifice, and are very probably covered with cilia, by which, solid particles of food taken into the body during respiration, are borne towards the mouth.(l) 1 With many Acephala, as with the Ascidiae and 1, 2, 1.), and Eschricht (Over Salperne, p. 26, Salpinae whose mantle is entirely closed with the fig. 4, 8, 18, m.); but they describe it as a dorexception of the two respiratory orifices, it is only sal furrow and a dorsal fold, for they have taken in an improper manner that the terms oral and the abdominal cavity of these animals for the back. anal can be given to these orifices. That of Salpa gibbosa is quite distinctly figured in 1 With Salpa cordiformis, and maxima, I have the Catalogue of the Physiological Series, &c., I. seen this furrow quite distinctly. It appears to be P1. VII. fig. 1, k. This furrow corresponds, prob. present in all species. Cuvier has already men- ably, less to an open cesophagus, than to the tentioned and figured it (MRm. sur les Thalides, &c., tacle-furrow which, with all the Lamellibranchp. 12, fig. 1, 2, 3, &c., q.), and it has also been no- ia, is situated upon the two sides of the mouth. ticed by Savigny (MRm. &c. p. 124, P1. XIV. fig. 204 THE ACEPHALA. ~ 189. The intestinal canal is short, without a distinct stomach, and somewhat spirally convoluted.(2) Its extremity opens by a large anal orifice near the mouth. (3) With the Ascidiae, the intestinal canal is quite distinct. The mouth is situated in the respiratory cavity, far removed from the so-called oral tube, or more properly speaking, the respiratory orifice. It is surrounded with thick lips, and has at its posterior extremity with many species, a semi-canal closely resembling, and undoubtedly of the same signification as the ventral furrow of Salpa. This canal is formed by two narrow folds arising below the circle of tentacles which surround the interior of the oral cavity; it passes along the large curvature of the respiratory cavity, and rising upon its opposite side, ends, after a longer or shorter course, below the oral cavity. 4) The mouth opens into a short Esophagus, and this last ends in a long or round stomach, which is often quite circumscribed and plicated longitudinally on its inner surface.'3' The intestine passes first towards the base of the body by a short. arch, then by a longer one it rises towards the mouth, and thence passes to the anal tube, opening, by a fringed anus, sometimes close behind the mouth, and sometimes further below it.(6) With' the Brachiopoda, the mouth is simple and concealed between the base of the two tentacular arms. With Terebratula, the oesophagus is very long and curving, opening into a large stomach;(7) but with the other Brachiopoda, the stomachal dilatation is wanting, and the intestine is simply convoluted. With Orbicula, and Terebratula, the intestine is short, and has only a single convolution which passes to the right and terminates in a lateral anus hidden between the lobes of the mantle. But with Lingula, it is much longer, and its turns are quite numerous; the anus here is lateral also, and opens through a small papilla which projects from the cavity of the body into that of the mantle.(8) With the Lamellibranchia the intestinal canal is highly developed, but always buried in the midst of other abdominal viscera. The mouth, situated at the bottom of the cavity of the mantle, and beneath the anterior adductor muscles, is surrounded by two pairs of tentacles in the form of tactile lobes; these often form a furrow leading to the mouth, and along which pass the particles of food drawn in by the cilia.(9) The mouth opens, either 2 See Home, Lect. on Comp. Anat. II. PI. With Phallusia intestinalis, there is, opposite IAXXII. (Salpa Tilesii). this canal and upon the side of the respiratory cav3 For the oral and anal orifices of Salpa, see the ity corresponding to the anal tube, a longitudinal figures of Cuvier, and Savigny, loc. cit. Some row of very long thickly-set filaments, extending species however differ from the descriptions here even to the oral aperture. Eschrichkt has seen a given. Thus, according to a preparation in Hun- row of similar tentacles with Chelyosoma; see loc. ter's Museum, the intestine of Salpa gibbosa has cit. p. 10, fig. 4, 6, z. fwo caecal appendages (Home, Lect. &c. P1. LXXI. 5 The stomach is elongated with Boltenia, Phalfig. 2, 3, and Catalogue of the Phys. Series, I. p. lusia, Cynthia, Sigillina, and spherical with 132, P1. VII. fig. 1, 2, i. i.). The intestinal canal Aplidium, Eucoelium, &c. Its longitudinal folds -:,f Salpa pinnata presents a still more remarkable are often very distinctly marked externally by deep exception. No nucleus is formed, but the mouth grooves, as is the case with Sigillina, Aplidium, )pens directly into the stomach which is curved and Botryllus; see for this, Savigny, loc. cit. and sends off an intestine in front, and the anal According to him also there is a small caecum at orifice is situated near the anterior extremity of the the base of the stomach with Botryllus Schlosventral groove; see Cuvier, loc. cit. p. 11, fig. 2; seri, and polycyclus; see Mlm. &c. p. 201, P1. Hom e, loc. cit. P1. LXXIII fig, 2, and the Catalogue XX. fig. 52, P1. XXI. fig. 14, c. of the Phys. Series, I. P1. VI. fig. 4. 6 Upon the course of the intestine with the Asci4 Savigny has described this canal with the most diae, see Cuvier, Savigny, and Home, loc. cit, P1. different Ascidians as a Sillon dorsal; see the LXXIV. and the Catal. of the Phys. Ser. I. P1. V. figures (loc. cit. P1. VI. &c.) of Cynthia, Phallu- (Phallusia). sia, Diazona, Syno icum, Aplidi/um, Eucoelium, 7 See the figure given by Owen, loc. cit. Polycli/num, Botryllus, Pyrosoma, ~c. 8 For the intestinal canal of several BrachioCarus also has called the attention to this canal poda, see Cuvier, Owen, and Vogt, loc. cit. with Cynthia microcosmus (Nov. Act. Acad. 9 With Cardium, Isocardia, Avicula, &c., these Physico-Mled. loc. cit. p. 432, Tab XXVII. fig. 1, 2, two pairs of gustatory lobules are very distinctly q.). seen passing towards the mouth by as many lateral ~ 190. THE ACEPHALA. 205 directly, or by a short oesophagus,(l-) into a large stomach lined with numerous papillae and apparently perforated by many biliary canals. The intestine, when short, forms a single arch only; but when long, it has many convolutions; it terminates in a rectum which lies along the dorsal surface of the abdomen,(l and passes between the lobes of the mantle, under the hinge and above the posterior adductor muscle, finally terminating above in a ciliated anus, situated upon a small prominence.(2) With the majority of this order, the rectum traverses the heart.(3) There is often, near the pylorus, a long caecum ~l4) extending between the convolutions of the intestine to the lower extremity of the abdomen, and which contains, through its whole extent, a cylindrical transparent cartilaginoid body — the so-called crystalline-stalk.(~) A longitudinal fold extends along the inner surface of the entire intestine and a large part of that of the rectum, and thereby the intestinal surface is increased. ~ 190. The anterior portion of the digestive canal of the Acephala is entirely without a Salivary gland.() The Liver, however, is always present; it is grooves, whose borders as already mentioned According to Ocwen (Anat. of Clavagella, &c., (~ 185) are blended above and below with the oral P1. XXX. fig. 16, r.), Clavagella has a very short orifice. With Pectunculus, and Arca, there is a and rudimentary caecum. still more remarkable arrangement. 15 With the exception of Anomia, the crystalline Their lobules of this kind consist only of two stem is wanting in all the Mononmya (Garner, loc. narrow folds upon each side of the mouth, and be- cit. p.'89). But it exists with many Dimya, as tween which is a transverse furrow, resembling the Pholas, Solen, Arca, AIactra, Donax, Cardisum, ventral-groove of Salpa, or the semi-canal of the Tellina, Anodonta, Unio, AIya, &c.; see Poli, Ascidiae. The important part which this appara- loc. cit. Tab. VII. XIII. XIV. XVI. XIX. XX. tus serves in the prehension of food, can be seen XXIV. With many of these, there is no caecum by covering those of Anodonta and Unio with a and the crystalline stem is situated in the intestine powdered colored substance. itself. It has always a cylindrical form, and is of a This powder is carried by cilia from the surface decreased size at its lower end, while at the oppoto the borders of the tentacles, thence upon their site one it is usually divided in several irregular transversely grooved internal surfaces even into the lobes which project into the cavity of the stomach angle formed by these last, thence into currents of and appear to close up the orifices of the biliary the grooves, and so direct into the mouth. canals. With the Naiades, where the caecum is 10 A distinct but short oesophagus is found with wanting, I have found this singular body, which Arca. Chama, Pinna, Cardium, and Mlactra. extends from the stomach into the intestine, coin11 The intestine is short and has a single arch posed of a cortical and a medullary portion. The with Spondylus, Pectesn, Arca, and Chama. It is first which forms a kind of tube, is homogeneous, long and has many turns with Pholas, Tellina. transparent, and formed of concentric layers of the Cardium, Mactra, Pinna, Ostrea, &c. consistence of the white of an egg. The second is 12 The anus is short and situated directly behind equally homogeneous and transparent, but is of a the anal fissure of the mantle with Unio, An.o- more gelatinous nature and contains a quantity of donta, Cardium, Isocardia, &c. * while with As- small granules (Unio), or batons (Anodonta), inpergillum, Lutraria and Solen, it is situated far soluble in acid, which, at the points where most removed from the siphon. With Arca, Pectuncu- aggregated, give this organ a whitish color when lus, Pinna, and Avicula, the rectum passes examined by reflected light. According to Poli's around a large portion of the adductor muscle and description and figure of this organ with Pholas ends in front in a papilla, which, in the last two dactylus, it has an analogous structure with the genera is quite long. With Lima, it ascends a other Lamellibranchia (loc. cit. I. p. 47, Tab. little way along the anterior surface of the adduc- VII. fig. 11). As yet nothing positive can be said tor muscle, and with Pecten and Ostrea, it leaves of the function of this organ. It may be also added the median line upon the back of this muscle and that often with some individuals it is looked for in passes obliquely towards the smaller valve. vain, while with others it is very distinct though 13To this, Arca, Ostrea, and Teredo, form an variable as to its development and the number of exception, and especially with the last, where the layers composing its cortical portion. Hence it intestinal canal is distinguished for several other seems that it disappears at certain times, to be peculiarities, Thus, the stomach is double and developed anew. anteriorly divided to its base by a longitudinal sep- That of Anodontca as figured by BojanuLs (Isis, tum; see Home, Lect. &c. PI. LXXX., and Des- 1827, Taf. IX. fig. 9, 10) was undoubtedly in the hayes, Comp. Rend. 1846, XXII. No. 7; or Fro- state of being formed, or disappearing. riep's neue Not. No. 813. 1 Cuvier (Sur la Lingule, loc. cit. p. 7, fig. 10, 14 For the caecum of Solen, Mactra, and Car- 11, a.), and Vogt (loc. cit.) have regarded the glanddium, see the figures of Garn er, On the Anat. of ular mass which, with Lingula, opens into the dithe Lamellibr. &c. P1. XVIII. fig. 8-10 i and for gestive canal, as a solitary organ. But Owen (loc. ihe disposition of the intestinal canal in general, cit.) is opposed to this view and says that all the Fee the Plates of Poli, loc. cit. 18 206 THE ACEPHALA. ~ 191. connected with'he walls of the intestine, almost inseparably, and opens into it through numerous canals. With the Tunicata, its structure is quite simple, being composed of small, single, or ramified glandular follicles, thickly-set together and covering a large portion of the stomach and intestine.(2) With the Brachiopoda, there are groups of green follicles removed from the digestive canal but communicating with it by excretory canals.(3) With the Lamellibranchia, this organ is voluminous and composed of lobes which occupy the upper part of the abdominal cavity. These lobes are made up of distinct Acini formed of brownish-yellow hepatic cells.(4) The biliary ducts which open into the stomach or the anterior part of the intestine, are always few in number. CHAPTER VI. CIRCULATORY SYSTEM. ~ 191. This system with the Acephala, as well as that of the Mollusca in general, is of a higher grade than that of the Zoophytes and Worms, in having the movement of the blood due always to a contractile central organ, or Heart. This heart is, it is true, very simple in some, but then with others it is so developed as to contain both auricles and ventricles. It receives the blood from the respiratory organs and distributes it over the body, and is therefore an Aortic heart. As to the blood-vessels themselves, the hitherto received opinions have been of late quite seriously objected to; and it appears very probable that all these animals have only arteries and veins, glandular appendages of the intestine of Brachi- follicles opening into the stomach; with Orbicula, opoda are hepatic organs.* these are replaced by a mass of long hepatic ones; 2 The intestinal nucleus of Salpa owes its yellow- and with Lingula, by three principal glandular ish-brown color to these hepatic organs. But masses,'opening at different points into the intestiwith Salpa democratica, and caerulescens, it is nal canal; see Owen, Cuvier, and Vogt, loc. cit. of a beautiful blue color. 4 Poli (loc. cit. Tab. XI. XV. XVI.) has given a Salpa pinnata, whose straight intestine has al- good representation of some hepatic lobes with their ready been mentioned, is distinguished also by its interanastomosing ducts of several species. See liver which is separated from and runs parallel also Bojanus' figures of the liver and its ducts with the intestine; see Cuvier, and Meyen, loc. cit. of Anodonta (Isis, loc. cit. p. 757, Taf. IX.). This last-mentioned author affirms that he has seen As to the intimate structure of this organ, I have with this species a kind of green gall-bladder (loc. found with Cyclas cornea, lacustris, and rivicit. p. 389, Tab. XXVII. fig. 19, m.); but probably cola, Unio pictorum, and Tichogonia polymorhe confounded the stomach of the animal with its pha, short, cylindrical, transparent filaments, a litliver. For the intimate structure of the glandular tie flexed, but projecting stiffly from the base of the layer upon the intestine of Salpa cordiformis, follicles into their cavity. I am yet ignorant as to see Eschricht, Over Salperne, p. 27, Tab. III. fig. their function, but have in vain sought for it, with 20. With the Ascidiae, the liver is a simple gland- Unio batava, tumida, Anodonta anatina, cygular layer upon the stomach and intestine in the nea, Mya arenaria, Cardium edule, and Mytilus various species of Phallusia and Diazona; while edulis. with Cynthia, it is isolated near the pylorus, and For the intimate structure of the liver of Lamellicomposed of large follicles; see Savigny, loc. cit. branchia, see H. _Meckel (Miiller's Arch. 1846, P1. XII. fig. ld (Diazona). p. 9, Taf. I.) and Karsten (Nov. Act. Nat. Cur. 3 With T'erebratula, there are two groups of XXI. p. 302, Tab. XX.). * ~ 190, note 1.] Frey and Leuckart declare the presence of salivary glands with Teredo nava.l &is j see loc. cit. - ED. ~ 192. THE ACEPHALA. 20T which are connected by no capillary net-work except that situated in the respiratory organs. The blood leaving the open ends of the arteries passes into the interstices /Lacunae) of the parenchyma of the body; thence it is taken up by the open mouths of the venous radicles.(1) The Blood is colorless and contains many pale, granular globules, which are indistinctly nucleated.(2) ~ 192. With Salpa, the circulatory system is composed of two main trunks, one upon the dorsal, and the other upon the ventral median line. At the anterior extremity of the body these trunks connect by two arcuate vessels; and at the posterior extremity by a single slightly-dilated canal situated directly in front of the intestinal nucleus. This last-mentioned canal is divided into several chambers by two or three constrictions, and, from its rhythmical contractions, may be regarded as a heart.() It is surrounded with a delicate pericardium, (2) and by its pulsations the blood is thrown across,the walls of the body in different ways,('3 thus forming extra-vascular currents. But it will here be observed that the heart, thus forcing the blood.alternately in one direction and then in another, will regularly change the.arterial into a venous current, and vice versa.(4) With the Ascidiae, this system is equally feebly developed. The blood passes for the most part out of the vessels into the lacunae which often con-:sist of ramified canals resembling vessels. The Heart is always present, and is surrounded with a very thin pericardium. It consists of a long canal, which, at both extremities, passes into a vessel which lies loop-like between the vascular sac and the intestine at the lower part of the cavity of the body.(5) Its pulsations quite resemble the peristaltic movements of the 1 This effusion of the blood into the parenchyma 2 Meyen (loc. cit. p. 376) has denied the pres-of the body and its return into the veins without ence of a pericardium with Salpa; but Cuvier (loc. the intervention of capillaries, or in general with- cit. p. 10), Savigny (loc. cit. p. 127), and Delle out walled canals, has been maintained recently, es- Chiaje (Descriz. &c. III. p. 43, Tav. LXXVIII.) pecially by Milne Edwards (Obserlv. et exper. sur affirm the contrary. la circul. chez les Mollusques, Comp. Rend. XX. 3 The direction of these blood-currents in the 1845, p. 261), and by Valenciennes: Nouv. observ. body of Salpa is satisfactorily shown by the de-.sur la constit. de l'appareil de la circul. chez les scriptions and figures of Quoy and Gaimard (loc. Mollusques, Ibid. p. 750). Their observations cit.) and especially of Delle Chiaje (Descriz. &c.) were not limited to Satpa, and the Ascidiae, but Sars (Faun. litt. &c. p. 66), has also observed were extended upon Ostrea, Pinna, Mactra, Ve- with Salpa runcinata, that the blood beyond the nous, Cardiurn and Solen. See also Ann. d. Sc. aorta and vena cava, circulates in wall-less pasNat. III. 1845, p. 289, 307, or Froriep's nieue Not. sages. Nos. 732, 733, 743. 4 This remarkable alteration of the blood-currents Milne Edwards is about to publish an extended which is possible only with a valveless heart, has work on the circulation with the Mollusca. Ile has been observed and described by different observers figured from his beautiful injections the partly la- in a conformable manner. Before the heart changcunal circulatory system of Pisnna * see Ann. d. Sc. es the direction of its contractions it remains still Nat. VIII. 1847, p. 77, P1. IV. for a short time, and this slackens the course of the 2 For the blood of Phallusia, Cynthia, and Ano- blood-currents in the body a little, before they re-.donta, see Wagner, Zur vergleich. Physiol. d. ceive an impulse in the opposite direction- see B3lutes Hft. I. p. 20, II. p. 40. The blood-corpuscles Van Hasselt (Ann. d. Sc. Nat. III. 1824, p. 78). of the Naiades have always appeared to me of an Eschscholtz (Miller's translation of the annual irregular form; and they run together when placed report of the Swedish Academy upon the progress of in a watch-glass. This is probably due to the fibrin Natural History, &c., 1825, p. 94), Quoy and Gaicementing them together. When treated with ace- mard (loc. cit. p. 559, or Isis. 1836, p. 111), and tic acid they become separated again, their contour Delle Chiaje (Descriz. &c. III. p. 43). becomes very clear and almost imperceptible, and 5 For the heart and blood-system of the Ascia hitherto invisible nucleus is seen. diae, see especially, Milne Edwards (Sur les Asci1 See Csuvier, loc. cit. p. 10, fig. 21, A, &c. Ac- dies composies loc. cit. p. 4), who has indicated the cording to Meyen (loc. cit. p. 375, P1. XXVIII. fig. presence Of the heart in Phallusia and Clave1, d.) the heart of Salpa mucronata has two con- lina, as well as in Polyclinum, Botryllus, Districtions i and, according to Eschricht, that of demnunm, Pyrosoma, A4c. Salpa cordiformis is divided into four chambers,loc.: cit. p. 26, fig. 8, ca). 208 THE ACEPHALA. g 192. intestine; and, as with Salpa, the direction of the current is changed so alternately that the two terminal vessels serve in rotation as an Aorta and: a Vena cava. (1) The blood not only traverses the lacunae of the intestinal sac, but also penetrates the walls of the mantle, and even passes into the common support of the compound forms. In this last case, it circulates in ramified canals, which, as prolongations of the cavity of the body, extend even into this portion of the mantle. (') With the Brachiopoda, this system is quite remarkable. The branchial afferent veins of the mantle do not open into a single heart, but into two hearts which are situated right and left of the intestinal sac.(8) These hearts, by pulsation, throw the blood into the intestinal canal, which ought therefore to be considered as a common visceral sinus.t') With the Lamellibranchia, the heart, situated at the posterior extremity of the back, is divided, usually into three chambers, and surrounded with a large pericardium. Two lateral, triangular, thick-walled auricles receive the blood from the branchiae and send it into a simple muscular ventricle which is nearly always traversed by the rectum. Thence the blood passes into the body by a posterior and an anterior aorta. Its return into the two auricles is prevented by valves.(0) The walls of these aortae disappear after considerable ramification, and the blood passes into a system of lacunae which extends through the whole body and forms a net-work of sinuses and anastomosing canals.(tu) The venous blood is received into special6 This change in the direction of the blood-cur- Descriz. &c. III. p. 33, Tav. LXXXIV. fig. 2. rents was first noticed by Lister (Philos. Trans. According to Koliker (Ueber das Vorkommen der 1834, Pt. II. p. 365, or Wiegmann's Arch. 1835, Holzfaser im Thierreich. loc. cit.), these multiraI. p. 309) with Perophora, a, new genus of the mose vessels which come directly from the heart compound Ascidiae; and Mlilne Edwards has and whose extremities are penicillated, appear to be-. since confirmed it with Pyrosoma (Ann. des Sc. continuous directly beneath the skin with other Nat. XII. 1839, p. 375), and several other Ascidiae vessels returning by the course of these arteries. both simple and compound. see his Observ. sur 8 See Cuvier, Owen, and Vogt, loc. cit. les Ascidies simples et composies, p. 7. 9 Owen was the first to notice this analogy of These inter-alternating peristaltic and anti-peris- the circulation of the Brachiopoda with the extra. taltic motions show that the heart of the Ascidiae vascular one of other Acephala * see his Lettre sur is valveless. It is therefore surprising that Delle l'Appareil de la circulation chez les Mollusques de la. Chiaje has described it with valves; but this is Classe des Brachiopodes (Ann. d. Sc. Nat. III. 1845, not the only point in which he differs from other p. 315, P1. IV., or Froriep's neue Not. No. 793). observers on this subject, for he describes the heart 10 For the arrangement of this central part of the of the Ascidiae as bifurcated into two auricles; see circulatory system, see Poli, loc. cit. Tab. IX. fig. his Mem. &c. loc. cit. III. p. 193, Tav. XLVI. fig. 12 (Unio); Tab. XIII. fig,5 (Solen); Tab. XXII. 13, ab. (Cynthia papillata), and Descriz. &c. III. fig. 10 (Spondylus); Tab. XXVII. fig. 8, 12 (Pecp. 29, Tav. LXXXII. fig. 11, 12 (Phallusia in- ten); Tab. XXIX. fig. 7, 8 (Ostrea); Tab. xxxI, testinalis). fig. 8, 9 (Mytilus), and Tab. XXXVIII. XXXIX. 7 This circulation of the blood in the common (Pinna). Also Bojanus, in the Isis, 1819, l 42, Ascidian-stock has been observed by Lister (loc. Taf. I. II. (Anodonta); Treviranus, Beolbacht aus cit.). Milne Edwards has seen also the ascending d. Zoot. u. Physiol. p. 44, fig. 67 69 (MIytilus and and descending currents in the ramified and coecal Anodonta); and Garner, Trans. of the Zool. doc. prolongations of the peritoneal sac, in Botryllus, II. p. 90, P1. XIX. fig. 4 (Pecten). Diazona, Didemnum, and Polyclinum; see Sa- An arrangement quite different from this type is. vigny, Mlm. loc. cit. p. 47; Delle Chiaje, Descriz. found with Arca, whose two auricles are attached &c. III. p. 34, Tav. LXXXIII. fig. 13, 15 and to the two widely-separated ventricles, and send, Milne Edwards, Sur les Ascidies, loc. cit. p. 41, out on each side an anterior and posterior aorta, P1. VII. fig. 1, lb. 1e. This last-mentioned author which meet and join upon the dorsal median line, has also observed that, with Clavelina (Ibid, p. see Poli, loc. cit. Taf. XXV. fig. 2, 3.* 9. P1. II.), these canals terminate in caeca which 11 This system of lacunae forms, especially in the communicate with the cavity of the body, and are mantle, a beautiful net-work of delicate canals extended into digitiform prolongations upon the ex- which, with the Naiades, are visible to the naked. tremity of the peritoneal sac, and herein the blood eye. It should not, however, be confounded with. moves alternately up and down. The ramified ca- another net-work more difficult to be seen, and nals which abundantly traverse the mantle of Ptial- which probably constitutes a system of aquiferous lusia, are, according to authors, real blood-vessels; canals, which is easily seen in the mantle, foot anti. see Cuvier, loc. cit. p. 16, P1. III. fig. 1; Savigny, other parts of the body by inflation. Delle Chiloc. cit. p. 102, Pl. IX. fig. 1, B., and Delle Chiaje, aje has called it Rete lymphatico-vasculosum, * [~ 192, note 10.] See also Deshayes, loc. cit. p. 63, 64, &c., P1. VIII. fig. 1, 2, 3, and Quatre — fages, loc. cit. p. 47, P1. I. fig. 7 (Teredo). - ED. %$ 193) 194. THIE ACEPHALA. 209 lacunae situated at the base of the branchiae, and into which it thence passes. CHAPTER VII. RESPIRATORY SYSTEM. ~ 193. With all the Acephala, the blood, just before returning to the heart, passes through a branchial, or distinctly respiratory organ, which, either simple or multiple in structure, is always hidden in the cavity of the mantle. The renewal of water takes place by special openihlgs of the body, or through the slits of the mantle, which are often prolonged into two respiratory tubes. One of these openings is fbor the ingress, and the other for the egress of the water, and their currents carry in and out, respectively, food and faeces. In the cavity of the mantle, the water circulates in a definite direction and passes over the branchiae by means of the cilia covering their external surface. ~ 194. The Branchiae of the Acephala are formed after four different types:1. With Salpa, there is one only of these organs which stretches, frionm above downwards and firom before backwards, across the cavity of the body. The water enters through an anterior orifice which is usually valvular, and is expelled through a posterior opening by the contractions of the body.('Y The branchia itself, which, near the heart, is bent a little in fi'ont at itslower posterior extremity, consists of a narrow band having upon one of its sides numerous transverse, thickly-set folds.2). Its remaining portion is flat,101 or the lateral borders are rolled up like tubes.(4) The branchial ves — sels are ramified in the interior, communicating, at the superior extremity and has figured it very beautifully; see his Des- posterior orifice, the animal closes the valve of the criz. &c. Tav. LXXV. fig. 6, and Tab. XC. fig. 1, anterior one, so that the body is thrown forwards. 2 (Mantle of Pecten and Solern), Tav. LXXXIX. On this account the cavity of the body is often, fig. 11 (foot of a Mactra). called natatory. The vascular net-work W;hich Poli (loc. cit. Tab. 2 See Cuvier, and Savigny, loc. cit. XXXVIII.) has figured in the mantle of a Pinsna, 3 Salpa costata, and maxima. is probably only one of aquiferous canals. 4 Salpa pinnatca, cylindrica, octofora. When. I shall again (6 195) allude to this confusion the branchia is contained in a tube it has often been between the blood and aquiferous vessels.* compared to a Trachea; see Savigny, loc. cit. P1L 1 These respiratory motions aid also for the lo- XXIV. Comotion of Saipa; for, when water escapes by the * [ 192, note 11.1 This lacunal system is well- heart, and on the other hand, all the other lacunae marked with Teredo according to Quatrefages, and the arterial system beside may be filled by inwho denies that these animals have a proper venous jecting through one lacuna; see MRmoire, loc. ciL. system. The grounds of this conclusion are, that p. 55. -ED. these lacunae are always filled by injecting the 18* 210 THE ACEPHALA. ~ 194. of the branchiae with those of the body, and at its opposite one with the heart. Externally, it is covered with large cilia.(5) 2. With the Ascidiae, the walls of the body are, for the most part, lined with a membranous branchial apparatus. In the place of respiratory orifices, there are, what are usually called an oral and an anal tube. By the first of these, the water containing food passes directly into that part of the cavity of the body which contains the branchial apparatus, and which is therefore called the respiratory cavity. By the second, this cavity is emptied of the refuse water containing faeces. (6 The branchial membrane, which, in some of the simple Ascidiae,(7) forms numerous longitudinal folds extending entirely over the respiratory cavity, presents a trellis-like aspect with rectangular meshes. 8) These meshes which form prominent lines, have often small fleshy papillae,() and are always provided on each side with a row of very long cilia which produce regular currents of water. Two longitudinal sinuses pass off from the base of the respiratory cavity and ascend along its greater and lesser curvature even to the oral tube, where they intercommunicate by a circular canal. These sinuses send numerous transverse vessels into the branchial membrane, where they anastomose vertically and thus form a net-work corresponding to the trellis just mentioned. From the continual changes in the direction of the blood-currents it is impossible to determine which is the arterial and which the venous of these sinuses. (10) 3. With the Brachiopoda, the internal layer of the mantle serves as a branchia. The internal surface of the halves of this organ is occupied with a system of very apparent blood-canals. With Terebratula, and Orbicula, there are four large canals upon the surface corresponding to the imperforate valve, and two upon the other surface. These arise from two hearts, and are subdivided into numerous minute branches. Parallel to these last, are others, smaller, and which appear to communicate with them on the borders of the mantle; perhaps they are the branchial arteries, while the larger canals are veins.(") With Lingula, the branchial vessels are contained in collar-like projeclions, giving the inner surface of the mantle a very peculiar aspect.(") 4. In the cavity of the mantle with the Lamellibranchia, there are two pairs of branchiae, which, as four lamellae, embrace each side of the abdomen, and the foot.(l3' The water which bathes them comes in partly through an opening in the mantle, and partly by a particular respiratory orifice upon the border of the abdomen, or by the respiratory tube of the siphon. It passes out through the anal orifice, or by another tube of the siphon. (14) 5 These ciliated organs were first described by partly known this arrangement of the branchial Meyen, loc. cit. p. 385. vessels. 6 With the compound Ascidiae, the arrangement 11 Owen, loc. cit. is such that several individuals are disposed in a 12 See Cuvier, Owen, and Vogt, loc. cit. star-like manner about a cavity in which their anal 13 The two external branchial lamellae are usutubes open. ally a little smaller than the two internal; and this 7 Cynthia microcosmus, momus, &c. difference is well marked with Cardium. Accord8 See the figures of Savigny, and 3Milne Ed- ing to Valenciennes (Comp. Rend. XX. p. 1688, wards, loc. cit. XXI. p. 511), there is only a single pair of branchiae 9 Pihallusia sulcata, monachus, intestinalis, with Lucina jamaicensis, and columbella, Cyand Diazona violacea i see Savigny, loc. cit. PI. therea tigerina, Tellina crassa, and Solen radiIX.-XII. atus. In this last species, they consist only of two 10 See Milne Edwards, Sur les Ascidies compo- narrow, longitudinal swellings. sees, p. 7. Cuvier, and Savigny, had already 14 The ingress and egress of the water through 194. THE ACEPHALA. 211 These four branchial lamellae, whose lower border is free while the other is attached to the viscera, always extend along the abdomen, and not unfrequently come together above. (15) Each lamella is formed, essentially, by a widely-projecting cutaneous fold, the two leaves of which are connected by numerous transverse septa, to which correspond externally as many furrows which pass from the base of the branchia to its borders. All these furrows have upon each margin a row of long cilia, which, upon the borders of the branchia, connect with an ordinary ciliated epithelium.(l6) The compartments formed by these interleaved septa are also lined with a very delicate ciliated epithelium, and;connect with the cavity of the mantle at the base of the branchiae.(17) With an entire group of this order, the branchial structure is quite different from that just described. Externally, these organs appear like ordinary branchiae, but examined more closely it will be found, that, instead of lamellae, they are composed of numerous thickly-set ribands arranged in rows.(18) These ribands are formed of two lamellae blended together at their extremity. Their circumscribing space is without doubt solely for the lodging of the branchial vessels; for, at their base, there is no orifice anal-.ogous to those found in the other species of this order. The blood collects.at the base of the branchiae in the longitudinal canal, from which the lat-,eral vessels are given off, at right angles. Thence it passes into the branchiae, traversing a trellis-like net-work quite resembling the analogous one of the Ascidiae.(19) Another series of lateral vessels serves as the branchial veins, pouring the blood into other longitudinal canals, whence it passes into the two auricles of the heart. (20) the different orifices of the mantle may be clearly 18 This pectinated form of the branchiae has seen by observing these animals, when they, at rest, been observed by Baer (M3eckel's Arch. 1830, p. -protrude between the valves either their siphon or 340), with Mytilus, and by Aleckel (Syst. d. verthe borders of the mantle and tinge the surround- gleich. Anat. VI. p. 60), with Spondylus, Pecten, ing water with coloring matter, which makes the and Area; see, also, the RMgne animal de Cuvier, currents quite distinct. nouv. 6dit. Mollusques. P1. LXXIV. fig. 2, a. I 15 With Unio, Anodonta, Mactra, Cardium, have seen similar branchiae with Pectunculus. Isocardia, Lutraria, &c., the four branchial layers Avicula, and Lithodomus. Philippi (Wieg-.are united at their posterior extremity. But with mann's Arch. 1835, I. p. 274) has seen them even Pecten, Avicula, Arca, Pectunculus, and Pin- still more developed with Solenomya..na, they are disconnected and extended backwards This peculiar branchial apparatus with Mytilus by two free prolongations. has been described with much detail by Sharpey 16 These ciliary movements tend to carry the wa- (Cyclop. of Anat. I. p. 621). I have myself, durter, with the internal branchiae, towards their free ing the autumn of 1847, completely verified the border; and with the external, towards their base. statements of this author, upon living specimens of 17 These orifices of the branchial compartments the generaMytilus,arca, and Pecten, and would are easily seen at the base of these organs; ex- insist here only on a single remarkable fact. Each -cepting, however, those belonging to the two exter- riband-like branchial filament has, upon both of nal branchiae,which are concealed beneath a kind of its surfaces, several cap-like papillae by means of canal formed by the mantle. These two canals, which these filaments are united together in a trelclosed in front, open behind between the end of the lis-like manner. When the branchiae are forcibly abdomen and the anus into that portion of the cavity distended, the papillae of the filaments are separof the mantle leading to the anal fissure or tube, and ated from each other. But this separation is not which may be regarded as a Cloaca; see Unio, very extended, for there is a cord composed of delAnodonta, Venus, Cardium, Isocardia, Mlactra, icate fibres, between each two papillae and binding &c. With many, as for instance with Unio, and them together; but sometimes, from undue force. Anodonta, the compartments of the external bran- this cord is broken in its middle, and then each chiae are much more developed than those of the broken extremity appears as a bundle of moving internal, and their orifices can be closed in a lip- vibratile cilia which projects from the cavity of the like manner by the vesicular enlargement of the capsule (see Sharpey, loc. cit. fig. 305, E. a). The septa which limit them on each side. With Pinna, function of this apparatus, which ceases to be visithe branchiae are quite different. Their leaves are ble when the papillae are united together, is yet united by short filaments instead of by septa; and wholly doubtful. tthus, although not divided into compartments, 19 Unio, Anodonta, Lima, Pinna, Ostrea, &c.; there are orifices at their base which lead into the see Treviranus, Beobacht. aus d. Zoot. &c. fig. 62, interior, and which are situated upon the internal 63, 65 (Ostrea and Anodonta); and Poli, loc. cit. surface of the internal, and upon the external sur- Tab. IX. fig. 17 (Unio). {ace of the external branchiae. 20 For the branchial vessels, see, especiaily, Bo. 212 THE ACEPHALA. g 195. ~ 195. It now remains to speak of a particular system of canals traversing in all directions the body of the Lamellibranchia, which as yet has been called the aquiferous system, because it is supposed to servefor an internal respiration like that of the tracheae of insects. (1) But, in the first place, the existence itself of such a system has been denied, although there are certain facts in its favor. WANhen one of these animals is suddenly taken from the water, numerous fine jets of water are seen to pass from these organs while the animal is withdrawing its foot and the borders of the mantle within the shell. From this fact it is evident that these orifices connect with aqueous reservoirs. But these openings are very small and probably are closely contracted, for they cannot be discovered either before or after the jetting out of the water.(2) Orifices of this kind have as yet been found in a few species only such are those in the extremity of the foot of Solen,3) and that singular tube found above the pedunculate anus of Pinna.(4) The aquiferous canals themselves are not very, apparent, being seen only after injection. This last is easily performed by blowing through a small tube inserted under the skin. There will then be seen a very beautiful network of canals, which, nearly all of the same size, are spread out under almost the whole skin and enter the interior of the body by larger canals. These canals appear to be without walls, and have, in general, the aspect of simple lacunae traversing the parenchyma of different parts of the body. By some naturalists, this net-work of canals is regarded as a system of lacunae circulating the blood;(5) but when they are inflated, another netjanus, Isis, 1819; Treviranus, Beobacht. &c. p. des organisch. Lebens. I. p. 276). The orifice 44, and the beautiful figures of Poli, loc. cit.* which Garner has figured upon the middle of the 1 Baer was the first to call the attention to this foot of Psammobia and Cardium, and to which aquiferous system with the Naiades (Froriep's neue he has given the name of Porus pedalis, belongs Not. No. 265, 1826, p. 5) after an analogous one undoubtedly to this system; see Trans. of the Zool. had been pointed out with the Gasteropoda by Soc. II. P1. XVIII. fig. 2, 13, f. Delle Chiaje. Poli, it is true, had recognized it 4 I have easily inflated the reticulated aquiferousn before this, but he had taken them partly for tra- canals of this animal by this tube, which, in Pinna cheae and partly for lymph oy blood-vessels. nobilis, sometimes protrudes far beyond the bor2 Meckel (Syst. d. vergleich. Anat. VI. p. 64) ders of the mantle, and which Poli (loc. cit. II. went certainly too far when he affirmed that these p. 241, Tab. XXXVI. fig. 3, N. fig. 7, Z. and Tab, orifices are only accidental fissures. I have been XXXVII. fig. 1, S.) has figured as a Trachea. unable to find the orifices, which, according to Poli 5 See above ~ 192, note 11. The vascular net(loc. cit. Introductio, p. 42, 52), are upon the summit workl which Poli (loc. cit. I. p. 8, Tab. IX.) has inof the cirri of the mantle and lead into a tracheal jected with mercury in the mantle of a Unio, and system. which he regarded as a lymphatic system, belongs 3 Orifices of this kind have been described and probably to the aquiferous system. The same infigured by Delle Chiaje with Solen si/iqua, as terpretation ought perhaps to be put upon a sanFori aquiferi (Descriz. &c. IlI. p. 60, Tav. XC. fig. guineous net-work which he has figured in the man11). These pores communicate probably with an tle of a Pinna (loc. cit. Tab. XXXVIII.). Delle Chiaquiferous system which Treviranus has seen in aje (Descriz. &c. III. Tav, LXXV. fig. 6, Tav. the foot of Solen ensis (Die Erschein. u. Gesetze LXXVI. fig. 3, 6, and XC. fig. 1, 2, LXXXIX. fig. * [ ~ 194, note 20.] For full details on the branch- " 2. That the branchiae in all species are comialvessels of Teredo, and beautifully illustrated, posed of straight parallel vessels returning uloa. see Deshayes, loc. cit. p. 69, P1. VII. and Quatre- themselves. fages, Mimoire, loc. cit. p. 57, P1. II. See also "3. That the heart is systemic and not branchial. Williams, On the Structure of the Branchiae and "4. That the parallel vessels of the gills are Mechanism of Breathing in the Pholades and other provided with vibratile cilia disposed in a linear seLamellibranchiate Mollusks, in the Report of the ries on either side of the branchial vessel, causing Brit. Assoc. for the Advancem. of Sc. for 1851, p. 82, currents, which set in the direction of the current His first four conclusions are: of the blood in the vessels." - ED. " 1. That the blood of all ]amellibranchiate mollusca is richly corpusculated. I, 19J6. THE ACEPHALA. 218 work of nluch slniilel canals is seen expanded between and above them, and which can be oily the blood-canals that were already visible before inflation.(6" But the existence with these animals of a double system of lacunae having this interpretation, is attended with many difficulties. For then it must be admitted that one of these systems contains only water, and the other blood; and it is difficult to understand how two kinds of wall-less canals can traverse the body without passing into each other. But then, on the other hand, if the aquiferous canals are regarded as veins, and the other canals as arteries, how can this be reconciled with the fact that, in this case, the blood system would open externally and the blood escape through the natural orifices, while the water would be mixed with it from passing into the body?(7) At all events, this portion of the organization of these animnals still requires a more thorough investigation. CHAPTER VIII. ORGANS OF SECRETION. ~ 196. The relations of the mantle to the secretion of the shell-substance and the byssus-forming organ, have already been spoken of.() It now only 11) has given very beautiful figures of the aquifer- 1 See above ~~ 174, 179. According to Deshayes, ous system of the mantle and foot of Pecten, Pin- Teredo has, at the anterior extremity of the body, ~a, Solen and Mactra, but has regarded it as a a gland concealed between the valves and which Rete lymphatico-vasculoszum. 3Milne Edwards communicates with the mouth of the animal. Its (Compt. Rend. XX. p. 271, or Ann. d. Sc. Nat. III. product would serve to dissolve the wood in which 1845, p. 300, or Froriep's neue Not. No. 733, p. this animal bores. This glandular apparatus 99), who has seen these canals in Pinna, Mactra, which, according to Deshayes exists also with Ostrea, &c., regarded them simply as a system of other Teredina which live in calcareous matters, lacunae common to all the Acephala. demands a further examination; see Comp. Rend. 6 I have seen it thus, at least with Unio, and XXII. p. 38, 300, or Froriesp's neue Not. XXXVII. Anodonta. p. 324, XXXVIII. p. 103.* 7 Delle Chiaje (Descriz. &c. III. p. 53) thinks that, with the Lamellibranchia, the sanguineous system opens externally through special orifices. r[~ 196, note 1.] The means by which the bodies are highly refractive, and are for the most Teredina penetrate the woody or stony substances part pretty regularly distributed over the whole conin which they live, have received some investiga- vex surface of the foot, but are occasionally congretion of late, and I refer here to the subject from its gated in masses." This author thinks that this, as alleged anatomical relations. also all other boring Mollusks, excavate by means According to Hancock (Proceed. Brit. Assoc. of these parts which rasp down the substance to be for the Advancem. of Sc. 1848, or Ann. of Nat. removed. See as corroborative of these views, Clark Hist. 1848, II. p. 225, P1. VIII. or Silliman's Ann. Nat. IIist. 1850, v. p. 6. But naturalists Amer. Jour. of Sc. 1849, VII. p. 288), " On a mi- are not agreed on this point, and however it may nute examination of the surface of the foot of Te- be with Teredo, yet with Pholas, other observers redo IYorvegica it is found under the microscope have failed to find these rasping particles in questo be crowded with minute brilliant points which, tion; see a report on the discussion of Hancock's on being compressed, consist of comparatively paper in the Athenaeum No. 1086; also Quatrelarge crystalline bodies imbedded within them. fages, Mimoire sur le Genre Taret, Ann. d. Sc. These crystals are numerous and of various sizes Nat. 1849, XI. p. 33, and History of British Moland shapes, chiefly five and six sided, but not by lusca by Forbes and Hanley, p. 105. any means regularly so. They all agree in having After all, it would seem that it is most probable one or more elevated points near the centre. These that this process is effected by the action of cilia 214 THE ACEPHALA. t 19G6 remains to notice a very remarkable organ found in all the Lamellibranchia, and known as the Gland of Bojanus. This organ, undoubtedly of a renal nature, is always double, and consists of a large long sac with glandular walls, and of a dirty-yellow or darkgreen color. It is situated each side of the back between the pericardium and the inferior adductor muscle, and extends usually upon the sides of the abdomen to the base of the branchiae. Quite often these glands are united upon the median line of the back - their cavities being separated only by a thin septum. They communicate with the cavity of the mantle by two small openings which have swollen borders and are situated sometimes at the upper, and sometimes at the lower end of the sac.(2) The usually very thin walls of these two sacs have numerous folds or plicae, which form compartments or areolae, all of which are covered with. a very delicate ciliated epithelium. The parenchyma of these walls is composed of a very loose tissue, which, upon the least disturbance, sepa-. rates into small granular cells.(3) Most of these cells, contain a blue-black. round nucleus, to which is due the more or less deep color of these organs. (4) 2With Unio, and Anodonta, these orifices are that by spreading apart the branchiae, the comat the superior extremity of the renal sacs close partments and cells of these glands can be distinctbeside the two genital openings; see Bojanus, Isis, ly seen; see Treviranus. Beobacht. aus d. Zool. u. 1819, p. 46, Taf. I. fig. 1; Baer, in Muller's Arch. Phys. p. 51, fig. 68, b.* 1830, p. 319, Taf. VII. fig. 1, 2; Pfeiffer, Natur- 3 It is only recently that the intimate structure gesch. deutsch. Land-und Susswasser-Mollusken, of these organs was known..Yeuwyler was quite Abth. II. Taf. II. fig. 19, b.; and- Neuwyler, in mistaken in regarding them as two testicles (loc.. the Neue Denkschr. VI. p. 22, Taf. I. II. They cit. p. 25). He speaks of tubes in which he affirms lie in the angle formed by the abdomen and the in- that he has seen spermatic particles, but he gives ternal branchiae, and concealed beneath the inter. neither a detailed description nor a figure of one nal leaf of these last. They had already been ob- or the other. I have never been able to find served by Poli (loc. cit. I. p. 6, Tab. IX. fig. 15, anything of this kind in the Lamellibranchia. If i. i.), who, however, did not recognize their true the walls of these organs are prepared in any way nature. for microscopic examination, a part of their parenWith Pecten, and Spondylus, these renal sacs, chyma separates into a vesiculo-granular mass, which are situated in front of the adductor muscle, the particles of which have a very lively dancing have their two orifices at the lower extremity; see motion. The motions are due to portions of ciliated Garner, Trans. of the Zool. Soc. loc. cit. P1. XIX. epithelium adhering to the cells and granules. It fig. 2,j. (Pecten). is in this way, probably, that Neuwyler has been With many, the genital organs open into the deceived, taking these moving bodies for spermatic urinary ones. This is so according to Garner (loc. particles. cit. p. 92), with Tellina, Cardium, Mactra, Pho- 4 These round nuclei, usually of a deep brown or las, and Mya. I have very distinctly seen with blue color, can easily be seen in the kidneys of Pinna nobilis, the two orifices common to the kid- Unio, Anodonta, and Cyclas; but with the young neys and genital organs. Their borders were individuals their number and size are quite limited, swollen, and they were situated upon the anterior making the kidneys very pale. They resemble, surface of the dorsal wall a little in front of the moreover, perfectly the bodies contained in the posterior adductor muscle. They opened into a renal substance of the Gasteropoda (see below). very large sac with thin walls which had no gland- This analogy is particularly striking with Asperular structure except at their lower extremity gillum vaginiferum, whose renal sacs are trinear the principal adductor muscle * see Poli, loc. angular and situated between the heart and the cit. Tab. XXXVII. fig. 2, D. extremity of the rectum, thus resembling in all reThe genital orifices open into the two sacs di- spects the kidneys of the Gasteropoda, although rectly back of these external orifices. With Myti- Leuckart has taken them for the liver (Neue. wirlus edulis, the kidneys have a yet more singular bellose Thiere d. roth. Mleeres, loc. cit. p. 46, Taf.. arrangement; their two sacs situated at the base XII. fig. 6, g.). of the branchiae are open their whole length, so alone. This would seem inefficient did we not re- * ~ 196, note 2.] According to Frey and, member their unceasing action; and this view is Leuckart, the bodies of Bojanus are absent in the only one which will explain the exact conform- Teredo navalis, but these observers think the kidation of the excavation to the shape of the body in neys are present in another part of the body; see all its parts. It is the view of Agassiz, and others, loc. cit. p. 46. - ED. who have specially examined the subject. I have here thus noticed the matter in a suggestive point of view for microscopical anatomists. - ED. e 197. THE ACEPHALA. 215 These nuclei are very solid and ought to be regarded as the secreting bodies. They are sometimes so large as to be visible to the naked eye as inorganic concretions, and, as they contain uric acid, they may well be compared to renal calculi.(5) The walls of these kidneys are surrounded by a distinct net-work which arises from the large venous reservoir in which the afferent blood of the body is accumulated. A small portion of the blood which circulates in the kidneys passes directly to the heart; but the rest is emptied into the pulmonary arteries.(6) CHAPTER IX. ORGANS OF GENERATION. ~ 197. The Acephala throughout, propagate by genital organs. With the Tunicata only, is there also observed multiplication by gemmation. This occurs with the compound and some of the simple Ascidiae, which remind one of the Zoophytes and more particularly the Polyps, which they resemble from other conditions of the organization. The buds are always developed at the lower extremity of the body, appearing first as small pyriform projections, covered by the general envelope of the mantle, into which the circulation is prolonged. Gradually,an Ascidian is developed upon the round summit of this projection, while its peduncle is lengthened and somewhat constricted; this continues until the body of the new individual is entirely separated from 5 Similar concretions had already been seen and aside from the fact of their containing uric acid described with several of the Lamellibranchia by (Garner, Trans. of the Zool. Seoc. loc. cit. p. 92, and Poli, who has regarded the kidneys as organs for Owen, Lect. on Comp. Anat. &c. p. 284), a point the secretion of the lime of the shell; see his classic upon which I was noebefore satisfied. work, Introductio, p. 18, also Tom. II. p. 86, The chemical composition of these concretions, Tab. XX. fig. 4, 6, k, fig. 12, 13 (Cytherea chio), however, satisfies me that these organs are truly p. 143, Tab. XXVI. fig. 11, 12, 13, y. (Pectun- kidneys. culus pilosus), and p. 241, Tab. XXXVII. fig. 5, 6 This is the mode of circulation of the blood 6, 3, D- (Pinna nobilis). through the kidneys,according to Bojanus, loc. cit. These concretions were irregular and of a red or But the opinion of Treviranus is different. Acyellow color. I have recently found, in several in- cording to him all the blood returning from the dividuals of Pectunculus pilosus, amber-colored branchiae traverses the glands of Bojanus before concretions, mostly round, of variable size, giving reaching the heart (Beobacht. aus. d. Zoot. &c. p. these two organs the appearance of a fish's ovary 49). As these organs are not easily found, it will filled with eggs. Having collected a considerable be difficult to determine this point positively by quantity of these concretions, I sent a part of them direct observation. It is only by following analogy to Herrn Von Babe of this city, who has favored that Bojanus' opinion can be probable in its essenme with their qualitive analysis. The result was tial point, - which is, that if the glands of Bojanus that those with a conchoidal fracture were com- are the analogues of the venous appendages of the posed principally of phosphate of lime with a trace Cephalopoda, and of which I am persuaded with of magnesian phosphate, and a small quantity of Van der Hoeven (Meckel's Arch. 1828, p. 502) is organic matter which behaved with nitric acid ex- the case, then they connect with the veins which actly like uric acid. Notwithstanding Bojanus go to the branchiae, and not with the arteries which (Isis, 1819, p. 46, 1820, p. 404) has taken much go from the branchiae to the heart. pains to prove that these organs are pulmonary, The blood-current in the glands of Bojanus, yet the view that they are kidneys has found most therefore, ought to pass towards the branchiae and support (Treviranus, in Tiedemann's Zeitsch. f. not towards the heart. Phys. I. p. 53, and Carus, Zoot. 1834, II. p. 650), '216 THlE ACEPIHALA. ~ 198. -that of the parent, and the envelope of the mantle alone is common to both.'1 ~ 198.s. With the Acephala, the sexes are sometimes separate, sometimes united in one individual. But the genital organs are very fully developed, and, as with the Zoophytes, consist of an ovary and a testicle with an excretory duct; but in none are there copulatory organs, or uterine reservoirs for the:eggs. The eggs are usually spherical, rarely pyriform or elliptical. The pale yellow or reddish vitellus is finely granular, and surrounded with a vitelline membrane and a smooth colorless chorion. The germinative vesicle has usually two nucleoli cemented together. Often there is a layer of white substance interposed between the chorion and the vitelline membrane.(l) The sperm is milky, and, at the epoch of procreation, quite full of very active spermatic particles. These always consist of an oblong, oval, or pyriform body, to which is abruptly attached a delicate tail, whose motions are not affected by the water in which these animals live.(2) With the Acephala of separate sexes, the ovaries and testicles so closely resemble each other, not only as to their form and the arrangement of excretory ducts, but also as to their locality in the body, that they are with difficulty distinguished each from the other, except at the period of procreation. The copulatory organs being absent, here, as with the Zoophytes, the water is the fecundating medium. 1 This multiplication by buds has been observed 2 The spermatic particles of the Acephala have'by Milne Edwards with Botryllus, Polyclinum, been described and figured by Wagner, in WiegAmaroucium, Didemnum, and Perophora. It mann's Arch. 1835, II. p. 218, Taf.-III. fig. 8 occurs also, undoubtedly, with other compound (Cyclas); Siebold, in Miiller's Arch. 1837, p. Ascidiae, and is the cause of the increase of the 381, Taf. XX. fig. 12-14 (Unio, Anodonta, MyAscidian-stock with the colonies of these animals. tilus, Tichozonia, Cardium, Tellina, Mya and With the simple Ascidiae- Clavelina lepadifor- Cyclas); Kslliker, Beitrage, loc. cit. p. 37 (Pho-.mis, and producta, the buds take the form of las), and Krohn, in Froriep's neue Not. No. 356, suckers (Stolones), and the new individuals are p. 49, 52 (Phallusia and Salpa). Those of Ainaseparated from their parents with the separation of roucium described by Milne Edwards (loc. cit. p. the mantle; see Milne Edtvards, Sur les Ascidies 21, P1. III. fig. 1c.) differ from the usual type in compos6es, loc. cit. p. 41, P1. III. fig. 20. (Ama- being fusiform and very long, - their tail not being Youcium proliferums), P1. VII. 1, Ib. 1c. (Bo- distinct from the body. Those of a Cynthia have trylloides rotifera), and PI. II. fig. 1o. 3 (Clav- appeared to me of a similar form, - only the tail elina), Eysenhardt (Nov. Act. Acad. Leop. Carol. was much longer and more delicate. With PhalXI. p. 263, Tab. XXXVI. fig. 1, &c.), has also ob- lusia, on the contrary, I have distinctly seen them:served these stolons upon a simple Ascidian. with an oblong body to which is abruptly attached I These eggs have been figured by Watager, Pro- the tail. The sperm of Polyclinum, Botryllus, dromus, &c., p. 7, Tab. I. fig 5 * Carus, Erlauter- Didemneum, Diazona, and Phallusia, contains ungstafeln, &c., Hft. V. Taf. 1, fig. 2, and Nov. Act. spermatic particles of a Cercaria-form; while those Acad. Leop. Carol. loc. cit. p. 26, Tab. I. (Ano- of Salpa are filamentoid; see Ktlliker, Neue Jdonta and Unio), and by Mine Edwards, Sur les schweiz. Denkschr. VIII. p. 43, fig. 30, 49, 53-57.* Ascid. comp. p. 25, PI. IV. fig. 1-3 (Amaroucium). * [ 198, note 2.] The spermatic particles of particle I have found to differ widely, yet in each.the Acephala throughout, are according to my own case to present an uniformity of a zoological value. observation, of a Cercaria-like form, - that is, hav- Sometimes it is perfectly globular (Polyclinum), ing a distinct head to which is attached a more or sometimes oval (Unio, Anodonta), sometimes ovoless delicate tail. Their development, which I globular (Ostrea), sometimes oblong (Ascidia), have traced in many cases, is in special, daughter- sometimes pyriform (Mytilus), sometimes conicocells as with all other animals. They may, as pyriform (Mya), and sometimes long-conical (Cy indeed they often do, assume various groupings prina). These forms may seem a refinement more -afterwards, but the real development appears sim- ideal than real, but the exact forms are determined gple and invariable. The shape of the head of the by micrometrical measurements.- ED. $ 199. THE ACEPHALA. 21T ~ 199. The genital organs of Salpa are yet quite imperfectly known. They cannot be found except at the procreative period, and in a very few species only Ovaries have been discovered. These consist of two flexuous zigzag cords, situated each side of the median line of the back, between the mantle and peritoneum. Sometimes they are prominent from their violet color.(') The young are always developed near the nucleus, in a cavity circumscribed by the peritoneum, but it is yet not determined whether it communicates with the ovaries by -an oviduct, and whether it has distinct walls, so as to be comparable to an,uterus. As to the Male genital organs, we are yet in almost complete want of Teliable researches. From a single observation, it would appear that there is a testicle con-,cealed in the nucleus, between the coils of the intestine, and communicat-ing,near the anus,with the cavity of the body.(2) But this still leaves it -uncertain whether these animals are hermaphrodites or of separate sexes.(3) The Ascidiae are evidently hermaphrodites, for the male and female organs, varying as to number and position, are found upon one and the -same individual between the walls of the muscular and branchial sacs. With the compound forms, as well as with many of the simple ones, the long, compact and usually yellowish ovarian mass is situated at the base sf the cavity of the body. From this there arises a large thin-walled oviduct lined with ciliated epithelium, which ascends along the rectum towards the anal tube and opens into the cloaca through a papilla. Along its side and often beneath it, there is another long mass, which is evidently, from its contents, a testicle. It has a narrow and very tortuous Vas deferens filled with sperm, which runs parallel with the oviduct to its very extremity. (4 Cynthia presents a remarkable exception in this respect. The gen1 These two ovaries have been most thoroughly with Salpa pinnata, lies along the intestinal canal, observed with Salpa pinnata, see Forskal, Des- is a Vas deelrens. crip. in itinere orient. observ. p. 13, Tab. XXXV. 3 At all events, the question needs careful examB. be, 4 Cuvier, loc. cit. p. 12, fig. 1. 2, tp; ination, whether both the simple and the compound 4Chamisso, loc. cit. p. 6, fig. 1 Delle Chiaje, Me- forms of Salpa have male organs, or only one of,mor. &c. III. Tav. LXV. fig. 8, h.; Meyen, loc. them. In this last case, these animals would have icit. p. 399, Tab. XXVII. fig. 1, 21, f.; and the some resemblance to the Aphides. Sars (loc. cit. Catal. of the Phys. Series, &c., I. P1. VI. fig. 1-4, p. 77) having declared that the solitary individ-. Cuvier (loc. cit. p. 22. fig. 8) has also observed uals of Salpa are sexless, then the aggregate inditwo ovaries with Salpa cylindrica. It must also viduals ought to be considered as representing the,be added here that, according to Forskal and Cha- perfect state of these animals; but as yet ileither.misso, there are two violet ovaries, with Salpapin- this author, nor Krohn (Froriep's neue Notiz. XL.,nata both in a simple and an aggregated form. p. 151, and Ann. d. Sc. Nat. 1846, VI. p. 110) have 2 It was Krohn (loc. cit. p. 52) who recognized. been able to show the existence of ovaries in these with Salpa maxima a round testicle in the centre animals. At least these two naturalists pass in of the nucleus. It was composed of numerous silence the violet ovarian striae of.Salpa, mentioned:seminiferous delicate canals filled with a white sem- by other observers. inal liquid, and opening by a short canal into the 4 Cuvier and Savigny have known, and often natatory cavity. This testicle is probably the same figured the female organs of the Ascidiae. Those organ that Delle Chiaje (Descriz. &c. III. Tav. of both sexes have been figured by Milsne Edwards LXXVIII. fig. 4, d.) has described as an ovary. (Observ. sur les Astid. comp. p. 21, Pl. III. fig. 1, The assertion of MIeyen, on the other hand (loc. 2A. II. fig. 1, 3) with Clavelina, Amaroucium, -cit. p. 397, Tab. XXVIII. fig. 5-10), that a coni- and Polyclinum. The testicle of Plhallusia and,cal organ which, with Salpa mucronata, is situ- Rhopalaea is quite peculiar. It consists of a white.ated in front of the cervical ganglion, belongs to multiramose canal widely spread over the hepatic the male genital organs, is unfounded and cer- layer of the intestinal canal i while the ovary altainly incorrect. But the observation of Krohn, ways lies in a loop of the intestine; see Delle Chion the contrary, gives support to the opinion aje, Memor. III. p. 192, Tav. X.LV. fig. 16, i.,and of Delle Chiaje (Mem. &c. III. p. 62, and De- DIescriz. &c. III. p. 27, Tav. LXXXII. fig. 13,,scriz. &c. III. p. 42) that this white canal which, LXXXIV. fig. 1, i. (Phallasia intestinalis and 19 218 THE ACEPHALA. g~ 99. ital organs are situated upon both sides of the body between the branchial membrane and the muscular wall with which they are intimately blended. They form, sometimes several round or angular projections divided into two groups, and sometimes four long crests whose four distinct secretory ducts open, after a short course, into the space included between the branchial membrane and the muscular sac, at a variable distance from the anal tube.~~ With the Brachiopoda, ovaries only have as yet been found. These surround the liver, and stretch upon both valves of the mantle around the minute branches of the branchial vessels. (6 With the Lamellibranchia, there are both hermaphrodites and separate sexes. But the last are much the more common; for the first have as yet been confined to Cyclas,() Pecten,() and Clavagella.~() The testicles and ovaries lie directly behind each other on each side of the body, between the liver, intestine, and kidney. Their excretory ducts have not yet been satisfactorily made out; all that has been observed, is, that with Cyclas, the eggs pass between the lamellae of the base of the external branchiae, and, being here developed, produce sac-like swellings.~101 With those species which are of separate sexes,~) the two ovaries or testicles are situated usually in the sub-hepatic region of the abdomen. mentula). The same arrangement has been ob- danica, I. p. 4, Tab. 5, fig 1, 7) of those of an Orserved by Krohn (Froriep's neue. Not. No. 356, p. bicula is very beautiful; while that of Poll is not 49) with the testicle of Phallusia, and by Philippi as good (loc. cit. II. p. 191, Tab. XXX. fig. 19, with that of a Rhopalaea (Miller's Arch. 1843, p. 20). 48, Taf. IV. fig. 9). 7 For the hermaphroditism of this genus see my 5 Carus has distinguished, with acuteness, from memoir in Miiller's Arch. 1837, p. 383. the ovarian group, as being a testicle, a collection 8 According to Milne Edwards (Ann. d. Sc. of projecting angular glands lying with Cynthia Nat. XVIII. 1842, p. 322, PL. X. fig. 1), with microcosmus, upon the internal surface of the Pectenglaber, the male gland is situated at the muscular sac (Meckel's Arch. II. 1816, p. 577, upper, and the female gland at the lower part of Tab. II. fig. 1, 2, &c.- and, Nov. Act. -Acad. loc. the abdomen, The two orifices found at the base cit. Tab. XXXVII. fig. 1, 2, k. k.). Savigny of the groove of the byssus belong to the testicles. also (loc. cit. p. 92, P1. VI. fig. 2, 3) has seen with With another species of Pecten which I have exCynthia microcosmus, and pantex, two glandu- amined, I was unable to confirm this hermaphrolar groups with their excretory ducts as the sexual ditism, for I found in the abdomen only either organs, but without determining that one of these testicles or ovaries alone. Moreover the orifices was a testicle; while Cuvier (loc. cit. p. 28, PI. I. just alluded to, appear to me to belong to a gland fig. 3. d. d.) who has observed the testicular secreting the byssus; see above ~ 179, note 4. group with Cynthia microcosmus, did not know 9 With Clavagella, Krohn found the testicles what to call it. According to Delle Chiaje (Me- beneath the liver, while the ovary surrounded it mor. &c. Tav. XLV. fig. 2, h. h.), the genital or- and the stomach (Froriep's neue Not. No. 356,. gans of Phallusia phusa consist of numerous gland- p. 52). ular projections united into two groups, and hav- 10 These pouches, which, with Cyclas, contain; ing two distinct excretory ducts. With Cynthia but a single egg, have been figured by Carus (Erlcanopus, the genital glands lie upon four long iuterungstafeln, Hft. III. p. 10, Taf. II. fig. 2b. 3) crests, from the upper extremity of each of which after Jacobson. passes off an excretory duct towards the anal tube 11 Leeuwenhoek (Contin. arcan. natur. detec. (Savigny, M6m. loc. cit. p. 96, P1. VIII. fig. 1l, Lugd. Batav. 1722, Epist. 95, p. 16) had already 22). With Cynthia papillata, there are two of distinguished male and female individuals with these crests curved in a loop-like manner. (Savig- certain Lamellibranchia. Notwithstanding this, ny, loc. cit. p. 92, P1. VI. fig. 41, 42, or Delle he afterwards affirmed that all these Mollusks Chiaje, Memor. III. p. 191, Tav. XLVI. fig. 1, 1. 1. were exclusively females,- an opinion still enand Descriz. &c. III. p. 27, Tav. LXXXII. fig. 11,. tained by some naturalists (see Deshayes, in the h. h.). From the two extremities of each of these Cyclop. Anat. I. p. 700, and Garner, in the passes off an excretory duct; and in comparing Trans. of the Zool. Soc. II. p. 96). I had, however, this arrangement. with that of Cynthia canopus, several years before, shown that the sexes were it might be inferred that this loop-like disposition is separate with Unio, Anodonta, Mytilus, Tichodue to the fusion of two glandular crests. As to g-onia, Cardium, Tellina, and Mya (Miiller's which of these crests are ovaries and which testi- Arch. 1837, p. 380). The fact has been concles, it would appear from Krohn (Froriep's neue firmed by Milne Edwards (Ann. d. Sc. Nat. Not. No. 356, p. 50) that all are ovaries, for he has XIII. 1840, p. 375) with Venus, by Owen observed, with a species perhaps identical with (Lectures, &c., p. 287) with Anomia, and by KelCynthia canopus, near the four oviducts, four other liker (Beitrage, loc. cit. p. 37) with Pholas. I can excretory ducts not easily seen, and which, as Vasa also add to this list, Area, Pectunculus, and deferentia, arise from the ramified seminiferous Lithodomus. I have already mentioned (6 196, tubes spread out over the ovaries. note 3) how Neuwyler, in taking the ciliary mo6 For the ovaries of Terebratula and Orbicula, tions for those of spermatic particles, regarded the see Owen, loc. cit. The figure of Miiller (Zool. kidneys of Anodonta and Unio as the testicles, 200. THE ACEPHALA. 219 They surround the coils of the intestine, and often ascend along the back, covering the liver with their folds. Their excretory ducts are lined with ciliated epithelium, and open each side of the bottom of the abdomen through a fissure with smaller borders, communicating either with the cavity of the mantle close by the renal opening, or with the renal sacs.1(2) With those species which have a very small abdomen, these organs are spread out by numerous ramifications into the substance of both halves of the mantle.(13) The two external branchiae serve, for the most part, the function of an uterus; for the eggs, having escaped from the oviduct, are lodged in their compartments, and, by the aid of the cilia covering the cavity of the mantle, receive the sperm which is introduced in the water for respiration.(14) The quantity of eggs thus accumulated is so great, that with Anodonta these organs are extraordinarily enlarged during the development of the young; and on this account the shells of the females of this genus are more convex than those of the males. In this way the sexes of these Naiades can be quickly distinguished from each other by the shell alone.,') ~ 200. Most of the Acephala undergo during their development, which always begins by a complete segmentation of the vitellus, a metamorphosis which is quite remarkable in many respects. Among the Tunicata, the embryology of the Ascidiae is the best known. An oval embryo follows upon the segmented vitellus,1l) and is quickly changed into a Cercaria-like larva.(2) The tail is not formed from a gradand therefore considered the Naiades as hermaph- the anal fissures under the form of oval discs rodites.* shaped like the branchial compartments. For a long 12 The genital and urinary openings are contigu- time it was inexplicable how the eggs should alous with the Naiades; see above ~ 196, note 3, and ways pass exclusively into the external branchiae, Neumann, De Anodontarum et Unionum oviductu. when the cavities of the internal ones were so Diss. Regiomont. 1827. This is the same also with much nearer the genital orifices. But Baer Tichogonia; see Van Beneden Ann. d. Sc. Nat. (Meckel's Arch. 1830, p. 313) has shown that VII. 1837, p. 128. With Pinna nobilis, I have their route is circuitous; they glide along the base found the genital orifice close behind those of the of the internal branchia to the cloaca, they then renal sacs. According to Garner (loc. cit. p. 92), ascend by a special canal of the mantle and pass a similar arrangement exists with Tellina, Car- into the external branchiae. This course is the more dium, Mactra, Pholas, Mya, and Pecten. The easily understood from the ciliated structure of two genital orifices which Valenciennes (Arch. these organs. Will (Froriep's neue Not. No. 620, du Mus. &c. I. P1. II. fig. 5) and Delle Chiaje p. 57) affirms that with Tellina the sperm of the (Descriz. &c. III. Tav. XC. fig. 2) have seen at the males is evacuated in an analogous manner through lower end of the abdomen of Panopaea and Solen, the anal tube, and being there taken up by the belong probably also to the urinary system. females through their respih'atory tube is conducted 13 Mytilus.(Poli, loc. cit. II. p. 202, Tab. XXXI. to the external branchiae. fig. 3), Anomia, Hiatella, Modiola, and Lithodo- I have also found embryos within the branchiae mus (Garner, loc. cit. p. 97). With Lithodonmus of Teredo navalis. dactylus, I have, however, always found the abdo- 15 At present, this difference in the convexity of men filled with testicular or ovarian masses. the valves appears to me to exist only with Ano14 It is with the Naiades that the branchiae as donta (Wiegmann's Arch. 1837, I. p. 415); but reservoirs of eggs, are best known; see Poli, loc. Kirtland (Ibid. 1836, I. p. 236) has succeeded very cit. I. p. 5, Tab. IX. fig. 18; Pfeiffer, loc. cit. wellin distinguishing, by this character, the males Abth. II. p. 11, Taf. II. fig. 16-18; Carus, Nov. and females of Unio, of North America. Act. Acad. &c. p. 17, Taf I. fig. 8 i and NVeu- 1 The complete segmentation of the vitellus has wyler, loc. cit. p. 18, Taf. III. fig. 14 (Unio and been observed by Milne Edwards (Sur les Ascid. Anodonta). While remaining in the compart- &c. p. 30, P1. IV. fig. 1-4) with the eggs of Amaments of the branchiae the eggs are slightly glued roucium. together. With Unio, they often escape through 2 These Cercaria-like foetuses had already been * [ ~ 199, note 11.] The hermaphrodite character this article in the Proceed. Amer. Assoc. Advancem. of the Naiades has recently been urged, and Kirt- of Sc. 5th meeting, Cincinnati, 1851, p. 85. I have land's marks of the different sexes by the shape of examined this subject with some care by the microthe shell called in question; see article Zoology in scope, and have satisfied myself from an analysis the Iconographic EncyclopAdia, edited by Spencer of the contents of the organs that the genera in F. Baird, p. 70. But see Kirtland's criticism of question are of separate sexes. - ED. 220 THE ACEPHALA. ~ 200. iual elongation of the posterior part of the body of the embryo, but is produced by the fusion of a series of globules which result from the vitelline segmentation. These globules lie upon the surface of the embryo and, in their separation from it, assume a tail-like body which is folded in front, and only latterly is extended out behind. With some of the compound forms, it forms also two eye-specks upon the back of the larva.() At this period of development the eggs are still in the cloaca, or perhaps have been discharged through the anal tube. Subsequently, the embryos rupture their shell, and then swim freely about by means of their very active tails. Soon after this, the larvae are completely surrounded by a transparent structureless envelope, which ultimately becomes the mantle. They are then fixed by their anterior extremity, -lose their tail and assume their adult form.(4) With the compound forms, before the larvae have become fixed and deprived of their tails, numerous button-like prolongations arise from the anterior extremity and extend into the mantle; these, after the fixation of the embryo, are changed into as many individuals.(5) The development of the Salpae has yet been incompletely observed, for its earlier conditions have received no attention. But the later ones present very curious phenomena. In the first place, it is quite remarkable that the two forms of these ani. mrals which are always viviparous, produce young wholly dissimilar. The solitary individuals produce others joined together in a chain-like manner,(6) while these last give rise again to the solitary forms. But in neither case do the embryos undergo a metamorphosis. This chain of individuals is usually composed of two rows joined together by several cords and enveloped in a common membranous tube. The individuals at the anterior extremity of this tube are the more developed,- there being a gradation in this respect to the posterior extremity, where they appear only as simple punctiform bodies. This tube usually surrounds also the nucleus of the parent, into the cavity of whose body its anterior extremity often widely observed by Savigny (Mdlm. &c. PI. XI. fig. 23, 4 For the development of a simple Ascidian, see PI. XXI. fig. It.) with Clavelina and Botryllus. Dalyell, loc. cit. Subsequently they have been described by Au- 5 According to Milne Edwards (loc. cit. p. 30), dotsin and Milne Edwards (Ann. d. Sc. Nat. these aninals use these processes like suckers to fix XV. 1828, p. 11) Sars, Beskrivelser, &c., p. 69, themselves. But this is contradicted by the obserP1'. XII.), and Dalyell (Edinb. new Philos. Jour. vations of Kslliker, and Van Beneden.* Jan. 1839, p. 153). Latterly Milne Edwards (Sur 6 T1lis mode of propagation first described by Chales Astidies, &c., loc. cit.) has furnished an exact misso (loc. cit.), has been doubtedl by Eschricht, embryology of these Ascidians, but which has been who thinks that the young Salpae produce solitary completed by Van Benedesn (31dm. sur l'embryog. foetuses, while those of a more adtvanced age prol'anat. et la physiol. des Ascid. loc. cit.), and by duce the aggregated form. But, as Steenstrup (UeKolliker (Ueber das Vorkommen der Holzfaser im ber den Generationswechsel, p. 36), has justly obThierreich loc. cit.). served, there is no observation to support this view. [Additional note.] The memoirs cited above The alternate generation of theSalpae, as first hlave since been published, that of Van Beneden described by Chamisso, has been confirmed in all in M1m. de l'Acad. de Bruxell. XX. 1847, PI. II. particulars by Sars, and Krohn (loee. cit.). It is howIII.; that of Kblliker in Ann. d. Sc. Nat. V. 1846, ever, singular that, according to Krohn, the single 217, P1. YTI. egg of the aggregate Salpae is formed in an ovary, 3'Amaroucium and Aplidium, according to while the whole development of these same animals KIlliker, and as confirmed by Van Beneden. when solitary occurs from an internal gemmation. * [ ~ 200, note 5.] The embryology of the Ascidiae published; the published portion (loc. cit.) refers has been followed out by AXassiz (Proceed. Amer. more particularly to the formation and intimate Soc. for the Advancem. of Sc. 2d meeting, 1849, structure of the egg. Those of Krohn are chiefly Cambridge, p. 157): and by Krohn (Miller's Arch. confirmatory of those of Edwards and other ob1852, p. 312). The observations of Agassiz are servers above mentioned. - ED. complete throughout, but unfortunately not yet all 200. THE ACEPHALA. 221 extends, while its opposite end appears attached near the nucleus to the dorsal portion of the walls of the body. (7) The solitary individuals, which are produced by the chain-like forms, are also developed near the nucleus, and adhere quite singularly to the dorsal wall of the parent by a peduncle resembling an umbilical cord. These pedunculated embryos are always few in number, and have a proper vitellus. Often, however, there is only one.(8) It may be questioned, moreover, if these eggs are not gradually developed with their peduncle at their place of incubation, or whether they become fixed at this place after having been developed in, and separated from the ovary. At least, one might almost think that, after all, this is only an internal gemmation. With the Lamellibranchia, the Naiades particularly, are those whose embryology has been observed. When the vitellus begins to segment, there are two superficial contiguous vitelline cells that do not participate in this process.19) These are gradually changed into two three-sided valves, while the remaining portion of the vitellus is transformed into a round embryo covered with cilia, which turns upon itself in the egg —being partly enveloped by the valves.(10) This rotatory movement, however, soon ceases, and the embryo divides itself into halves, each covered by a valve.("3) Each of these valves has a ciliated mouth near the hinge, and a proper intestinal canal. (12) InI the middle of the angle formed by these halves is raised a short, hollow cylinder, -- the byssus-forming organ, and out of which projects a very long transparent byssus.l3) (7) See the figures of Chamisso, loc. cit., of Qusoy and by Carus (loc. cit. p. 27), for they did not know and Gaimard (Ann. d. Sc. Nat. X. 1825, p. 226, of the existence of cilia. P1. VIII. fig. 3-6, and Voyage de l'Astrolabe loc. 11 This division of the embryo with valves often cit.), of Delle Chiaje (Descriz. &c. III. p. 42, Tav. lying entirely open, has perhaps led Rathkd LXXVI. fig. 1), and especially those of Eschricht (Schrivter af Naturhist. Selsk. loc. cit. p. 166, Tab. (loc. cit. p). 35, Tab. I. II. IV. V.). X. fig. 3), and Jacobson (Observ. sur le develop. (8) See Chamisso, loc. cit. fig. 1, D. 1, J. (Sal pretendu des oeufs des Moulettes ou Unio et des pa pinnata, with a very developed foetus), fig. 3, Anodontes dans leurs branehies, An. d. Sc. Nat. F. (Salpa zonaria with three button-like foetuses XIV. 1828, p. 22, and De Blainville's report upon little developed), Qsuoy and Gaimard, Isis, 1836, this work) to regard the young of Naiades for Taf. VI. fig. 12 (Salpa pinnata, with a very large parasites, under the name of Glochidium parasitifoetus), and Ann. d. Sc. Nat. loc. cit. P1. VIII. cuen. See also the works of Carus (loc. cit.), and fig. 7-9 (Salpa microstoma, with four button- of Quatrefages (Sur la vie interbranchiale des like foetuses); Meyen, loc. cit. p. 399, Tab. petites Anodontes, Ann. d. Sc. Nat. IV. 1835, p. 283, XXVII. fig. 9-16 (Salpa pinnata), Tab. XXVIII. V. 1836, p. 321, P1. XII.). fig. 1, 2 (Salpa mucronata), Tab. XXIX. fig. 1. Loven informs us that the young of Modiola, h. (Salpa antarctica), fig. 2-4 (Salpa maxima); and Kellia are formed upon a wholly different Eschricht, loc. cit. p. 65. fig. 27, q. 36 (an individ- type. Their two Halves, which are only slightly ual from the chain of Salpa cordiformis contain- separated, are overlapped by two lobes (as Maning five, isolated, pedunculated foetuses; perhaps tle?) which are everted and provided with very here should be mentioned the five pedunculated active vibratile cilia; the young swim by means bodies which he (p. 39, fig. 18, p. 23) has de- of these lobes (Arch. skandinav. Beitr. zur Naturscribed and figured with Salpa zonaria); finally gesch. Th. I. p. 155, Taf. I. fig. 9-11). I also have Delle Chiaje, Descriz. &c. loc. cit. Tav. LXXVIII. observed with Teredo navalis, the embryos swimfig. 3 (Salpa maxima, with a pedunculated body), ming freely about by means of a foot-like organ and fig. 8, 13 (Salpa scutigera, with a developed which protrudes between the valves and presents foetus\. an active ciliary movement. 9 These may be easily distinguished with Unio 12 Quatrefazes, loc. cit. P1. XII. fig. 20. and Anodonta, a clear nucleus in each segmented 13 Quatrefages (loc. cit.) has figured with division of the vitellus. Carus (Nov. Act. Acad. each embryo two byssus-organs out of which prop. 43, Tab. II. fig. 1, 3, 10, 11) has seen the vitel- jects a double byssus. I have been unable to obline cells nucleated, but he thought that the eggs, serve this, and, like Carus, have always found a which contained the faceted cells out of which are single byssus-organ with a single byssus. ultimately formed the valves, were diseased and It is quite remarkable that not only the Naiades, dead. but other Lamellibranchia also, have this byssus10 This rotation of the embryo of mollusks had organ when quite young. Thus in the young of already excited the astonishment of Leeuwenhoek Cyclas cornea, I have distinctly seen a hollow (Continuat. arcan. nat. Epist. 95). Its cause was pyriform glandular organ in the foot, and from explained in a very unsatisfactory manner by which projected a long simple byssus. Home (Philos. Trans. 1827, pt. I. p. 39, or in Heu- The embryos of KCellia have also a byssus acsinger's Zeitsch. ffir organische Physik. I. p. 394), cording to Loven (loc. cit.). 19* 222 THE ACEPHALA. ~ 200. Internally, the embryonic halves have three tentacular, stiff points, whose bases are surrounded by collars. (14) Near the hinge a large muscle passes from one valve to the other; this, from convulsive contractions which occur from time to time, gradually approximates the valves, which are wide open when the young individual escapes from the egg. These valves are trigonal and slightly convex. One of their sides goes to form the hinge, while the two remaining, which are a little arched, unite at an angle opposite. With this angle is articulated a prolongation curved downwards and inwards, and whose convex side has several spines.(15 After their escape from the eggs, these embryos are held together by their entangled byssuses. Subsequently, when the adductor muscle has definitely closed the valves, the embryonic halves are blended together, probably by a new metamorphosis.* 14 Carus, loc. cit. Tab. IV. fig. 14. 15 See Rathke, Carus, and Quatrefages, loc. cit. * [End of ~ 200.] For the embryology of the 1848, p. 531, or in Wiegmann's Arch. 1849, Acephala with almost a profuseness of detail, see p. 312). This observer has observed with care Loven (Ofversigt af Kongl. Vetenskaps-Acad. the formation of all the organs and their muForhandlingar, 5te Argangen, 1848, Stockholm, tual embryonic relations; even the resumd is toe 1849, or its transl. into German in Miller's Arbh. lengthy to be here quoted. - ED. BOOK TENTH. CEPH ALOP HIORA. CLASSIFICATION. ~ 201. TaE organization of the animals composing this class is quite dissimilar; and, as in the preceding class there were species which approached the Zoophytes, so here there are those which are scarcely above the Worms. Thus, it is a question whether the genus Sagitta, which is placed at the head of this class, is really in its right place, although all the attempts to place it in another group have furnished results no more satisfactory. Then. again, it may be objected that the name Cephalophora should have been given to a class composed of the Pteropoda, Heteropoda, and Gasteropoda, since it belongs equally well to Cephalopoda; but I have adopted it for the sole reason of being unable to find a better.(') The sub-order Apneusta with its two families Anangia and Angiophora, has been established by Kdliker in opposition to the other Gasteropoda, which have distinct respiratory organs.(2) This division, composed of small and very interesting species, is the more admissible since it is based upon the anatomical structure of these animals; and also as the most recent investigations have shown that the term Phlebenterata used by quatrefages, is improper. ORDER I. PTEROPODA. Animals with natatory organs composed of wing-like or fin-like cutane ous lobes, symmetrically arranged upon the two sides of the body. 1 Meckel (Syst. der vergleich. Anat.) has al- He has placed these, with those which Quatre-:ready used this word in the same way. fages has described under the nanme of Phleben2 Kolliker has communicated to me a yet un- terata, in the division of Apneusta which he published work in which he has described, beside divides into two sections: 1. Angiophora, having Flabellina and Polycera, three new genera of the a heart and rudimentary vascular system. 2. inferior Gasteropoda, under the names of Acan- Anangia, without either heart or vessels. ~thina, Lissosoma, and Rhodope 224 THE CEPHALOPHORA. 201. FAMILY: SAGITTINA. Genus: Sagitta. FAMILY HYALEACEA. Genera: Hyalea, Cleodora, Cymbulia, Tiedemnania, Cuvieria, Creseis, Limacina. FAMILY: CLIOIDEA. Genera: Clio, Pneumodermon, Spongiobranchaea. ORDER II. HETEROPODA. Animals whose locomotion is performed by a carinated natatory apparatus situated under the abdomen and provided often with a sucker. Genera: Phiyllirrhoj, Pterotrachea, Carinaria, Atlanta. ORDER III. GASTEROPODA. Animals which creep by means of a muscular disc situated under thebody. SUB-ORDER I. APNEUSTA. Without distinct respiratory organs, and without a shell. FAMILY: ANANGIA. Genera: Rhodope, Pelta, Actaeon, Actaeonia, Lissosoma, Chalidis, Flabel — lina, Zephyrina, Amphorina. FAMILY: ANGIOPHORA. Genera: Tergipes, Venilia (Proctonotus), Calliopoea, Eolidina, Aeolis(Eolidia). SUB-ORDER If. HETEROBRANCHIA. The branchiae inserted more or less freely upon various parts of tha body. Sometimes there is a very simple patelliform shell. FAMILY: NUDIBRANCHIA. Genera: Scyllaea, Tritonia, Thetis, Doris, Polycera, Plocamophorus. FAMILY' INFEROBRANCHIA. Genera: Diphyllidia, Phyllidia, Ancylus. FAMILY: CYCLOBRANCHIA. Genera: Patella, Chiton. FAMILY: SCUTIBRANCHIA. Genera: Haliotis, Fissurella, Emarginula. 201. THE CEPHALOPHORA. 22. FAMILY: TECTIBRANCIIIA. Genera: Gasteropteron, Umbrella, Doridium, Bulla, Bullaea, Aplysia, Notarchus, Dolabella, Pleurobranchus, _Pleurobranchaea. SUB-ORDER III. TUBICOLAE. Animals which are enclosed, together with their branchiae, in simple slightly curved or irregularly flexuous tubes. FAMILY: CIRRIBRANCHIIA. Genus: Dentaliuzm. FAMILY: TUBULIBRANCIIIA. Genera: Vermetus, Magius. SUB-ORDER IV. PE C TINIBRANCHIA. Branchiae in a special cavity situated at the anterior part of the back. Shell regularly spiral. FAMILY: SIGARETINA. Genus: Sigaretus. IFAMILY: PURPURIFERA. Genera: Buccinum, Harpa, Cassis, Purpura, Eburnea, Terebra. FAMILY: CANALIFERA. Genera: Murex, Strut/iolaria, Tritoniurm, Turbinella, Fasciolaria. FAMILY: ALATA. Genera: Strombus, Rostellaria, Pterocera. FAMILY: CERITIIIACEA. Genus: Cerithium. FAMIILY: VOLUTACEA. Genera: Voluta, Olizva, Jlitra. FAMILY: INVOLUTA. Genera: Cypraea, Ovula. FAMILY: CONOIDEA. Genus: ConiUs. FAMILY: TROCI1OIDEA. Genera: Scalaria, Turbo, Trochus, Phasianella, Rotella, Littorina, Jan. thina. FAMILY: NERITACEA. Genera: Natica, Nerita. 226 THE CEPHALOPHORA. ~ 201. FAMILY: POTAMOPHILA. Genera: Rissoa, Paludina, Ampiullaria, Ceratodes, Valvata. SUB-ORDER V. PULMONA TA. FAMILY: AMPHIPNEUSTA. Genus: Onchidium. FAMILY: LYMNAEACEA. Genera: Lymnnaeus, Planorbis, Amphipeplea, Physa. FAMILY: HELICINA. Genera: Helix, Caracolla, Succinea, Bulimus, Achatina, Clausilia. FAMILY: LIMACINA. Genera: Lirnax, Arion, Testacella, Parmacella. FAMILY: AURICULACEA. Genus: Auricula. FAMILY: OPERCULATA. Genus: Cyclostoma. BIBLIOGRAPHY. Cuvier. M6moires pour servir a l'Histoire et. l'Anatomie des Mollusques. Paris 1817. A collection of monographs upon Clio, Hyalea, Pneurnoder. w.on, Tritonia, Doris, Scyllaea, Aeolis, Glaucus, Thetis, Phyllidia, Pleuro. branchus, Aplysia, Bullaea, Bulla, Limax, Helix, Dolabella, Testacella, Parmacella, Onchidium, Lymnaeus, Planorbis, Phasianella, Janthina, Paludinaa, Turbo, Buccinum, Sigaretus, Haliotis, Fissurella, Emarginula, Patella, Chiton, and Carinaria. Most of these appeared separately in the Ann. du Museum d'Hist. Naturelle. Meckel. Beitrlige zur vergleiehenden Anatomie. Bd. I. lift. 1, 2, Deutsches Arehiv ffir die Physiologie, Bd. VIII. p. 190, and Archiv fir die Anatomie und Physiologie, 1826, p. 13, containing anatomical details upon Thetis, Doris, Diphyllidia, &c. Wohnlich. De Helice pomatia. Wirceeburg, 1813. Leue. De Pleurobranchaea. Diss. Halae, 1813. Kosse. De Pteropodum ordine. Diss. Halae, 1813. Feider. De Haliotiduni structure. Diss. Halae, 1814. Stiehel. Lymnaei stagnalis anatome. Diss. Gotting. 1815. Deshayes. Anatomie du genre Dentale, in the Mdm. de la Soc. d'Hist. Nat. de Paris, It. 1825. Rang. Observations sur le genre Atlante. Ibid. III. 1827, p. 372. 4n Abstract of both treatises may be found in the Isis. 1832, p. 462, 471. 201. THE CEPHALOPHORA. 227 Treviranus. Ueber die Zeugungstheile und die Fortpflanzung der Mollusken, und fiber die anatomischen Verwandtschaften des Ancylus fluviatilis, in his Zeitsch. fuir Physiologie. Bd. I. p. 1, and Bd. IV. p. 192. Leiblein. Beitrag zu einer Anatomie des Murex brandaris, in Heusinger's Zeitschrift fur die organische Physik. Bd. I. p. 1, or Ann. d. Sc. Nat. XIV. 1828, p. 177. Quoy and Gaimard. Voyage de la corvette l'Astrolabe sous le commandement de Dumont Durville. Zoologie, II. III. 1832; also in abstract in Isis, 1834, p. 283, 1836, p. 31. Contains many observations on the anatomy of the Cephalophora. Rymer Jones. Cyclopxedia of Anatomy and Physiology, II. p. 377. London, 1839. Art. Gasteropoda. Escbricht. Anatomische Untersuchungen fiber die Clione borealis. Kopenhagen, 1838. Van Beneden. Exercices zootomiques, Fasc. I. II. Bruxelles, 1839. Monographs on Amphipeplea (Lymnaeus glutinosus), Pneumodermon, Cymbulia, Tiedemnannia, Hyalea, Cleodora, Cuvieria, and Limacina, extracted from the Nouv. MWm. de 1'Acad. Royale de Bruxelles. That upon Pneumodermon is contained in Miiller's Arch. 1838, p. 296. Vogt. Bemerkungen fiber den Bau des Ancylus fluviatilis, in Miiler's Arch. 1841, p. 25. Pouchet. Recherches sur l'Anatomie et la Physiologie des Mollusques. ]Paris, 1842. Quatrefages. Memoire sur l'olidine paradoxale, and Memoire sur les Gasteropodes Phlebenteres, in the Ann. d. Sc. Nat. XIX. 1843, p. 274, I. 1844, p. 129. Nordmann. Versuch einer Monographie des Tergipes Edwardsii. St. Petersburg (1843), from the Mem de 1'Acad. imperiale de St. Petersburg, IV.; abridged in the Ann. d. Sc. Nat. V. 1846, p. 109. Krohn. Anatomisch-physiologische Beobachtungen fiber die Sagitta bipunctata. Hamburg, 1844, also Ann. d. Sc. Nat. III. 1845, p. 102, and Annals of Nat. Hist. XVI. 1845, p. 289. Hancock and Ermbleton. On the Anatomy of Eolis, in the Annals of Nat. Hist. XV. 1845, p. 1. Allman. On the Anatomy of Actaeon. Ibid. XVI. 1845, p. 145. ADDITIONAL BIBLIOGRAPHY. Rymer Jones. Cyclopmdia of Anatomy and Physiology. Art. PteroToda, IV. p. 170. Wilm. Observationes de Sagitta mare germanicum circa insulam Helgoland incolente. Berol. 1846. [Refers especially to the sexual and nervous systems.] Middendorff. Beitrage zu einer Malacozoologia Rossica. St. Peters-;bourg, 1847 (from the M111m. Sciences Nat. Tom. VI.). Mollusken, from the author's Sibirischer Riese II. Th. I. St. Petersbourg, 1851. [These works although chiefly zoological contain many anatomical details.] Milne Edwards. Observations sur la circulation chez les Mollusques (Patella, Haliotis, Aplysia, Thetis, Limax, Triton), in the Ann. d. Sc. Nat. VIII. 1] 47, p. 37. Blanchard. Recherches sur l'organisation des Mollusques Gast'ropodes 228 THE CEPHALOPHORA. ~ 202. de l'ordre des Opisthobranches (Milne Edwards), Tectibranches, Nudibranches, Infdrobranches (Cuvier); Ann..d. Sc. Nat. IX. 1848, p. 172, XI. 1849, p. 74. Alder and Hancock. A Monograph of the British Nudibranchiate Mollusca with figures of all the species. Part I. 1844. Part V. 1851. Unfinished. [This fine work contains very valuable anatomical details and includes Hancock's contributions upon these animals given also in the Ann.. of Nat. Hist.] On the Anatomy of Oithonia, in the Ann. of Nat. Hist. IX. 1852, p. 188. Hancock and Embleton. On the Anatomy of Eolis (Contin.). Ann. Nat. Hist. 1848, I. p. 105, also 1849, III. p. 183. Hancock. On the olfactory apparatus of the Bullidae. Ibid. IX. 1852, p. 188. On the Anatomy of Doris, in the Philos. Trans. 1852, Part II. p1. Souleyet. Memoire sur le genre Acteon d'Oken, Journal de Conchologie, 1850, No. I. p. 1. Leidy. The Terrestrial air-breathing Mollusks of the United States, &c. Described and illustrated by Amos Binney. Edited by Aug. A. Gould, M.D. 2 vol. Boston, 1851. Special Anatomy by Joseph Leidy, M.D. [For beauty of execution Leidy's drawings are unsurpassed.] Leydig. Ueber Paludina vivipara: im Beitrag sur naheren Kenntniss dieses Thieres in embryologischer, anatomischer und histologischer Bezieo hung; in Siebold and Killiker's Zeitsch. II. 1850, p. 125. Anatomische Bemerkungen fiber Carinaria, Firola und Amphicora. Ibid. III. 1852, p. 325. Koren and Damelssen. Bitrag til Pectinibranchiernes Udviklingshistorie, Bergen, 1851, or its Transl. into the French, in the Ann. d. Se. Nat. XVIII. 1852, p. 257. Gegenbaur. Beitrige zur Entwickelungsgeschichte der Landgastropoden, in Siebold and Killiker's Zeitsch. III. 1852, p. 371. Bau der Heteropoden und Pteropoden. Ibid. IV. 1853, p. 334. MiToquin-. Tandon. Histoire naturelle des Mollusques terrestres et fluvi-. atiles de la France, 1847, avec un Atlas de 25 Planches, &c. Anatomie de Ancyle fiuviatile, in the Jour. de Conchol. 1852, No. I. p. 7, No. II. p. 121, and No. IV. p. 337. Rang and Souleyet. Histoire naturelle des Pteropodes, Paris, 1852.. CHAPTER I. CUTANEOUS SYSTEM. ~ 202. The cutaneous envelope of the Cephalophora consists of a dense dermis, of a cellular structure, often containing pigment matter which is free or in cells. It is covered with a delicate ciliated epithelium, which, with ,~ 203. THE CEPHALCPHORA. 229 the aquatic species, is extended over nearly the whole body, but with those which are terrestrial, is confined to certain spots.(') With the Gasteropoda, its external surface is striated or tuberculated; on the whole, the,skin of these animals closely resembles a mucous membrane and secretes Constantly a large quantity of mucus. It has an extraordinary contractility, due to a muscular layer intimately blended in its texture. With many species, the skin forms around the neck or back a fold, which is usually circular; the posterior or the upper part of this fold is dilated into a hernial sack containing a portion of the viscera. This portion of the skin is called the mantle.(1' With many, it can be wholly withdrawn into the body, and then the orifice of the fold acts as a sphincter.'2) ~ 203. Very many of the Cephalophora carry upon their back a univalve shell)' vwhich is formed by the border and external surface of the mantle, and, in a few cases only, in its interior.(2) The border of the mantle is the tissue most concerned in the formation of the shell. The shell's increase depends upon it, and for this purpose it is always in contact with the orifice. With the majority of the terrestrial Gasteropoda (3) the completed shell has a lip at its orifice, which, in some aquatic species,~4) is repeated several times at regular intervals during the development. In many Pectinibranchia, the border of the mantle has prolongations, which also secrete lime and produce around the orifice of the shell wing-like or spinous processes.5' With many species of this sub-order, one of these processes has a kind of canal, called the Siphon, which conducts the water into the respiratory cavity. With some, this siphon is contained in an appendix to the orifice of the shell,A5 while, with others, it is protruded through a fissural opening of this last. (7 With some Gasteropoda, the mantle is folded over a large portion of the external surface of the shell, which it covers with a calcareous substance.(5) The borders of the mantle have numerous, short, glandular follicles, whose walls are composed of large cells, some of which contain a finely-granular 1 Ciliated epithelium covers the entire surface of 1 With Chiton, exceptionally, the shell is the body with Lymnaeus, Planorbis, Physa, formed of several imbricated pieces so united as to Paludina, Valvata, Tergipes, Flabellina, and be movable. In some species the organic so much Polycera. With the terrestrial Gasteropoda, I exceeds the calcareous substance, that the shell have found it only on the surface of the foot, and has a horny aspect, as with Aplysia, Hyalea, with Arion, upon also the borders of this organ, and Cleodora. With Cymbulia, the shell is even which is separated from the rest of the body by a cartilaginous; that of Cypraea, on the contrary, is longitudinal furrow. I cannot, therefore, support composed almost exclusively of lime, - the quanthe assertion of Yalentin (Watner's Handwtrt tity of organic substance being very small. erbuch der Physiol. I. p. 429) that with Helix and 2 With Bullaea, Limax, and Testacella, the Limax, the whole surface of the body and even the shell is wholly concealed in the mantle. With tentacles are covered with this epithelium. Arion, the lime secreted in the interior does not 2 With Limax, Arion, and some allied genera, unite with the shell, but forms a mass of loosely this mantle is quite rudimentary, - covering like, a juxtaposited granulations. shield only a small portion of the back. 3 With the Auriculacea, and many of the Heli3 The genus Sagitta differs, in this respect, from cina. all the other Cephalophora. Its skin is without 4 Murex, Harpa, Scalaria. folds, forms a kind of cylinder, and consists of a b Strombus, Pterocera, Murex. dense dermis perfectly smooth and non-contractile. 6 Cerithium, MIurex, Rostellaria, Turbinella, At first, its structure appears to be homogeneous, Fasciolaria. but a more careful examination shows extremely 7 Harpa, Oliva, Voluta, Buccinum, Dolium, delicate parallel fibres running from before back- Conus. wards in uninterrupted and apparently varicose 8 Ovula, Cypraea. rows; they resemble nuclear fibres [of Henle]. 20 230 rHE C:EPIIALOPHORA. ~ 2083 substance (carbonate of lime) which effervesces with acids,(9) while the others enclose pigment granules.t'1) Calcareous cells are also found, but fewer, in the parts of the mantle covered by the shell. These portions of the mantle serve to increase the thickness of the shell, and to repair the loss of substance in places relmoved from the mantle-borders. The intimate structure of the shells of these animals is much simpler than that of the Acephala. They are homogeneous throughout, and correspond to. the internal layer of the Bivalvia. When the carbonate of lime has been extracted, the remaining organic base consists of a homogeneous membrane having numerous folds varying very much as to form and number, according to the genera. This organic base is produced by the external surface and border of the mantle, in the form of a mucous liquid containining calcareous and pigment granules, and which, hardening, forms the successive layers of the shell. 11) Usually there is no epidermis connecting the border of the mantle with the orifice of the shell; it can, therefore, together with the body of the animal, be drawn deeply into the shell. With some Gasteropoda, however, the shell is covered with a kind of epidermis, which has even hairlike processes. (2) Many of this same order have, upon the posterior dorsal surface of the foot, a peculiar plate, by which they can tightly close the c-:m!,- of their shell after having withdrawn their bodies. This plate, or operculum, composed, sometimes of concentric rings, and sometimes of lines spirally rolled together in the same plane, is composed of a calcareous, or a horny substance.'3' In both cases its organic base is lamellated or plicated like that of the shell. The operculum (Ojperculum caducumn) with which certain Helicina close their shell at the beginning of winter, is completely structureless, and without rings, spiral lines or lamellae. Beside these external calcareous products, there are certain species of these animals, which have other deposits of the same nature inside the skin and in various parts of the body, which, in the form of needles, form superposed, reticulated masses.(4) 9 See IH. Meckel, UIeber die Kalkdrdisen der 14 With Paludina vivipara, there are, between Gartenschnecke, in Miller's Arch. 1846, p. 17. the cutaneous layers, numerous globular calcareous 10 According to Gray (Lond. Med. Gaz. pt. V. bodies formed of concentric lamellae and with 1837, 38, vol. I. p. 830), some Gasteropoda have, in Limax, not only is there a calcareous plate in the the border of their mantle, numerous glands which mantle, but also a powder of the same nature scatsecrete pigment matter i and the shell will ii tered here and there in other parts of the skin. marked according as this secretion is continuous or imle white striae which adorn the sides of the neck irregular. and foot of Helix are composed of short, cylindri11 The only solid particles I have been able to cal, thickly-set calcareous needles. find in this mucus are calcareous molecules which According to K6lliker, the entire skin of Polydisengage gas when dissolved in acids. cera is crowded with analogous, but ramified In the shells of Helix, Bulimus, Cyclostoma, needles. Paludina, Neretina, and Cypraea, I have also Similar, probably, are the concretions which,. been unable to find the cellular structure which with Tergipes, are found everywhere beneath the Bowerbank (Ann. of Nat. Hist. No. 68, 1843) af- skin (Nordmann, loc. cit. p. 9, Taf. III. fig. 4 a.), firms exist in those of several Gasteropoda. and the calcareous net-work found in the mantle 12 Helix hirsuta, hispida, villosa, and the and foot of several species of Doris (Lovin, Isis, young of Paludina vivipara. 1842, p. 361, raf. I. fig. 3). 13 The operculum is horny with Paludina, Conus, Buccinum, Cassis, lurex; and calcareous with Nerita, Turbo, Cyclostoma. 204. THE CEPHALOPHORA. 231 CHAPTER II. MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION. ~ 204. The muscles of the Cephalophora are composed of smooth, primitive bundles, which are easily separated into short oblong fragments, and often have numerous nuclei scattered through their substance.* The cutaneous muscular system is highly developed; it consists of a muscular layer made up of oblique, longitudinal and transverse fibres,, which are not divisible into separate muscles, and are intimately united with the skin.(l) Upon the ventral surface, with the Gasteropoda, this cutaneous layer is very thick and forms a long disc, - the foot. The fibres of this foot, by contraction, produce wrinkles which succeed each other from behind forwards in a wave-like manner; by this means the whole foot glides easily over solid bodies or on the surface of the water.(2) MIany Gasteropoda use their foot for a sucker also, and then there are circular, tendinous fibres inwoven between those of the muscle proper.() With the Heteropoda, there is, upon the ventral surface, a laterally compressed process which has numerous muscular fibres. These animals swim upon their back and use this as an organ of locomotion; while a sucker, situated upon its borders, is used, it is said, as an organ for attachment.(4) The Pteropoda, Thetis, and Aplysia,have, upon certain places of their body, wing-like expansions, which are traversed by numerous muscular fibres,. and are used as oars for swimming.(Z) The horizontal fins which are found 1 Here again the genus Sagitta forms an excep- have had various interpretations as to their nation. Its muscular fibres are distinctly striated, ture, from the ease with which they are detached and its whole muscular system consists of a simple (see Meckel in his programme; Additamenta ad cutaneous layer composed only of longitudinal historiam Molluscorum, Piscium et Amphibiorum. fibres. Halae, 1832). 2 The breadth of this foot varies much according Rudolphi (Synop. Entoz. p. 573), and Otto to the species. With Scyllaea, and Tritonia, it (Nov. Act. Nat. Cur. XI. p. 294, Tab. XLI. fig. 1,. forms only a very narrow furrow, with which these a-f.) have taken them for parasites under the animals can embrace marine algae. names of Phoenicurus varius, and Vertumnus 3 Thus, with Patella and Haliotis. thetidicola. 4 See Forskil, Icones, &c., Tab. XXXIV. fig. A.; Delle Chiaje, who formerly described them Delle Chiaje, Memor. loc. cit. Tav. XLI. fig. 1, under the name of Planaria ocellata, has since and Descriz. loc. cit. Tav. LXIII.-IV.; Quoy and concurred in the opinion of the last two naturalistsGaimard, in the Ann. d. Sc. Nat. XVI. 1829, Pi. but he suggests that they may be the young of TheII. fig. 4-6, or in Isis, 1833, Taf. VI. (Pterotra- tis attached to the back of their parents to obtain chea and Carinaria); and Rang, in Mlim. de la nourishment; see his Memor. loc. cit. I. p. 59, Tav. Soc. d'Hist. Nat. de Paris, loc. cit. p. 375, P1. IX. II. fig. 9-15, II. p. 265, III. p. 141, Tav. XXXIX. fig. 1, 10, a. d. (Atlanta). fig. 1, and his Descriz. &c. II. p. 37. Although the 5 See Eschricht, loc. cit. Tab. I. fig. 5 (Clio) real nature of these appendages was made known and Van Beneden, Exercises, &c., Fase. II. P1. I. long ago by Macri (Atti della reale academia delle II. (Cymbulia and Tiedemannia). It is possible scienze di Napoli. II. 1778, p. 170, Tav. IV.), yet it that Thetis uses as natatory organs, beside its is only recently that it has been confirmed by Velarge cephalic fin, the contractile appendages rani (Isis, 1842, p. 252) and Krohn (Miiller's Arch. which exist on each side of the back. These last 1842, p. 418). * [ ~ 204.1 For histological studies on the muscu- are finely punctated through their whole length. lar tissue of the Cephalophora, see Lebert and With Paludina,, Helix, Bulimus, Carocolla, Robin (Miltter's Arch, 1846, p. 129) and Leydig Leydig found the essential. element of this tissue loc. cit. (Siebold and Kolliker's Zeitsch. II. 1850, to consist of a tube, formed hy the fusion of cells p. 191). According to the first-mentioned observers, linearly arranged i the nuclei of- these cells were the intimate composition of this tissue with species often visible. they examined (Mytilus edulis, Buccinaturn My own observations on A1 -.tica heros agree nudatum, and Pecten), is very delicate primitive with those of Leydig - that the essential structure fibrillae which are either smooth and uniform, or is a fibre and not a fibrilla. -ED. 232 THE CEPHALOPHORA. ~j 205, 206. upon various points of the body of Sagitta, differ from the locomotive,organs of the other Pteropoda in being composed wholly of parallel, homogeneous fibres, which decrease in size from the base to the border of this,organ, but which have not the least resemblance to those of muscle.(6) Some Pteropoda have tentacle-like processes situated in bufidles about the mouth, which have a small sucker at their end; they are, therefore, probably used as organs of attachment.('' ~ 205. Beside this cutaneous muscular system, the cavity of the body contains isolated muscles which serve different uses. With the turbinated Gasteropoda, a large muscle arises from the columella, and, after dividing into,many parts, is spread over the sides of the body to be inserted into the foot, and serves as its retractor. Several other muscles of variable size arise also from the columella, and are distributed, some to the tentacles, and ethers to the pharynx and the penis —serving also as retractors of these organs. With the shell-less Cephalophora, the retractors of these various organs arise from the inner surflce of the mantle, or from the foot.(') CHAPTER III. NERVOUS SYSTEM. ~ 206. The central part of the nervous system of the Cephalophora consists of a group of closely approximated ganglia, connected together by several nervous filaments, and which surrounds, like a ring, the base of the pharynx or the esophagus. This esophageal ring may be divided into several portions; one situated above, one below, and one each side of the osophagus. The portion lying above consists usually of two very large contiguous ganglia, which may be called the brain, since they furnish nerves to most of the organs of sense, - that is, the tactile organs, the eyes, and sometimes also the organs of hearing. The portion lying below, varies much in its form and size. It consists, sometimes of a group of ganglia blended together, or circularly united by short connecting filaments, and sometimes of a simple transverse cord. The two lateral portions consist always of tWo cords connecting the upper and lower parts just mentioned. The lower portion, which sends nerves principally to the muscles of the foot and to several viscera, is often asymmetrical. The peripheric nerves are always given off from the ganglia and never from the connecting cords, of the oesophageal ring. 6 See Krohn, Io, cit. p. 6. mon), and Eschricht, loc. cit. p. 8, Tab. II. fig. 7 See Cuvier, i em. loc. cit. p. 8, P1. I. B. fig. 12, 13 (Clio). 8 (Pneumodermon); D'Orbigny, Voy. dans 1 For these isolated muscles, see Cuvier, M6m. l'Amir. m6rid., or Isis, 1839, p. 497, Taf. I. fig. sur la limace et colimapon, loc. cit. p. 11, PI. IL IX. 1-15 (Spongiobranchaea and Pneumoder- fig. 2, 3. ~~ 207, 208. THE CEPHALOPHORA. 233 ~ 207. The nervous system of the Cephalophora is enveloped by a very distinct ibrous neurolemma containing often various pigments, which, in some species, give it, and especially the ganglia, a well-marked color.(') The neurolemma enters the ganglia and forms there numerous septa which separate the ganglionic globules into groups. These are very distinct,'and although of variable size, always contain a very large nucleus -composed of obscure granules in the midst of which are seen usually two -to four transparent nucleoli of unequal size.(2) These ganglionic globules are very often pedunculated,(3) and then their'very slender peduncles or processes usually extend far into the nerves which are given off from the ganglion, thus leading one to infer that these globules are the origin or termination of the nervous fibres.(4) Moreover, -these primitive fibres which traverse the ganglia, are always situated in that portion of them which is contiguous to the oesophagus.or pharynx,'while the opposite portion is occupied by the ganglionic globules. ~ 208. There is a great variety in the form and arrangement of the different parts of the nervous centre, according to the orders and families,- as follows. (1) i. The Heteropoda quite resemble the Lamellibranchia by their widely-separated ganglia connected by very long commissures. At the anterior extremity of their body, and above the cesophagus, there is a cerebral mass which sends backwards two long nervous cords, which, after passing along each side of the intestinal canal, terminate by entering the inferior ganglionic portion (Ganglion pedale), situated near the ventral (surface. The cerebral portion furnishes nerves to the organs of sense, to the skin, and to the lips, while the posterior portion sends them chiefly to the foot, and to the muscles of the tail.(2) 1 These ganglia are orange-colored with Lym- 4 See Helmholtz, De fabr. Syst. nerv. evert. loc..naeus, and red with Planorbis, Paludina, Hya- cit. p. 10; Hannover, loc. cit. and Will, in Mil-.lea, Pleurobranchus. ler's Arch. 1844, p. 76.* 2 Hannover (Recherch. microscop. sur le Sys- 1 For the descriptions and figures of the nervous t6me nerveux, 1844, p. 69, PI. VIII.) has very well system of several Cephalophora, see Cuvier, WMm. described and figured the ganglion-globules of loc. cit. Garner, Trans. of the Linn. Soc. XVII. Helix and Limax. p. 488; Rymer Jones, Cyclop. of Anat. p. 392, 3 Judging from Ehrenberg's figure (Uner- Art. Gasteropoda; Anderson, Ibid. III. p. 605, kannt. Struktur &c. Tab. VI. fig. I. 12.) of the Art. Nervous System.; and Vans Beneden, Exer — pedunculated ganglion-globules of Arion emrpiri- cises zoot. loc. cit.t -corum, he was not aware of the large nuclei which 2 See Milne Edwards, Ann. d. Sc. Nat. XVIII. they contained. 1842, p. 326, PI. XI., and Delle Chiaje, Descriz. II. * [~ 207, note 4.] Leidy's results, after very para, &c., loc. cit. p. 152, Taf. XIII. fig. 49, a. [. careful dissection, do not accord with these, for he (Paludina); Blanchard, Ann. d. Sc. Nat. XI. observed none of the nerve-fibres originate or ter- 1849, p.' 78, P1. III. fig. 1, P1. IV. fig. 1 (Janus); rminate in the ganglionary globules; see loc. cit. Middendorff, loc. cit. pl 75, Taf. IX. (Chiton); vol. I. p. 243.- ED. Leidy, loc. cit. P1. I. fig. I. 11-14 (Limax), Pl. t [ ~ 208, note 1.] See also.Alder and Hancock, IV. fig. V. 15-17 (Vaginulus), P1. V. fig. I. 32, 33, soc. cit. Part. II. P1. II. fig. 9 (Dendronotus), P1. 34 (Bulimus), PI. VI. fig. II. 25, P1. VII. fig. IV. fig. 16 (Doto); Part. III. P1. VIII. fig. 8 VIII. 20, P1. IX. fig. IV. 26, 27, P1. X. fig. IV..(Eolis); Part. IV. P1. V. fig. 1, k. (Scyllaea); 24, 25, 26 (Helix); P1. XIII. fig. IV. (Helicina), Part V. P1. II. fig. 13 (Doris), P1. XLIII. fig. 10 P1. XIV. fig. IV. P1. XVI. (Glandina).- ED. (Antiopa); then Leydig, Ueber Paludina vivi20* 234 THE CEPHALOPHORA. ~ 208. The nervous centre of the genus Sagitta is in many respects like that of the Heteropoda. A hexagonal cerebral ganglion lies upon thle upper surface of the oesophagus; another quite large is situated in the centre of the ventral surface of the trunk. These intercommunicate by two large, very long cords. The cerebral ganglion gives off two pairs of nerves; — of these the anterior are distributed to the base of the oral hooks, andc the posterior to the organs of vision; each sends, internally, a filament which passes backwards and joins at the middle of the posterior part of the head with the one from the opposite side, thus forming a loop. The ventral ganglion sends off backwards two considerable, diverging nerves, froim whose external surface pass off numerous, delicate, cutaneous filaments.() 2. With some Tectibranchia, a simple cerebral gangKion above, and two others, quite widely separated, below, are, all three, connected together by as many cords, thus forming a large cesophageal ring.() 3. With many Pteropoda the cerebral ganglia are wanting, while the lower portion is highly developed. This last is composed of two or three pairs of ganglia blended together, and from which passes off a simple commissure embracing the oesophagus. () 4. With very many of the Apneusta and Nudibranchia, as also with several other Heterobranchia, the cerebral mass is highly developed, while the remaining part of the oesophageal ring consists of a simple nervous cord. The two or four cerebral ganglia are either connected by transverse commissures, or intimately blended together.() p. 99, Tav. LXIII. (Carinaria). Pterotrachea eyes and tentacles, has a transversal row of six has a similar disposition. According to Delle sub-cesophageal ganglia, but no cerebral ganglia - Chiaje (loc. cit. Tav. LXIII. fig. 14, Tav. LXIV. see Cuvier, Garner, and Rymer Jones, loc. cit. fig. 11), a short commissure arising from the cere- For the nervous system of the Pteropoda, see bral ganglionic mass, embraces, in a ring-like man- also Souleyet, Comp. rend. XVII. No. 14 i or ner, the cesophagus of Carinaria and Pterotra- Froriep's neue Not. XXVIII. p. 84. t chea; but this is not mentioned by either Cuvier, 6 With Bullaea, Doridium, and Phyllidia, or Milne Edwards. there are two cerebral ganglia united by a more or 3 See Krohn, loc. cit. p. 12, fig. 2, 5, 13.* less long commissure; while with Tritonia, and 4 With Aplysia, according to Cuvier, Mim. loc. Scyllaea, there are four united by short commiscit. p. 22, Pl. III. IV., and with Pleurobranchus, sures; see Cuvier, loc. cit. With Aeolis, the according to Delle Chiaje, Memor. loc. cit. Tav. cerebral mass is also composed of four ganglia XLI. fig. 8, o. v. v. I have found the cesophageal transversely arranged (Delle Chiaje, Descriz. ring arranged in the same way with Pleuro- loc. cit. Tav. LXXXVIII. fig. 12, 15, and Hanbranch.aea. cock and Embleton, loc. cit. P1. V. fig. 16). With 5 This form is found especially in those species Eolidina, Zephyrina, Amphorina, Pelta, and where the eyes and tentacles are abortive or en- Chalidis, there are two pairs of fused ganglia tirely wanting; see Van Beneden, Exercices zoot. which are connected together by a delicate comFasc. II. (Hyalea, Tiedemannia, Cleodora, Cu- missure (Quatrefages, Ann. d. Sc. Nat. XIX. vieria, Limacina, and Cymbulia). Probably to 1843, p. 293, P1. XI. fig. 3, 4, I. 1844, P1. VI. fig. the absence of these organs is due, with the Ptero- 1-4). With Thetis, and Doris, on the other poda, the often confounding of the dorsal with the hand, the brain is a single mass, of considerable ventral surface. It is, moreover, interesting that, size, and situated in the neck (Cuvier, loc. cit.).++ among the Gasteropoda, Chiton, which is without * [ ~ 208, note 3.] For the cutaneous nerves Nervi labiales to borders of the mouth (Taf. IX. and their mode of distribution with Carinaria, fig. 6, 8).- ED. see Leydig (Siebold and Kelliker's Zeitsch. III. + [ ~ 208, note 6.] Blanchard (Ann. d. Sc. Nat. 1851, p. 325). Here, the nerves branch into finer XI. 1849, p. 78) describes the central nervous sysand finer filaments, and finally lose themselves in tem of Janus (Eolidia) as consisting of six meda terminal net-work 5 these terminal branches have ullary masses around the cesophagus, - the cerefrequent ganglionic corpuscles in their course. bral, the cervical and the pedal ganglia 5 see his These corpuscles appear to be developed in the figures, PI. III. fig. 1, and P1. IV. fig. 1. For the nerve-tube; see loc. cit. Taf. IX. fig. 5.- ED. Cephalic nervous system of the Nudibranchia, see t [ 208, note 5.] Middendorff (loc. cit. p. 75) Alder and Hancock, icc. cit. Part II. P1. II. fig. has described with Chiton a fiat and almost per- 9 (Dendronotus, Dotol, cerebral ganglia, four, pendicular nervous band situated on the internal and give off ter pairs of nerves; Part III. P.. sphincter of the mouth, and which he thinks is VIII. fig. 3 (Eolis), cerebral ganglia, four, and probably two ganglia cerebralia fused together give off twelve pairs of nerves 5 Part IV. P1. V. fig.. (Taf. IX. fig. 6, a) i this band sends off numerous 13 (Eumenis), cerebral ganglia, four, and give ~ 209. THE CEPHALOPHORA. 235 5. With other Apneusta, the cesophageal ring is composed of several contiguous ganglia which closely bind the oesophagus, but have no appar. ent commissures. (7) 6. The other Gasteropoda, and especially the Pectinibranchia and Pulmonata, have a highly-developed superior and inferior ganglionic mass; the oesophageal ring is formed by these ganglia, being connected on each side by a cord, which is oftener double than single.~) The superior mass is composed usually of two ganglia which are connected by a transverse commissure, or are contiguous, and sometimes even blended together.(9) The inferior mass also presents many variations. With some species it consists of a circle of distinct ganglia, connected by commissures;(O) while with others, it is composed of a group of ganglia more or less fused together. (11) ~ 209. With many of the Cephalophora,(x) there is a Splanchlnic nervous system. This can be divided into a Plexus splanchnicus anterior and posterior. The first is composed usually of a double Ganglion pharynggeum inferius, connected by a transverse commissure, or contiguous, but rarely blended together. They are situated under the (esophagus and connect with the cerebral mass by two filaments; they send off nerves principally to the pharynx, to the oesophagus and the salivary glands; and when the posterior plexus is wanting, they send nerves also to the liver and the genital glands.(2) 7 This cesophageal ring is composed of eight gan- commissures; see Berthold, loc. cit., and my obglia with Tergipes (Nordmann, loc. cit. p. 35, servations in Wie-mann's Arch. 1841, I. p. 153, Tab. II.), but with Actaeon, there are only seven, Taf. VI. fig. 3 (Lymnaeus stagnalis). Judging the lower one of which, asymmetrical, sends two from the figure of VYan Beneden (Exercices zoot. very long cords of communication to two large loc. cit. Fasc. I. Mim. sur le Lymnaeus gluticerebral ganglia, while the two lateral ganglia con- nosus, p. 30, P1. I. fig. 12, and Ann. d. Sc. Nat. nect by a short commissure passing under the VII. 1837, p. 112, P1. III. B.), of the cesophageal cesophagus (Allm.an, loc. cit. p. 194, P1. VII. fig. ring of Amphipeplea, this genus resembles, in this 1). According to-a communication which Keilliker respect, Lymnaeus. With Pneumnodermon viohas made to me, this ring, with Flabellina, has laceum (Van Beneden, loc. cit. p. 45, P1. I. fig. 2), only five ganglia. and with Clio (Eschricht, loc. cit. p. 6, Tab. III. 8 See Berthold, in Miller's Arch. 1835, p. 378. fig. 28), the lower portion appears also to consist 9 There is a transversal commissure between the of a circle of ganglia. two cerebral ganglia with Patella, Haliotis, Pha- 11 Helix, Limax, Arion. With Limax (Pousianella, Janthina, Turbo, Paludina, Lymna- chet, Recherch. loc. cit. p. 8), there remains in the eus, Planorbis, and with many other species having middle of the fused ganglia only a small opening, a shell. These two ganglia are contiguous with which, with several species of Helix, entirely disapHelix, Limax, and Cypraea; but they are fused pears.* into one with Buccinum, Alurex, Oliva, Harpa, 1 See Brandt, Ueber der Mundmagennerven der Voluta, and other Pectinibranchia. Evertebraten, loc, cit. p. 43. 10 Haliotis has two, and Patella four inferior 2 The two ganglia of the Plexus splanchnicus ganglia disposed transversely, which send off or Sympathicus anterior, which is situated more from each side a double cord of communication to or less in front of the inferior portion of the cesophthe brain. With Ancylus, Lymnaeus, Planor- ageal ring, have, together with their correspondbis, Physa, Succinea, Bulimus, the inferior por- ing nervous filaments, already been regarded tion is composed of five to seven ganglia, unequal and by Cuvier as a sympathetic system, with several disposed asymmetrically, and onnected together by Gasteropoda i see his Mem. sur le Genre Aplyoff eight pairs of nerves; Part V. P1. II. fig. 13 With all these genera, the cesophageal ring is (Doris), cerebral ganglia, five pairs, and a single formed by lateral commissures which unite with the ganglion,- the pairs are symmetrically placed sub-cesophageal ganglia which are sometimes two with regard to the median line and give off fifteen (Dendronotus, Doto, Eumenis), sometimes four pairs of nerves; the single or visceral ganglion (Eolis, Doris, Antiopa). -ED. gives off four nerves which are distributed to the * [ ~ 208, note 11.] The nervous system of the organs of reproduction, to the stomach, to the two terrestrial Gasteropoda has been most carefully hearts. and to the branchiae, and can be traced described and beautifully figured by Leidy (loc. into ganglia of the sympathetic system belonging to cit.). The details are so full that I can only indi. these several organs; Part V. P1. XLIII. fig. 10 cate the work. - ED. (Antiopa), cerebral ganglia, six, and give off ten or eleven pairs of nerves. 236 THE CEPHALOPHOIRA. ~ 210. The posterior plexus is composed of a single mass, rarely of two separate ganglia. It is situated under the digestive canal or between its coils, and from it pass off nerves to the intestine, the liver, and the genital glands, beside two cords of communication with the lower portion of the cesophageal ring.~3t CHAPTER IV. ORGANS OF SENSE. ~ 210. The Tactile organs of the Cephalophora consist of two to four contractile tentacles situated upon the head, or the anterior part of the back.(1) They receive nerves of considerable size from the cerebral mass, which have sometimes a ganglionic enlargement in the extremity of the tentacle.(2) With some Gasteropoda these tentacles are hollow and button-like at their extremity, and can be inverted like the finger of a glove.() But with the sia, p. 23, P1. IV. fig. 1, c.; sur la Lymnne, p. 13 (Cymbulia, Tiedemannia, Hyalea and Lima9, P1. I. fig. 11, u.; sur l'Onchidie, p. 14, P1. I. cina.) * fig. 6, o. Brandt (Mled. Zool. II. p. 328, Tab. 3 The Plexus splanchnicus posterior with its XXXIV. fig. 11, 13) has described it with Helix two long cords of communication is quite apparent pomatia; Van Beneden (loc. cit.), with Amphi- with Aplysia (see Cuvier, loc. cit. p. 23, P1. IV. peplea, and Treviranus (Beobacht. aus. d. Zoot. fig. 1, R.). Delle Chiaje (Memor. Tav. V. fig. 1, und Physiol. p. 42, Taf. IX. fig. 60), with Limoax. m, X. fig. 7, o. and XLI. fig. 8, y. y.), has observed See also the resealches of Schlemml (Dissert. defhe- it with Doridium, and Pleurobranchus, bepate ac bile crustaceorum et molluscorum quorun- side the genus just mentioned, and in Pleuro-. dam, Berol. 1844, p. 22, Tab. I. fig. 2, 3), upon the branchus, he found it composed of two entirely hepatic nerves of Gasteropoda. Delle Chiaije also, separated ganglia. Van Beneden (Exerc. zoot. has seen this plexus with Doridium and Pleuro- Fasc. I. p. 46, PI. I. fig. 3-5) has found it combranchus (Mtemor. II. p. 123, Tav. X. fig. 7, p. posed of only a single ganglion with Pneu.moderand III. p. 153, Tav. XLI. fig. 8, p.). According mnon. I/ilne Edwards (loc. cit. p. 329, P1. Xl. to Garner (loc. cit.), there is a double Ganglion fig. 1, u. v. 6), has observed in the visceral sac of pharyngeum inferius with, also, Scyllaea, Doris, Carinaria, first, a double Ganglion abdominale, and Eolis. With Patella, on the contrary, he which receives two long cords of communication found this anterior Plexussplanchnicus composed from the cerebral mass and from the Ganglion of three ganglia, two upon the sides, and the third pedale, and then a Ganglion anale, communimedian and a little behind. cating with the two abdominal ganglia. According to Van Beneden (Exercices zoot. 1 There are most usually two tentacles. But with Fase. I. p. 30, P1. I. fig. 12, c.), there is a similar Limax, Arion, Helix, Achatina, Clausilia, and disposition with Amphipeplea. With the Iletero- other'I1elicina., there are four. They are wholly poda, this plexus is highlly developed, composed of wanting with Sagitta, Cleodora, Cuvieria, Hyatwo ganglia, from which pass off long cords of com- lea, Pterotrachea, Lissosoma, Rhodope, Phylmunication to the cerebral mass; see Milne Ed- lidia, and Dentali/zm. wards, Ann. d. Sc. Nat. XVIII. p. 327, P1. XI. 2 This swelling exists not only with the inferifig. 1, s. x. and fig. 2, e. f.; and Delle Chiaje, or and eyeless tentacles, but also the superior ones Descriz. &c. loc. cit. Tav. LXIII. fig 14, 1. and bearing eyes, with several Limalllcina and Helicina. LXIV. fig. 11, d. (Carinaria and Pterotrachea). However, no ganglionic globules are seen in it, and The Pteropoda also have this plexus; but its two only a finely-granular substance lies interposed beganglia are more or less intimately fused, and as tween the primitive fibres. the cerebral mass is here replaced by a simple col- 3 With the Limacina and Helicina, these organs lar, it does not connect with it, but with the infe- are invested. by a muscle which arises upon the rior portion of the cesophageal ring; see Van Be- columnella or upon the internal surface of the sseden, Exercices zoot. Fasc. II. p. 11, et seq. P1. I. mantle, and is inserted at the extremity of each fig. 9, 10, II. fig. 8, 10, III. fig. 6, 9, and Y. fig. tentacle. * [~ 209, note 2.] For the splanchnic nervous and Hancock, loc. cit. (Eolis, Do7is, Antiosystem of the terrestrial Gasteropoda, see Leidy, pa, &c.). loc. cit. P1. XIII. fig. IV. 2 (Helicina), P1 XIV. According to Middendorff (loc. cit. p. 76), Chifig. IV. 3 (Glandina), and PI. XVI. fig. II. 2 ton has a complex splanchnic nervous system (Helix). which is widely distributed over the digestive orSee also for that of the Nudibranchia, Alder gans and their auxiliary glands. - ED. ~ 211. THE CEPIHALOPHORA. 237 majority of the Cephalophora, they are solid and usually conical, and sometimes are replaced by two groove-like, cutaneous processes, which, from contractions of their muscular fibres, can be shortened, but not inverted.(4' Beside these tentacles, many Cephalophora have also as tactile parts, organs, which consist of two contractile lobes situated on each side of the cutaneous fold which rests over the mouth like a second lip.(5) The prehensile organs about the mouth of certain Pteropoda, and the contractile filaments and processes on the border of the mantle of other Cephalophora, are also used, probably, as tactile parts.(') ~ 211. The organs of Hearing, which as yet have been found in all the orders of these animals, are, as in the Acephala, of a very low order. Like them also they consist only of two simple round auditive capsules whose transparent, solid walls contain sometimes a single, sometimes several otolites, suspended in a clear liquid, and which are composed of carbonate of lime.(l) When 4 With the Pectinibranchia, there are usually have attempted to show the analogy of these organs two conical tentacles; more rarely are there four with the auditive organs of the embryos of fishes as with Amphorina, Eolidina, Flabellina, and (Wiegmann's Arch. 1841, I. p. 148, Taf. IV. or Aeolis. Cutaneous furrow-like prolongations are Ann. d. Sc. Nat. XIX. 1843, p. 193, PI. II. B.). observed with Notarchus, Dolabella, Pleuro- Kolliker (Ueber das Gehirorgan der ltollusken, branch bs, Pleurobranchaea, and Aplysia. With in Froriep's neue Not. XXV. 1843, p. 133) also Doris, Tritonia, and Scyllaea, the, two conical has described them with many marine Ileteropomda, tentacles can be withdrawn into particular tubular and Gasteropoda, so that they nlay be said to exist excavations of the mantle.* in all the Cephalophora which have been subjected 5 Flabellina, Aeolis, Doris, Phyllidia, Dori- to dissection. The following are the genera in dium, Aplysia, Pleurobranchus, Pleurobran- which they have been observed. Among the Pterchaea, Dolabella, Ampullaria, Ceratodes. These opoda: Cymbulia, T'iedemannia, Hyalea, Crecutaneous lobes are often so large, that one is dis- seis, Pneumodermson, Limracina, I eteropoda: posed to include them among the real tentacles. Carinaria, Pterotrachea, Phsyllirrhoe, stlanta; I refer here to the tentacle-like organs by which Gasteropoda: Rhodlope, Flabellina, Lissososea, Clio, Pneumodermon, and Spongiobranchaea Amphorina, Pelta, Chalidis, Ze~phyrina, Actaefix themselves upon marine bodies (~ 204), to the on, Actaeonzia, Aeolis, Venilia, Tersipes, Dofilaments of the anterior lobes of the mantle of ris, Polycera, Tritonia, Thletis, Diphyllidia, Thetis, Plocamophorus, and Tritonia thetidea, Ancylus, Doridiuen, Aplysia, Gasteropteron, and to the prolongations of the lateral border of the Umbrella, Notarchus, Pleurobranchls, Pieurosame organ with Haliotis, Doris Jimbriata, and branchaea, Paludina, Lymnsaeus, Platosrbis, Cypraea erosa. Physa, Buslimus, Clausilia, $uccinea, Helix, 1 EZudoux and Souleyet (Institut. 1838, No. Arion, and Limax. It is remarkable that the 255, p. 376, or Froriep's neue Not. No. 174, auditive organs are developed so early, for they 1838, p. 312,) were the first to notice the auditive may be distinguished while the embryo is still in organ with the Cephalophora. They found with the errg. From the account of Pouchet (Ann. d. Pterotrachea, Carinaria, Pneunmodermon, and Sc. Nat. X. 1838, p. 64), it appears that he saw the Phyllirrhoe, as also Gaudichaud with Atlanta, otolites ill motion in an embryo of a Lymnsaeus, that the auditive capsules are small round semi- but without knowing their nature. Loven also, transparent bodies attached by a peduncle upon who saw the two capsules in the young Eolis the cerebral mass. Laurent (Appendl. aux re- (Kongl. Vetensk. Acad. Itandl. 1839, p. 227, or cherch. sur les organes auditifs des MIollusques, in Isis, 1842, p. 360, Taf. I. fig. 1, o.) did not knlow the Ann. franc. et 6trang. d'Anat. et de Physiol. what to think of them. Fan benedens (Asl. d. Sc. Mai, 1839, p. 118, fig. 1-16) has described these Nat. XV. 1841, p. 127, P1. I. fig. 13, 15, 17, d.) organs with their crystalline contents a little more mistook them in the embryos of Lirnmax and Aplyfully, for, beside the figures of Eudoux and Sou- sin, for nervous ganglia.; while Allnan (loc. cit. leyet relative to Hyalea, Cleodora, and Creseis, p. 153, P1. VII. fig. 10-12, d.) regatrded them as he has added others concerning Limax and Helix. eyes in the embryos of Actaeon. Sars (WiegSince then these organs with their otolites of differ- mann's Arch. 1845,. I. p. 8, Taf. I. tig. 7-11) and ent IHeteropoda, Pteropoda, and Gasteropoda have Iordmann (loc. cit. p. 44, 87, Taf. IV. Y.),on the been desclibed in detail by Krohn (Il'tller's Arch. other hand, very correctly recognizedl them as or1839, p. 335, or Froriep's neue Not. XIV. 1840, gans of hesaring in the emlbryos of Doris, Tritop. 310, XVIII. 1841, p. 310). In another series sia, T'ergipes, Buccinum, Littorina, Cerithium, of the terrestrial and fresh-water Gasteropoda, I * [ ~ 210, note 4.1 Hancock and Embleton See also Hancock (Ann. Nat. TIist. 1852, IX. p. (loc. cit.) regard these tentacles as olfactory organs, 188) on this apparatus with the Bullidae. In these, a view which is sustained by their special anato- no proper tentacles exist, as is wvell known, but this aly, by their special and comparative relations. author shows that here the head-lobe, which is the MZoquin-Tandon also (Bibl. Univer de Genive. result of the fusion of tentacles, is the seat os this Nov. 1851, p. 247) regards this sense as located in sense. - ED. the end of the tentacles, with the Gasteropoda 238 THE CEPHALOPHORA. ~ 211. single this otolite is spherical and crystalline, but when multiple they are fusiform, a little compressed, and usually very numerous, there being with some Gasteropoda, thirty or forty, and even eighty in each capsule.( The movements of these bodies are even more marked with the Cephalophora than with the Acephala; and the balancing and rotation of each, producing a kind of trembling of their whole mass which occupies the centre of the capsule, is a wonderful spectacle. It has been recently discovered that these motions are due to very small cilia upon the internal surface of the capsule.~ The situation of these two auditive capsules varies according to the orders, families, and genera. With several Heteropoda, and Apneusta, they lie a little under the skin, behind the eyes, and are connected with the cerebral mass by a longer or shorter auditive nerve.(4) In some Nudibranchia, they lie upon the cerebral mass itself, contiguous with the posterior part of the eyes. () With the other Cephalophora, they are situated at the lower side of the body, and usually touch the inferior portion of the 6esophageal ring. In only a very few of the genera are the two auditory nerves separated and distinct from each other."61 Phasianella, and Rissoa. I have myself seen ways remain at a little distance from it, and when them quite early in the embryos of Vermetus.* there are several,they are grouped in the centre; 2 There is a single otolite only with the Ietero- indeed when one has strayed from this central popoda, the Tubulibranchia and several of the Ap- sition it is always quickly returned. Wagner neusta; see Delle Chiaje, Descriz. &c. II. p. 100, (Lehrbuch der Physiol. ed. II. 1843, p. 463) positiveTav. LXIII. fig. 5, 6 (Carinaria), and Quatre- ly affirms that he has seen cilia in these capsules. fages, Ann. d. Sc. Nat. I. 1844, p. 160, P1. VI. fig. They have been very distinctly seen by Kblliker 8-10 (Actaeosn, Pelta, Chalidis). According to also (loc. cit.) with Tritonia, Thetis, PleuroKrohin's and my own observations, there are branchaea, Diphyllidia, Hyalea, Lissosoma, and groups of small fusiform otolites with some Ptero- Rhodope. poda, and very many of the Gasteropoda, as Cym- 4 See Laurent, loc. cit. fig. 1-6, and Quatrebulia, Hyalea, Doris, Tritonia, Thetis, Aeolis, fages, Ann. d. Sc. Nat. I. loc. cit. P1. IV. VI. AcVenilia, Pleutrobranchaea, Paludina, Plansorbis, cording to Delle Chiaje (Descriz. &c. loc. cit. Tav. Lymnaeus, Helix, Limax, and many others. It LXIII. fig. 3, d. 14, f.), and AIilne Edwards is not rare to find among these fusiform otolitz, A.r. - Sic Nat. XVIII. 1842, Pl. XI. fig. 1, z. others composed of two or four calcareous corpus- fig. 3, h.), the auditive nerves are very long with cles. Those of a spherical or spindle shape divide, Carinaria. -With many Cephalophora which are from pressure, into four to eight fragments in the transparent, the auditive organs may be perceived direction of cruciform lines which may often be seen by the naked eye, through the skin, as two white before division. According to the observations of spots.+ Laurent, Krohin, and myself, in the centre of 5 Doris, Thetis, Tritonia, Aeolzs (Krohn, loc. these bodies, a single otolite is first developed, in the cit.), and Tergipes (Nordmann, loc. cit. p. 44,, capsules which are to contain several, and others Tab. II.). are ad(ded as the embryo increases; see Frey, in 6 According to Krohn (loc. cit. No. 394, p. 311)Frroriep's neue Not. XXXVII. No. 801, p. 132, the two puditive capsules of Pleurobranchaea, and and Wiegm.ann's Arch. 1845, I. p. 217. Taf. IX.t Paludina receive distinct auditive nerves from the 3 A priori, it might have been inferred that these inferior portion of the cesophageal ring. Ile has motions are due to cilia, for the otolites never come observed the same with Cymbulia, and Hyalea in contact with the sides of the capsule, but al- (loc. cit. No. 306, p. 311) i but Van Beneden (Ex[ [~ 211, note 1.] See also Alder and Hancock t [ ~ 211, note 2.] See, for the auditory apparaloc. cit. Part II. P1. II. fig. 11 (Dendrosnotus), P1. tus of Aeolis, Hancock and Embleton, Ann. Nat. IV. fig. 18 (Doto); Part. III. P1. VIII. fig. 4, 5, IIist. 1849, III. p. 196. The otolites which have 6 (Aeolis); Part V. P1. II. fig. 15 (Doris); then hitherto been regarded calcareous, they found not Leydig, Ueber Paludina vivipara, &c., loc. cit. p. to be materially affected by long treatment with 139, 155, Taf. XI. fig. 12, k. Taf. XIII. fig. 14-24, acetic acid. -En. 49, R. (Paludina); and Leidy, loc. cit. p. 246, P1. + 211, note 4.] See also Leydig (Anat. BeIX. fig. VII.-IX. (Helix), P1. XIII. fig. IV. 4 merk. Uib. Carinaria, Firola und Amphicora, in (Helicina). Leydig has furnished valuable con- Siebold and Kblliker's Zeitsch. III. 1851, p. 325). tributions in the development of this organ i in Pa- Ilis Taf. IX. fig. 4 (Carinaria) gives a very clear ludina, it appears, prior to the nervous system idea of the structure and relations of the auditory wvith which it is connected, as an almost solid body capsules with these animals. His observations with a very small, round, central cavity; with the upon the cause of the movements of the otolites are growth of the organ, this cavity increases, and confirmatory of those of Milne Edwards with finally the whole becomes a capsular organ in which Firola; see L'Instit. Jour. univ. des Sec. say. XIII. are developed otolites. - ED. 1845, p. 43.- ED. A~ 212. THIE CEPHALOPHORA. 239 ~ 212. The organs of Vision are absent with only a very few genera of the Ce-'phalophora.(') They are never more than two in number, and their size, compared to that of the body, is usually small; they are smallest with some Heterobranchia, and the largest with the Pectinibranchia.(2) The eyes consist usually of two round bulbs concealed under the skin; this last is colorless at this point, and lies over them like a thin lainella. Each bulb is limited outwardly by a tissue resembling a Sclerotica, but beneath the skin, this tissue is more convex than elsewhere, and thus forms a kind of' Cornzea.(3) The sclerotica is lined by a dark pigment layer, or C'horo. dea, which, near the corner, ends in a free border, forming thus a Ptupilla. With some Gasteropoda, the pupillary border has a very thick pigment layer which serves, perhaps, as an Iris.(4) The internal surface of the choroidea is covered by a whitish pellicle which undoubtedly is a Retina, for the optic nerve enters the selerotica at a point opposite the cornea.(5) The cavity of the eye-bulb is filled with a gelatinous, vitreous body, which, in front, envelops a spherical crystalline -lens. (6) The Optic nerve arises from the cerebral ganglia, and runs along, for a longer or shorter distance, in company with the tentacular nerve of the.same side. ) erc. zoot. Fasc. II. p. 13, P1. I. fig. 8, f. 9, c. 10, 1829, p. 208, Taf. VI. fig. 4-8, and Ann. d. Sc. P1. V. fig. 13, x.) affirms that with the first of these Nat. XXII. 1831, p. 7, P1. III. IV., or in the Isis, -genera, and with Tiedemnannia, and Linzacina, the 1835, p. 347, Taf. VII.), and Krohn (l'liiller's auditive vesicles lie directly upon the two principal Arch. 1837, p. 479, 1839, p. 332, Taf. X. fig. 6-8) inferior ganglia; this agrees with Delle Chiaje's upon the eyes of Helix, lurex, Palu.dina, and,description of these organs with Cymbulia; see his Pterotrachiea. Descriz. &c. I. p. 94, Tav. XXXII. fig. 2, i. 3 The eyes of the Ileteropoda present a remarkEschricht (loc. cit. p. 6, Tab. III. fig. 28, s.) has able exception; their very convex cornea is surfigured, with a Clio, two ganglia with short pe- rounded by a collar of skin; the ocular bulb is very duncles, situated close by the two anterior ganglia long, and, at its base, the sclerotica spreads out of the cesophageal ring. These, I infer, are only interiorly and posteriorly, forming a round promthe auditive capsules receiving two short auditive inence see Milne Edwards, Ann. d. Sc. Nat. nerves. XVIII. 1842, PI. XI. fig. 1, c. (Carinaria), and With those Gasteropoda whose inferior cesophageal especially the description of Krohn (loc. cit. 1839) ganglia are arranged in a circle, as, for examples, of the eye of Pterotrachea. The ocular bulb of with LymnaeuLs, Planorbis, Physa, Succinea, Clio is also very long, but has no prominence; see Bulimus, Ancylus, these capsules lie upon the Eschricht, loc. cit. p. 7, Tab. III. fig. 29. Those posterior surface of the two large anterior ganglia. of Actaeon are long and pyriform; see QuatreBut when, on the other hand, these ganglia are fages, Ann. d. Sc. Nat. I. 1844, P1. VI. fig. 5, and approximated, or even fused into one common mass, Allman, loc. cit. P1. VII. fig. 2. as with htelix, these capsules lie upon the inferior 4 A dark iris is" distinctly seen with Paludina surface of this mass, and especially upon the and Alurex. That of Strombus is very brilliant nodules corresponding to two large anterior ganglia. and multicolored, according to Quoy and Gai1 Phyllirrhoe, Diphyllidia, Chiton, Dentali- mard; see, Voy. de l'Astrolabe, Zool. III. p. 56, Ilolutm, and the Pteropoda with the exception of Sa- lusques, P1. L. It. I am not yet certain whether gitta and Clio, are blind. In many of the Ptero- or not the iris of these Gasteropoda is susceptible poda, the auditive appear to have been taken for of movements of contraction and dilatation. It the ocular organs. may be well to add that the choroidea of the Ite2 Swoammeredamm (Bibel der Nat. p. 47, Tab. IV. teropoda has several spots of its surface free from fig. 5-8) made out very correctly the structure of the pigfment.* eyes of Hfelix. The later works of Stiebel (Meck- 5 Krohn (loc. cit. 1837, p. 482) affirms that he el's Deutsch. Arch. 1819, p. 206, Tab. V.), Huschkce has seen this white layer with a Paludina. (Beitr. zur Physiol. u. Natttlgesch. 1824, p. 57, 6 The existence of a distinct vitreous body was Taf. III. fig. 8), and of De Blainville (De lO0rgan- known to Swacmmerdamm,and has been confirmed isat. des Animaux, 1823, p. 445), upon the eyes of by Krohn (loc. cit. 1837). Helix, Paludisna, and Voluta, have been much 7 According to Krohn (loc. cit. 1839), the two improved by those of Mill"er (Mleckel's Arch. optic nerves of Paludina, Murex, Aplysia, Cy* [ ~ 212, note 4.] For the visual organs of Pa p. 159, Taf. XII. fig. 25, Taf. XIII. fig. 26-28..ludina, with histological details, and especially See also this same author in Siehold and Kolliconfirmatory of Krohn's observations, see Leydig, her's Zeitech. 1851, III. p. 327 (Carinaria).- ED. loc. cit., Siebold and Kblliker's Zeitsch. II. 1850, 240 THE CEPHALOPHORA. O 212. There is, moreover, a series of Cephalophora with which the eyes are much more simple and often nearly abortive. Such is the case with Sagitta,. and many of the Apneusta and Heterobranchia.~) Here, the eyes are not always nicely limited by a sclerotica, but the light-refracting bodies lie surrounded in a mass of pigment granules, and situated more or less distant from the external surface of the cervical region. The cornea is absent, and often also the optic nerve, in which case, the eyes lie directly upon the cerebral mass.t91 The most complete eyes are nearly always connected with the tentacles,. although their position varies quite widely.(") Very often they are situated at the base of the external surface of these organs.(") With many Pectinibranchia, they are more or less elevated upon the outer side of' the tentacle on a protuberance or on a support which exceeds the extremity of the tentacle in length and size.121 With many Pulmonata, these organs are situated upon the very extremity of the tentacles, and are upon the posterior pair, when these last are four in number.(11) praea, Rostellaria, Buccinum, and Littorina, laea, &c., these organs are comparatively small arise from the cerebral ganglia by an origin which and appear more or less distinct through the skin,. is distinct from that of the tentacular nerves. I sometimes in front of, and sometimes behind, the have been able to confirm this for Helix, Limax, tenmacles.* Caracolla. According to luiller (Ann. d. Sc. Nat. 10 This is so with various Ileteropoda, all the loc. cit. p. 12, PI. III. fig. 5), the optic nerve is Pulmonata, Pectinibranchia, and with some of only a special branch of the end of the tentacular the Iteterobranchia; see LovUn, loc. cit. and nerve. Isis, 1842, p. 364. 8 The two pretty simple eyes of Sagoitta, forming 11 The eyes are situated at the base of the tentatwo prominences oil the top of the head, are spher- cles on a small prominence, with Carinaria, Atical, and rest directly upon the ganglionic enlarge- lanta, Vermetus, with the Lymnaeacea, the Operment of the optic nerve, see Krohn, loc. cit. 1i. 13, culata, Patella, Emarinula, Fissurella, Sibafig. 5, 14. retus, Paludina, Littorina. A kind of peduncle 9 According to Qusatrefages (loc. cit. I. p. 158, replaces this prominence with Haliotis, Navicella,. PL. VI. fig. 6, 7), the eyes of Pelta, and Chalidis, Phcasianella, Trochus, Ceratodes, Ampullaria. have, instead of a choroidea, a mass of pigment 12 The prominences supporting the eyes are situcontaining neither a sclerotica nor a cornea. Ac- ated on the outer side of the tentacles with Buccicording to the observations of NVordmann, and nsrm., Harpa, Dolium, Cypraea, Murex, Oliva,. Kolliker, the eyes of Tergipes and Polycera are Turbo; and at a variable distance from the ex — without optic nerves, and lie directly in contact tremity which they sometimes surpass in breadth, with the cerebral ganglia. With Doris, Glaucus, and length, as, for example, with S'trombus. Thetis, Aeolis, Doridium, A4plysia, Bulla, Bul- 13 Amphipneusta, Helicina, and Limacina.t * [~ 212, note 9.] For the eyes and their inti- "(1.) The eye at the extremity of the tentacle mate structure with the Nudibranchia, see Alder (Helix); and Hancock, loc. cit. (Dendronotus, Doto, Aeo- " (2.) The eye at the internal base of the tentalis, Scyllaea, Eumenis, Doris, Antiopa); with all cle (Limnaea); these, the optic nerves were distinct, and the eye "(3.) The eye at the exter'nal base of the tenta. itself was furnished with a well-rounded, black pig- cle (Cslclostonma). ment-cup, often a spherical crystalline lens (Doris, "3. These organs presentialso three types as to Aeolis, Antiopa), with an arched cornea in front, their organization: and the whole enveloped by a transparent mem- "(1.) The lenticular crystalline lens, the vitrebranous capsule. - ED. ous humor fluid, non-adherent (Helix); t [ ~ 212, note 13.] See, in this connection, Lespds "(2.) The lenticular crystalline lens, the vitreous (Recherches sur l'oeil des Mollusques Gast6ropodes humor thick and united to this last terrestres et fluviatiles de France, Thesis. Tou- "(3.) The crystalline lens thick and slightly con louse, 1851). His conclusions are: vex, the vitreous humor viscous and slightly ad"t1. All the terrestrial and fluviatile Gastero- herent to the lens." -ED. poda have eyes; " 2. These organs present, as to their position. three different types: ~ 218. TITE CEPHALOPHORA.'241 CHAPTER V. DIGESTIVE APPARATUS. ~ 213. The highly-developed digestive organs of the Cephalophora always com — mence at the anterior extremity of the body, with a rourid, oral orifice,, which is surrounded with tumnid lips, but rarely has special prehensile organs.l) These lips are quite contractile, and can evert and invert the mouth; with many species, they can be prolonged into a cylindrical proboscis.(2) The walls of the oral cavity are very muscular, and, with the majority of the species, form a round and often very large pharynx. The epithelium of this cavity is frequently developed into collars or callosities which serve as masticatory organs. With some Gasteropoda, this apparatus is composed of two horny, lamelliform jaws, which have a truncate, convex, internal border, and move upon each other in a lateral manner.(3) These jaws are situated, sometimes directly behind the oral orifice, and sometimes at the base of the pharynx. Many other Gasteropoda have only an upper jaw enchased in the roof of the oral cavity, and which is easily seen from its deep-brown color. It consists of a transverse, semilunar, horny plate, upon whose anterior surface are several vertical crests, which terminate upon the free border by as many tooth-like processes.(4) Nearly all the Cephalophora have a longer or shaorter fleshy mass, adhering to the base of' the pharynx, and which is sometimes grooved longitudinally; it is quite comparable to a Tongue. Sometimes it is very large and contained in a membranous sheath at the base of the pharynx. It is always armed with horny, denticulated spines and plates, which are very delicate, and arranged in quite elegant, longitudinal and transverse rows. The 1 Such are the tentacular appendages which have 147, P1. V. fig. 5, and Nordmann, loc. cit. P. 12,. a sucker, of Pteropoda (Clio, Spongiobranchliea, Tab. I. fig. 7). With Dentaliumn, on the contrary, and Pneumodermon), already mentioned above the jaws are situatedat the base of the oral cavity (~ 204). (Deshayes, loc. cit. p. 333, PI. XV. fig. 11, b. b, 2 There is a retractile proboscis with Pneu- 15, 16, or in the Isis, 1832, p. 463, Taf. VI. fig. 15, modermon, Spongiobranchaea, Pterotrachea, 19, 20). Thetis, Buccinum., Dol/ium, Cypraea, Mlaltrex, 4 This upper jaw is particularly developed with. Conus, VoluLta. and many other Pectinibran- the Limacina and lIelicina; see Cuvier, Mlm. loc. chia. cit. Sur la Limcace, &c., P1. IT. fig. 4 (Limax); 3 The external borders of these jaws are easily Troschel, in WZie5mann's Arch. 1836, I. p. 257, perceived between the lips, as with Scyllaea (C1u- Taf. iX. fig. 3-9 (Ai-on, Limax, Helix. Clau vier, Melm. loc. cit. fig. 6, a. 6, b.), with Tritonia silia, and Succinea), and Erdl, in lo'r. Wlaor (Savigny, Descript. de l'Egypte, 1Iist. Nat. II. ner's Reisen inder Regentsch. Algier. III. p. 268, P1. II. figr. 1'-11 and Delle Chiaje. Descliz. loc. Tab. XIII. XIV. With Lymnaemsq, and Plan.orcit. Tav. XLII. fig. 1), and with Diph.yllidia and bis, there are, beside, two smalllateral jlaws v thiese Bulla. They are found also directly behind the exist also with Valvata, and Pal-dina, where the lips with Venilia, Aeolis, Amphorinla, and Ter- upper jaw is wanting. With Zephyrina, there arl gipes (Alder, Hancock/ and Embleton, Ann. of also three jaws at the base of the harynx x; see Nat. Hist. XIII. p. 162, P1. II. fig. 3, 4, XV. p. 4, Quatrefages, loc. cit. I. p. 132, P1. V. fig. 1.* P1. II.; also Quatrefages, Ann. d. Sc. Nat. I. p. *[ ~ 213, note 4.] For many details upon the die Mundtheile einiger Helicien, in WTiezmann's oral organs of the HIelicina, of an anatomical as Arch. 1849, p. 225). -ED. well as a zoological import, see Troschel (Ueber 21 242 TIHE CEPHALOPHORA.' 214. points of these spines turn backwards, and thus the retractile tongue can serve as an organ of ingestion, and as such is used with much address.(5) ~ 214. The intestinal canal has often longitudinal folds and a ciliated epithelium extending from the (esophagus to the rectum, and even into the hepatic ducts. () It is usually two or three times the length of the body, and has therefore several convolutions, which, with the species which have a shell, are contained in its spiral cavity. It commences at the base of the pharynx by an CEsophagus, of variable length, which is sometimes dilated at its posterior extremity into a kind of crop.(2) The stomach, which, from constrictions,13) is often divided into several portions, consists sometimes of a simple dilatation with thin walls,14 and at other times of a nicely-defined cavity whose walls are thick and fleshy,(5) and provided, sometimes, with thick epithelium, and even, in certain cases, with plates and horny teeth.16) The cardiac and pyloric ori5 See the description and figures of Troschel Phaenom. motus vibrat. loc. cit. p. 48), and with the (loc. cit. Taf. IX. X.) of the tongue of our terrestri- Apneusta (Quatrefages, Ann. d. Sc. Nat. I. p. 166). al and fresh-water Gasteropoda, and also of Am- I have also seen the ciliary motions, with Lymphipeplea (Ibid. 1839, I. p. 182, Taf. V. fig. 8). naeus, Planorbis, and Clausilia; but not with For that of the marine Gasteropoda, see principally Limax, Arion, and Helix. Valentin may. Quoy and Gaimard (loc. cit.), also Poli, Testacea therefore, be mistaken in affirming (Wagner's Siciliae, &c., I. p. 5,. Tab. III. fig. 9 (Chiton), Sa- Handworterbuch d. Physiol. I. p. 492) that ciliated vigny, Descrip. de l'Egypte, Hist. Nat. II. P1. II. epithelium exists generally in the intestine of the fig. 29-213, III. fig. 57, 50 (Aplysia and Chiton), Gasteropoda. Rang, Hist. Nat. des Aplysiens, Pi. XX. fig. 9-13 A ciliary movement has also been observed in With the Cyclobranchia, and some of the Inferobranchia, the lamelliform branchiae are situated on the furrow which separates the border of the mantle from the foot,(7) under the form of a continuous cord, or of two lateral rows. With the Scutibranchia, the two pectinal rows, which are wholly concealed in the cavity of the mantle, have, nevertheless, a certain symmetry (s) which is wholly absent with the other Gasteropoda. Thus, all the Tectibranchia have only a single lamellate or pinnate branchia situated on the right side, rarely on the left, and which is more or less covered and sometimes wholly concealed by a fold of the mantle.(9) The Pectinibranchia and Tubulibranchia have a pinnate or pectinate branchia, contained in' a cavity which is situated upon the anterior portion of the back and often provided with a siphon on its left side.(~) With many Nudibranchia, the returning blood from the branchiae is emptied by several veins into the simple auricle of the heart, which (the heart) is situated upon the middle line of the back.(ll) With only a few Gasteropoda, as also with the Cirribranchia, Cyclobranclla, and Scutibranchia, the branchial veins are united into two trunks which open into the simple or double auricle. (12 With the other Gasteropoda, which have an uneven, lateral branchia,(l3) the blood passes from this last, through a short, simple, venous trunk, to the heart situated near its base. II. Lungs. ~ 221. The pulmonary cavity, formed in the mantle of the Pulmonata, is situated 6 With Scyllaea, there are, on the back, two cealed under a fold of the mantle (Treviranus, pairs of cutaneous lobes, between and which are loc. cit. p. 192, Taf. XVII. fig. 1, 2, d., or Vogt, numerous branchial vessels. With Glaucus, there loc. cit. p. 28, Taf. II. fig. 1-3, p.). are, upon the sides of the body, three pairs of pro- 10 With Valvata, there is a single pinnate longations which have long, digitiform branchial branchia which projects out of a cavity in which it filaments. With Thetis, the back is surrounded is contained (Gruithuisen, Nov. Act. Acad. Nat. by a double row of semi-pinnate branchiae; while Cur. X. p. 441, Tab. XXXVIII. fig. 2, 3, 5, 12). with Tritonia, there is on each of its sides a single The branchia is simple and pectinate with Vermerow of multiramose branchial tufts. With Doris, tus (Philippi, Enumer. Mollusc. Sicil. I. p. 169,. and Polycera, there are twenty to twenty-five Tab. IX. fig. 24), Rostella, and Struthiolaria. more or less ramified branchiae, arranged circu- It is bi-pectinate with Turbo, and Janthina, and larly around the arms, and capable, from contrac- tri-pectinate with Paludina. With many Pectinition, of being withdrawn into the mantle. branchia, as, for examples, with Harpa, Cassis, 7 The branchial lamellae form a complete circle Conus, Buccinum, Terebra, Murec, Voluta; with Patella, Chiton, and Phyllidia, and two Oliva, &c., there is, beside a very large unipectilateral rows with Diphyllidia. nate branchia, another organ of this kind which is 8 With Fissurella, and Emarg'inula, there is a smaller and bi-pectinate. The epithelium, which row of branchiae on each side of the cavity of the covers not only the branchia, but also the walls of mantle, while, with Haliotis, there are two rows the respiratory cavity, plays an important part in on the left side. the renewal of the water in the branchial cavity, 9 With Umbrella, Pleurobranchaea, and Pleu- which takes place through its opening, or by the robranchus, this branchia, situated on the right siphon of these Gasteropoda which is situated upon side and half exposed, is easily seen. On the same the neck usually a little to the left side.* side also is situated the branchial lamella often deep- 11 Scyllaea, Thetis, Doris. ly concealed between the folds of the mantle, of Gas- 12 Tritonia, Dentalium, Patella, Chiton, teropteron, Aplysia, Bullaea, N1otarchus, &c. Haliotis, Fissurella and Emarginula. Among But with Doridium, the branchia is on the left the Inferobranchia, Phyllidia should also be side and quite behind. cited here. But with Diphyllidia, on the contrary, Ancylus, which differs from the other Infero- the veins appear to pass each into the auricle of the branchia by its simple branchia, has, moreover, heart. this peculiarity, that this organ has the form of a 13 The Tubulibranchia and Pectinibranchia. simple cutaneous enlargement on the left side, con*[ ~ 220, note 10.] See also Leydig, loc. cit. are unipectinate with Paludina vivipara, and not for the branchiae and their intimate structure, tri-pectinate, as above mentioned of this genus in with Paludina. According to this observer, they general.- ED. 222. THE CEPHALOPHORA. 251 at the anterior part of the back, rarely at the posterior part.() Its orifice, which can be closed by a kind of sphincter, is upon the right side; it is upon the left with those species only which have sinistral shells, and in one genus alone, it is upon the median line at the posterior extremity of the body.(2) The pulmonary cavity is triangular with those species which have a shell, and round with those which are without it.(3) Its interior is lined with a raised vascular net-work which, with the aquatic species, is covered with a ciliated epithelium.(4) With the naked Gasteropoda, this net-work forms a uniformly-meshed trellis;(5) while with the others, there may here be usually seen several large pulmonary veins, which, in passing towards the middle principal vein, are spread over the borders of the respiratory cavity, frequently anastomose with each other, and receive several other veins of a dendritic form. The principal vein opens, at last, into the auricle of the heart at the posterior corner of the pulmonary cavity. ( Carefully examined, these veins will be found to be wall-less canals directly surrounded by the transverse and longitudinal fibres of the mantle, so that, apparently, they are only a continuation of the venous canals of the walls of the body. II. Aquiferous System. ~ 222. The existence of aquiferous vessels and reservoirs, with the Cephalophora, is not yet satisfactorily settled. However, it appears that here, as with the Acephala, there is an aquiferous system with wall-less canals, of which some are singly ramified, while others form an anastomotic net-work, but all accompany the venous canals and open upon the surface of the body, -presenting an arrangement analogous to the trachean system of insects. With some Apneusta, the existence of this system, which may have the function of an internal respiratory apparatus, can scarcely be doubted; 1 The respiratory cavity is situated in the middle nary cavity of the Lymnaeacea, but not in that of of the back with Parnzacella, and wholly behind Helix or Arion. with Testacella, and Onchidiumn. 5 Onchidiunm, Limax, &c.; see Cuvier, MWm. 2 Onchidium. Whether or not the contractile, loc. cit. PI. II. fig. 8-10 (Arion). ramified excrescences at the posterior part of 6 See Cuvier, Ibid. PI. I. fig. 2-4, and Trevithe back of this amphibious mollusk, of which ranus, Beobacht. aus. d. Zoot. u. Physiol. Tab. Ehrenberg has counted more than twenty, serve VIII. fig. 57, 58 (Helix pomatia). In the vascureally as branchiae as this naturalist asserts lar net-work which Erdl (De ielicis algirae, &c., (Symb. physic. animal. evertebr. Mollusca), cannot fig. 6, copied in Carus, Erlauterungstafeln, Taf be determined except from a most exact analysis II. fig. 10) has figured with many details, all the of these organs. Troschel (Wiegmann's Arch. vascular trunks do not run towards the principal 1845, I. p. 197, Taf. VIII.) has shown with more vein, but with some their large extremity is directed certainty that Ampullaria is amphibious, for he towards the border of the lungs. found a pulmonary above the branchial cavity This disposition, however, does not exist in nacommunicating with this last, and lined with blood- ture. The pulmonary vessels of this species are vessels. arranged like those of Helix pomatia, which is 3 With Limax, and Arion, the respiratory cav- also confirmed by Van Beneden's figure of it; see ity has an annular form, its centre being occupied his Anat. de ilHelix algira, in the Ann. d. Sc. by the heart and kidney. Nat. V. 1836, P1. X. fig. 3, f.* 4 I have found ciliated epithelium in the pulmo. * [~ 221, note 6.] See, for the respiratory organs of the terrestrial Gasteropola, Leidy, loc. cit. p. 235. - ED. 252 THE CEPHALOPHORA. ~ 223. for, upon the back and directly behind the heart, there is a reservoir filled with water, from which ramifying canals pass off in all directions.(') The older observations upon these aquiferous canals of the Pteropoda, HI-eteropoda, and Gasteropoda, have been but indifferently increased by more recent labors. Wi.th these Cephalophora, the substance of the envelope of the body is permeated by a beautiful net-work of wall-less canals, which are filled with1 water, it is supposed, through several orifices upon the surface of the body.(2) It is, nevertheless, far from being settled that these canals belong to an aquiferous system, for the existence of their external orifices is doubtful, and it may be urged that they are only a continuation of the venous system.(3) At all events, this question demands further researches based upon facts observed with the Acephala and Cephalophora. CHAPTER VIII. ORGANS OF SECRETION. I. Urinary Organs. ~ 223. With most of the Cephalophora, the Urinary apparatus consists of an uneven, lamellate gland, which is usually situated near the branchial or princiI According to Souleyet (Compt. Rend. XIX. p. has named it Apparato idro-pneumatico or Sis360, XX. p. 93), there is, with Actaeon, an aquif- tema linfatico-venoso; see his Descriz. I. p. 88, erous system, arising from a reservoir of water &c., Tav. XXXI. XXXIV. XL. &c. (Cymbulia, situated behind the heart, and which he has called Hyalea, Carinaria, Pterotrachea, Doris, TriPoche psulmolnaire, which is spread through the tonia, Thetis, Pleurobranchaea, Diphyllidia, whole of the body. Vogt, as he has written me, Doridium, Gasteropteron, Aplysia, Bulla, Sihas distinctly seen this system with a canal open- garetus, and Janfthlina). With Cymbulia, and ing on the right side behind the anus. Allman Gasteropteron, this aquiferous canal communi(loc. cit. p. 148, P1. v.. fig. 4, a. a. b.) has also cates with a large sinus from which passes off a observed it in the same species, but he took it for a long afferent canal which projects from the surface blood system. The canal, which, with Venilia, of the body (see Delle Chiaje, Descriz. loc. cit. Tav. opens at the posterior part of the back, and which XXXII. fig. 1, 2, g. LV. fig. 2, b. f. 4. c. a.). has been taken by Alder and Hancock (loc. cit. 3 Meckel (Syst. d. vergleich. Anat. VI. p. 72) XIII. P1. II. fig. 1, 7, b.) for the rectum with its positively denies the existence of an aquiferous anus, belongs also, perhaps, to an aquiferous sys- system and its external orifices. But he maintains tem, as well as the orifice figured by Delle Chiaje that the marine Cephalophora can absorb and re(Descriz. loc. cit. Tav. LXXXVIII. fig. 2, d.) in ject simply by their skin, considerable quantities the same region, wtih Aeolis cristata (Venilia?). of water, without the need of special orifices. 2 Delle Chiaje is as yet the only natunrlist who Milne Edwards (Compt. IRend. XX. p. 271, has published quite detailed researches upon the or Froriep's neue Not. No. 733, p. 98) declares aquiferous canals of the Cephalophora indicated in that this apparatus, such as described by Delle the text. In an earlier work, he has described Chiaje, belongs to the venous system. He also them with Doris, Thetis, A/plysia, Pleuro- denies the existence of external orifices, explainbranchus, Pleurobranchaea, Bulla, Doridium, ing the ingress and egress of water which has Diphyllidia, Turbo, Trochus, Nerita, Conus, been observed with these animals, as due to endosCypraea, Voluta, Buccinum., Murex, Ceri- mose and exosmose. Van Beneden, also (Ann. d. thiunm, Rostellaria, Haliotis, and Patella, as Sc. Nat. IV. 1835, p. 250), says that he is convinced canals which traverse the foot, opening, for the that with Aplysia the so-called aquiferous canals most part, on its borders by numerous orifices (see are only a dependence of the venous system. On his Descrizione di un nuovo apparato di canali ac- the other hand, he is inclined to admit that, with qluosi scoperto negli aninaali invertebrati marini, Aplysia, and Carinaria, &c., there are small oriin his Memor. &c. II. p. 259, Tav. XVII. fig. 10- fices by means of which these animals can mix 15). Since then, he has described this system, water with their blood (Compt. Rend. XX. p. 520, which, he says, is wanting with the aquatic Pulmo- and l'Institut. No. 627, or Froriep's neue Not. No ilota, as a beautiful, subcutaneous net-work. He 727f', p. 4, and No. 797, p. 65). ~ 223. THE CEErALOPHORA. 253 pal pulmonary vein. Its excretory duct accompanies the rectum and often opens near the anus. 1) The kidney is nearly always of a dirty yellow, or reddish color, of a lamellated structure, and its surface is wholly without vibratile organs. It is surrounded by a sac-like envelope which is continuous with the internally ciliated, excretory duct. Each renal lamella is composed of thicklyset, delicate cells loosely bound together. In their transparent liquid floats an obscure nucleus which, by direct light, appears brown or violet. These nuclei, which are round and embossed, have a very dense crystalline structure, and are undoubtedly a product of the renal secretion.'() Certainly they contain the uric acid which is found when the whole gland is chemically analyzed.(~ The ramified canals upon the membranous envelope of the kidneys, return, probably, the blood into the respiratory organs. But in the gland itself no blood-vessel has been observed.'4) With Sagitta, and the other Pteropoda, nothing like a renal organ has yet been found. With the Heteropoda, and Apneusta, on the contrary, there are vestiges of certain organs which further researches hay show to be of a urinary nature.(5) With the Pectinibranchia, the kidney is replaced by a gland which is situated behind the branchia, between the heart and liver, and which, in some marine species, secretes the purple liquid. It is composed of several ramified lamellae, and opens by a large orifice, or by a duct of variable length which accompanies the rectum, at the base of the branchial cavity. 6) With the other branchiated Gasteropoda, the existence of this gland is yet doubtful, although with most of them, and 1 This is the gland which, with the Gasteropoda, a urinary gland. The long, yellow ciliated body, has been considered by the older anatomists such but without excretory organs, which Nordnmann as Swaorzmerdanm-, Poli, and Blszmenbach, asan (loc. cit. p. 24, Taf. II. Q.) observed with Tergipes, organ secreting the calcareous salts, and by Cuvier between the stomach, liver, heart and rectum, is as a muciparous gland. also, perhaps, a kidney; at all events, as such 2 This gland corresponds, consequently, as to its cannot be regarded another and neiglboaring body, position and intimate structure, to the bodies of larger, lobulated antd of a yellowish color, having Bojanus, which, with the Lamellibranchia, have apparently an excretory canal opening externally, been considered as kidneys * exceptilg that they and which already has been nientioned as being anll have no ciliated orgais. For the intimate struc- hepatic glatLel. Perhaps a like interprettLtion ture of the kidneys of Gasteropod0a, see H. Aleckel, should also be pllt upon. the yellow bodies observed in Mailler's Arch. 1846, p. 13, Taf. I. by Qlatrefages in the pl;sterior port of the body 3 Jacobson (Jour. de Physique, XCI. p. 318, or of Zep/hyrina, Actaeon, and Ampholrina (Ann. d. Meckel's Arch. VI. 1820, p. 370) was the first who Sc. Natt. I. p. 136, PI. IV. fig. 1-3). showed the presence of uric acid ii this glalldl, withl 6 WTith Tritosniu.n, and ilq.'Irex, this gland Helix pomatia, and nemor alis, Limax niger, openls by a largte orifice into the cavity of the mall.Lymnaeus stagnalis, and Planorbis cornea. tie; see Eysenshardt (Mleckel's Deutsch. Arch. But, Aoma time previous, D1)lling.er and WFohnlich VIIi. p. 216, T1:1. II. fig. 4, r.), arid Leibleins (Diss. de Helice pomatia, Wirceb. 1813, p. 23) hald (He ussi ger's Zeitsch. fiilr. i. gan. Phys. I. p. 4, regarded this organ as t kidney. The presence of Taf. I. h. i., or Ann. d. Sc. Nat. XIV. 1828, p. 179, uric acid can be easily shown in the dirieod kidneys P1'l. X. h. i.). A similar urinary gland has been of Helix pomatia and Paludiina vivipara, for described with Janthina, by Delle Chicae (Dewhen treated with nitric acid arid amnmonia, a con- scriz. It. p. 108, Tav. LXVII. fig. 3, e., LXYllI. sidertoble quantity of murexid is disengagel. fig. 14, i. i.), as an accessory respiratory ctvity. 4 According to Treviranus (Beobacht. aus. d. VW'ith Palltdina, this gland has a quite long exAnat. u. Physiol. p. 39), with Helix and Arion, a cretory duct i see Cuvier, Alem.!oc. cit. fig. 3, 1. 7 portion of the blood of the lungs, instead of going p. q. The kidney has, moreover, been described to the heart, passes into the kicdneys, and thence by Cuvier (loc. cit.), and Quoy anld Gailmar' enters the great pulmonoary vein. But it must be (Voy. de l'Astrolabe Zool. II. or, Isis, 1834, p. 285, very difficult to show the course of this liquid in 1836, p. 31) under the names of Jlfttciparous the interior of the kidnexs. gland, Organ of the purple, and Depurating or5 The spongy substance mentioned by Delle gan, with Phlasianella, Turbo, Buccinum, MiChiaje (D)escriz. II. p. 9G, Tav. LXIII. fig. 3, tra, Oliva, Cajpraea, Harpa, L'olium, Cassis, s.) as existing near the heart and at the base of Purpura, Fusus, Auricula, &c.* the branchiae, with Carinaria, is undoubtedly *[ ~ 223, note 6.] For the renal organs with Paladina, see Leydig, LUeber Paludina vivipara, &c., loe. cit. p. 180, Taf. XIII. fig. 49, 0. - ED. 22 251 THE CEPHALOPHORA. ~ 224. especially with the Nudibranchia, and Tectibranchia, there is a glandular apparatus which may perhaps be of this nature.") With the terrestrial and aquatic Pulmonata, the lamellated kidney is quite distinct. In the species having a shell, it is of riband-like, or triangular form, and situated beside the heart and the large pulmonary vein. Its excretory duct arises from the anterior extremity and passes, first, backwards to the rectum, near the posterior corner of the gland, then turns and runs forwards terminating, finally, in the respiratory cavity near the anus.s') With the Limacina, on the contrary, the kidney surrounds the pericardium like an annular collar, and its excretory duct opens near the respiratory orifice.(9). Or gans of peculiar Secretions. ~ 224. Mention has already been made of the parts of the mantle which secrete the calcareous substance,(1) and further on, I shall speak of the dif ferent glandular appendages attached to the genital organs.(2) As to the other organs of particular secretions which are less common, I will mention the following: 1. With those Apneusta which have cutaneous appendages, there is, in the dorsal and lateral lobes, a follicle whose excretory orifice opens at the extremity of the lobe, and which secretes a granular mucous substance, and peculiar corpuscles which resemble the nettling organs of certain Zoophytes. (3) 7 With Doris, there is found between the lobes cretes a large quantity of a red liquid; this also is of the liver a gland, which sends off backwards a probably a kidney.see Cuvier, loc. cit. p. 11, P1. long excretory duct which opens externally close by II. fig. 1, c. D. E. fig. 3, B. C. D., and Delle Chithe anus and has sometimes near its extremity, a aje, Memor. II. p. 55, Tav. II. fig. 2, r. t. 5, 6. vesicular dilatation. This gland, formerly taken With Vermnetus, and oIagilus, there is an analofor a liver, is probably a urinary organ; see Cuc- gous gland behind the branchiae. However, this vier, loc. cit. p. 16, P1. I. II.; MecLkel, Beitr. zur renal apparatus of the branchiferous Gasteropoda vergleich. Anat. I. Hft. 2, p. 9, Taf. VI. fig. 3, 1. demands a more careful investigation in both an and Delle Chiaje, Descriz. II. p. 25, Tav. XLI. histological and a chemical point of view.* fig. 12, n. y. C. fig. 21. 8 See the figures of the kidney of Helix and The orifice found with Thetis, directly behind Lymnaeus in Cuvier, loc. cit., and in Treviranus the anus in the dorsal region, is also in communi- Beobacht. &c. Tab. VIII. fig. 58; see also Paasch,. cation with a gland which may be regarded as a in Wie mann's Arch. 1843, 1. p. 78, and, De Gaskidney; see Cuvier, loc. cit. fig. 1, e. and Delle teropodum nonnullorum hermaphroditicorum, sysChiaje, Descriz. II. p. 35, Tav. XLVII. fig. 1, q., tem. genit. et uropoltico, Diss. Berol. 1842. XLIX. fig. 3. Delle Chiaje (Ibid. Tav. XLII. fig. 9 See Cuvier, loc. cit. P1. II. fig. 8-10, and Tre1, 3) has seen with Tritonia, a similar gland viranus, Beobacht. Tab. IX. fig. 59 (Arion), and opening into the rectum; and with Gasteropteron Paasch, loc. cit. p. 82.t (Ibid. p. 86, Tao. LIV. a.), another situated be- 1 See ~ 203. tween the base of the branchiae and the heart. 2 See below, Chapter IX. The large triangular glandular mass, which, with 3 These glandular follicles which, from spontaneAplysia, is situated in the cutaneous fold envelop- ous contraction can empty their contents, commuing the shell, and lies in the space between the nicate, according to Quatreqages (Ann. d. Sc. Nat. heart, the base of the branchiae and the anus, se- XIX. p. 287, 291, P1. XI. fig. 5, 6), with Eolidina, * [ ~ 223, note 7.] See, in reference to this gland structure consists of arborescent digitations from a with Doris, Alder and Hancock. loc. cit. Part V. central canal. - ED. P1. II. fig. 1, g. g. t [ ~ 223, note 9.] For the renal organ and its For the renal organs of Chiton, see Midden- intimate structure with the terrestrial Gasteropoda, dorft; loc. cit. p. 72, Taf. VI. fig. 1, N. and Taf. see Leidy, loc. cit. p. 239. See also for the differVII. fig. 5, N. They consist of a velvet-looking ent varieties of this organ with this order, De St. substance which stretches on each side of the body, Simon (Jour. de Conchol. 1851, No. IV. p. 342), over the tendinous mass of the ventral muscles, who speaks of it as La Glande praecordiale. - and join together horse-shoe-like on the anterior ED. Iorder of the posterior diaphragm. Their intimate i 225. THE CEPHIALOPHORA. 255 2. The genus Aplysia has an apparatus of particular secretion, consisting of a group of pyriform follicles situated under the branchia, inside of the skin. Its excretory orifice is, behind the female genital opening, and its secretion is a whitish liquid with attributive corrosive qualities.(4) 3. Many of the Pectinibranchia, and Tubulibranchia, have upon the upper wall of the cavity of the mantle, a row of folds which secrete an extraordinary quantity of viscous mucus which is not excreted through any particular duct. () 4. With several terrestrial Gasteropoda, the median line of the foot is occupied by a straight canal lined with ciliated epithelium, which ends in a large orifice situated under the mouth. On each side of this canal, are rows of follicles that secrete a granular mucus which, passing into its cavity, is excreted externally, probably by means of cilia.(6) CHAPTER IX. ORGANS OF GENERATION. ~ 225. The Cephalophora propagate solely by means of male and female genital by a narrow canal, with the prolongations of the Feuillets muqueux, are also found with Murex digestive cavity which enter into the dorsal ap- (Eysenhardt, in Mleckel's Deutsch. Arch. VIII. pendages, and their contained liquid is subjected to p. 215, Taf. III. m. m.), Terebra, Turbo, Voluta, a process of respiration. But N~ordmann (loc. cit. Cypraea, Harpa, Dolium, Cassis, Tritonium, p. 33, Tab. II. R. R.) has been unable to find any &c. (Qucoy and Gaimard, Voy. de l'Astrolabe, loc. such communication between these two organs, cit., or Isis. 1836, p. 35, Taf. II. fig. 6, q. Taf. III. with Tergipes, and he has distinctly seen the fig. 10, X. 18, in.). Carus (Museum Senckenberg. granular mucus which is expelled from the follicles II. 197, Taf. XII. fig. 8, h.) has seen similar mufrom contraction, escape through an orifice on the cous folds with MagilhLs. With Vermetus, on the extremity of each dorsal appendage. With Aeolis, contrary, I have found only a single, but a very according to Hancock and Embleton (loc. cit. p. considerable, longitudinal fold which runs along 50, P1. IV. V.), the product of these follicles is quite by the side of the rectum and covers the excreinteresting. It contains elliptical vesicles which im- tory duct of the genital organs.:mediately burst when put in water, exposing a 6 This muciparous apparatus of Bulimus, Hetransparent cylinder, out of which a filament, lix, Limax, and A ion, was announced in 1829, sometimes of a spiral form, is-projected as swift as by Kleeberg, at the Congress of Naturalists at lightning. They compared these bodies to sperm- IIeidelberg (Isis, 1830, p. 574); but it had not esatic particles; but to me, they appear exactly like caped the observation of Delle Chiaje with many fhe nettling organs of Actinia. Hancock and Ilelicina and Limacina (Descriz. II. p. 10, Tav. Embleton have also seen and figured with Aeolis, XXXVII. fig. 17, x.). It is therefore surprising a canal of communication between these follicles that it remained thus long unknown to other natuand the prolongations of the digestive canal, but it ralists. The assertion of Kleeber-, that with Li3may be questioned if this was not an artificial max, and Arion, the mucous canal communicates formation produced by compression of these organs with the venous system, I have been unable to conduring the examination.* firm by observations upon Arion. Leydig de4 Sse Cssvier, loc. cit. p. 4, fig. 2, C.; Delle clares that this mucous canal with the terrestrial Chiaje, Memor. II. p. 56, Tav. II. fig. 2, 0. fig. Gasteropoda is the seat of the sense of smell i; see 3; andi Rang, IIist. Nat. des Aplysies, p. 25. Schleidesn and Froriep's Notiz. IV. p. 24, or Ann..5 These muciparous organs described by Cuvier, of Nat. Hist. XX. p. 210. -with Buccinum (2Mhm. loc. cit. p. 5, fig. 3, f.) as * [ ~ 221, note 3.] See for further description, are analogous to the nettling organs of the Polyps. together with figures of these peculiar bodies con.Agassiz has carefully observed them, and they taining a spiral thread, Alder and Hancock, loc. have all the characteristics of a true lasso-cell; to cit. Part III. Pl. VIII. fig. 14 (Aeolis); they correct this I may add my own observations upon other their former view (mentioned above) and admit, Mollusca. - ED. what I think is not in the least doubtful, that they 256 THE CEPHALOPHORA. ~ 225k organs. These are either combined in one individual, or the sexes are sepi. arate. In most species there are copulatory organs. The genital organs. have several uneven divisions, which, when fully developed, are arranged as follows:. A Tuba Fallopii passes from the ovary into the uterine sac, at whose base is an organ which secretes albumen, while at the point where it is continuous with the vagina, there is a Receptaculum serninzis. The male genital organs consist of a testicle, a Vas deferens, and a Ductus ejaculatorius which opens into a retractile penis. With the hermaphroditic species, these two kinds of genital organs are more or less blended together, - the testicle with the ovary, and the Vas deferens with the Tuba Fallopii; very often also the vagina is united with the Ductus ejaculatoris, forming a. cloaca into which open several particular secreting organs. These different male and female organs are usually lined internally with ciliated epithelium. The eggs of these animals have, at their escape from the ovary, a round. and sometimes an elliptical form, and are composed of a thin chorion enclosing a finely-granular vitellus of variable color, which contains a germinative vesicle and dot.(l) The sperm is white and opalescent, and quite crowded with very active spermatic particles. These last are either of the form of Cercaria, or consist of a very long filiform body, one extrem — itv of which is incrassated and often of a spiral form. The trembling, undulatory movements of these particles cease when placed in water, with: those species which have copulatory organs; they become twisted into looplike forms and are finally rigid and motionless.(2) 1 See Carus, Erlauterungstafeln lift. V. Taf. II. early and its contents are condensed into a solid nufig. 4, al. (Limax), and in Muller's Arch. 1835, p. cleus around which are grouped the daughter-cells, 491, Taf. XII. fig. 2 (Helix pomatia); Wfagner, ultimately forming a bundle of spermatozoa. See,. in Wiegmann's Arch. 1835, I. p. 368, and Pro- beside these observations of Kollilcer, Nordmann, dromus, loc. cit. p. 7, Tab. I. fig. 6, 7 (Helix and and Paasch, loc. cit., those of H. Meckel, in _iil,Buccinum); and Allman, loc. cit. p. 152, Pi. II. lert's Arch. 1844, p. 483, Taf. XIY. fig. 9-13, andi fig. 7 (Actaeon). the more recent researches of KElliker, in the Neue 2 Wasner and Erdl (Froriep's neue Notiz. No. Denkschrift. d. allgem. sch.veizer. Gesellsch. f. d. 249, p. 98) have found with Chiton, Patella, and gesammt. Natnurwissensch. YIII. 1846, p. 4, Taf. Haliotis, spelmatic particles of a Cercarian-form, I. fig. 1-10 (Helix ponlatia). that is with a long body to which is abruptly at- The presence of two kinds of spermatic parti — tached a hair-like tail. I have seen a similar form cles in the sperm of Paludinza viviparai is a very with Vermetus gigas and triqueter. Those of remarkable fact; see my observations in Mliiller's Trochus also have this form, according to Kolli- Airch. 1836, p. 245, Taf. X. ker (Beitr. loc. cit. p. 28), but the middle of their Beside the hair-like spermatic particles already body has a slight constriction. They are hair-like, mentioned, there are long cylindrical bodies, fromn and taper at both extremities with Turbo, Bucci- one of the extremities of which project many delinum, Purpura (KbIlliker, loc. cit. p. 25, Taf. I. cate flaments having very lively motions. These fig. 5), and Sagitta (Krohn, loc. cit. p. 10, fig. 12). have been described by Ehrenberg (Symbol.. With other marine Gasteropoda. as for examlple, physic. Anim. evertebrat. Dec. I. Phytozoa entoCarinaria, these particles are hair-like, but with zoa, Appendix) as parasites under the name Phaone of their extremities slightly itcerassated (3lfilne celura paluedinae. Edwuards, Ann. d. Sc. Nat. XVIII. p. 324, P1. XI. Paasch (Wiegmann's Arch. 1843, p. 99, Taf.. fig. 7); and with Doris, Ter-gipes, and Paludina, V. fig. 8), on the other hand, regards them as bunnthis th;ckened extremity has a spiral form (K1lli- dies of spermatic particles of the normal form, and ker, Beitr. loc. cit. p. 35, Taf. I. fig. 6; Nsord- Killiker (Beitr. loc. cit. p. 63, and Neue Denkschr. mann, loc. cit. p. 52, Taf. III. fig. 8, 9, and my loc. cit. p. 41) considers them only as two forms. observations in 3lIiller's Arch. 1836, p. 240, Taf. of the same kind of spermatic particle: the second X.). With the pulmonate Gasteropoda, the sperm- he regards as elongated mother-cells containing atic particles have only a short incrassated extrem- many ordinary spermnatic particles. ity of a spiral form; see my observations loc. cit. For my part, I do not know how to explain this 1836, p. 45, Taf. II.; Paasch, in Wiemnzann's fact, and I would willingly place the second formn Arch. 1843, I. p. 71, Ttaf. v., and Diejardin, Ob- in the category of Spermatophora i but against this serv. au Microscope, Atlas, Pl. III. opinion, as against that of Kolliker, and Paasch, The development of these spirmnatic particles it can be urged that, with the second form, the extakes place in two large cells (Mother-cells), in tremities are never thickened or spiral, as is true which are formed others (Daughter-cells) which are of the first, and that both forms are simultaneously changed into the spermatic particles. But the cell- developed in the testicle.* membrane of the mother-cell, disappears quite * [~ 225, note 2.] My own observations on the development, correspond closely with the above spermatic particles of the Cephalophora and their account. Theif dd elopment in special ce Us I have ~~ 226, 227. THE CEPHALOPHORA. 257 ~ 226. Among all the hermaphrodite Cephalophora, the genus Sagitta stands wholly alone, in having all parts of its genital apparatus double. The ovaries consist of two straight, non-ciliated tubes situated at the posterior extremity of the cavity of the body; these open externally by au arcuate oviduct, situated upon the back directly over the median line of each of the posterior lateral fins. The two internally ciliated testicles fill the caudal cavity, which is divided into two chambers by a longitudinal septurn. They send backwards: two short deferent canals, which open in front of the caudal fin, by two tumlid: orifices, but are without copulatory organs.(0) ~ 227. As for the other hermaphroditic Cephalophora, to which belong the Pteropoda and a majority of the Gasteropoda, the genital organs of the Nudibranchia, Inferobranchia, Tectibranchia, and Pulmonata, have been the most thoroughly investigated. But the different divisions of these organs have been interpreted in a manner so varied and contradictory, that one can almost despair of having any positive knowledge of their relations. 1) 1 See Krohn, loc. cit. p. 9, fig. 2, 7-9. The cil- tions, regarded this gland, with the Pulmonata. as, iated epithelium which covers the male genital an ovary, and the albumen-secreting organ, as a organs of Sagritta, from the posterior extremity to testicle. Treviranus (Zeitscll. fur Physiol. I. the genital orifice, produces a general up-and-down p. 3. V. p. 1-40) was of the opposite opinionl; hemovement of the sperm in the testicle, a phenome- considered the hermaphrodite gland as a testinon which Darwin has compared to the ulotions cle and the other as an ovary. This view has. of the sap in Chara (Ann. of Nat. Hist. XIII. p. been adopted by Prevost ( Mlem. d. 1. Soc. Phys. U3, P1. I. fig. 1, or Froriep's neue Notiz. No. 639, p. de Gen4ve, V. p. 119, and Ann. d. Sc. Nat. AXX. 3, fig. 62, and Ann. d. Sc. Nat. I. 1844, p. 362, p. 33, 43), and by Paasch (Diss. loc. cit. andi PI. XV. B). For the genit'l organs of Safitta, Wiermanun's Arch. 1843, 1. p. 71, 1845, I. p. 34). see also the researches of Wilms (loc. cit. p. 12). In England, Rymer Josses ad:)pts the view of Cu — 1 It has been quite difficult to reconcile the fact vier-, and OLen that of Treviranuzs. Woohnlich that, with these animals, the testicle and the ovary (loc. cit. p. 32) names as ovary, the albumen are united in a single body, -the Hermaphrodite gland * and as testicle, the half-calllal which runs; gland. Cuvier, whose opinion has been followed along the uterus but he is in doubt as to the by Meckel, and Carus, in their different publica function of the hermaphrodite gland. Erdl, who: observed exactly likle K6iliker. I have found these recently gone over the ground, according his views. particles throughout this group, generally, to consist with those of Siebold and others above-mentioned of a delicate thread, one end of which is more or less (see Beitrag, loc. fit. in Siebold and K6lliker'sincrassated and twisted in a cork-screw manner Zeitsch. II. 1850, p. 125, Taf. XIII. fig. 31-43). (Elolis, Physa, Lymnaeus, Natica, Helix, Li- Leydi,, however, has watched their forination max, &c.); in some, however, the form is remarka- from cells; and here I may remark as being evibly different. Thus, with Buccinum, it consists of a dence against their being spormatic particles, that, thread with a terminal third somewhat incrassated, according to him, they are produced by the metabut which terminates in a delicate filament. This, morphosis of an entire nucleolated cell, and not, as as will be seen above, KIilliker has also noticed. is the grand law with spermatic particles, from a. As to the remarkable statements made above cell-nucleus. From this and from the above-men — upon two kinds of spermatic particles with Palu- tioned reasons, based upon analogy, I cannot addina vivipara, they deserve our especial attention. mit that these peculiar bodies are true spermatic My own investigations have led me to regard it as particles. Leydlig's observations on their developa law in Spermatology, that each animal had only ment of course render invalid the hypothesis of one kind of spermatic particle, the shape and size of Gratiolet that they are modified spermatic partiwhich in that animal, are invariably the same; this cles, having undergone changes, like those of the point I have regarded as so well established that Helicina, in the Vesicula copulatrix; see Jour. deI have proposed the basis of an animal classifica- Conchol, No. II. 1850, p. 116, and No. III. p, tion from spermatological data. I was therefore 236, P1. IX. fig. 3-7. -E D. surprised to find an observer like Leydig wvho has 22* 258 THE CEPHALOPHORA. > 227. It is only lately, that, from microscopical analyses of the contents of these parts, this point has been made clear. A peculiarity which distinguishes principally the Pteropoda, Apneusta, Nudibranchia, Inferobranchia, Tectibranchia, and Pulmonata, is the existence of a hermaphrodite gland. An exact knowledge of the structural relations of this gland has been the means of reconciling the hitherto confused opinions upon the genital organs of the (Cephalophora. This gland, which is nearly always buried in the substance of the liver, is composed of digitiform or botryoidal ramose caeca, bound together in groups of variable size forming a lobulated organ. Upon each caecum is an external sac, producing eggs, and an internal one, folded in the first, producing sperm. The walls of these two invaginated follicles are usually in direct contact, and are not separated fiorn each other except at the points where there are eggs which push the ovarian sac outwards and the testicular one inwards. (2) From these sacs pass off excretory canals, which, also, are invaginated, and terminate in two principal ducts, the external of which is the Tuba Fallopii, and the internal the Vas deferens which is usually tortuous.(3) attributes to this last the function of an ovary scribed exactly the structure of this hermaphrodite (Beitr. zur Anat. d. Helicinen, loc. cit.), has ex- gland (Mliiller's Arch. 1844, p. 483, Taf. XIV. XV). pressed no positive opinion as to the function of It is, therefore, astonishing that Steenstrup the albumen gland. Steenstrup (Unders5gelser (Undersegelser, &c., p. 76, Tab. If. fig. 3,4), who over iHermaphroditismens Tilvaerelse i Naturen, knew the researches of Meckel, and who, judging 1845, p. 76, Tab. II.) has expressed a very singu- from his figures, saw distinctly the line of separalar opinion on the subject of the genital organs of tion between the ovarian and testicular follicles, the Pulmonata. He regards the Gasteropoda as has determined two fragments of this gland taken of separate sexes with which the different parts of from different individuals of Helix pomatia, the genital apparatus are double, and that only one as being one an ovary, and the other a testicle. In side is developed, the other remaining atrophied as this last-mentioned fragment, he has Salled spermin female birds. According to this, the hermaphro- atic cells not only those really such of the internal dite gland would represent the active ovary, in the follicle, but also the eggs contained in the external individuals which Steenstrup regards as females, follicle; while in the first-mentioned fragment, or and the albumen-gland would be the ovary on the the so-called ovary, he has named as eggs not only other side imperfectly developed. The uterine canal the real eggs but also the internal spermatic cells. wvould belong to the active side, the Vas deferens The spermatic particles, which he also saw at the would be the abortive uterus on the other side, and same time, would, according to him, be brought out the penis as an abortive analogous vesicle would by coition. correspond to the pedunculated vesicle of the active 3 Under the Pteropoda, Kolliker (Denkschrift. side. &c. VIII. p. 39) has found the hermaphrodite In the other individuals of the same species re- gland with Hynlea. From this, the organs degarded by Steenstrup as males, the hermaphro- scribed by Cuvier, Eschricht, and Van Beneden,,dite gland would be the active testicle, and the al- (loc. cit.), as ovaries and oviducts with Clio, Cymbumell-gland, the same organ on the other side, bulia, CleodoTa, Cuvieria, Limacina, &c., may abortive; the uterus would be the developed Vas be regarded as an hermaphrodite gland, and as,deferens, and the proper Vas deferens the unde- invaginated excretory canals. Under the Apneusveloped organ on the other side. The pedunculeated ta, thit gland has been seen by Killiker, with vesicle would have the same signiiication as with Aeolis, Lissosora, and Flabellina. It exists the female individuals, and the penis would be this also with Actaeon, judging from the description vesicle imperfectly developed.* of Allmann (loc. cit. p. 152, P1. VI. VII. fig. 8) 2 After R. Wagner (Wiegmann's Arch. 1836, I. of its voluminous and multiramose ovaries, in p. 370) had found in various Pulmonata, eggs and which, he says there are observed, beside the pro-,spermatic particles at the same time in one and the jecting sacs filled with eggs, others smaller filled same genital gland, aned I myself had expressed my with a granular substance. The first are very conviction (Ilbid. 1837, I. p. 51) that with these probably ovarian, and the others testicular follicles. Gasteropoda the ovary and testicle were united Tergipes, also, has a similar ramified ovary; but in a single organ, H. lieckel was the first who de- it was incorrectly interpreted by Nordmann (loc. * [~ 227, note 1.] This structure- a hermaph- where the androgynous apparatus is minutely derodite gland - is not mentioned by Alder and Han- scribed. stance. (7) With the Poecilopoda, Stomapoda, and Bopyrina, the hepatic organs are inserted at various points along the digestive canal.~(1 Finally, with the Decapoda, the liver consists of two glandular masses composed of more or less ramose caeca loosely bound together. Each of these glands, which sometimes occupies only the sidcles of the cephalotholax, but sometimes, also, largest portion of the alimentary caial dotted with 1837, p. 435) consists of three pairs of yellow varismall, yellowish-brown follicles, which I can only cose tubes. WXithl Oniscc s, Porcellio, As.ellus, regard as hepatic organs, althousgh other Zooto- and Ly2'idiumZ, there are four very long varicose mists considler them as Xpllpi lihian canals (see heplatic tubes Nwhich open right and left illto the ~ 287). L. Dufou.r (lc. cit. p. 96, P1. Y. fig. 4, pylorus (TreviranCtus, Yeire. Schrift. I. ). 57, Taf. B.) has found these follicles in the stomach of Scus- 8II. fig. 38, Taf. IX. fig. 50O Taf Xi. fig. 64 tigera, but did not regard them as hepatic. Brandt, Metliz. Zool. II. p. 75, Taf. X'. fig. 39 The numerous large cells, which, according' to Ler ebo/llet, loc. cit. p. 130, P1. V. fig. 25; KacrisSerres (Ann. du Mus. d'list. Nat. XX. p. 250), ten, loc. cit. p. 296, Tab. XXS IIX. fig. 1). Trecover the externlal tunic of the int stile of Lith/o- virlecats, who dild nt observe the excretory ducts bines, are certainly only follicles of this kind.* of these glands re'arldedl theml as masses of fat, 5 With Daphnia, there are two lateral, back- while Rameedohr (Ablensdl. iib. cid. V elidauunisw. wardly-curved caeca, which ascend frol the e ante- &c. p. 201, Taf. SXX III. fig. 5),) cwhoi pl robably by rior extremity of the digestive canlal tocwards the cnistakle, has figulred with Porcellio three silmilar dorsal surface of the hea cl see Schaefea, loc. cit. apl)endagces has talen thelm for salivary olgans. p. 41, Taf. II. fig. 2, k. Ik.; Strases, lee. cit. p. There are thricee pairs of hepatic canals w-ith Cyosco401, P1. XXIX. fig. 6, s. o. s., and JTerinse, Iist. d. thoa (tLeclcel, Syst. d. verg'leich. Anat. IV. p. 154), Alonocl. P1. IX. X. fig. 7, XI.-XIII. With Aega (Rath/lc, Nov. Act. Nat. Cur. XX. p. 30, Branchipus, and Artem.ia (Joly, Ioc. cit.), the Tab. VI. fig. 16,'d. d. 18), alnd Lygia (islne Edanterior extremity of the digestive tube has also wards, Ilist. Nat. d. CrusL. Pl. IV. fig. 3). I cantwo short caeca which, with the glacdulacl tunic not now decide whel-lther Hiella has reclly only one with which the remainder of the intestine is cover- va ricose hepatic tube, or whllether thle others were ed, should be regarded as a liver. XWith Argulus, overloolked by Strauts (loc. cit. p. 590 P1. IV. fig. the stomach has two multiraminose caeca, whichl lie 15). With Gaimarus, and the other Amlphipoda, in the parenchyma of the body (JSierine, ioc. cit. p. I have found two pairs of long hepatic tubes. 441, P1. XXVI. fig. 1-3, 9, or Vogt, loc. cit. p. 8, Frey and Leuc/lcari t (Beitr. p. 104) have found fig. 1, 9). With Apses, these caeca are given off with Caprella, as with C'yamis, two silmple hepa-. from the anterior extremity of the digestive caalle tic coeca. and do not extend beyoicld the anterior borderl of the 8 With Limeulus, there are four groeups of intercephalothorax (Schaffer, loc. cit.. 7p 0, Taf. V. laced caecal canals situaLted in both sides of the fig. 15, a. a.). Accordiing to Zaddach (loc. cit. p. cephalothorax. Th'le bile is poured into tile ante8, Tab. I. fig. 10-13, and Tatb. IV.), these caeca rioe porotion of the intestine by foti distinict exerecontain numerous gcladularl foillicles.t tory ducts, which asre widlely separattl ilfrom each 6 Beside the tigcures of these stomachic appencd- other (Van der Lloeven, loee. cit. i) 18, Pi. II. fig. ages in the works of Cusvier,. Burneister,. an. c 1, 5, 8). With Squilla, /BopyrLs, anc d cciP/r'yxLs, Martin St. Anve, see alsl lparticularly tihose whlich the digestive caccnal has raimose or varic;)se hepatic Karsten (Nov. Act. Nat. Cut. XXI. p. 301, T>ab. caecsa on both sides, at irreguilar intelrvals, of its XX. fig. 1-4) has given of the hepatic organs sur- whole len(gth (liiller, -De Glcllcd. Ssluct. p. 70, rounding the pylorus with Balanuls. Tab IX.; Duvernoy, Ann. l. Se. Nat. tI. 1836, 7 With Cyamits, there are two long hepatic p. 243, PI. XV. fig. 1 (Sqic/lal); anld Pathlike, De canals which winld over the digestive cansal (Rosts- Bopyro et Nereide, p. 9, TIb. I. fig. 7, andl Nov. sel de Vattzeme, loc. cit. p. 252, Pi. IX. jig. 19). Act. Nat. Cur. XX. p. 47, (1oopyr tS;tlld P/hryThe two stomachlic appendlages of Idothea which us.) The genus liysis (1'r ey, loc. cit. p. 19) on Rat/shk (loc. cit. p. 121) has tatken for adclipose the contrary, which has eight hepacitic ctlals openbodies, belonsg to the hepltic apptaslstus which here, ingc right slald left into the ibase of the stomach, reaccording to my observationis (MAlller's Arch. sembles again tie Amphipediocl and Isopoda. * [~ 230, note 4.] For the liver of Jcc/es, see by Leydi- (Ueber Argulus, &c., and Ueber ArLeidy, loc. cit. Hie salys, "At the terminationl temia, &c., loc. cit. Sicbold and Kllliker's Zeitsch. of the proventriculus, there open two biliary tubes, II. p. 334, and III. p. 2S6) on histological groulds; and from it, surrounding the commencement of the it is most probable howerer that they serve as a ventriculus, is suspended a broad, white, opaque, liver, since Will (Miller's Arch. 1848, p. 506) has reticulated band, apparently composed like the shown, by chemical analysis, the hepactic nature of rete adiposa of insects." -ED. analogous caecal tubes with Dap/hnia and Cyclops. t [~ 230, note 5.] The hepatic nature of these — ED. appendages with Artemia and Argulus is denied 334 THE CRUSTACEA. ~> 281, 282. reaches even to the tail, pour their secretion, by a short duct, into the digestive canal on both sides close behind the pylorus.~() ~ 281. With many Crustacea, the digestive canal is surrounded with fat-cells, the contents of which are often of a beautiful orange or blue color. These cells either consist of a few scattered globuies,(l) or are disposed in lobes of valrious foims.~') This tissue is undoubtedly analogous to the Corpus adiposus,. so comlmon in insects. The fat which these cells contain, plays a part, probably, in digestion and assimilation; for with these animals the excess of nutriment is deposited as fat to be used in times of need, as, for example, during the act of moulting. This explains why the quantity found is so variable, or even may be entirely wanting. CHAPTER VI. CIRCULATORY SYSTEM. ~ 282. Although the blood of Crustacea traverses the body by a very regular circulation, yet, as with all the Arthropoda, the vascular system is here quite imperfect, the blood-currents not always being contained in proper canals. But a central, propelling organ is very rarely absent, and consists of a heart, sometimes round and vesic.uliform, somutimes long and tubular. With the higher Crustacea, it is the point of departure of an arterial system which, with the lower orders, gradually becontes abortive, and at last entirely disappears. The more or less long arteries do not terminate peripherically in a capillary net-work, but the blood is freely effused into the 9 For the liver of the common crawfish, which is 13; and Delle Chiaje, Descriz. &c. Tav. LXXXVI. loarge but contained in the cephalotholax, see the fig. 6.* descriptiOLns and figures of Roesel, Sltck-o?, 1 These fat-globules, of an orange color, are often G6eveke, Brandt, and Schlemm, also those of Mul/- found scattered about in Cyclops, Daphnia and ler (De Gland. Stract. p. 69). Thils last mentioned Gamnmars. author foun(l the liver contformable with that of i Such lobes and of a blue color are found with many of the other Macrura and Bniachyura. Milsne Branchipous on the sides of the digestive canal. Edwards (Ilist. d. Crust. P1. IV. fig. 5) has fouind, Other whitish adipose masses form a kind of netwith Iaiea, a hepatic mass very remarkable in being work around the intestinal canal of Lernaea, Lersymmetrically d'vided into several lobes. With naeocera and Lamproglena (Rathki, Nov. Act. Pag0erus, there is, on each side of the pylorus, a Nat. Cur. XX. p. 129, and Nordmann, loc. cit. p. long bliliary vessel, which extoends along the intes- 6, 125, 132, Taf. I. fig. 4, Taf. VI. fig. 4). This tine to tile extremity of the tail, and into which last observer has regarded this reticulated mass as asmerouslateral follicles empty their product; see a liver. With the Myriapoda, these adipose Svoammcrdamm, loc. cit. p. 86, Taf. XI. fig. 4, 5; masses are large, lobulated, and occupy quite a iltIuller, De Gland. &c. p. 70, Tab. VIII. fig. 12; space in the visceral cavity. * [ 281, note 9.] For the intimate structure microscope, see Leidy. Amer. Jour. Med. Sc. 1848} of the liver of Crustacea, as elucidated by the XV. p. 1. -'D. S 283. THE CRUSTACEA. 335 lacun;ae which lie between the different visceral organs and appendages of the body. But, notwithstanding the absence of vascular walls in these interstices, the blood moves in determinate directions, until, after a course of variable length, it is returned to the heart. During their course, the blood-currents are often taken up by particular reservoirs, which, as venous sinuses, nmay be regarded as forming the rudiments of the venous system. In this manner, notwithstanding the imperfection of this vascular apparatus, all the organs constantly receive fresh blood, which is nowhere stagnant; also, the arterial may be clearly distinguished from the venous currents, even when the arterial walls are wanting. The Blood, itself, is either colorless, or of' a faint red or violet hue. These colors belong to the blood-liquid, and not to the contained globules, which are few and always colorless. These globules are round, oval, or pyrifbrinm; their surface is rough, and they contain fine granules, and, often a very large nucleus.(1) ~ 283. The Heart of the Crustacea is always situated in the axis of the body, directly under the shell, at the anterior part of the back, and is often attached to the internal surface of the skeleton by muscular fibres. Usually, its walls are thin and composed of scattered muscular fibres interlaced in various ways. By the contraction of these fibres the blood is propelled from behind forwards through the arterial orifices, - those of the veins being closed at the same time by valves. The number of these different orifices, and the form and divisions of the Heart, have the following modifications: 1. With many of the lower Crustacea, especially with the Siphonostoina, and the Lophryopoda, the heart is a simple, thin-walled sac, of either a spheroidal or an elongated form, but invariably with only two orifices, - a posterior or venous, and an anterior or arterial.() 1 For the blood of Crustacea, see Wagner, Zur 57. P1. V. fig. 4) thinks he has observed a distinct -vergleich. Physiol. d. Blutes, p. 21. It is pale red auricle underneath the heart of Cyclops; but for,with the craw-fish * I have found it deep red with my own part I have been unable to see it. As to a Apus, and violet with Garnrmarus. That of Pa- second or ventral heart, situated under the dorsal linurus is also pale red, according to Luond and heart, which, according to Perty (Isis, 1832, p. Schultz (Isis, 1830, p. 1223). See also Nord- 725), is found with Daphnia, I have been as unable mann, loc. cit. p. 73 (Achtheres); Joly, loc. cit. as Wagner (Vergs Anat. 1834, p. 166) to find it. p. 238 (Artensia); Zenker, loc cit. p. 20 (Gam- With Argulus, the heart is long and situated under marus); Frey, loc. cit. p. 21 (Mysis), and Carus, the dorsal shell, as Vogt (loc. cit. p. 9, Taf. I. Von d. aUisseren Lebensbeding. d. weiss-und Kalt- fig. 1, 10, eM.) has shown, contrary to the opinion Slutigen Thisre, p. 80. of Jurine (loc. cit. p. 437, P1. XXYI.). With'The heart is round or ovoid, and its pulsations Achtheres, Dichelestiusm, ChondracatIn.hs s, the quite frequent, with Daphnia, Lyncesus, Poly- heart consists of a long cylindrical tube (Nordphemnus, and Evadne, where it is situated at the an- mann, loc. cit. p. 73, and Rathki, Nov. Act Nat. terior part of the back, and very easily seen (see the Cur. XIX. p. 153, and XX. p. 125). The anterior figures of it given by Straus, Jusrin e, and Losen, and posterior valvular system which Pickering loc. cit.). According to Nordmuann (loc. cit. p. and Dana (Isis, 1840, p. 206) have seen with Cali11), there is also a round heart in the cephalo- gus, lead us to think that here also there is a heart thorax of Ergasilus. Jurine (Hist. d. Monocl. p. between these valves.* * [ ~ 283, note 1.1 With Caligus, the circula- form the functions of this organ; see Dana, Calition is wholly lacunal, and appears to consist of gus, &c., Amer. Jour. Sc. XXXIV. p. 257, PI. III. broad irregular streams, passing through the fig. 6, a. 6, b. spaces left by the internal organs, - there being in A corresponding structure has been found with no part distinct vessels. A single centre of circu- Argulus, by Leydig (loc. cit. Siebold and Killilation, or a heart, can scarcely be said to here exist, ker's Zeitsch. II. p. 335, Taf. XIX. fig. 3), who has but there are two points in the median line where given, moreover, many histological details upon the there is a valvular action, and which perhaps per- circulatory systenm of these animals. - ED. 336 THE CRUSTACEA. 283. 2. With the other Crustacea, excepting the Myriapoda, the heart has, likewise, the form of a short simple sac, or that of a simple tube. In both cases, it is perforated by very numerous arterial and venous orifices. During the systole, the blood is propelled through the arterial orifices leading, nearly always, into vessels of the same nature; at the same time, the venous orifices are closed by valves, which open, however, during the diastole, to allow the ingress of the blood into the heart. With the Decapoda, the heart is vesiculiform, situated in the middle of the cephalothorax, and its projecting corners often give it a star-like aspect. This heart has arteries passing off in front, behind, and below, and the returning venous blood enters it through venous orifices on its upper lateral portion.(2) With the Poecilopoda, Isopoda, Armphipoda, and probably, also, with the Laemodipoda, and Cirripedia, the tubular heart, occupying a large portion of the anterior and middle regions of the back, sends off arteries before, behind,. and laterally, and receives the venous blood through lateral venous orifices. C) This organ is most highly developed with the Stomapoda, where it occupies nearly the whole length of the body like a tube;(4) but with the 2 There are, usually, in the polygonal heart of Isopoda, the tubular heart is continuous with the Decapoda, three anterior arterial orifices, two anl anterior and a posterior aorta 5 it receives only below and one behind. These open distinctly into three to five pairs of lateral vessels which have been as many main arteries; see Swammerdamm, loc. regarded sometimes as arterial andlc sometimes as cit. p. 87, Taf. XI. fig. 8 (Pagtrus); Roesel, loc. venous; see Treviranus, Verin. Schrift. I. p. 58. cit. p. 58, Taf. IX. fig. 14, and Suckoow, loc. cit. 65, Taf. VIII. fig. 46, and Taf. IX. fig. 55 (Porp. 58, Taf. IX. fig. 1, Taf. XI. fig. 2-4 (Astacus); cellio and Armadillidium); Bran.dt, 3led. Zool. Audouiz, and Mline Edwtards, Ann. d. Sc. Nat. I1. p. 75, Taf. XV. fig. 38 (Porcellio) LeireboulXI. 1827, p. 353, 363, P1. XXIV. XXVIII. fig. 1; let, loc. cit. p. 131, PI. V. fig. 3d3 (Lyg idiurm); and _Milne Edwards, Hist. d. Crust. P1. V. VII. Rathkk, in the Neuest. Danzig. Schrift. I.p. 122 (Ido(Mlaia and Homarus), and Cyclop. of Anat. loe. thea), and Nov. Act. Nat. Cur. XX. p. 31 (Aega). cit. p. 775, fig. 418 (Cancer). Not so easily seen It is, however, very probahle that these orifices are are the six venous orifices which always are only arterial, for they open into vessels, andi, moreover, valvular fissures, chiefly because they do not open the venous orifices are found, as with Limuluzs, on into veins. According to Lund, and A. W. F. the dorsal surface of the organ. For the AmSchultz (Isis, 1825. p. 534, Taf. III. fig. 2-4; phipoda, Gammaras puleex nmay be cited as a. Ibid. 1829, p. 1299, (fHomaruts), and 1830, p. 1226, type, and of which the heart as a cylindrical yeswith the figure of p. 1228, (Maia)), the heart of the sel occupies the axis of the anterior senments of the macrourous Dectapoda has two upper, two lower,and body. In this animal may be very easily seen. two lateral venous orifices, while that of the Brachy- how the blood, with the diastole, eilters the heart ura have only four upper and two lateral. Krohn through the several dorsal venous orifices, and (Isis, 1834, p. 54,'laf. XIt. fig. 1-3), has con- hos, with the systole, it is thrown forwards, backfirieled this observation witlih the crawfish. Suckow, wards and laterally through the arterial openings. however (loc. cit. p). 58, Taf. XI. fig. 2, a. a.), did We have not yet colmplete researches on the not perceive in this species only the two upper ori- heart of the Cirripedia but since MtCartin St. Arn e fices, while Astsdozsin and Miln/e Edwards (Ann. (loc. cit. p. 18) states that these aniinmals have a. d. Sc. Nat. loc. cit. p. 357, 364, P1'. XXV1. fig. 3, dorsal vessel with lateral trunks, it may be coniN.1l.) halve not observed in the heart of Homrrarus cluded that their heart is like that of the Amphiand Masa only the two lateral orifices. This poda, Isopoda, &c. As to the Laemodipoda, we last hasturalist (lIist. d. Crust. I. p. 94. P1. V. VI.) have only the imperfect details given by Trevirefuses to admit the description of the heart of ranus (Verm. Schrift. II. p. 8), and Roussel de the Decapoda given by Lund, and brings to Vauzm.e (loc. cit. p. 254), according to whiclh Iis suppolrt (Cyclop. loc. cit. p. 777) Hunter's there is, with Cyamus, only a simple tube opening preparations of the lobster; but, judging from the before and behind a and we are therefore unalble to beautiful figules of them given by Olwenl (Catal. of say whether this heart is formed after the first or the Physiol. Ser. 11. PI. XV. h. h. P1. XVI. fig. 2, d. second type indicated in the text. d. and especially fig. 1, f. f. f.) these are just the pre- 4 With _Mysis, the heart consists, according to paratiolls to support the view of Litnd, Schultz, Frey (loc. cit. p. 21), of a dorsal vessel extending and Krohn. I, tt least, have perceived distinctly from the cephalothorax into the back part of the the ulpper, lowser aind lateral venous orifices, as body; but the blood enters it only through a "the three orifices of the veincs assing into the posterior Ostiu/m venosum, and passes out into heart, f. f. f." See also the description of Owlen the body through an anterior Ostiuim arteriosum. of the heart of the lobster in his Lectur. onl Comp. If this orgoanization is confirmed, MIysis will differ Ana,t. p. 179, fig. 91. remarkably in this respect from the Isopoda, Am3 For the heart of Limtulis, see Strauis, Consid. phipoda, &c., but especially from another Stomagin. sur 1 asnat. comp. des anim. articulis, p. 346, pode genus, - Sqsilla a for in this last, the heart ansd especially Van der Hoeven, loc. cit. p. 18, with its anterlior, posterior and lateral orifices, P1. II. fig. 9. Beside the anterior and poster- reaches its greatest development, occupying the ior arterial orifice, there are, with these Crius- entire abdominal cavity excepl the cepihalothorax, tacea, seven others belonging to the seven pairs and sends off laterally fourteen to seventeen pairs of lateral arteries, and on the di'soal portion of arteries, beside being perforated on its upper of the organ, anl equal number of valvualar open- p-ortion l)y various pairs of venous orifices; see ings belosnging to the venous system. Withl the Dzovernoy, Ann. d. Sc Nat. VIII. 1837 p. 42, P1. 284. THE CRUSTACEA. 337' Phyllopoda, it is less elongated and has numerous constrictions, thereby resembling the following type.10) 3. This type, the third, is found with the Mlfyriapoda, and considerably resembles that of the so-called Dorsal Vessel of' the Insecta. With the Chilognatha, and Chilopoda, it consists of a ilore or less articulated lube, occupying the whole dorsal line of the body. It is divided by constrictions and imperfect muscular septa into chamlbers, nearly as numerous as the segments of the body. Each chamber is attached, as with the Insecta., right and left to the internal surface of the segments of the body, by trianrgular muscles. The Diastole is produced chiefly through these mlusles. At its anterior extremity, this dorsal vessel passes throngh an Osti/lm aerte-iosumn into an aorta, while, from the posterior extremity of each of these chambers are given off two lateral arteries. The returning blood enters the heart through the two venous orifices on the dorsal surfa.ce of each colipartment. The Systole consists of an unddulatinig action froml behind foiwards, and the blood is thereby propelled partly fiom onle chamber to the next; forward, and partly into the lateral arteries.(j' ~ 284. The Circulation outside of the heart, with the Crustacea, has very varied relations, as has already been mentioned. With the lower Crustacea, witlh the Siphonostoma, the Lophryopoda, and the Phyllopoda, the blood forms regular currents in the intervisceral lacunae and interstices, but there is no trace of vascular walls. The aortic current, shortly after leaving the heart,. divides into a right and left portion, which, also, sub-divide, enter the. appendages of the cephalic extremity, then turn and run along the abdominal surface of the body - furnishilg, in their course, several lateral, looplike currents, which ellter the locomotive organs, then turn again towarlds. the posterior extremity of the back, where they enter the heart.(l) II. fig. 1, and especially Audou.in and Milne.El- and fig. 25 (Sctti-era). According to these in — wards, Ibid. Xi. 1827, p. 376, P1. XXXLL.'3's'e vestig'ati.)ls, the iiterventricullar septa are scarcely last natur~alists have very distinctly reprlesKet.3d d evclI )d with the Chiiognatha, although very the dorsal venous orifices of the heart just men i- much S) iwith thl Chilpili)Oeit. tioned. 1 Ais ext'la vasculrL' circulation has been ohb5 With Branchipus, Artemia, Isaitra, aLd srvec wit th tle Lriarnaeodea, by Nordm'rtn (I;c. lpus, the Ileart which has severatl c)tstrictiotns cit. I). 7;, 933), aend wits the Caligina, by Pickieerand whose venous orifices are very apptl'leat, occu- ing a.l( Dsarnt (Isis, 1:40, p. 205, 13-1, Taf. IV.). pies the enitire dorsal median line excel)ti:lg iL the' J. rine (lec. cit. p. 4:37, Pi. XXVi. gfi. 8), and, caudal extremity; see Joly, Ann. id. Sc. N tt. with m:'-.e exalctaness, Vot (l:). cit. 1). 9, Taf. I. XIII. p. 239, P. VIII. fig. 4, j., XVTI. p. 307, Pl. fi0. 10), have describ.dl the circulation with Jrgu_ — IX. fig. 43, r. also Krohel, Froriep's nleu Not. lies. F'.r thott or Dtp/lnia, see Gruitlusisen, XLIX. p. 305, fig. 1, 2; aid Zaddach, loc. cit. p. Nov. Act. Nat. Cui. XIV. p. 403, Tab. XXIV. fig. 17, Tab. I. fit. 17, C., Tab. It. fig. 4-11:* 6; Perty, Isis, 1832, p. 725, mand Ehrenber-, 6 Although Treviranus (Verm. Schrift. It. p. Abhasllhl. d. Bd il. Ak3ad. 1835, I). 189, note. Zad31, Taf. VI. fig. 6), and Kiltor-g (l)c. cit. p. 18) dCch/ (loc. cit. lp. 23, Tab. I. fig. 17) has relprehave, indeed, furuished some commuliicatio:)as Oil seeted in much detail that of Apus. In order to the heart of Lithobius and Scolo)endra, yet we be c.)nvincedl of thle entire watnt of vascular walls are really indlebted for wllhat is knoWv[ of tlhe struc- with the )weri CIrust;cea, tllere is perhaps eec ture of this organ with tie MyriapodA: to the excel- species which will serve better than Arletluss bfolilent researches of Newport * see Pililos. Trains. aceus whose body is wholly flattened anld transXXIII. p. 272, PI. XII, fig. 18-22 (5'colopendra), parent throughlout.t [ ~ 283, note 5.] See also Leydi,, loc. cit. Sie- Siebold and KIlliker's Zeitsch. II. p. 337) upon bold and KIoliker's Zeitsch. III. p. 287 (Arltertia this saome species. IIis schema of the circulation and Branchipus). -ED. with these animals is as follows: "Thie blood is t[ ~ 284, note 1.] This statement of the coom- thrown from the heart into the interstitial lacunaeplete absence of true vessels in Argall8s, is con- of the organs; thereupon it is collected in tlle firned by thle researches of Leydi, (lc. cit. posterior portion of the heart; a portion of it 29 338. THE CRUSTACEA. ~ 284. With the other Crustacea, with which the heart is unarticulated, the blood passes from this organ into arterial canals; but the walls of these last sooner or later entirely disappear, so that here also the blood circulates at liberty between the interstices of the body. The regular arterial currents thus formed finally bend about and become those of the venous system. With the Isopoda, and the Amphipoda, perhaps, also, with the Poecilopoda, and Laemodipoda, the anterior, posterior, and lateral arterial trunks disappear after a very short course.(2) With the Stomapoda, and Decapoda, the arterial system is pretty well developed, and can be traced even to its ultimate ramifications. With the first, the heart, at its anterior extremity, sends off a simple, pretty long aorta, which ramifies to the eyes and tentacles; while frtom its sides, pass off numerous arteries for the segments of the body and their appendages, and, posteriorly, a branch which extends to the very extremity of the tail. (3) With the Deeapoda, on the other hand, the heart has three anterior aortae, of which the middle one goes, almost unbranched, to the eyes, while the two lateral, belonging to the antennae, give off; in their course, branches to the cephalo-thoracic organs. The two hepatic organs, alone, have special arteries, which arise directly from the lower surface of the heart. Behind, there is a posterior aorta which, immediately after its origin, divides into a dorsal and an abdominal branch. The first of these, either simple as with the Macruma, or bifurcated as with the Brachyura, extends even to the end of the tail, sending off branches right and left. The second passes below, and is distributed principally to the feet, the pincers, the foot-jaws, and the maxillae.~4) 2 According to the researches of Treviranus 3 This disposition of the arterial systeim has (Verm. Schrift, I. p. 78) upon Asellus, and of been observed by Audouin, Mlilne Ediwards, and Zenker (loc. cit. p. 21) upon Gammarus, the Duvernoy (Ann. d. Sc. Nat. Xi. 1827, p. 377, P1. arterial system is very rudimentary with the Iso- XXXII. and VIII. 1837, p. 33, P1. II. fig. 1), with poda, and Amphipoda.'This may be easily proved Squilla, while Mysis appears from its circulatory by an examination of allied species. Itmay be asked, organs to be allied to the Isopoda and Amphihowever, if the blood-currents of these Crustacea poda) see Thompson. Zool. Research. loc. cit. I. are not enveloped in vascular walls so delicate as to p. 13, and Frey, loc. cit. p. 13. escape observation i but with proper care one may 4 The arterial system of M'aa and Homarus has be satisfied that no such walls exist. From mus- been described with many details in the so-often-cular contractions or the bending of the articula- quoted memoir of Audouin and Milne Edwards tions, the current of the blood is often stopped, and (Ann. d. Sc. Nat. XI. 1827, p. 352, P1. XXIV.then the blood-globules evade the obstacle by XXIX.). Lund, also (Isis, 1825, p. 393, Taf. III. passing at ally point directly from the arterial into fig. 1), has very well described the arteries of the the venous current. lobster. But especially should be noticed the exGoodsir (Edinb. new Philos. Jour. July, 1842, cellent preparations of Hainter of the arterial sysp. 181) was certainly deceived when he affirmed that term of this same animal (Catal. of the Physiol. Ser. he had observed the blood of Caprella circulating II. P1. XV.-XVIII.). For this system with the in arterial and venous vessels. crawfish, see Brandt, Med. Zool. loc. cit. p. 63, The absence of vascular walls with Caprella, Taft. XI. fig. 2 ) and for that of Cancer pra-urus, already observed by Wiegmnasnn (Arch. 1839, I. Miiilne Edwzards, in the Cyclop. loc. cit. p. 775, fig. p. 111), has been confirmed by Frey and Leuck- 418. art (loc. cit. p. 104, Taf. 11. fig. 19, 20), and, according to them, the circulation here is analogous to that of the Amphipoda.P enters this organ without passing to the branchiae, front, into the main cavity of the body, moves backbut the other portion traverses the gills and after- wards along the lower part of that cavity without wards returns to the heart." - ED. being enclosed in vascular walls, and returns to [~ 284, note 2.] In a private letter Agassiz the dorsal vessel through the lateral valves. The has communicated some interesting facts on the circulation was traced in a living animal into which circulation of Caprella. ile says "Caprella has a solution of a small quantity of carmine had been a tubular, dorsal vessel with lateral valves, exactly injected." - ED. ike the larvae of Insecta, - the blood is emptied, in 284. TIIE CRUSTACEA. 339 With all the Crustacea, the venous currents gradually converge from the lower part of the body into various intercommunicating sinuses, situated, some upon the median line, and others at the base of the feet.() From these sinuses the blood proceeds to the branchiae, and thence into the dorsal sinus the walls of which are thin and uncontractile, and within which the heart is entirely enclosed. This dorsal sinus is filled during the systole, and the arterialized blood which it contains is absorbed during the diastole through the venous orifices of the heart, without any aid on the part of the walls of the sinus.(6) With the Myriapoda, also, the arterial system is highly developed. Not,only are there numerous arteiries arising from the sides of the heart, which ramify in the segments of the body, but also, beside an anterior dorsal,aorta, two other considerable arteries which embrace the cesophagus, then bend below and unite to form, on the abdominal cord, a Supra-spinal artery. This artery gives off numerous lateral branches, which accompany the principal nerves, and terminate, at last, in ramnuscules.(7) But what distinguish the Myriapoda fiom the higher Crustacea, are the venous currents, which, equally extra-vascular, do not run towards the respiratory organs, but pass directly into the dorsal sinus, and thence are absorbed into the chambers of the heart through the venous orifices.(8) 5 Of the absence of vessels around the venous compared sometimes to an auricle, sometimes to a currents one may easily be convinced from an ex- pericardium; but, strictly speaking, neither of these amination of small Amphipoda and Isopoda. comparisons is correct. This absence exists also with the higher Crustacea; 7 The division of the anterior dorsal aorta, with see Duvernoy, Ann. d. Sc. Nat. VIII. 1837, p. Scolopendra,was first noticed by Straus (Considlr.:4, or in Cuvier, Legons d. Anat. Comp. VI. p. &c. p. 347). More detailed researches on the arterial 404 (Squilla). I am quite of the opinion of Lund system of the same have been published by Kuand Schultz (Isis, 1830, p. 1225), who have torga (loc. cit. p. 18, Tab. III.), and Lord (Med. combated the opinion of Audouin and Milne Ed- Gaz. part VI. vol. I. 1837, p. 892), who were wards and have described the venous system of chiefly occupied with the supra-spinal artery. But the Decapoda as having proper walls (Ann. d. Sc. of all the observers, Newoport (Philos. Trans. 1843, Nat. P1. XXVI.-XXXI.). But,Milne Edwards, p. 274, P1. III. XIV.) has worked out the arterial who, at this time, advocates with so much zeal the system of the Myriapoda in the most complete and -vall-less condition of the circulating currents with masterly manner. His researches have shown Mollusca, appears, moreover, to entertain the that this system is least developed with the Julidae,,opinion of a similar circulation with the Decapoda; and rises gradually through the Glomeridae and Geat least, such would be inferred from what he has ophilidae - reaching its highest grade of structure:said upon the circulation in general of Crustacea; with the Scolopendridae. Kutorga has entirely see Hist. d. Crust. I. p. 101, and Cyclop. loc. cit. mistaken the nature of the heart in regarding it as p. 777. a vena cava, and the supra-spinal artery as an 6 According to ludouin and ZMilne Edwards aorta. Gaede, also (Zool. Magaz. I. p. 108, Taf. ~(loc. cit. P1. XXVI. fig. 3), the returning blood I. fig. 7, g. f.), is qtite in error as to the vascular from.the branchiae enters the heart direct through system of Scolopestdra; for he has evidently seen inter-anastomosing vasa branchio-cardiaca. But the three vessels arising from the anterior extremithis statement has been reasonably doubted by va- ity of the heart, namely: the dorsal aorta and the rious observers, for these naturalists had overlooked two vessels which, uniting, form the supra-spinal the sinus which envelopes the heart of the higher artery; but he has taken them for nerves. Crustacea, and receives, first of all, the branchial 8 Newport, who has so well observed the circublood; see Straus, Consider. &c. p. 345; Lund latory system of the Myriapoda, says nothing of and Schultz, Isis, 1830, p. 1226; and Krohn, veins, and describes the dorsal sinus as a pericar Ibid. 1834, p. 522. This dorsal sinus has been dium. 34C THE CRUSTACEA. s 285. CHAPTER YII. RESPIRATORY SYSTEMI. ~ 285. The majority of Crustacea respire by Branchiae; but among the lower orders, there are many which have no trace of respiratory organs, while the IMyriapoda respire by aeriferous tracheae. With most Siphonostoma, Lophyropoda, and many Stomapoda, there are no particular respiratory organs, the respiration being, therefore, cutaneous; and with some species of these orders, the water is renewed by the oar — like action of some of the locomotive organs.~5) The Branchiae of Crustacea are sometimes lamelliform, sometimes cylindrical, and often appear either distinct and separate, or consist of compouncd serrated organs, branched in various ways, on which the branchial lamellae are disposed in a regular row, and the branchial tubes united in larger ancd smaller tufts. Bnt these lanmellate or tubular branchiae are invested witi a membrane so thin that it widely differs from those of the other regions of the body. It is never ciliated, and is usually without fiinges, bristles, &c. The interior of these organs presents only a few parenchymatous points, and, whatever may be their form, they are always traversed by numerous canals and large interanastomlosing lacunae, which are wholly without proper walls, alnd are filled by the arterial and venous currents.(2) The branchiae are often in connection with their neighboring appendages. These last consist of imulti-articulate lashes or cirri, or of scales, or large plates, and serve either as gyratory organs, or as opercula shielding the respiratory organs; sometimes, indeed, they perform both of these functions at the same time. Nearly always these organs are fiinged with long, stiff, and often pinnate bristles.,") 1 The branchiae are wanting with the Penellina, and Bot. I. p. 520, P1. XVI. fig. S. These organs Lernaeodea, Ergasilina, and with some Caligina. appear to have been wholly misapprehended by With Daphnia, Lyncerus, and some other allied Treviranms (Verm. Schrift. II. p. 59, Taf. IX. fig. Lophryopoda, the small oar-like feet concealed 5). With Mysis, Le.cifer, and Amp/zion, there under the belly are probably designedl for the agi- are ro traces of branchiae, while with the other tation of the water, while the two feet projecting allied Stomapoda, such as zli/a and P}yllosoma,. in front of the body, and which are larger and they sometimes exist in a rudimentary form. As. usually branched, are the principal swimming, branchiae, have been regarded, also, the articulated organs. Indeed, even when these animals are at processes of. the cloven feet of Mlysis rand some rest, these organs are seern in perpetual motion - other Stomapoda; but, certainly, they are organs. thus causing in the cavity of the shell a continual for swimminig or for the agitation of the water, and current of fresh water; this supports the observa- their organization has nothing in common with that tion of Ehrelnberg (in his third Beitr. loc. cit. p. of branchiae. 189, note) that, with these Entomnostraca, the inter- 2 It is owing to this small rquantity of parennal surface of the valves performs the function of chyma in the lamelliforinm branchiae and to the branchiae. The active, hairy, clavate corpuscles slumerous lacunae lilled with blood that, when the inserted on the base of the first pair of feet with circulation in these orgarus is arrested, the tw(> Cyclopsina castor, and which hsave been usually larmellae of which they are composed, separate regarded as posterior antennae (Ifiiller, Entomostr. from each other, and the whole branlchia, swollen p. 106, Tab. X-VI. fig. 5, 6, c., or Jureine, Hist. d. from accumulated blood, has the form of an amMonocl. p. 52, Pl. IV. fig. 1, P'l. V. fig. 1. b. P1. VI. pulla. The blood then changes its natural color. fig. 13, a.), are nothing but organs for the agitation This pathological state may be easily seen with inof the water. With Cypris, only, are there perhaps dividuals of Aselluts, Gammairas, and Apaus. when special branchial organs. Tllese little animals allowed to be a long time dying. These ampullae have at the base of the posterior pair of jaws two are violet, with GanLmaorus; and of a bearutiful redl, semilunar, pectinated plates, curved upsvards, hav- with Apus; see my note upon the ampullae of ing completely the aspect of branchiae e see Ramn- Apus cancriformis, in the Isis, 1831, p. 429. dohr, Beitr. loc. cit. p. 15, Taf. IV. fig. 5, B. and 3 Hairy and bristled appendages of this nlature fig. 8, L.; also Straus, loc. cit. p. 49, P1. I. fig. are often taken for branchiae. These organls are 4, o. and fig. 8, e., or Bai'rd, in the Magaz. of Zool. not only surrounded by a thick skin which of it ~ 286. THE CRUSTACEA. 341 The branchiae are usually inserted at the base of the anterior true feet, or the posterior false feet, floating fieely in the water; or, they are contained in a special respiratory cavity, into which water is admitted through -various ways. ~ 28s6. The principal differences observed with the Crustacea in the disposition:trnd structure of their branchiae, are the following: 1. Many genera of the Caligina and Argulina, have upon various parts of their body, such as the back, the abdomen, and the tail, several thin, simple, naked lamellae, which may be regarded as branchine.a1> 2. The feebly-developed branchiae of the Lepadea consist of cylindrical,or lanceolate processes inserted at the base of some of the cirrate feet, and curved towards the back of the animal, so that they are always concealed in the cavity of the shell. But the water is renewed upon their surface by the regular movements of the long posterior feet.(2) With the Balanodea, the branchiae have left the body of the animal, and are developed on the internal surface of the mantle as more or less numerous soft folds or lamellae. (s) 3. With the Laemodipoda, and some Stomapoda, the branchial apparatus is reduced to a few vesicular or cylindrical, sometimes wholly rudimentself would render them unfit for the respiratory it possible, as has Vogt (loc. cit. p. 11). that these function, but they are not traversed except by feeble lateral portions are the only respiratory organs of blood-currents which do not enter the bristles or these anilals.* hairs. From the complete absence of ciliated epi- 2 In the various species of Lepas, there are thelium, the vortex-producing organs are of much from two to five arcuate branchiae which hang importance. On this account, many species with from each side at the base of the first pair of cirri. which these organs are wanting, use their feet for With Cineras, beside the six branchiae, there is this purpose. one, very short, upon the back of the animal, at the 1 Eeuryphorus has four such pedunculated base of the third, fourth, and fifth pairs of feet branchial lamellae on the dorsal surface of the two while with Otion, there is a seventh pair inserted.,grand segments of the body. These are what onl the second pair of feet see MZertens in MiilMilne Edwards (Hist. Nat. d. Crust. III. p. 462, ler's Arch. 1835, p. 502; Wagner, Lehrb. d. Pl. XXXIX. fig. 1) has called Appesndices Fly- vergleich. Anatl. p. 200; Cucvier, Mlma. loc. cit. p..troides. With Dinenm.atura, the last pair of feet 6, fig. 2, 5, o. p.; Burmeister, Beitr. &c. p. 31, is changed into two naked, deeply-fissured bran- P1. I. fig. 14, c. c., and Mlartins St. Asngee. AIim. chial lanmellae (Krsyer, Isis, 1841, p. 275, Taf. I. loc. cit. Pl. II. fig. 17, 19, K. K. (Lepas). fig. 5, i.). With Plhyllophora, the branchial ap- 3 These broanchial lacmellae are extraordinarily paratus is still more fully developed, for each foot developed with Corosnula diadema (Burmeister, of the last four pairs terminates with two ovoid, Beitr. &c. p. 38, Taf.,JI. fig. 10, a. a.). They are,glabrous, braonchial lamcellae (Milne Edwards, few in number with Balanlus (Cuvier, Mlme. loc.' loc. cit. III. p. 471. P1. XXXVIII. fig. 14). cit. p. 14, fig. 18, c. c.). It is true that BurmeisThe two tllin, lamceolate caudal lamellae of ter subsequently (Handb. d. Naturgeschicht. p. mdrgulus, through which pass strong blood-cur- 551) did not regard as branchicLe but rather as renlts interrupted only by some islets of sub- ovarian sacs, these organs which as to form and stance, are certainly respiratory organs to which position correspond somewhat to the branchiae of the oar-like organs whi'ch Jurine (loc. cit. p. certain Branlchiopoda (Ling'ula). But even if 442) has erroneously considered as branchiae, they do serve at the same time as receptacles of the serve as vortex-producing organs. I am yet un- eggs, this would be no reason for refusing to the determined if the respiration is performed by these folds of the mantle of the Balanodea the function of lamellae alone, or in part by the lateral portions of a respiratory organ, for, witih other lower animals, the dorsal shield through whicll pass nemnerous as for example witIc the Lamellibranchia, the blood-currenlts. But in any case, I cannot believe branchiae serve as receptacles for the eggs. * [~ 286 note 1.] Leydig (loc. cit. Si'ebold and and 3rd, of a lacunal net-workl (Liiclennetz). Kolliker's Zeitsch. II. p. 337) has carefully exam- The glands and the muscles constitute what is deined the intimate structure of these caudal append- scribed above as the islets of substance. Leydig ages witlh ArgulGas they are composed, 1st, of denies that these lamellae, thus composed, have, simple glands such as are found under the skin over peculiarly, a gill function. - ED. ilhe whole body; 2nd, of a rich muscular net-workl 29* 342 THE CRUSTACEA. ~ 286. ary appendages, which hang fteely from the base of some of the feet, or are inserted isolatedly on the sides of the body.(4) 4. The Phyllopoda have, at the base of each of their numerous swimming feet, an ovoid or lanceolate branchial lainella, pointing forwards. It is quickly distinguished by its thin, glabrous covering, in opposition to that of the other divisions of feet, which are bristled.(t~ 5. With the Amphipoda, the rapacious and ambulatory feet, excepting the first and last pairs, are those only which are provided with respiratory organs. These last tconsist of oval or round glabrous lamellae, situated internally at the base of the five middle feet. They receive, constantly, fresh water by the movements of the three anterior pairs of post-abdominal feet, whicle act as gyratory organs.(6) 4 With Phyllosoma, there is, at the base of the These branlchiae are easily perceivedl with Apus anterior feet, a small, ovoid, pedulculated append- after death, and from the form whvllich they thenl age, which may perhaps be regarded as a rudi- assume, they have long been known as the probmentary branchia 5 see MIilne Edwtards, Hist. lematical red sacs (Schaeffer, loc. cit. Tab. II. II. Nat. d. Crust. II. p. 474, Pl. XXVIII. fig'. 15, a. VI.; Zaddach, loc. cit. p. 14, Tab. II. fig. 13, B. It is remarkable that, with another Stomapode Tab. XIV.). In 1830 (Isis, p. 429) I gave the corgenus, Squilla, there are at the base of the ten rect interpretation of these organs which, like the rapacious feet similar pedunculated appendages of swimming feet of these animals, diminish in size the form of oval lamellae (Mil/ne Edwards, HIist. from before backwards; but, already, before mar Nat. d. Crust. II. p. 512, P1. XXVI. fig. 15, P1. Loschge (Naturforsch. Stuck. XIX. p. 68, Taf. IlI. XXVII. fig. 13, 14, b.). These, also, would be re- fig. 6, 7, 10) had recognized their nature. With garded as rudimentary branchiae, did not these Lzmnadia, and Isaura, the branchiae are very Crustacea have distinct branchial organs (see long and of a brown-red color, but are wanting on. below). With A/lima, the oval feet have some- the last swimming feet; see Brongniart, loc. cit. times very rudimentary branchiae in the form of p. 86, P1. XIII. fig. 7, 8; Straus, iMus. Senckenb. simple vesicles or ramified processes (Milne Ed- loc. cit. p. 124, Taf. VII. fig. 13, 14, r., 15, k.;. wards, loc. cit. II. p. 506). With Caprella, and Joly, loc. cit. p. 299, P1. VII. fig. 2, 6, 7, f. and Aegina, the first two posterior abdominal seg- P1. VIII. fig. 8, f. With Chirocephalus, BrasLments have, upon the sides, a simple, very soft, chipus, and Artemia, they have a more oval form pyriform branchia; while with Leptomera, there and exist on all the swimming feet. Rathke (Zur is a vesicle of the same nature at the base of the Fauna der Krym. p. 108, Taf. VI. fig. 14, 19-21),. six feet of the first three posterior abdominal seg- has figured, probably from dead individuals, those ments * see M/ller, Zool. Danic. Tab. LVI. fig. 5, of Artemia as vesicular bodies. In the figures of and Tab. CI. fig. 2; Templeton, Transact. of the Jurine (Hist. d. dMonocl. P. XXI. XXII.), made Entomol. Soc. I. p. 193, Pl. XXI. fig. 7, f. and for the memoir of Prevost, the branchiae of ChiroKIr6yer, Naturhist. Tidskr. IV. p. 490, P1. VI.- cephalus are not seen at first, but with a little atVIII. With Cyamus, the respiratory organs are tention may be discovered. Gaede (Wiedemann'.c even more developed. They consist of four long, zool. Magaz. I. p. 88), Berthold (Isis, 1830, p. 689,. simple cylinders inserted on the sides of the first Taf. VII. fig. 1), and Zaddach (loc. cit. p. 11, Tab. two posterior abdominal segments, and projecting I. fig. 17, Tab. II. fig. 10) have regarded the large over the back; see Treviranus, Veirm. Schrift. II. dorsal shield of Apus as a respiratory organ, p. 9, Taf. I. ig. 1-3, and Beobacht. aus. d. Zoot. u. since its lateral halves are traversed by blood-curPhysiol. p. 32, Taf. VII. fig. 48 —50 also Krsyer, rents running close to each other (Schaeffer, loc. loc. cit. IV. p. 474, P1. V. fig. 70-476 and Roussel cit. p. 72, Tab. I. fig. 5, b. b.), and thence passing de Vauz/me, loc. cit. p. 248, PI. VIII.; according directly towards the anterior extremity of the to this last mentioned author, Cyamus ovalis has heart. four double, branchial cylinders. These branchiae Indeed, from the vascularity and delicateness of of Cyamus have often been taken for metamor- the uhder surface of this shield, one would be quite phosed feet, but it is only necessary to examine disposed to attribute to these parts a participation them in their earliest condition in order to be con- in the respiratory act. vinced that they are special organs (Milne Ed- 6 For a long time, the multi-articulated, bristly,. wards, Ann. d. Sc. Nat. III. 1835, p. 329, P1. XIV. anal feet of these small Crustacea were regarded as fig. 14). At this epoch they are as pyriform as those branchiae, for the true branchiae are quite concealed inserted on the side of the feet of Leptomera. The under the internal surface of the anterior feet. passage to Squilla,whose branchiae are more highly Even after the attention had been directed to these developed, is made by Cynthia. Each anal foot has organs, their form was often misapprehended i for here a bifurcated branchia, the two cylindrical when these animals are a long time dying, their divisions of which are curved towards each other; branchiae are changed, from congestion, into ampulsee Milne Eldwards, 3list. Nat. d. Crust. II. p. lae. With the Amphipoda, it is easy to distinguish 462, P1. X. fig. 5. the branchial lamellae from the incubatory lamellae 9 The delicate branchial lamellae lsually assume at their side, for the borders of these last are brisafter death the form of vesicles, from being filled tied; see Straus, loc. cit. p. 57, P1. IV. fig. 10, 11, with blood, a phenomenon already mentioned (~ 285, h. (Hiella); Zenker, loc. cit. p. 8 (Gamnzarus); note 2). But, formerly, they were taken for special Milne Edw/ards, Ann. d. Sc. Nat. XX. 1830, p, organs whose function was unknown, and Berthold 357, P1. X. fig. 7, P1. XI. fig. 1, also Ibid. III. 1835, (Isis, 1830, p. 693) has regarded those of Apus as P1. XIV. fig. 9, and Hist. d. Crust. III. p. 6, PI. male genital organs while the remaining pilose II. fig. 15, c., P1. XXX. fig. 1, 13, 16 (Gammarus divisions of swimmsing feet were, according to him, Phronima, Vibilia, Hyperia). According to respiratory organs. Savigny's figure (Descrip. de l'Egypte, loc. cit. P1. 0 286. THE CRUSTACEA. 343: 6. With the Isopoda, the five pairs of post-abdominal feet are nearly always colcerned exclusively in the function of respiration. The two multi-articulate cirri of each of those feet, have been changed into plates, which, pointing backwards, are imbricated and applied against the under surface of the last caudal segment, which is usually very large. ) The form of these plates is sometimes lanceolate, sometimes discoidal or rhomboidal, and they often differ widely in the different sexes of even the same species. Upon the same foot, the external or anterior plate is usually leathery and bristled on its external border while the internal or posterior plate is covered with a very thin envelope, and is usually entirely glabrous. This last, therefore, should be regarded as the proper branchia, of which the first is only the operculumn, serving, also, often as a gyratory organ. The first case is observed with the terrestrial Isopoda, where the branchial opercul' are fixed, rhomboidal, slightly concave, and completely cover the branchial iamellae preserving them front desiccation.t8) With most of the aquatic Isopoda, on the other hand, this apparatus is in perpetual motion, and the branchiae are often of the same form and size as the operculate plates. The opercula of the first pair are so large that they extend beyond all the rest.(9) With the Idotheoidae, the operculate apparatus has an entirely peculiar structure. The two feet of the last caudal segment are developed into two valves which move laterally like the two folds of a door, and can open and close the branchial cavity, which is provided with five pairs of double plates.(0) The branchial apparatus of the Bopyrina differs, in many respects, from that of the other Isopoda. With some species, it is reduced to four or five pairs of simple, superposed plates, without any accessory organ; while with others, there are four to six branchiae which, as more or less deeply fissured cordiform plates, or as long and XI. fig. 4~. 43.) of Amphithoe filosa, this animal branchial opercula; but the branchial apparatus, has, beside the ten round branchial lamellae, a sixth moreover, is composed of only three pairs of plates and rudimentary pair on the two posterior feet.* on each side (Treviranus, Verm. Schrift. I. p. 75, 7 For the respiratory organs of the Isopocla, see Taf. X. XII.), while with Sphaeroma, Cymothoa, especially Duvernoy and Lereboullet, Ann. d. and allied genera, there are five pairs on each side S3c. Nat. XV. 1841, p. 177, Pl. VI. (Savigny, loc. cit. Pl. XI. XII.). 8 With the terrestrial Isopoda, the branchial With some species of Sphaeroma, Cymodocea, apparatus is somewhat abortive, for true branchiae Nesea, and Amophoroidea, the branchial plates of are wanting beneath the two anterior pairs of oper- the last two pairs of branchiae, have numerous cula, and those back of the three posterior pairs transverse plicae, which connect these Sphaeromaare very small and delicate; see Treviranus, toda with the Poecilopoda (Duvernoy and LereVerm. Schrift. I. p. 62, Taf. VI. VIII. IX. (Por- bosullet, loc. cit. p. 215, P1. VI. fig. 15-23, and cellio); Savigny, Descript. de l'fgypte, loc. Mlilne Edwards, Hist. d. Crust. III. p. 223, P1. cit. P1. XII. fig. 7 (Lygia), and P1. XIII. (Tylos, XXXII. fig. 9). With Serolis, the branchial strucPorcellio and Armadillidium); Brandt, Mediz. ture is quite different, the fourth and fifth pairs Zool. II. Taf. XV. fig. 35-37 (Porcellio), and Lere- of feet being changed into broad branchial plates boullet, loc. cit. p. 118, P1. IV. fig. 17, P1. V. fig. (MilLne Edwards, Arch. du lMus. d' Hist. Nat. II. 18-22 (Lygidium). This abortion of the brans- p. 21, P1. II. fig. 1-6). chiae is compensated With some Oniscidae by the 10 See Rathki, loc. cit. p. 115, Taf. IV. and existence of lung-like organs. (See below, ~ 287.) Milne Edwards, Hist. d. Crust. P1. X. fig. 6, 7 9 Asellus has two very large, common, anterior (ldothea). * [ ~ 286, note 6.] Leydig (loc. cit. Siebold natatory foot of Branchipsus, a peculiar and new and K/lliker's Zeitsch. III. p. 289) does not admit structure. This is a roundish, dark-orange-colored, that the red pouches, above-mentioned with Apus, pedunculated body, situated on the under side of the are of a respiratory character, at least with Arte- leg near the coxal joint. This body is composed of mia and Branchipus, where he has examined their large nucleated cells which contain a yellowisl histological composition. In this connection it may liquid. The use of this structure is unknowms be mentioned that this observer has found on each - ED. :344 THE CRUSTACEA. ~ 286. sometimes branched tubes, project considerably beyond the lateral borders of the posterior segments of the body.(") 7. The Poecilopoda hold a place between the Isopoda and the Deca. poda, their branchiae being, as in the first, inserted oil the abdominal feet, -and, as with many of the second, composed of numerous plates. With Limulus, the five posterior abdominal feet, which are inserted on the second dorsal segnient, and changed, as well as the first pair of abdominal feet, into very large plates, have upon their posterior surfaie numerous semioval, branchial plates lying upon each other. The first pair of feet appears to play, also, at the same time, the part of an operculate apparatus.("1' 8. The Stomapoda, with which the respiratory apparatus is most highly developed, have numerous branchial filaments disposed pectinately on a long stalk, and float fireely in the water. The Squillina have a silmilar brauchial tuft on the anterior surface of the external plate of each of the ten swimming feet, which are only the ten post-abdominal feet of the posterior part of the body, transformedl.(l' ) With Thysanopocla, only, these branchial tufts are inserted at the base of the anterior abcolinal feet. (14) 9. With the Decapoda, all the branchliae are joined together at the base of the anterior abdominal feet and of sorne of the foot-jaws; but at the:same time they are contained in a special branchial cavity, which is covered by the lateral parts of the cephalotholrax. Each of these two cavities communicates externally by two fissures. One of these is situated at the unlder surface of the body between the lower border of the cephalothorax and the base of the feet; through it the water enters the branchial cavity. The other is upon both sides of the masticatory orgfans, and through it the water is ejected. In this last, which is sometimes prolonged into a semicanal,(10) are several multi-articulate cirri and lamellae, which belong to the second and third pairs of foot-jaws.(1'1 ) Their continual motion piroduces a regular current of water from the branchial cavity outwards. (17) As to the number of branchiae, there are wide differences in the various families of this order. There may be six, seven, fourteen, eighteen or even twenty-one in the same respiratory cavity. When numerous, there are usually two or three fixed on the four posterior foot-jaws, three or four on 11 Both sexes of Bopyriets sqiillae have five pairs chial tubes pointing blllkwards, and owith the of smalil branchlial plates lyinlg cover each other like femllle~ of this sanle gellus the five aniterior pairs sca(les (Rathkie, De LBopyro,? &c., ip 7, Tab. I.). are branched on one sile. In this sex, also, the This is probalbly true also of thle rales of Plhr yxes organization of the Almphipodii appears to be rehippolytes (Ratlhke, Nov. Act. Nat. Cur. XX. l p ated, for, from the base of tlle aterior feet hlangs 48).''he females of this same speci5s acnd of a long ribctnd-like band (ecanchia?). See Ml]ilne P/hrycxs paouri have four pairs of eordate, and Etlasrds, I-ist. d. Crust. IIl. p. 279, P1. XXXIII. nearly doublle plates, which stand off latcrally a fig. 14, 15. little frlom the posterior lpart of thle bodyl; see 12 See Vanz der F/ioeven, loc. cit. p. 19, P1. I. Ratlh/c, ibid. p. 46, a53,Tab. II.; Kryer, Naturhist. fig. 10, PI. II. fig. 1, 1-15;o aend Duvernsoy, Ann. Tidlskr. III. p. 102, 1P. I. II., or icn Isise 181-1, p. d. Sc. Ntt. XV. 1841, p. 10, Pi. Ii. 63l, 707, Taf. I. Ttsb. 1, and Taf. III. Tab. 2, or 1t Squilla and Sqseillerzechthis; see Tre/irain Ann. d. Sc. Nat. X~II. 1842, p. 142, Hl. VI. nus, Beoblachct. aus d. Zoot. u. Physiol. p. 22, Taf.'With Ceponl, the brcanchit al pparatus is higchly de- VI. fig'. 36-39 i and Mliltne Edwarcds, Hist. d. veloped in that, beside the five pairs of lanceolate andc Crust. P. X. fig. 4, PI. XXVII. fig. 7. pretty long plhtes which project fromn the sides of 14 3Iilne Edwlards, Ibid. Pl. X. fig. 3, P1. thle tail with the males, the five albdominal and the XXVI. fig. 6, actd Ann. d. Sc. Nat. XIX. 1830, p. last caudal segment, have six pairs of long, narrow 453, P1. XIX. diverging lamcellae with pectinated borders. Du.- 15 With rmny Brachyura. vernoy (Ann. d. Sc. Nat. v.. 141, p. 120, P1. 16 See Sullckow, loc. cit. Taf. X. fig. 1, p. q., fig. Iv. fig. 1-11), has described these twelve append- 2, p. r., fig. 3, d. s. e. (Astacucs); Milne Edwards, ages as the principal branchiae of Cepon, wvhile llist. d. Crust. Pl. III. fig. 8-10, i. j. (Maima). to me, they appear to be accessory, and are, 17 For this mechanism of the respiratory organs perhlaps, vortex-producing organs -the result of a of the Decapoda, see Miilne Edwards, Ann. d. metamorphosis of the anal feet. With Jone, all Sc. Nat. XI. 1839, p. 126, P1. III. IV. the abdominal segmcents have a pair of long bran 287. THE CRUSTACEA. 345 each of the four anterior pairs of feet, and one only on the last pair. With these Crustacea, moreover, the organs have no connection with the movable basal joint of the feet; but, on the other hand, most of them are inserted on the base itself of the respiratory cavity above this joint. Many Macrura, which have numerous branchiae, are those exclusively which have one of these organs inserted on the coxa of the feet.t(18 As to their structure, these organs vary also very much. Usually, they have the form of a long, acutely-pointed pyramid with a solidly-attached base, the axis of which is formed in its whole length by a shaft traversed by an arterial and venous canal, and covered by numerous thin lamellae or cylindrical filaments, the size of which decreases gradually towards their apex.'l9) ~ 287. Many terrestrial Isopoda have a branchial apparatus, the organization of which is entirely peculiar, and distinctly indicates a pulmonary respiration. With Porcellio, and Armadillidium, there are four white spots on the two anterior pairs of the branchial opercula. These spots comnmuni.:cate with as many cavities which ramify like vessels. They are situated between the two plates of these four opercula, and are filled with air. At the base of each of these opercula there is a narrow opening through which, when these cavities are compressed, the air will escape, and then the white spots disappear. By these means, these animals are undoubtedly in 18 The branchiae are fewest with the Brachyura, support numerous cylinders set together in a.and Caridoidae alnong these last, Clrangon and brush-like manner. In the figures which Judoutin Alpheus have only six in each respiratory cavity, and Mfilne Edswards (Ann. d. Sc. Nat. XI. 1827..and Palaemon and Hippolyte seven. Uca, also, also,. XIX. fig. 1, PI. XXX. fig. 2, P1. XXXI.) have has only six on each side, while with the majority given of the branchiae of Homarus, this structure of Brachyura, namely, Portnunus, Groapses, maybe easily seen. With Astacus, the cylinders are T/elephusa, Gecarcinus, Pisa, 1aina, Can.cer, much less numerous, and disposed only on two of &c., there are eighteen in all, the two anterior the sides of the branchial shaft, - giving it a pilnpairs of which are usually only feebly developed nate aspect; and those which are inserted on the.and belong to the two pairs of posterior foot-jaws, coxae are terminated by a thin, multiplicate laemelliwhile the others are in general (Malia, Cancer, form dilation, which has completely the structure LDpea, &c.) so aggregated at the anterior part of a brancllial lamella (Suech/os', loc. cit. p 59, Taf. of the bottom of the respiratory cavity, that the X. fig. 1, 2, 25, 26, Taf. XI. fig. 5, 6; Brandt, space corresponding to the last two pairs of feet Medic. Zool. II. Taf. XI. fig. 23). With Homarus, appears gill-less. The majority of the Brachyura and Palinu.rus, also, the coxae leave an analogous have fourteen blanclliae on each side, and these plate inserted close by the side of the coxal organs are even more numerous with various branchia but it is of a leathery consistence and Alacrura. Thus, I have counted eighteen with covered with numerous hairs, so that it cannot Astacus, Homarus, and Palinurus; two of participate in the function of respiration, but is which, with Pali/nurts, and Astacus, are in con- prolbably only a septum to separate the different nection with the middle, and three with the pos- groups of branchiae. Aristeus, which has sixterior foot-jaw; while with Hoosarues, this last teen branchiae on each side, differs widely from hlas also three branchiae, but the second foot- the other MAacrura in having its penniform branljaew has only a rudimentary one. As to the chiae composed of a shaft from which pass off other branchiae, there is, in these three genera, right and left numerous curled filaments whose a branchia inserted on the coxa of the four anterior convex border is covered by tufts of very delicate feet. Above each of these same feet are other thick-set brancllial cylinders (Dutevernoy, Alnn. dl.:branchiae disposed, in couples, with Astacus, and Sc. Nat. XV. 1841, p. 104, P1. V.). The seconlld in threes above the fourth foot, with Hoeesaruis, and type is formed by these branchiae to the shafts of above the second, third and fourth, with Pali- which adhere at right anglles ituleerous thin so-nenurus; while above the last foot that is gill-less, times rhomboidal, sometimes spheroidal lameilae, there is only a single branchia. With Nvephrops, contiguous, and decreasing ill size towareds the altpex there are twenty branchiae on each side, and with of'the shaft. This type occurs especially with the Scyllarus, twenty-one. See, for the number and Brachyura, the Anomnura, and with GrleithLea of disposition of those organs with the Decapoda, the Macrura; also of the Caridoidae, with Palae-.Duvernoy, in Cuvier's LeOons d'Anat. Colmp. mons, Hippolyte, Alpheus, Penaeus, Crangson, VII. p. 393. &c. * see Altdosuine and Millne Edwarcds, Ann. d. 19 The various forms of the branchiae of the De- Sc. Nat. XI. 1827, P1. XXVI. sand XI. 1839, Pl. capoda may be reduced to two types. The first, III. fig. 1, PI. IV. fig. 1, 4 (Mlaia, Ranina, Palaethe less common, exists with many Macrura, for oron); also Kreye?', loc. cit. Tab. I.-V. (Hippoexample with Scyllarus, Palinurus, Gebia, and lyte), and Joly, loc. cit. p. 71, P1. III. fig. 24 Bomarus. The shafts of their branchial arches (Caridina). 346 TIIE CRUSTACEA. ~ 287. a condition to respire atmospheric air.(1) But with Tylos, this pulmonary apparatus is still more highly developed; for, under the four pairs of opercula, there are, instead of simple branchial plates, oblong appendages on which is a transverse row of aeriferous sacs having a kind of stigma on their under surface.(2) All the Mlyriapoda respire by true tracheae. Their blood does not require, therefore, special organs to receive the influence of the air, for this last is carried into every part of the body. The stigmata for the ingress and egress of the air, are easily seen with the Chilopoda, for they are usually surrounded with a ring of brown chitine, and situated on each side of the body between the base of the feet and the dorsal shields; they are not found, however, above all the feet, for the segments which have them alternate more or less regularly with those that are without them.s) With the Chilognatht, the very small stigmata are on the ventral surface. They are situated on the anterior border of the ventral plates, from the posterior border of which arise the feet.(4) The intimate structure of these tracheae, which are usually brown, is exactly like that of those of insects.t() Among the Chilognatha, the Julidae are noticeable for the very simple character of their trachean apparatus. Each stigma leads into a tuft of tracheae from which arise air-canals which neither ramify nor anastomose but gradually become smaller and smaller and surround the various organs.(6) With the Glomerina, on the contrary, the tracheae, which arise from the stigmata by two trunks, are branched, but do not anastomose with the neighboring branches.(7) Those of the Chilopoda most closely resemble those of the Insecta, — being very ramose, and their large trunks intercommunicating at their origin by longitudinal and transverse anastomoses, so that each stigma can introduce air into the entire trachean system.(8) 1 According to Duzvernoy and Lereboullet (loc. a. a. (Joulus). These stigmata with Julus were cit. p. 231, PI. VI. fig. 14), these cavities secrete a entirely overlooked by Treviranus. IIe had reliquid for the moistening of the branchiae. See garded as such the orifices of a row of glands upon this subject, my observations in Miiller's which are situated on the sides of the segments of Arch. 1842, p. 141, note 2. the body (Verm. Schrift. II. p. 42, Taf. VIII. fig. 2 See Savigny, Descript. de l'Egypte, loc. cit. 4, S. S.). P1. XIII. fig. 1.6-1.8 5 but especially Milne Ed- 5 The characteristic spiral filament of the Insecta eoards, Institut; 1839, p. 152, and Hist. d. Crust. is also not wanting hereo see Kuftorga, loc. cit. p. III. p. 187, and his figures in the Iconograph. du 14, Tab. II. fig. 8. ]Rgne anim. Crust. PI. ILXX. 6 Straus, Considirat. &c. p. 307, and Burmezs3 With Lithobius, there is a stigma above the ter, loc. cit. Taf. I. fig. 3 (Julus). first, third, fifth, eighth, tenth, twelfth, and four- 7 Bs7andt, in Mitller's Arch. loc. cit. p. 323, Taf. teenth pairs of feet (Treviranus, Verm. Schrift. II. XII. fig. 4, 5 (Glomeris). p. 29, Taf. IV. fig. 7, Taf. VI. fig. 5). With Scolo- 8 Straus, loc. cit. p. 307, and Traits d'Anat. pendra, the stigmata have a similar disposition comp. II. p. 161; Treviranus, Verm. Schrift. II. (Kutorga, loc. cit. p. 14). p. 30, Taf. VI. fig. 6 (Lithobius), and Muiiller, 4 Se.) Savi, Isis, 1823, p. 219, Taf. II. fig. 9, a. a., Isis, 1829, p. 5513 Taf. II. fig. 1. and Bsrmeister, Ibid. 1834, p. 134, Taf. I. fig. 2, V~ 288, 28)3. THE CRUSTACEA. 347 CHAPTER VIII. ORGANS OF SECRETION. I. Urinary Organs. ~ 288. As yet, Urinary organs have not been observed with the Crustacea except in the Myriapoda. Here, as with the Insecta, they consist of long, small, brownish vessels, caecal, and describing many convolutions about the stomach and intestine. These Malpighian vessels, as they have been termed, open into the digestive canal at the boundary between the stomach and intestine, and secrete as certainly as do those of the Insecta, uric acid.(') With the Chilopoda, there is usually one on each side of the pylorus; but with the Chilognatha, there are two, which open, however, into the intestinal canal by a common orifice.(2) It is now undetermined whether these organs exist also in the other families of Crustacea. But with some Decapoda, there are certain caecal vessels which are imperfectly known. They open into the intestine at various points between the pylorus and rectum, and a more complete examination may, perhaps, show them to be of a urinary nature.(3) II. Organs of Special Secretions. ~ 289. The Astacina have a very remarkable secretion commonly known as Crabs-eyes. These are a kind of calculi composed of carbonate of lime 1 For the Malpighian vessels, which were for a 678) is very common with the Macrura, Brachyura, long time regarded as biliary canals, see further and Anomura, and notably with Astacus fluviaunder the anatomy of the Insecta. tilis, Homasrus marinus, Cancer pagurus, Por2 Ramdohr, Abhandl. iber d. Verdauungsw. tunuspuber, and Cancer maenas. But although &c. p. 149, Taf. XV. fig. 1 (Julus); Treviranus, Mlilne Edwards admits the same also (loc. cit. I. Verm. Schrift. loc. cit. p. 24, 44, Taf. V. fig. 4, Taf. p. 76), yet it does not appear to be agreed upon, for vIII. fig. 6 (Lithobiuzs and Julus), and L. Du- Ilieckel (Syst. d. vergleich. Anat. IV. p. 161) confour, Ann. d. Sc. Nat. loc. cit. p. 86, 96, P1. V. tradicts Cuvier in this respect, and declares that fig. 1, 4 (Lithobius and Scutigera). Scutigera he has never found this caecum either with the differs from the other Chilopoda in having two Crabs or with Astacus, Scyllarus, and Palinupairs of urinary canals. rus, but only with Pagurus, Penaeus, and See also Kutorga, loc. cit. p. 6, Tab. I. fig. 2, Palaemon. Duvernoy, also (Legons d'Anat. and Miiller, Isis, 1829, p. 550, Taf. II. fig. 5 Comp. V. p. 228), has not observed it in the Ma(Scolopendra); finally Brandt, in Miller's Arch. crura just cited, nor with Galathea squaloc. cit. p. 322, Taf. XII. fig. 2 (Glomeris). mnifera, and Palaemon serratus, although he 3 Swammerdamm (loc. cit. p. 87, Taf. XI. fig. 3) perceived it with Portunus puber directly behind had already figured, with Pagurus, a pretty long the pylorus, and with Cancer pagurus, near the coecim opening at the posterior extremity of the rectum. Like Milne Edwards (Hist. d. Crust. intestine. With Maia squinado, there are three I. p. 115, P1. X. fig. 2, j. (Maia)), I must leave unsuch pretty long, of which two are inserted on each determined the point whether or not, this glandular side of the pylorus, and the third a little further mass which, with the Decapoda, is concealed under behind (lMilne Edwards, Hist. Nat. d. Crust. I. the floor of the respiratory cavities in the bottom p. 76, P1. IV. fig. 1, m. n.). Lund (Isis, 1829, p. of the cephalothorax, and which opens externally 1302) has also seen two glandular canals rolled up by an excretory canal between this same cephaloin a knot, which open each side of the pylorus, thorax and the first abdominal segment, —is while a third entered the rectum. This last, ac- really a urinary organ. cording to Cuvier (LeQons d'Anat. Comp. III. p. 348 TI1E CRUSTACEA. g 290. and formed in the two lateral pouches of the stomach of the Astacusfiuviatilis.~1) As they are not observed during the whole year, but only just before the moulting, and as, when this process occurs, they pass from the cast-off stomach into the cavity of the new one, it may be inferred that they are in some way connected with the act of ecdysis, and that if the lateral pouches of the stomach secrete firom the blood the excess of calcareous salts, it is in order that these last may be subsequently used for the forimation of the new shell. (2) The caustic, brown fluid, which most Myriapoda, when touched, emit from a row of orifices situated on the sides of the segments of the body (Foramina repugnatoria), and which exhales an odor like that of chlorine, is secreted by small, pyriform, glandular follicles, situated immediately beneath the skin. Its use is, perhaps, for the lubrication of the articulations of the segments of the body.'3 In the following chapter will be mentioned many other glandular organs connected with the genital functions. CHAPTER IX. ORGANS OF GENERATION. ~290. The Crustacea reproduce by Male and Female Organs, situated in different individuals, and have, for the most part, copulatoLy organs. Nevertheless, the Cirripedia form an exception in this respect, being hermaphrodites; while, on the other side, many Entomostraca differ from the general rule, in their species being almost exclusively females, which produce, during many successive generations, individuals exclusively of the female sex, and only at long intervals, those of the male sex.(') There is, 1 See Suackow, loc. cit. p. 53, Taf. X. fig. 10, 11, luminous liquid. Branzdt (Recueil, &c., p. 151, e. This author is nlistaken in supposing that those 157) has observed, with Glosmeris, that these folgreen glandular bodies mentioned in connection licles are situated, in pairs, ons the dorsal surface with the organs of hearing (~ 276), secrete the of each segmintt of the body.*:' Crabs-eyes." See also Brasndt, Mledic. Zool. II. 1 This is so with the Dapilnioiidae, Cypridoidae. p. 63, Taft XI. fg. 8, 9, c. and Apodidae. In the second of these clgroups, the 2 For the nature of these crabs-eyes, see the re- males are so rare, that these Entomlostraca have searches of Boer (11afller's Archi. 1834, p. 510) and been taken for hermaphrodites, anld Strauts (lec. Oesterlen, Ibid. 18-0, p. 432. cit. p. 52, P1. I. fig. 15) has said that if this swas; Treviracns (Veri. Schlrift. II. p. 42, Taf. really the case, he regsarded as testicles two long VIII. fig. 4,f.f. fig. 5, d. e.) has regarded these cylinldrical problematical bodies which he had olorgans as respiratory with Joelus, while Savi (Isis, selrved with all the females of Cypris. In the 1823, p. 218, Taf. II. fig. 1, 13, 14, a. b.), and genus tApus, no individuals swhich can with cerBtrmeister (Ibid. 1834, p. 136, Taf. I. fig. 1, a. a.) tasinty be regarded as emasles, have been found. have well perceived that they are cutaneous glanlds. Berthold (Isis, 1830, p. 693) has thleoken the According to Waga (levue Zool. 1839, No. 3, p. red ampullae found with these Crustacea for 76, or in Wiemalnnon s Arch. 1810, II. p. 350), testicles; but, as I have already remarled, these Polydesmnts, Platyulls, and Geophilus electri- amlpullae are only branchial lasmellae filled with cuos, have, upon the sisles of the body, analogous blood during the dying of the anirr i1. (See ~ 286, glands, out of which this last MIyriapod emits a note 5.) * [ ~ 289, note 3.] These odoriferous glands florence flask with the mouth drawn to a point. have been successfully studied by Leidy (Proc. This sac is composed of a basement membrane Acad. Sc. Philad. 18140 Iv. p. 235) with Julths. lined with a single layer of secreting cells. The Here, they consist of a globular body or sac, with neck of the glands has muscular bands. - ED. an elongated conical neck, and resemble in form a ~ 290. THE CRUSTACEA. 349 probably, some relation between this remarkable mode of generation and the fact that some females lay two kinds of eggs, one of which is developed peyntaneously, that is, without the influence of sperm, while the other requires to be fecundated.(2) The structure and disposition of the genital organs is so different in the various divisions of Crustacea, that it is difficult to make any general statement about them. Usually, there is a complete duplication of these organs, internal and external, with both sexes. With the females, there is nearly always, right and left, a longer or shorter, rarely-branched, ovarian tube. This is succeeded by a narrow oviduct, usually long, and often flexuous. This last continues into a large vagina, which opens at very different points on the ventral surfltce, sometimes quite in fr'ont, sometimes near the middle, or at the posterior extremity. It is rare that this vagina has a Receptaculum seminis; but, more commonly, the females have special glandular canals annexed to the genital orifice. The product of these last is a viscous mucus, which hardens in water, and serves to envelop the eggs, and to glue them together. The cg-os, thus bound together in chaplets or clusters, remain glued to the parts neighboring the genital orifice, or to the postabdominal feet, and are borne about by the females, until the embryos are fully developed. With other femlales, where these organs are wanting, they are replaced by a special pouch (Marsupin.am) situated, usually, at the infericr surfatce of the thorax. In this pouch the eggs are deposited and remain until their embryos are completely developed. With the males, the internal genital organs are disposed in a similar manner, and often have the same form as those of the females. A careful examination is, therefore, necessary, to perceive their distinctive character. Mloreover, they open, also, at the most varied points of the body. In many species, there are, near the genital orifices, copulatory organs in the form of stylets, or canaliculi, which serve to transfer the spermnl into the female organs. With others, the antennae, or some of the feet, are provided with a kind of hook, or pincers, with which they seize and retain the females during copulation. Sometimes the internal organs of the left communicate, by anastomoses, with those of the right side, or, in the place of two lateral genital openings, there is only one, situated on the median line. With many species, the genital organs, internal and external, are simple, and placed in the axis of the body; but it is rarely observed, that the oviducts and deferent canals are sitngle where the ovaries or the testicles are double, or that there are two genital openings for single internal organs. The Eogs of the Crustacea are usually of either a lively green, yellow, or violet color. They are always spherical, and composed of a dense chorion, containing a vitellus, which surrounds a germinative vesicle, with one or mnore nuclei. The vitellus is composed of numnerous oil-globules, which are held together by a clear, albuminous liquid, and give the egg its peculiar color."' The sperm is white and sometimes opalescent. The spermatic particles are of very varied and remarkable forms. Nearly always, they are 2 This phenomenon is undonlbtedly analogous to mal. Crust. generat., 1844, and his Bemerkungen ia that of the alternation of generation, which is so Froriep's neue Notiz. XXIV. 1842, p. 181 i Erdl, general with the other lower animals. Entwickelung d. Ilummereies, p. 13; and especially 3 For the eggs of Crustacea, see Rathke, De Ani- Wagner, Prodromus, &c., p. 8, Tab. I. fig. 12-17. 30 850 THE CRUSTACEA. ~ 290. stiff and motionless, and may be arranged under the following principal types. 1. With the Cyclopidae, and Chilognatha, the spermatic particles, which are developed in cells, retain their cell-form to their perfect state, without any trace of processes or appendages.~4) 2. With the Decapoda, they are likewise nearly always of a, granular oP cell form, but have small, filiform, sac-like processes; sometimes they are divided into two portions by a constriction.(t) 3. With the 3Mysina, Amphipoda, and Isopoda, they have the form of very long threads, pointed at both extremities, or with a cylindrical incrassation at one of them. They are motionless, and, upon the addition of water, do not roll up in a loop-like manner.~ 4. With the Cirripedia, and Chilopoda, they are capillary, very lively, and, from contact with water, become entangled, formling loops and rin's. (7) 4 With Cyclopsina castor, the spermatic parti- ra, are motionless, radiated cells, one part of cles are small, finely-granular, oval corpuscles (see which is separated by a constriction, and prolonged my Beitr. zur Naturg. d. wirbellosen Th.ll. p. 41,'lTaf. sometimes into a kind of peduncle * the rays II. fig. 41-43 c., or Ann. d. Sc. Nat. XIV. 1840, are often only three or four in number, and the p. 30, Pl. V. B.). As to the other Entolnostraca, cells themselves are sometimes conical or cylindriwe have not yet sufficient data to say anything in cal. The most simple of these spermatic particles general. But the form observed with Cyclopsina are observed with Cranegon vulgaris, and Palaecastor cannot be regarded as a typical one with scon squilla; and, according to my own observathese animals, for Wagner (Wiegisancn's Arch. tions, consist only of flattened cells with a short 1836, I. p. 369) has observed large, filiforml, flexu- pointed process. ous, spermuatic particles with Cypris. I, myself, 6 Simple capilliform spermatic particles are found have found those of Daphonia rectir'ostris to con- with Miysis, Oniscus, Porcellio, Idlothea, and sist of a long, semi-circular body, which became Gammarus; see my researches in iiller's Arch. motionless and disappeared by bursting on the ad- 1836: p. 27, Taf. III. fig. 19, 20, and Ibid. 1837, dition of water. Stein (Miiller's Arch. 1842, p. p. 433; also Kolliker, Beitr. loc. cit. p. 15. This 263, Taf. XIV. fig. 37, 40) has rightly figured those last naturalist (Beitr. &c. p. 14, Taf. III. fig. 28, of Glomeris as fusiformn cells; but he was less exact 29) has stated that the long capillary, but motionwith those of Julus and Polydesmuns, in describing less spermatic particles of Iphiimedia obesa and them as small transparent vesicles (Ibid. fig. 36, 39.) Hyperia medusarum are terminated by a cylinWith Julus subulosus, they look exactly like drical and slightly flexuous incrassation. I have very short cylinders containing a very distinct, found those of Asellus aquaticus to be similar, round nucleus. With Joulus hispidus, they are but the cylindrical extremities were straight. of the same form, but are not nucleated; while with 7 The spermatic particles of the Cirripedia, which Julus terrestris, they are conical and nucleated are simply capillary and very active when fully de(see my notice in Aliiller's Arch. 1843, p. 13). veloped, have been observed by me (lMuiller's Those of the Siphonostoma are, also, of a celloid Ar-ch. 1836, p. 29), with Balanus pusillus, and form; see Frey and Lesuckart, Beitr. loc. cit. p. by KIlliker (Beitr. p. 16, Taf. III. fig. 30, and 135, Teaf. II. fig. 21 (Caligus). Schweiz. Denks. loc. cit. p. 33) with many other 5 Henle (Muller's Arch. 1835, p. 603, Taf. XIV. species of Balanus, and with Chthlamalus, Lepas, fig. 12) and myself (Ibid. 1836, p. 26, Taf. III. and Polliaipes. Those of Lithobius and Geophifig. 23, 24) first called attention to the singular lus present a remarkable aspect from their extreme form of the spermatic particles of the common activity, and may well be recommended for study craw fish; but, subsequently, Kolliker (Beitr. &c. from their size (Stein, in Miiller's Arch. 1842, p. 1841, p. 7, Ta.. I IIi. and in.the Schweizerisch.. 250, Taf. XIII. XIV. fig. 19-33). Treviranits Denkschrift. f. d. gesanmmt. Naturw.'III. 1846, (Verm. Schrift. II. p. 26, Taf. VI. fig. 2, 3) has p. 26, Taf. II.) has shown that those of the most di- taken those of Scolospensdra, which are bound toverse species of Brachyura, Anomura, and Macru- gether in a long white cord, for a Helminth.* [ 290, note 7.] The spermatic particles of ied, and with results quite different from those of the the Crustacea are the most remarkable of any in authlors just mentioned. Mly observations were made the whole animal kiengdom. The strange, bizarre on those of Paguruls, Pilumnus and. Astacus. forms, here observed, have led to singular views as HIere, the development occurs in special cells like that to their development and character. The recent of those of other animals, and the particle, howevresearches of Kolliker have done much to clear up er singular its form, is the'transformed nucleus of this intricate subject, and these researches have these cells. The spine-like processes lie reverted been continued by Wagner and Leuckart (Art. on the body of the particle when this last is in the Semen, Cyclop. Anat. and Physiol.). The most special cell, but become erect and prominent when singular of these particles, as is well known, are those the particle escapes. The body of the particle, belonging to the higher forms of this class. The de- therefore, is solid, and not hollow and nucleated, velopment and nature of these I have recently stud- as has been supposed (see Kolliter and his , 291. THE CRUSTACEA. 351 With very many Crustacea, the sperm, at its emission, is contained in capsules (Spermatop/hores). I. Hermaphrodite Crustacea. ~ 291. With the Cirripeclia, the male and female genital organs are quite remloved from each other. With the Lepadea, the ovaries are lodged in the upper extremity of the peduncle and in the midst of the spongy substance, filling its cavity.(l) They consist of ramified caeca, while with the Balanoodea, the. ovarian follicles are situated between the lamlellae of the mantle.(2) With the Lepadea, the canal which extends fiom the lower extremity of the shell into the peduncle and communicates by a narrow opening with the cavity of the mantle, may properly be regarded as an oviduct.u' But new researches are required to show by what means the eggs of the Balanodea reach this same cavity, for, as is the case with the Lepadea, they remain there until the embryos are fully formed. These eggs, of a blue or yellow color, are always intimately glued together, and form, after the laying, a large sheet or layer which, with the Balanodea, is applied to the internal surface of the mantle, and often retained there by the branchial lamellae;(4) while with the Lepadea, it covers, bonnet-like, the rounded portion of the body. The Testicles are composed of numerous ramified follicles spread out between the skin and the two sides of the digestive canal. They join from the right and left into two very long and tubular Vasa deferentia which accompany, serpentinely, the alimentary canal to the anus, and then blend together, forming a more narrow Ductus ejaculatorius. As this last traverses the whole tail and opens at its extremity, it has been usually regard1 Burmeister (Beitr. p. 46), and Wagner (Miil- cause they are scattered in the walls of the mantle, Cer's Arch. 1834, p. 469, Taf. VIII. fig. 10), were and consequently scarcely visible, especially when the first to notice the ovarian follicles of the foot of empty. It is undoubtedly on this account that the Lepadea, the first with Otion, the second with Poli (Testac. utriusq. Sicil. &c. I. p. 19, 28, Tab. Lepas. lartin St. Ange (loc. cit. p. 20, P1. I. IV. fig. 13, x. x.. Tab. V. fig. 13, 15) has taken for fig. 10, 11) has verified this fact with this last ge- ovaries, with a Balanlts, the testicular follicles, alnus. I have found them also in the foot of Cinse- though he distinctly saw and has figured the ovariras, and I will remark that in the remaining spongy an follicles in another species of this same genus. substance of this foot, there are other round uncle- 3 Tllis canal, regarded as an oviduct by Wagner ated bodies which appear to be solid concretionls, (loc. cit.), had already been mentioned by Cuvier sand should not be confounded with the germs. (Mdim. loc. cit. 1'. 4, fig. 4). 2 The ovaries of the Balanodea are more difficult 4 With Balani its, the layers of eggs form usually of study than those of the Lepadea, probably be- two large discs (Poli, loc. cit. Tab. IV. fig. 18, c. c.). figures). The nuclear appearance is due, some- The whole stilject of the spermatic particles of times to a depression in the body (as with Astaceus), the Crustacea is sadly deficient in wsell-authentisometimes to a plastic membrane lying about one of cated observations, and particles and cell-like forms the spinous processes (as with Piltsmnus), all are constantly described as spermatic particles, made prominent by the refraction of the light i see which, according to all the laws of Spermnatology my researches in the Proceed. Boston Soc.' Nat. as yet known, cannot be such. It should be reHist. IV. p. 258. membered that the spermatic particle is never a In regard to the spermatic particles of the Ento- cell, but is the metamorphosed nucleus of a cell; it mostraca, I have examined those of Cypris, Cy- is, therefore, always a more or less solid corpuscle clops, and Daphnia. They are developed, as usual, (whatever be its form, &c.), and to wlich, moreover, in special cells - are exceedingly minute, and in there may be attached one or more appendages form closely resemble those of the Araneae; consist- - ED. ing of an arcuate rod to which is attached a short but very delicate tail. My results, therefore, do not agree with those above-mentioned. 852 THE CRUSTACEA.' 292. ed as a Penis.(') The length and mobility of this tail is such that it can be used, with the Cirripedia, as a copulatory organ, and, being brought in contact with the orifice of the oviducts, which is situated on the mantle, self-impregnation may thus take place.* II. Feemale Crustacea. ~ 292. The female genital organs of the Siphonostoma and Lophyropodla consist nearly always of two long and sometimes flexuous ovarian pouches, situated on both sides of the digestive canal. The oviducts pass backwards and terminate on both sides of the end of the body by separate orifices, or by a single genital opening on the median line. With those species whose body has a tail, these orifices are not situated like the anus, at its extremity, but at its base. Very often, they serve as the outlets of the excretory ducts of two caecal organs which secrete a viscous substance by which the eggs are glued together in clusters or chaplets.(1) Not unfrequently, there are hook-like or capsular appendages near the genital openings, for the retention of these clusters.(2) But these are wanting with the Daphnioidae, there being in their place an incubating cavity, situated between the 5 Cutvier (MIm. loc. cit. p. 9, fig. 8) has taken, Edinb. New Philos. Joinl. July, 1842, p. 178, or Ann. with Lepas, the testicles for the ovaries, and the d. Sc. Nat. XVIII. 1842, p. 181; liroyer, Natulh,. Vasa deferentic for the testicles. This error could Tidskr. I. PI. VI. or Isis, 141, p. 19-, Taf. Io not be rectified until the discovery of the true Tab. VI. fig. 4, C. (Caliges); aid Rathke, Nov. ovaries (see Btirmeister, Beitr. loc. cit. p. 33, Act. Nat. Cur. XIX. p. 145, Tab. XVII. fig. 2 (DiTaf. II. fig. 16; Wc;, gner, in Mliller's Arch. loc. chelestiumn). This last-mentioned author was the cit. p. 469, Taf. VIII. fig. 8 5 and Martin St. Ang e, first to notice the organs whicli,in various Crustacea. loc. cit. p. 21, P1. II. Lepas). It is more singular secrete the viscous matter mentioned in the text. ItIe to see Goodsir (Edinb. New Philos. Jour. 1843, Ju- found them highly developed with the NDicotho& ly, p. 88, PI. III. IV. or Ann. d. Sc. Nat. I. 1844, (loc. cit. XX. p. 106), where they extend, with the p. 107, P1'. XV. C. or Froriep's neue Notiz. No. ovaries, even into the wing-like appendages of this i651, 1844, p. 193), endeavor to confuse this ques- parasite. The ovarian follicles of Chonldracanthuz, tion by declaring the hermaphrodite animals of which are multiramose, differ very much from the Balanle/ s to be females which carly, in the cavity of usual form (Rathike, Ibid. XX. p. 123, Tab. V. fig. their mantle, dwarfish and abortively-formed males. 18). With the Cyclopidae, there is only a single Very probably those so-called males are parasitic genital opening, although the ovaries and the orCrustacea, as Kl/liker (Schweiz. Denks. loc. cit. p. gans secreting the viscous matter, are double. But 33) has supposed. with Argulhts, the female genital organs are the 1 The female genital organs are completely double most simple, consisting only of a single ovarian with the Penellilla, the Lernaeoldea, the Ergasilina tube, opening at the base of the tail (Jurine, loc. and the Caligina; see INordmann, loc. cit. p. 6, cit. p. 448, Pl. XXSV. fig. 3).t Tat. I. fig. 4, Taf. V. fig. 7, Tatf. VI. fig. 10 (Lamin- 2 Nordmann, ltoc. cit. p. 8, Taf. II. fig. 6 (Erproglena, Achtheres and Peniictulus); Goodsir, gasilus). * [ ~ 291, end.] That the Cirripedia are not uni- character to those of Ibla, that he considers therm versally hermaphrodites, was first discovered by to be true males of the species with which they ar6 Goodsir (Ed. New Phil. Jour. XXXV. p. 88), up- connected. Being thus supernumeraries, he has on Balaneis balaenoides. The male is very small, termed them complemental males. As spermatic and it is not strange that it before eluded observa- particles were distinctly observed in them, their tion. male nature is clear, but it would not appear Darswin has made some researches, lately, with equally clear that they really belong to the genus a similar result in some respects. Exceptions to and species with which they are connected. Facts the rule were found by this naturalist in the genera so singular require further research. See Darwin, Ibla and Scalpellum. With Ibla, the males lie MIonogr. &c. loc. cit. p. 207, 231. -ED. within the sac of the female, and have an elongated t [ ~ 292, note 1.] For further details on the febody with a pedicle below. He has also observed male genital organs of Argulus, with illustrations, that, with these genera, there are both females see Leydig, loc. cit. in Siebold and KIlliker's and hermaphrodites; and in some hermaphrodites, Zeitsch. II. p. 339 Taf. XIX. fig. 5, a. Taf. XX. -males have been observed so similar in general fig. 8, 10.- ED. 292. THE CRUSTACEA. 353 shell and the posterior part of the back.3) The females of Daphnia have; beside those eggs which are rapidly developed in this cavity, another kind known as the hibernating eggs, and in which no germinative vesicle is observed. They are always found in couples in a thickened, saddle-like portion of the shell of the animal, which is often of a black color, and separated from the shell by a kind of moulting. Thus enveloped in a bivalved. capsule, they are protected against the severities of the winter.(4) Among the Phyllopoda, the Apodidae are distinguished for the very large,. multiramose, ovarian follicles which border the two oviducts on every side; these last are straight and large, and situated on the side of the digestives canal. With Apus, each of them sends off, at about its middle, a shorts excretory canal, to the eleventh pair of feet, in which there are two alveolate receptacles with covers for the reception of the eggs. () With the: Branchiopoda, the ovaries consist of two straight coeca, situated in the tail, on each side of the intestine. Their upper extremity, beneath the last pair of'feet, passes into an elongated receptacle. These two receptacles, separated from each other only by a thin partition, have a narrow outlet at their posterior extremity, and form, under the base of the tail, a kind of oblong tumor, into which the hard and granular eggs are constantly cast from the contractions of special muscular bands.(') There are, moreover, on the sides of the body above the last pair of feet, two oblique horny plates, which the males, during copulation, seize with their cephalic pincers. With the Poecilopoda, the cephalothorax contains two ramified ovaries, 3 See Straus, M6m. sur les Daphnia, loc. cit. p. Tab. I. (Apus). With Limnadia, and Isaura, a 413, P1. XXIX. and Jurine, Mlist. d. Monocl. P1. special receptacle is wanting; the eggs are attached YIII.-XVI. The genera Argulus and Cypris dif- to the feet probably by the aid of their hairy fer, moreover, from the other Entomostraca, in external envelope; see Brongniart, loc. cit. p. 88; that they do not bear about their eggs after laying, Straits, Mus. Senckenb. loc. cit. Taf. VII. fig. 16, but deposit them on foreign bodies; see Jurine, and Joly, loc. cit. p. 308, PI. IX. A.t MIm. sur l'Argule, loc. cit. p. 451, and Straus, 6 See Prevost, in Jurine's Hist. d. Monocles, p. Mim. sur les Cypris, loc. cit. p. 54. 228, P1. XX. fig. 1, 10 (Chirocephalus). This an4 The formation of the saddle, which is intimate- thor erroneously declares, moreover (loc. cit. ply connected with the deposition of the hibernating 207), that the females of this animal have, also, at. eggs, has been called by Jurine the Maladie de la the end of the tail, openings into which the sperm is selle. But it has been before observed by iiller received duling coition. See also Joly (loc. cit. p. (Entomostr. p. 84, Tab. XI. fig. 9-11, Tab. XiI. 240, PI. VII. fig. 12, P1. VIII. fig. 4), who regardsfig. 5), and by Ramdohr (loc. cit. p. 28). See, also, the receptacles of the eggs, with Artemia, as the Straus, loc. cit. p. 415, P1. XXIX. fig. 16, 17, and ovaries. The eggs with a solid, granular shell, of Jurine, Hist. d. Monoct. p. 120, P1. XI. fig. 1, 4.* Branchipus, have been pretty distinctly figured by 5 See Sechaeffer, Der krebsartige Kiefenfuss, p. Schaefder (Der fischf rm. Kiefenfuss, fig. 14). 79, Taf. IV. fig. 2-7, and Zaddach, loc. cit. p. 51, * [~ 292, note 4.] Recent investigations upon the subject, see Liivin, Die Branchiopoden der Daneconomy and development of the Crustacea indi- ziger Gegend, 1848, p. 11. et seq.; Baird, Brit. cate that the phenomena above-mentioned, of the Entomostr. &c. loc. cit. passim; Zenker, Physiolreproduction by means of a second kind of eggs ogische Bemerkungen fiber die Daphnoidae, ink (so-called), is far from being limited to a few of Miiller's Arch. 1851, p. 112; Leydig, Ueber Arthese animals. Indeed, it is probable that all or temia salina und Branchipus stagnalis, in Siebold most of the Entomostraca reproduce by this mode. and K6lliker's Zeitsch. III. 1851, p. 297.- ED. As mentioned on a preceding page, these phenome- t [ d 292, note 5.] For the female genital organsg na do not appear to me to belong to true oviparous of Artemia and Branchipsts, see Leydig, (loc. cit. reproduction, but must be considered as a kind of Siebold and Kollicker's Zeitsch. III. p. 300). Jointernal gemmiparity. The so-called winter-eggs ly, it would appear, did not observe the ovaries of are, therefore, not eggs, but buds (gemmae) — a rtemia, but has described the egg-capsules asview which is borne out by their composition, - such. The real ovaries here consist of sacs or there being no germinative vesicle and dot. This pouches, lying near the dorsal surface of the abdosubject will be discussed with some detail below (note men, and extending to the second abdominal ring; under ~355) when speaking of the Aphides-animals these ovarian sacs pass into a vesiculiform dilatawith which I have traced these phenomena with tion, which has non-muscular walls, and correo some care. For many interesting details on this sponds to a uterus. - ED. 30* 354 THE CRUSTACEA. ~ 292. the large oviducts of which open at the base of the first pair of feet, near the median line of the body.(7) With the Laemodipoda, Isopoda, Amphipoda, and Mysina, there are two simple ovarian tubes wound about the digestive canal; these oviducts are sometimes terminal, sometimes lateral. The two vulvae are usually situated on the internal side of the fifth pair of feet.(8) The eggs, after laying, are always deposited in an incubating pouch, situated beneath the anterior extremity of the body, and the walls of which are formed in part by from two to five pairs of imbricated, and often concavo-convex lamellae.9 - These last are generally bristled on their borders, and are chiefly developed at the epoch of procreation, after which they disappear.(10) The ovaries of the Squillina differ remarkably firom those of the other higher Crustacea. They consist of numerous, ramified lobes, filling the lateral portions of the posterior abdominal segments, and the digitations of which extend even into the last and flattened caudal segment. All these divisions of each ovary join in a large, long tube, which surrounds the digestive canal. The portion of the ovary contained in the three segments to which are attached the ambulatory feet, sends towards the ventral surface, three branches, which join, upon the median line beneath the abdominal cord, with those of the opposite side, and form, in the middle of each of these three segments, a round sinus. These sinuses are connected by longitudinal anastomoses, and the anterior one is prolonged into a common papillary vulva, situated in the middle of the first abdominal segment beneath a horny process.(l1) 7 Van der Hoeven, loc. cit. p. 21, P1. II. fig. 15, pairs of ventral lamellae of this kind. With GamP1. III. fig. 1 (Limulus). marus, the borders of these ten lamellae are covy8 There are two ovarian tubes, each continuous ered with long bristles (Zenker, loc. cit. p. 8, fig. posteriorly into a short ovidnuct with Cyamus N. b.). With CymotLoa, the coxae of the first six (Roussel de Vauzdme,.loc. cit. p. 253, P1. IX. fig. pairs of feet have a semilunar lamella (tMilne 19), with Aega (Rathke, Nov. Act. Nat. Cur. XX. Edwards, Ann. d. Sc. Nat. III. 1835, P1. XIV. p. 32, Tab. VI. fig. 17), and with Mysis (Frey, fig. 2, and Cyclop. loc. cit. p. 784. fig. 436). The loc. cit. p. 25). The two oviducts meet in a com- same is true of Anilocra, judging from Savigny's mnon vulva in front of the anus with Bopyrus and figure (loc. cit. Crust. P1. XI. fig. 10-). With Phryxus (Rathke, De Bopyro, &c., p. 19, Tab. I. Bopyrus, and Phryxus, the incubating sac config. 7, and Nov. Act. Nat. Cur. XX. p. 47). With tains six pairs of lamellae which, in the first of the Asellina, the ovarian tubes are coecal at both these genera, are not wholly superposed (Rathki, of their extremities; the oviducts pass off laterally De Bopyro, &c., p. 6, Tab. I. fig. 5, and Nov. Act. and open in the articulation of the fifth and sixth Nat. Cur. XX. p. 44, Tab. II. fig. 12). The sixth segment of the body (Brandt, Mediz. Zool. II. p. or anterior pair of these lamellae is wanting with 16, Taf. XV. fig. 32). I have observed an analo- Cepon (l)Duvernoy, Ann. d. Sc. Nat. XV. 120, Pl. gous structure in the genital organs of Idothea IV. fig. 2)' —ut with the Bopyrina in question, is (Miiller's Arch. 1837, p. 434). With Caprella, singilarly attached to the head. According to the ovarian tubes are coecal in the same way, but Treviranus (Verm. Schrift. I. p. 61, Taf. IX. fig.,they interanastomose by two pairs of short, trans- 52), there are at the bottom of this sac with versal oviducts (Goodsir, Edinb. New Philos. Jour. Oniscidae, four short conical processes which seJuly, 1842, p. 184, Pl. III. fig. 2). This author crete a yellowish fluid; but Brandt (loc. cit. II. adds, contrary to all analogy, that these ovidnucts p. 72, Taf. XII. fig. 2, Taf. XV. fig. 33) was unaterminate in two vulvae situated one behind the ble to find them, while Rathki (loc. cit.) has been other on the middle of the belly. led to regard as secreting organs also, two fila9 The incubating sac of Cyamus and Caprella ments which, with Mysis, are attached to the venis composed of four lamellae situated back of the tral wall, and stretch into the incubating sac. branchiae upon the two footless segments of the 10 This origin and disappearance of the incubatbody (Roussel de Vauzime, loc. cit. p. 249, P1. ing lamellae I have seen very distinctly with IdoVIII. fig. 3, and Goodsir, loc. cit. p. 106, PI. III. thea entomon (Aiuller's Arch. 1837, p. 435). The fig. 3, 10). With AMysis, this cavity contains also females of Cyamus which Meuller (Zool. Danic. only four lamellae covered with stiff bristles and Tab. CXIX. fig. 16), and Treviranus (Verm. attached to the coxae of the last two pairs of feet Schrift. II. Taf. I. fig. 2). have figured, appear to i(Miiller, Zool. Danic. Tab. LXVI. fig. 1, 2 * Milne have been individuals whose incubating sac was Edwards, Hist. d. Crust. P1. XXVI. fig. 8, d.; not then fully developed. and Rathkce, in Wiegmann's Airch. 1839, I. p. 11 The ovaries of Squilla are so intimately blend199). With Nerocila, there are also four large ed in part with the liver, that they may be easilamellae arising from the coxae of the sixth and ly confounded with that organ. It is on this seventh pairs of feet. With Idothea, the Aselli- account that Duvernoy's figune (Anin. d. Sc. Nat. na and the Gammarina, on the other hand, the VI. 1836, p. 248, PI. XV. and VIII. 1837, p. 42, five anterior segments of the body have as many P1. II.) of this organ with this same animal, is not ~ 292. THE CRUSTACEA. 355 With the Brachyura, the cephalothorax contains four long ovarian tubes, two anterior, and two posterior. The first wind outwardly over the liver, and are anastomosed by a short transverse canal; while the second are straight, lie close to each other, and cover the anterior part of the intestine. The anterior and posterior tubes of each side unite in a short vagina, and, at their point of junction, open into a pyriform sac, which has been regarded by some as a Bursa copulatrix, and by others as a gland secreting the viscous substance which envelops the eggs, but which, upon a more careful examination of its contents, will be found to be a Receptaculum seminis.(l2) The two vaginae open near the ventral median line in the segment which bears the third pair of feet.(") With the other Decapoda, - the Anomura and the Macrura,- these sacs, just mentioned, are wanting, while the ovaries themselves are disposed, in general, like those of the.Brachyura. l4) But the genera Pagurus and Astacus, alone, form an,exception in this respect. In the first, the two ovaries with their oviducts lie concealed principally beneath the dorsal surface of the tail; while in the second, they are aggregated in a trilobed mass in the pyloric region,:from which pass off two short oviducts.(l~5 The female genital openings.are situated, with the Anomura, as with nearly all the Macrura, in the -coxal joints of the third pair of feet.(6) With the females of all the Decapoda, the feet of all the caudal segments are highly developed and very hairy. They serve to support the eggs which are glued together in clusters by a viscid substance which hardens in water; these clusters are attached to the bristles or hairs of these feet. But with the Brachyura, and Anomura, these eggs have an additional protection in the tail, which is folded against the body.(7) The Chilognatha have only a single long and large ovarian tube, provided with two short oviducts which are narrower, and open externally at two squamous bodies situated on the under surface of the third segment of the body. These two bodies contain two short caeca one of which is dilated at its base into a vesicle, and each pair opens by a common orifice in the vulva. They represent a Receptaculizm seminis. (1) With the perfectly clear. This naturalist has, moreover, re- 16 The two vulvae of the crawfish may be seen garded alarge part of the ovaries as venous sinus- in the figures already cited. For those of the,es, and the white eggs which they contain as coagu- Anomura, which, except with Paeolgrus, are covlated blood. In order to have a general idea of the ered by the tail curved in front; see Milne Ed-,disposition of the female genital organs with these wards, Hist. d. Crust. III. p. 172, P1. XXI. fig. 8, animals, it is only necessary to cast a glance over 18 (Dromia and Remipes), and Arch. du Mlus. II. Delle Chiaje's figure (Descriz. &c. Tav. LXXXVI. P1. XXVI. fig. 1, e. Lithodes). But the Carifig. 4, b. g. g.); it is true that hei has represented doidae form an exception in this respect, - their them as testicles, but they are perfectly exhibited, female genital openings being situated in the same with the exception, however, of the anterior por- places as those of the males, that is on the external tion. side of the coxae of the posterior feet; see Krtyer, 12 See Cavolini, loc. cit. p. 138, Taf. II. fig. 3 loc. cit. p. 27, fig. 54, A. f. and fig. 97, B. g. (Hip)(Grapsus); Milne Edvards, list. d. Crust. I. p. polyte). 170, P1. XII. fig. 12, and Cyclop. loc. cit. p. 784, 17 With Pagurus, the anal feet are developed fig. 434 i Carus, Erlauterungstaf. loc. cit. Heft. V. only on one side of the tail. ps. 7, Taf. III. fig. 7, and Erdl, Entwickel. d. 18 Many erroneous opinions have been ernterIlummereies, p. 11 (Maia). trained by Zootomists on the subject of the female 13 Cavolini, loc. cit. Taf. II. fig. 2, a. (Grap- genital organs of the Chilognatha. Thus, Trevi8us); MIilne Edwards, Hist. d. Crust. P1. III. ranus (Verm. Schrift. II. p. 45) with Julus, and fig. 4, i.; and Carus, loc. cit. Taf. III. fig. 8, b. Brandt (Miiller's Arch. 1837, p. 325, Taf. XII.,(Mlaia). fig. 8) with Glomeris, think they have obl)serveed 14 Milne Edwards, Hist. d. Crust. I. p. 171, double ovaries, as is also true of Stein (Miiller's and Duvernoy, in Cuvier's Lemons, &c., loc. cit. Arch. 1842, p. 246, 2468); but Newport (Phil. Trans. VIII. p. 349. 1842, p. 99, or in Froriep's neue Not. XXI. p. 161; 15 The internal female genital organs of the craw- see, also, Rymer Jones, Cyclop. loc. cit. p. 552, ibgh are represented in Roesel, loc. cit. Taf. LX. fig. 315, 316) has noticed only a simple ovarian fig. 24, 25; in SLckou,, loc. cit. Taf. X. fig. 16; tube with Julus, which I have been able to conand in Brandt and Ratzeburg's Mediz. Zool. II. firm; and as for Glomeris, Brandt (Recueil, loc. Taf. XI. fig. 15. cit. p. 157) has himself recently perceived the same. 356 THE CRUSTACEA. $ 293. Chilopoda, also, the ovary is a single long tube, but extends from before backwards and terminates by a short oviduct in the last segment of the body. The Receptaculum seminis consists, here, of two ovoid capsules, sessile or pedunculated, and inserted upon the sides of the extremity of the oviduct. Into this last, moreover, just before its termination, long excretory ducts enter from the two to four Glandulae sebaceae, which furnish probably the viscous coating of the eggs.(q)> III. Male Crustacea. ~ 293. The males of the Siphonostoma often differ very much from the females, not only as to their external form, but also in their smaller size, — their development being arrested at a very early period. On this account, some are still unknown, and the organization of others is not understood.(') With the Caligina, however, they have received more attention, for in size they are scarcely smaller than the females. Their posterior abdominal segment, which, usually, is not as large as that of the other sex, has, at its extremity, two genital openings, side by side. No testicles or excretory canals have yet been observed, but it may be inferred that their external form and their disposition are analogous to those of the oviducts.(2) But with Dichelestium, the male organs are better known. The two spheroidal testicles, and the somewhat tortuous Vasa deferentia of these There has been the same misapprehension and Scolopendra. Those of Scolopendra morsitanschanging of opinion on the subject of the position represented by Muller (Isis, 1829, p. 550, Taf. II. of the external genital openings. According to fig. 5) are probably the male organs. Stein (loc. Treviranus, and Brandt (loc. cit.), they should cit. p. 239, Taf. XII. fig. 2, 8) has described very be situated, with Julus and Glomeris, at the pos- accurately these organs with Lithobius, and Geoterior extremity of the body; but Latreille (Hist. philus. This last has two long-pedunculated semiNat. d. Fourmis, 1802, p. 385) had before indicated nal receptacles, and only two very long Glandulae their. true position with Polydesmus, and Savi sebaceae. (Isis, 1823, p. 217) has confirmed this with Julus. 1 Nordmann (loc. cit. p. 76, &c., Taf. V. VIII. Brandt (Recueil, loc. cit. p. 154) has since recti- IX. X.) was the first to discover some of these fled his error in respect to Glomeris. But Stein small male Crustacea which are nearly always has treated with. most detail the subject of the geni- attached to their females in the neighborhood of tal openings with Julus and Glomeris, as well as the genital openings. He observed them with their seminal receptacles (Miller's Arch. 1842, p..Achtheres, Brachiella, Chonzdracanthu.s, and, 246, Taf. XII. fig. 12, and Taf. XIII. fig. 15. See, Anchorella. But with an individual of the first also, my observations, Ibid. 1843, p. 9). of these genera only, he found in the posterior part, 19 For the female genital organs of Lithobius of the body, four round masses, which perhaps and Scutigera, see-L. Dufour (loc. cit. p. 89, P1. may be the internal genital organs. Burmeister V. fig. 1, 4) who regards the two stalkless Recep- (Nov. Act. Nat. Cur. XVII. p. 320) refuses to tacula seminis of Lithobius as a reservoir of the recognize these small males for the above-melnfour Glandulae sebaceae, and with Scutigera, as tioned Siphonostoma, while Kroiyer (Natur. the Glandes sibac/es themselves. I cannot now Tidskr. 1. P1. III. or Isis, 1840, p. 710, Taf. I. say whether these last organs are wanting in Scu- Tab. III.) sustains the opinion of Nordmann witla tigera, or whether they escaped the attention of cogent arguments, and has described and figured this naturalist. Treviranus (Verm. Schrift. II. several of these males belonging to Lernaeopoda p. 28, Taf. V. fig, 8) has very well observed the and Lernaea. See also the description of Chonsimple ovary with its appendages of Lithobiuss; dracanthus published by Rathk/, Nov. Act. Nat. but he did not recognize the use of these last. Cur. XX. p. 126, Tab. V. fig. 13. Kutorga (loc. cit. p. 8, Tab. I. fig. 5) has not been 2 See Kroyer, Naturh. Tidskr. 1. P1. VI. or more fortunate with the female genital organs of Isis, 1841, p. 194, Taf. I. Tab. VI.* * [ 293, note 2.1 Dana (Caligus, loc. cit. length of the thorax into the abdomen where it Amer. Jour. Sc. XXXII. p. 261, also, Report. passes into the seminal organs. Described more Crust. &c. p. 1344) has observed, with Caligus, a particularly, the testicles are rather larger than the well-formed male apparatus. Here, the testicle buccal mass, and are situated just anterior to the (and the ovary, also, is the same) consists of a large stomach, in part beneath the base of the prehensile pyriform body of an internal glandular appearance, legs, and the spine of the preceding pair. - ED. and continuous into a duct extending the whole ~- 293. THE CRUSTACEA. 357 Crustacea completely resemble, as to form and situation, the ovaries and oviducts of the females, except that the deferent canals are dilated, before their termination, into two seminal vesicles.(3)' With Argzlus, the males have, at the base of their last pair of feet, a book which is used in copulation. But as to their internal organs, there are, as yet, no credible observations.(4) With the Cyclopidae, the male organs consist of a single pyriform testicle, the Vas deferens of which curves, first forwards, then backwards, and opens at the. base of the tail on the median line. In the lower end of this,canal, a homogeneous, cylindrical envelope is formed around the sperm, - -a real spermatophore, which has a narrow neck, and which the males glue to the vulva of the females.() For effecting this last, the males have one or even both of their antennae incrassated at their base, and provided with a special article near their extremity, which gives these organs a forficulate character.(6) When the male, by the aid of these antennae, has embraced the abdomen of the female, he bends the' posterior part of his body forwards, and seizes hold of the female a second time with the forficulate foot of the second pair, at the same time grasping, with the other and digitiform foot, the spermatophore as it is escaping from the genital opening, and attaches it to the vulva.(7' As yet we possess only quite incomplete observations upon the males of Daphnioidae, Cypridoidae, and Apodidae, which are found only at cer. tain seasons of the year.(8) With the species yet observed, the testicles 3 Rathkd, Nov. Act. Nat. Cur. XIX. p. 149, Tab. sina castor), and by Templeton, loc. cit. p. 37, XVII. fig. 17. I do not know how it is with the P1. V. fig. 1, 18 (4nomalocera). males of the other Ergasilina, for as yet we know 7 These spermatophores, the true signification of only the females of these animals. which was unknown until lately, are found, often 4 Jurine, who was the first to notice these in the numbers of four to six, upon the same copulatory organs of the male Argulus, says he female, after several coitions occurring at different perceived at the base of the penultimate pair of feet intervals; see M51iuller, loc. cit. Tab. XVI. fig. 5, a vesicular swelling containing, he thinks, a fecun- 6, and Jurine, loc. cit. P1. IV. fig. 6 (Cyclopsina dating liquid (Ann. du Mus. loc. cit. p. 448, P1. castor); also Ramdohr, loc. cit. Taf. III. fig. 6, 9, XXVIII. fig. 1, 21).* and Jurine, loc. cit. P1. VII. fig. 2, 14 (Cyclop5 For the formation of these spermatophores with sina minutus). The spermatophores of this last ~Cyclopsina castor, and minutus, see my Beitr. have the form of a curved horn, and become, after zur Naturg. d. wirbellosen Thiere, p. 36, Taf. II. a time, of a brown color. With Cyclops quadrifig. 41-44, or Ann. d. Sc. Nat. XIV. 1840, p. 26, cornis, the sperm does not appear to contain P1. V. B. I have shown how their contents are spermatophores at the moment of its evacuation. thrust out in passing the neck by the action of a 8 The males of Polyphemus, Limnadia, and peculiar substance which swells when in contact Apus, have not yet been observed. It is said, it is with water. true, that Kollar (Isis, 1834, p. 680) has discov6 The two antennae are thus endowed, with Cy- ered those of Apus,cancriformis; but as yet clops quadricornis, Cyclopsina minutus, and nothing definite has been learned about the matter. alpestris; while this organization obtains with one At all events, the description given by Zaddacl antenna, only, with Cyclopsina castor, and Ano- (loc. cit. p. 53, Taf. I. fig. 15, 16, and Taf. III. fig. malocera Patersonii; see the figures of idiller, 1, P.) of the male genital organs of these Crustacea, Entomostraca; and Jurine, Hist. d. Monocles, is unsatisfactory, for at the point, where, according also -Vogt, Schweiz. Denksch. loc. cit. p. 18, Taf. to this naturalist, are found the two male genital II.; and Templeton, Trans. of the Entomol. Soc. orifices surrounded by short spines, that is, on the II. p. 35, P1. V. fig. 1, 5. The asymmetrical pos- dorsal surface of the last segment of the body, are terior pair of feet has been figured by Jerine, loc. found, with all the females also, similar orifices. It cit. p. 61, PI. IV. fig. 2, PI. VI. fig. 11 (Cyclop- is therefore probable that the ramose testicles which * [ { 293, note 4.1 For the male genital organs coming from an accessory gland, which is pouchof Argulus, see Leydig (loc. cit. Siebold and like, and stretches back of the seminal vesicle. As KElliker's Zeitsch. II. p. 341). The testicles con- auxiliary copulatory organs may be regarded a sist of two pouch-like organs, situated, one in each hook situated on the anterior border of each of the caudal fin 5 they send off, each, a vas deferens last pair of feet, and a nodule or papilla in the which terminates in a seminal vesicle; from this posterior border of the penultimate pair, correlast pass off two deferent ducts which end in the sponding, oppositely, with the hook. These hooks common genital orifice. Just before reaching this were taken by Jurisne for penises, and the papilorifice, each of these ducts is joined by another lae for seminal capsules. - ED. 858 THE CRUSTACEA. ~ 293,. consist of two spheroidal bodies which open externally, by two deferent canals, in front of the tail.() The copulatory organs are attached to the anterior feet, and consist of hooks and long bristles, by which these animals adhere to the under surface of the thorax of the females.(10) With the Branchiopoda, the male genital organs have a very remarkable organization. The testicles consist of two long, straight, caecal tubes, stretching the whole length of the tail. From the upper and dilated extremity of each passes off, inwards and backwards, an excretory canal. These canals. shortly after their origin, dilate into a seminal vesicle, and then pursue their course between two longitudinal ridges which run backwards from the base of the tail. At the posterior extremity of these ridges, they open near a process covered with short spines. For the seizure and retention of the females for copulation, the two anterior cheliform feet are provided with antler-like hooks, and, also, at their base, with two peculiar, sometimes digitiform processes, curved above the front.(ll) With the Poecilopoda, the testicles consist of ramified canals situated in the cephalothorax, which terminate at that same point on the first pair of post-abdominal feet where are situated the genital openings with the females, in two short, perforated, penis-like organs.12)1 With the Laemodipoda, Isopoda, and Amphipoda, the testicles consist of two caeca situated by the side of the digestive canal, and continuous, posteriorly, into two more or less flexuous deferent canals upon the sides of Zaddach thinks he has observed with a small num- have the form of two short, obtuse antennae ber of individuals which had been preserved in alco- (Miiller, Entomostr. p. 87, Tab. XII. fig. 6 hol a long time, are only ovaries, the characteristics Ramdohr, loc. cit. p. 25, Taf. VII.; Straus, MIm. of which have been effaced by the spirit. As to du Mus. V. p. 419, P1. XXIX. fig. 18, 19; and Cypris, all we know about their males is that their Jurine, Hist. d. Monocles, p. 105, P1. XI. fig. 5spermatic particles, according to Wagner (loc. cit.), 8). With the males of Evadne, only the feet of the: are disproportionately large, and that Ledermiller first abdominal pair are provided each with a hook (Microscop. Gemiiths-und Augen-Ergitzung, p. and some pretty long bristles on their last two arti141, Taf. LXXIII. fig. d.) thinks he has seen them cles (Lovin, loc. cit. p. 157, Taf. V. fig. 11). With in copulation. Baird, also (Magaz. of Zool. and Isaura, on the other hand, the first two pairs of Beot. I. p. 522), has often seen two individuals of abdominal feet are armed at their extremity with Cypris together, but was not sure that they were stout nails (Straus, Mus. Senckenb. II. p. 123,, copulating.* Taf. VII. fig. 4, 13; and Joly, loc. cit. p. 298, PI. 9 Lovine', in Wiegmann's Arch. p. 160, Taf. V. VII. fig. 2, 6). fig. 13 (Evadne). 11 Schaeffer, Der fischfdrm. Kiefenf. fig. 3-11; and 10 With the males of Daphnia, there is a hook Miller, Zool. danic. Tab. XLVIII. (Branchipus). together with a small long lash on the two anterior The frontal digitiform processes are especially depairs of feet situated close under the head. The veloped with Chirocephalus; see Prevost, in first pair of feet situated on the beak in front of the Jurine's Hist. d. Monocl. p. 202, Pl. XXII.t mouth, is very long and provided with two small 12 Van der Hoeven, loc. cit. p. 20, P1. II. fig. pointed hooks while, with the females, these feet 14, 1 (Limulus). *[ ~ 293, note 8.] For the genital organs of were really spermatic particles, the time of obserCypris, see Zenker (Miller's Arch. 1850, p. 191). vation must have been soon after copulation.They closely resemble those of Cyclops. He has ED. also described the spermatophores (Taf. V. fig. 6); t [ ~ 293, note 11.] For the details of the male they are probably the very large spermatic parti- genital organs of Artemia and Branchipus, see cles seen by Wagner as mentioned above. These Leydig (loc. cit. Siebold and K1lliker's Zeitsch. observations I have recently confirmed. Wagner III. p. 297). With these Phyllopods, these organs and Leuckart (Cyclop. Anat. and Physiol. Art. consist of testes, vasa deferentia, and penises; all Semen, p. 496, note) must, therefore, be mistaken, of which are double and symmetrical. The testes when they assert the hermaphroditic nature of consist, each, of an oblong pouch which is directly Cypris, and say, " We beg to direct the attention continuous into its vas deferens; and this last to the simultaneous appearance of egg together passes into its penis. The two penises are situated with the spermatozoa in the same individual; and at the base of the abdomen, and point, bung-shaped, therefore to the hermaphroditic condition of the backwards. Besides these parts, there is an extergenitals in Cypris." It is probable that they ob- nal organ, style-like, used in copulation (loc. cit. served only females, a, —d if what they called such Taf. VIII. fig. 4, a.). - ED. ~ 293. THE CRUSTACEA. 359 which, with the Idotheoidae, and Asellina, are two pairs of similar seminal tubes. The two Vasa deferentia converge towards the posterior portion of the body, where they pass into a double, or a single excretory canal, which usually commences directly in front of the first pair of post-abdominal feet, on the median line of the body.'l3 ) ith the Isopoda, this excretory canal opens into a short, backwardly-curved penis, upon which are two long processes (secondary penises) inserted on the internal border of the second pair of feet.(4) With the Stomapoda, the testicles consist of more or less ramified, glandular lobes, from which pass off, laterally, two Vasa deferentia which terminate in two hollow penises projecting at the base of the last pair of feet. (15) With the Brachyura, and the short-tailed Anomura, the two testicles consist of a net-work of very small semeniferous canals, occupying the lateral portions of the cephalothorax, which gradually increase in size until they pass into the long Vasa deferentia. These last form numerous convolutions, and are finally continuous into two larger Ductus ejaculatorii.(l6):With the male Paguridae, the testicles are contained, like the ovaries, in the tail. They consist of two large tubes which rapidly contract into a Vas deferens, which is straight, at first, but afterwards. spiral. This then becomes larger and is gradually continuous into a Ductus ejaculatorius.1(71 With some Macrura, the cephalothorax contains two anterior and twoposterior testicular tubes, a:portion of the last being extended even into, the tail; while the first are connected, by a transverse anastomosis, behind the middle of the body. The two posterior join with the two anterior in the posterior extremity of the cephalothorax, and form on each side, a short, narrow, deferent canal, which terminates in a larger Ductus ejaculatorius. (18) 13 With Cyamus, whose caudal extremity is Taf. IV. fig. 16, 17, f. h. 25) with Idothea entoatrophied, the orifices of the two excretory ducts mon; but this last author is quite mistaken about are situated directly in front of the arms on two, the internal genital organs, having confounded side by side papilliform penises (Roussel de the male with the female (loc. cit. p. 123, fig. 22). Vauzmoe, loc. cit. p. 252, P1. VIII. fig. 7, 15). I have already corrected this error in Miiller's With Pega, the two testicular tubes are curved S- Arch. 1837, p. 434. Savigny, also (Descript. de like on the sides of the oesophagus. Their defer- l'Egypte, Crust. P1. XII. XIII.), has given beautient canals are dilated at the posterior extremity ful figures of the copulatory organs of Sphaeroma, each into a seminal vesicle of the same S-like form. Lygia, Idothea, Tylos, and Oniscuss. The They open through two approximated papillae secondary or auxiliary penises have been represituated on the under surface of the last foot-bear- sented by Lereboullet, loc. cit. p. 120, P1. V. fig. ing abdominal segment (Rathlek, Nov. Act. Nat. 19 (Lygidium), and by Milne Edwvards, Arch. diu Cur. XX. p. 32, Tab. VI. fig. 16). Mus. II. p. 21, P1. II. fig. 3.* b.1. (Serolis), and The three testicles which are found on each side Ann. d. Sc. Nat. XV. 1841, P1. VI. fig. 4 (Lygia). of the thorax with Idothea, Lygia, Lygidium, 15 As to both form and position, the multilobular Asellus, Porcellio, Oniscus, &c., are very atten- testicles of Squilla almost exactly resemble the uated in front, but behind, are enlarged into a kind ovaries. But their lateral lobes are not blended of bulb before passing into the Vas deferens. together at the anterior extremity of the body, and Cavolini (loc. cit. p. 155) has already carefully de- the two deferent canals are given off laterally scribed these with Lygia oceanica. See, more- (Delle Chiaje, Descriz. &c. Tav. LXXXVI. fig. over, Milne Edwards, Hist. d. Crust. P1. XII. fig. 4). The two penises of these Crustacea have been 13 (Lygia); Brandt, Mediz. Zool. II. 7. 76, Taf. correctly figured in Desmaret's Considerat. &c. XV. fig. 31 (Oniscus), and Lereboullet, loc. cit. Pl. XLII. n. n. p. 132, P1. V. fig. 134 (Lygidium). For the male organs of Mysis, of which the tes14 The copulatory organs of the Asellina have tides are composed of only a few lobes, see Frey, been described and figured by Brandt (loc. cit. p. loc. cit. p. 26. 73 and Taf. XV. fig. N. V. Z.). Treviranus, also 16 Cavolini, loc. cit. p. 144, and Milne Ed(Verm. Schrift. I. p. 59, 74, Taf. VIII. fig. 48, 49, wards, Hist. d. Crust. I. p. 166, and Cyclop, loc. Taf. XII. fig. 65-67), has well represented them cit. p. 783, fig. 418 (Cancer pagurus). with Porcellio, and Asellus, although he entirely 17 Scwammerdammn, loc. cit. p. 86, Taf. XI. fig. 6, overlooked the six testicles of these Crustacea. and Delle Chiaje, Descriz. &c. Tav. LXXXVI. The penis, and its auxiliary stalks, which, with the fig. 6. Isopoda are always concealed in the midst of the 18 Milne Edwards, Hist. d. Crust. P1. XII. fig. branchial lamellae, have been figured by Degeer 15 (Homarus), and Delle Chiaje, loc. cit. Tav. (Abhandl. zur Geschichte d. Insekt. VI1. p. 191, Taf. LXXXVII. fig. 6 (Scyllarus). XXXII. fig. 6, 20), and by Rathki (loc. cit. p. 125, 360 THE CRUSTACEA. g 293.'With other Macrura, the testicles consist only of a trilobed glandular mass covering the pyloric portion of the stomach, and from which pass off two long, very flexuous Vasa deferentia, which are dilated, near their extremity, into -a nearly straight Ductus ejaculatorius.'l() The excretory ducts of the sperm,are very distinct with the Decapoda, when filled with this fluid, from their'chalk-white color. With many species, the sperm, as it approaches the end sof these ducts, is divided into portions, around which capsules or spermatophores are developed. These last are usually pyriform, and connected together by a common'band. (20) The external genital organs of the male Decapoda are quite varied, although these excretory ducts almost invariably open on the coxal joint of the last pair of feet.(21) With the Paguridae, and Macrura, the fmale genital orifices are surrounded by a soft sphincter, without any trace.of a penis, but out of which the Ductus ejaculatorius is perhaps protruded during copulation.(22) But with the Brachyura and short-tailed Anomura, on the contrary, there are two longer or shorter tubular peinises, always covered by the tail, which -is pressed against the belly.(23) With very many Decapoda, the two feet of the first caudal segment are transformed into pedicellated processes (secondary penises), the extremity of which is sometimes grooved. With some short-tailed Anomura, the feet of the second post-abdominal pair take part also in the act of copulartion, and, for this purpose, are prolonged into stalk-like organs.(24) Among the Myriapoda, the Glomerina have two testicular tubes extending into the abdomen and composed of numerous vesicles partially blended together. They unite in the thorax into a common Vas deferens. With the Julidae, the testicles have a similar structure, but the vesicles open -separately into the external side of the two Vasa deferentia, which are close together, and are connected, in a ladder-like manner, by numerous trans19 With Astacus; see Roesel, loc. cit. Taf. V. Taf. III. fig. 12 (Astacus). In this last geLVIII. fig. 9, and Taf. LX. fig. 23; Suckow, loc. nus, these organs are slightly spiral at their extremtcit. Taf. X. fig. 15; Brandt, Mediz. Zool. II. Taf. ity. These penises are long, secondary, and conXI. fig. 14; Milne Edwards, Hist. d. Crust. P1. cealed under the tail with the male Brachyura and XII. fig. 14; and Carus, Erlauterungstaf. Heft. V. Anomura, with which the majority of the other'Taf. III. fig. 9. anal feet are wanting; see Milne Edwards, Hist. 20 These spermatophores, first made known by d. Crust. I. p. 169, PI. III. fig. 6, 15, 16 (Maia), Kelliker, are bound together, with Galathea, by in this genus the two pairs of anal feet are rudixamified pedieles; and with Pa-gurus, by simple mentary. This abortion is observed, also, with filaments; see Kalliker, Beitr. zur Kenntniss d. Grapsets, Cancer, Lupea, Ocypoda, Porcellana, SGeschlechtsv. &c. p. 9, fig. 21, 22, also, Schweiz. &c. See the beautiful figures of Sauvigny, in Denksch. VIII. p. 52, fig. 32-35. See, also, the Descript. de l'gypte, Crust. P1. II.-VII., and,description which I have given of the spermato- Cavolini, loc. cit. Taf. II. fig. 10 (Grapsus). With iphores of Pagurus Bernhardus, in Miillerl'sArch. Dromia, the two feet of the second caudal segment 1842, p. 136, note 1. But one must be careful not have the form of two long spines. With Homola, rto take, in the testicles of the Decapoda, the mother- the same feet are equally pedicellated, but termi~cells in which are developed the radiating cells for nate with a kind of sucker, and, therefore, are unthe spermatophores. doubtedly auxiliary in the act of copulation. No 21 The land crabs make an exception in this re- auxiliary organs have been found with Galathea,,spect, their male genital orifices being situated on Palinurus, and Scyllaru.s; but in the last two the last segment of the body; see Miln e Edwards, of these genera the feet of the first caudal segment Hlist. Nat. d. Crust. I. p. 168, P1. XVIII. fig. 6 are wholly wanting. With the Caridoidae, the.(Gecarcinus). copulatory organs are usually absent, and the first 22 For Astacus, see the figures cited above; for pair of anal feet does not differ from the others; Palinurus, Milne Edwards, Hist. d. Crust. P1. with Crangon, only, have I found the internal proXXIII. fig. 2; and for Hippolyte, Kreyer, loo. longation of these feet highly developed and glaIcit. p. 27, fig. 54, B. f. brous; while with the posterior feet, it is very 23 There are two very short, and soft penises small, and, like the external one, very hairy. Ac-with Ma'a, Pisa, Cancer, Grapsus, Lupea, cording to Joly (loc. cit. p. 43, P1. III. fig. 20), it.Gecarcinus, Porcellana, Homola, &c. They are is somewhat similar with Caridina. Kruyer (loc.;long, hard, and point forwards with Dromia. cit. p. 27, P1. II. fig. 54, B. g.) has observed, with 24 The canaliculated, secondary penises may be Hippolyte, between the feet of the fourth pair, two,very easily seen on the first caudal segment of short hooked appendages which may be regarded lIomarus, Nephrops and Astacus; see Roesel, loc. as secondary penises. cit. Taf. LVI. i and Carus, Erlauterungstaf. Heft. -e 294. THE CRUSTACEA. 361 verse anastomoses. In front, the testicular vesicles are lost in these canals, which finally diverge from each other in an arcuate manner, as is also true,of the Vas deferens of the Glomerina. In this manner, these canals, as two Ductus ejaculatorii, extend to a triangular scale situated under the third thoracic segment, and terminate at the lower angles of this scale in two short, conical, penis-like protuberances.(25) With the Chilopoda, the male organs are very complicated and formed upon a wholly different type. Their orifices are always situated at the posterior extremity of the abdomen. With some species, there is only a:single, long, testicular tube into which pass two lateral, also very long, coecal tubes (Epididymies?). At their point of junction, arise two short Vasa >;deferentia, which terminate in a common, short, campanulate penis. Other;Chilopoda have two to three varicose testicular tubes which anastomose, loop-like, at both of their extremities, and terminate, at last, in a longer or shorter Vas deferens, which bifurcates in its course, but its branches come -together again in a short penis. With all the Chilopoda, the common genital orifice is connected with the short excretory ducts of two to four oblong.accessory glands, the nature of which is yet unknown.(") ~ 294. The Development of the Crustacea occurs, as with all Arthropoda, ac-,cording to a special type.(') After the disappearance of the germinative vesicle, a partial segmentation occurs upon a given point of the surface of the vitellus. By this process, a transparent, finely-granular, proligerous disc is formed.(2) The borders of this disc gradually extend over, and finally cover the surface of the vitellus. It is then changed into a proligerous vesicle enclosing the remainder,of the vitellus. At the pole of the egg where the proligerous disc is first formed, are de25 For the male organs of the Chilognatha, see pedunculated vesicles (Vesiculae seminales). The.Newport, Philos. Trans. 1842, loc. cit. p. 99; posterior extremity of these testicles is continuous Rymer Jones, Cyclop. III. p. 551, fig. 314; and into two Vasa deferentia which become dilated.Stein, in Miller's Arch. 1842, p. 246, Taf. XII.- into as many Ductus ejaculatorii. Perhaps this XIV. (Julus, Polydesmus, and Glomeris). The abnormal organization of these animals in this retwo testicles of Glomeris were formerly described spect, will be reduced from further researches to,as ovaries by Brandt; see his Beitr. loc. cit. p. the type of the Scolopendra. 325, Taf. XII. fig. 8; but he has rectified this in his 1 The embryology of Crustacea has been brought Recueil, loc. cit. p. 157. For the copulatory out, especially by the numerous and exact reorgans of the Julidae, may be cited, also, the re- searches of Rathki; see his Untersuch. fiber d.,searches of Leatreille, and Savi (loc. cit.). Bild. u. Entwickel. d. Flusskrebses, 1829, then his 26 Lithobius has only a single testicular tube notes in Burdach's Physiol. II. 1837, p. 250; his with two epididymes and four accessory glands Abhandl. zur Bild. u. Entwickel. d. Mensch. u. d. (Treviranus, Verm. Schrift. II. p. 25, Taf. V. fig. Thiere, 1833; his Mittheilung. fiber d. Entwickel. 7; L. Dufour, loc. cit. p. 87, P1. V. fig. 2, 3, and d. Decapoden, in MiulLer's Arch. 1836, p. 187, or.Stein, loc. cit. p. 240, Taf. XII. fig. 1). Geophi- in Wiegmann's Arch. 1840, I. p. 241; and in the lus has three interanastomosing, varicose testicles, Neuest. Schrift. d. Danzig. naturf. Gesellsch. III. *and two accessory glands (Stein, loc. cit. p. 243, Heft. IV. 1842, p. 23; then, Zur Morphol., Reise-'Taf. XII. fig. 7). Judging from Mltler's figure bemerk. aus Taurien, 1837 his Beobacht. u..(loc. cit. Taf. II. fig. 5), Scolopendra morsitans Betracht. fiber d. Entwickel. d. Mysis vulgaris, in has also two anastomosing varicose testicles. But Froriep's neue Not. XXIV. 1842, p. 181; and this point is made somewhat uncertain from the finally his Comment. de Animal. Crust. generat. researches of Kutorga (loc. cit. p. 10, Tab. II. fig. 1844. See, also, Erdl, Entwickel. d. hiummereies, 4-6), who has shown positively the existence of four 1843; and Joly, Sur le developp. des Caridina, in:.accessory glands with this animal. L. Dufour's the Ann. d. Sc. Nat. XIX. loc. cit. p. 57, PI. IV. figures (loc. cit. p. 97, P1. V. fig. 5) of the male 2 Cancer maenas forms perhaps the only ex-,organs of Scutigera indicate here a very different ception in this respect. Here, the segmentation ap. organization. There are two testicular tubes which pears to be complete; see Rathkce, in Froriep's unite loop-like at the anterior extremity and then neue Not. loc. cit. p. 182 i and Erdl, loc. cit. p. send off a long very flexuous canal which has two 27. 31 362 THE CRUSTACEA. ~ 294, veloped the ventral portion together with the abdominal cord of the future embryo; while, at the opposite pole, where the borders of the disc meet, the dorsal portion of the animal appears. Quite early, the blastoderma can be seen composed of an external or serous, and of an internal or mucous layer. This last, after having enveloped the entire vitellus, is changed gradually into the alimentary canal. The hepatic organs are only deverticuli of-this last, while the antennae, the oral apparatus, the feet, and the branchiae, are developed from the serous layer. The embryos, thus formed, differ considerably, and their form is often so dissimilar from that of the adult animal, that, during their ulterior development, there is a real metamorphosis, which takes place by more or less numerous stages coincident with the act of moulting. An embryonic type quite general among the lower Crustacea, that is,. the (irripedia, Siphonostoma, Lophyropoda and Phyllopoda, is that which was first observed with Cyclops. There is here a long series of metamorphoses. The monocle-like larvae have an ovoid, unarticulated body, usuallyprovided with a single, simple eye, and two or three pairs of oar-like appendages covered with long hairs.(3) With some Brachyura, there is an equally well-marked metamorphosis; for, in leaving the egg, they have a long tail and two very large eyes; but with the first moulting they acquire two, enormous, spur-like apophyses, one on the front, and the other on the back.(4) 8 It is remarkable that the young Cirripedia, articulated body, and more than three pairs of feet. which are hexapod, have the characteristics of Those of the Cyclopidae which have six feet have the larvae of Monocles see Thompson, Zool. been known a long time. But Miiller (Entomostr. Research. loc. cit. p. 69, P1. IX. (Balanus); Bur- p. 39, Taf. I. II.) formerly divided them under the meister, Beitr. loc. cit. p. 12, Taf. I. (Lepas); names of Naupliusand Amymone. See Degeer Goodsir, Edinb. New Philos. Jour. No. 69, July, Abhandl. &c. VII. p. 181, Taf. XXX. (Cyclops);. 1843, p. 97, Pl. III. IV., or Isis, 1844, p. 901, Ramdohr, loc. cit. p. 5, &c., Taf. I. III. * but Taf. I. fig. 8, 11-17 (Balanus). The larvae of especially Jurine, Hist. d. Monocl. p. 15, &c., P1. these Crustacea, before becoming fixed in order I.-VII. (Cyclops and Cyclopsina). The young to undergo their metamorphoses, change into a Daphnioidae and Cypridoidae, on the contrary, rebivalve animal resembling Cypris. Among the semble the adults on their escape from the egg. The Siphonostoma, the monocle-like embryos are very simple eye is evidently the result of a very early general. NZordmann (loc. cit. p. 11, &c., Taf. II.- fusion of two eyes; see Jurine, loc. cit. p. 113v VII.) has recognized larvae of this kind, some with P1. VIII. IX. (Daphnia and Cypris); Rathkl, three(Ergasilus andLernaeocera),andotherswith Abhandl. z. Bildungs u. Entwickelungsgesch. &c. only two (Achtheres and Tracheliastes) pairs of p. 85 (Daphnia and Lynceus); Baird, Magaz. feet. According to Kollar (loc. cit. p. 87, Taf. X. of Zool. and Bot. I. p. 522, and II. P1. V. fig.. fig. 10), the embryos of Basanistes are monocle- 12 (Cypris); finally Loven, loc. cit. p. 161, Taf. like and have six feet, as are also those of V. fig. 12 (Evadne). Of the Phyllopoda, the moLernaeopoda described by Rathk/ (Zur Mor- node embryos of the Apodidae have two pairsphol. &c. p. 34, Taf. I.). Goodsir (loe. cit. No. of feet, kvhile those of the Branchiopoda have three; 65, July, 1842, p. 178, P1. III. fig. 19-23) has see Schaefer, Der krebsartige Kiefenf. p. 118, Taf. observed embryos with four feet in the eggs of I. fig. 3; and Zaddach, loc. cit. p. 55, Tab. IV. Caligus. The larvae of Nicothoe (RathkU, Nov. fig. 1-3 (Apus); Joly, loc. cit. p. 321, P1. IX. fig. Act. Nat. Cur. XX. p. 109, Tab. V. fig. 8-10) and 39 (Isaura); Preevost, in Jurine's 1ist. d. Monof Argulus (Miuller, Entomostr. p. 122, Tab. XX. ocl. p. 214, P1. XX. fig. 9 (Chirocephalus); and fig. 2, and Jurine, loc. cit. p. 453, Pl. XXVI. fig. Joly, loc. cit. p. 257, P1. VII. fig. 4 (Artemia).* 4) form an exception in this respect, for when 4 These embryos with such singular forms, have, they leave the egg they have two simple eyes, an hitherto, been figured as separate genera under the *[ ~ 294, note 3.] For many highly-interesting ances of the different organs. Argulus is quite details on the economy of the Entomostraca, see well developed when hatched, its muscles are transBaird (British Entomostr. &c. loc. cit. passim). versely striated and the locomotive organs well These details with their corresponding figures will formed. Artemia has, at this period, two antenrender clear many obscure economical points al- nae, two pairs of feet on the head, and the red pigluded to above. For the embryology of Argulus, ment spots on the forehead, but these last have as.Artemia and Branchipus, see Leydig, loc. cit. yet no light-refracting body. The muscles are still Siebold and Kolliker's Zeitschrift, II. p. 344, and ~ without striae, and even here and there are filled III. p. 304. The descriptions of this observer are with vitelline globules. The heart and blood-cirquite rich in details upon the successive appear- culation are still unformed. - ED. , 294. THE CRUSTACEA. 363 The young of the Paguridae and Macrura differ more or less from the adult. animals.(5) But this difference is less with the Poecilopoda, Laemodipoda, Stomapoda, Isopoda, and Amphipoda.(1) Finally, with the Myriapoda, the metamorphosis is limited to the increase of the number of the segments of the body, and of the feet. ( names Megalops, Monolepis and Zo'a (Milne embryos and the adults is less marked with AstaEdwards, Hist. d. Crust. II. p. 260, 431), until cus, Homnarus and other Macrura; see Rathke/ Thompson perceived their true nature; see his Entwick. d. Flusskr.) and in the Danzig. Schrift. loe. Zool. Research. &c. P1. I. and his Memoir on the cit. p. 23, Taf. II. (Hromarus); Du Cane, Ann. of double Metamorphosis in the Decapodous Crusta- Nat. Hist. II. 1839, p. 178, P1. VI. VII. or Frocea, in the Philos. Trans. 1835, pt. II. p. 539; see riep's neue Notiz. XIII. p. 3, fig. 4-9 (Palaealso the Edinb. New Philos. Jour. No. 20, p. 221, mon and Crangon); Kr6yer, Monogr. loc. cit. p.and the Entomol. Magaz. No. 14, p. 370. Although 37, P1. VI. (Hippolyte and Homarus); Joly, Ann. these observations have been confirmed from dif- d. Sc. Nat. XIX. loc. cit. PI. IV. (Caridina), and ferent sides, yet they did not, at first, receive full Erdl, loc. cit. p. 18, Taf. III. IV. (Homarus). assent, especially on account of the authority of 6 According to Milne Edwards (Instit. 1838,, Rathkd (Miiller's Arch. 1836, p. 187), who opposed No. 258, p. 397), a cephalothorox and abdomen may them. Templeton (Trans. of the Entomol. Soc. already be distinguished with the hatching embryII. p. 115, P1. XII.) and Westwood (Philos. Trans. os of Limulus. But the abdomen has only threea 1835, pt. II. p. 311, P1. IV.) refuse to give up the pairs of appendages and its long spine is wholly genus Zoea; but since Du Cane (Ann. of Nat. wanting. This naturalist, also, has figured an Hist. III. 1839, p. 438, P1. XI. or Froriep's neue embryo of Cyamus which closely resembles tfhe Notiz. XIII. p. 5, fig. 10-13), has verified, with adult (Ann. d. Sc. Nat. III. 1835, p. 328, Pl XIV;. Cancer m.aenas, the observations of Thompson, fig. 14). and Rathki himself (Wiegmann's Arch. 1840, I. For the embryos of the Isopoda and Amphipoda, p. 246, and Neuest. Danzig. Schrift. loc. cit. p. 39, see Rathki, Abhandl. loc. cit.; Ann. d. Sc. Nat. Taf. IV.) has seen the embryos of Hyas under the II. 1834, p. 139, P1. XI.; Zur Morphol. &c. 41, form of a Zoea, this wonderful metamorphosis of Taf. II. III. (Bopyrus, Idothea, Janira, Lygia the Brachyura can no longer be doubted. See and Amphithoe); Nov. Act. Nat. Cur. XX. p. 49, also Steenstrup, in the Oversigt over det kgl. Tab. I. (Phryxus); also Milne Edwards, Ann. d. danske Videnskabernes Selskabs Forhandlinger, Sc. Nat. III. 1835, p..323, P1. XIV. (Cymothoa, 1840, p. 15, or Miller's Arch. 1841, p. 218 (Hyas), Anilocra, Phronima and Amphithoe); finally and Goodsir, Edinb. New Philos. Jour. No. 65, Rathki, in Wiegmann's Arch. 1839, loc. cit. Taf. 1842, p. 181, P1. III. fig. 16-18 (Cancer maenas). VI. (Mysis). 5 The embryos of Pagurus which have a frontal 7 See Gervais, Ann. d. 1. Soc. Entomol. deo spine, were also, before the discovery of Thomp- France, 1837, and Institut. 1839, p. 22; Wzaga, Rev. son, taken for species of Zoea; see Philippi, in Zool. 1839, No. 3. p. 76, or WNiegmann's Arch., Wiegmann's Arch. 1840, I. p. 184, Taf. III. fig. 1840, II. p. 351 and especially Newport, Philos. 7, 8; also Rathki, Ibid. p. 242, and, Danzig. Transact. 1842, part II. p. 99, and Cyclop. loc. cit. Schrift. loc. cit. p. 29, Taf. III.; Steenstrup, loc. III. p. 353, fig. 317-326, also in Froriep's. neaue cit. * and Goodsir, loc. cit. No. 65, p. 182, P1. III. Notiz. XXI. p. 161. fig. 12-14. The difference in form between the BOOK THIRTEENTH. ARAC H NO I D A E. CLASSIFICATION. ~ 295. THE ARACHNOIDAE, which are organized after very different types, have always four pairs of feet. The Tardigrada form no exception in this respect; and although it may appear singular to find them placed in this class, yet this seems their most proper place; only they should be placed at the head, for they form the transition of the Arachnoidae to the Annelides, exactly as do the Cirripedia from the Crustacea to the Acephala.* The Arachnoidae are usually defined as Arthropoda wanting the anten. nae; this, however, is incorrect, for these organs are not wanting, strictly speaking, but take the place of the mandibles, which are absent, as will be shown hereafter. ORDER I. Cephalothorax multi-articulate. Special respiratory organs wanting. SUB-ORDER L TARDIGRADA. Legs rudimentary. Abdomen wanting. Genera: Milnesium, Macrobiotus, Emydiunz. SUB-ORDER HI. PYCNOGONIDAE. Legs very much developed. Abdomen rudimentary. Genera: Nymphon, Ammothea, Pallene, Phoxichilidium, Pariboea, Endeis, Phoxichilus, Pycnogonurm. *[ ~ 295.] For a detail of the data which fully Stellung der Tardigraden, in Siebold and Kolliker'e justify this position of the Tardigrada, see Kauf- Zeitsch. III. 1851, p. 220. -ED. mann, Ueber die Entwickelung und systematische 295. THE ARACHNOIDAE. 365 ORDER II. Cephalothorax unarticulated, or biarticulated. Respiratory organs consisting of tracheae. SUB-ORDER III. ACARINA. Abdomen unarticulated and fused with the cephalothorax. Palpi simple. FAMILY: ACAREA. Genera: Demodex, Sarcoptes, Glycyphagus, Tyroglyphus, Melichares, Dermaleichus, Acarus, Pteroptus. FAMILY: HYDRACHNEA. Genera: Limnochares, Arrenurus, Eylais, Diplodontus, Hydrachna, Atax. FAMILY: ORIBATEA. Genera: Hoplophora, Oribates, Zetes, Pelops, Damaeus. FAMILY: GAMASEA. Genera: Dermanyssus, Uropoda, Gamasus, Argas. FAMILY: IXODEA. Genus: Ixodes. FAMILY: BDELLEA. Genera: Bdella, Miolgus. FAMILY: TROMBIDINA. Genera: Erythrapus, Trombidium, Smaridia, Tetranychus, Rhyncholo. phus, Rhaphygnathus, Penthaleus. SUB-ORDER IV. OPILIONINA. Abdomen articulated, but indistinctly separated from the cephalothorax. Palpi simple. Genera: Phalangium, Gonyleptes, Eusarcus. SUB-ORDER V. PSEUDOSCORPIL Abdomen articulated, but indistinctly separated from the cephalothorax. Palpi forficulate. Genera: Obisium, Chelifer. SUB-ORDER VI. SOLPUGIDAE. Abdomen articulated, distinctly separated from the cephalothorax. Palpi simple. Genus: Galeodes. 31* 3 6 THE ARACHNOIDAE. $ 295. ORDER IM1. Abdomen and cephalothorax unarticulated, distinct from each other. Respiratory organs consisting of tracheae and lungs. SUB-ORDER VII. ARANEAE. Genera: Myigale, Thomisus, Uptiotes, Lycosa, Dolomedes, Salticus, Segestria, Dysdera, Scytodes, Clubiona, Drassus, Argyroneta, Clotho, Agelena, Lachesis, Teg~enaria, Micryphantes, Theridion, Linyphia, JEpeira, Tetragnathus. ORDER IV. Abdomen articulated. Cephalothorax unarticulated. Respiratory organs consisting only of lungs. SUB-ORDER VIII. PHR YNIDAE. Abdomen distinct from the cephalothorax. Cheliceres unguiculate. Genera: Thelyphonus, Phrynus. SUB-ORDER IX. SCORPIONIDAE. Abdomen indistinctly separated from the cephalothorax. Cheliceres forficulate. Genera: Scorpio, Buthus, Androctonus. BIBLIOGRAPHY. Leeuwenizoek. Continuatio arcanorum naturae, 1719, Epist. 138, p. S12. RoeseL Insekten-Belustigungen, Thl. IV. 1761, p. 241. Degeer. Abhandlungen zur Geschichte der Insekten, VII. 1783. Hermann. Mimoire apterlologique, 1804. J. F. Meckel. Beitrage zur vergleichenden Anatomie, I. Hft. 2, 1809, p. 105. Treviranus. Ueber den inneren Bau der Arachniden, 1812. Ver. mischte Schrift. anat. u. physiol. Inhalts. I. 1816. Ueber d. Bau d. Nigua (Acarus americanus), in his Zeitsch. f. Physiol. IV. 1831, p. 185. Serres. Memoires du Mus. d'hist. Nat. V. 1819, p. 86. Leon Dufour. Ann. g6ner. d. Sc. physiq. d. Bruxelles, IV.-VI. J. Miiller. Beitriige zur Anatomie des Scorpions, in Meckel's Arch. f. Anat. 1828, p. 29. Lyonet. Anat. de differentes espec. d'Insectes, in the MWm. du Mus. d'hist. Nat. XVIII. 1829, p. 282, 377. Brandt. Medizin. Zool. II. 1833, p. 87. Recherch. sur l'anat. d. Araignees, in the Ann. d. Sc. Nat> XTII. 1840, p. 180. Savigny. Descript. de l'Egypte. Hist. Nat. Arachnides, P1. I.-IX. Audouin. Lettre contenant des recherches sur quelques Araigne'es ~ 295. THE ARACHNOIDAE.:367 parasites, in the Ann. d. Sc. Nat. XXV. 1832, p. 401. Cyclop. of Anat. I. 1836, p. 196, Art. Arachnida. Duygs. Recherches sur l'ordre des Acariens, in the Ann. d. Sc. Nat. -I. 1834, p. 5, and II. p. 18; also, Sur les Araneides, Ibid. VI. 1836, p. 159. Walckenaer. Hist. Nat. d. Insectes apteres, I.-III. 1837-44. Doyere. Sur les Tardigrades, in the Ann. d. Sc. Nat. XIV. 1840, p. 269. Van der Hoeven. Bijdragen tot de kennis van het geslacht Phrynus, in the Tijdschrift voor natuurlijke Geschiedenis en Physiologie, IX. 1842, p. 68. Grube. Einige Resultate aus Untersuchungen fiber d. Anat. d. Araneiden, in Midller's Arch, 1842, p. 296. Menge. Ueber d. Lebensweise d. Arachniden, in the Neuest. Schrift. d..naturf. Gesellsch. in Danzig. IV. Hft. 1, 1843, p. 1. Tulk. Upon the anatomy of Phalangium opilio, in the Ann. of Nat. Hist, XII. 1843, p. 153, or in Froriep's neue Notiz. XXX. 1844, p. 97. Dujardin. Sur les Acariens, in the Comp. rend. XIX. 1844, p. 1158, and Mdm. sur les Acariens, in the Ann. d. Sc. Nat. III. 1845, p. 5; Quatrefages. Mem. sur l'organis. d. Pycnogonides, in the Ann. d. Sc. Nat. IV. 1845, p. 69. Blanchard. Observat. sur l'organis. d'un type de la classe des Arachnides, le genre Galeode, in the Comp. rend. XXI. 1845, p. 1383. Wasmann. Beitrige zur Anat. d. Spinnen, in the Abhandl. d. naturwissensch. Vereins in Hamburg, 1846. ADDITIONAL BIBLIOGRAPHY. Wilson. Researches into the Structure and Development of a newlydiscovered parasitic animalcule of the Human Skin, - the Entozoon folliculorum, in the Philos. Trans. 1844, p. 305. Wittich. Dissertatio sistens. observ. quaed. de Aranearum ex ovo evolut. Halis, 1845. Die Entstehung des Arachnideneies imn Eierstocke; die ersten'Vorgange im demselben nach seinem Verlassen des Mutterk6rpers; in Miiller's Arch. Hft. 2, 1849, p. 113. Leuckart. Ueber den Bau und die Bedeutung der sog. Lungen bei den ~Arachniden, in Siebold and Kiilliker's Zeitsch. 1849, I. p. 246. -J. V. Carus. Ueber die Entwickelung des Spinneneies; in Siebold and Ktilliker's Zeitsch. II. 1849, p. 97. Blanchard. De l'Appareil circulatoire et des Organes de ]a respiration dans les Arachnides, in the Ann. d. Sc. Nat. XII. 1849, p. 317. Dufour. Observations sur l'Anatomie du Scorpion, in the Ann. d. Sc. Nat. XV. 1851, p. 249. Kaufmann. Ueber die Entwickelung und systematisehe Stellung der Tardigraden, in Siebold and Kdlliker's Zeitsch. III. 1851, p. 220.- ED. 368 THE ARACHNOIDAE. CC 296, 2C9s7 CHAPTER I. EXTERNAL ENVELOPE AND CUTANEOUS SKELETON. ~ 296. The external envelope of the Arachnoidae is usually soft, or coriaceous,. Tarely horny;(1) but in no instance does it possess a proper contractility. In place of this, however, it is extensible in the highest degree with many species. This extensibility is seen especially with those species which are accustomed to long fasts, having only an occasional opportunity to fill their digestive canal with food consisting of the animal juices.(2) ~ The envelope is composed here, as with all the Arthropoda, chiefly of chitine.(3) To this last are undoubtedly due its solidity and indestructibility, which may be observed with the small and delicate Acarina and Tardigrada, not only when it is in a fresh state, but even after it has been cast off by a kind of moulting.(4) ~ 297. With most Arachnoidae, the cutaneous envelope may be separated into two tunics; an external and an internal. The first is the more solid and thick, and, in the cephalothorax and the extremities, has often a cellular structure. Upon the abdomen of the Araneae and Acarina, it presents peculiar, waving markings which, as concentric rings, surround the base of the hairs;(1) but it is difficult to determine if they are due to delicate plicae, or the effect of the intimate structure of the skin. With Ixodes, only, these prominent lines appear, unmistakably, as folds of the epidermis, for they completely disappear when these animals are gorged with food. The epidermis is often provided with papillae, clavate excrescences, spines, bristles, simple or plumose hairs, and even, sometimes, with scales.(2) These various cutaneous formations, which are usually hollow, either occupy only certain points, or are extended over the whole surface of the body, giving it a velvety or a furry aspect. The internal tunic of the skin consists 6f a thin, always colorless membrane, finely granular or fibrillated, which is perforated at those points where there are hair-like or other formations of the epidermis.(3) Directly beneath this membrane, which, undoubtedly, reproduces the epidermis after 1 For example, with the Scorpionidae and Phry- saigne (loc. cit.), and of that of Ascaris, Mecknidae. The cutaneous envelope is hardest and elia, Sabella, Hermione and Vephtys, made by most fragile with the Oribatea, where it breaks like Loewig and Kllliker (Ann. d. Sc. Nat. V. 1846,.glass from the lightest pressure. p. 198). 2 For example, with Ixodes, and Argoas, as also 1 For example, with Epeira, Segestria, Thomwith the parasitic larvae of certain IHydrachnea isus, Argyroneta, Salticus, Sarcoptes, &c. and Trombidina, known under the names of Achly- 2 PIumose hairs are very often found with the sia and Leptus. Araneae; and I have found lanceolate scales with 8 Lassaigne, Compt. rend. XVI. 1843. No. 19, Salticus, and clavate excrescences with the Tromor Froriep's neue Not. XXVII. p. 8, and Schmidt, bidina * see Hermann, loc. cit. P1. III. fig. O-Y. Zur vergleich. Physiol. p. 47. 3 1 am unable to say whether the internal mem4 This solidity of the skin with the Tardigrada, brane is prolonged at these points into the hollow is one evidence that these animals are more prop- excrescences of the skin, or whether the appear. erly classed with the Arachnoidae, instead of with ances alluded to are not produced artificially when the worms whose skin contains no chitine and is, the outer is separated from the inner layer of the therefore, quickly dissolved in caustic potass. See skin. the analyses of the skin of the earth-worm by Las. 298. THE ARACHNOIDAE. 369 moulting, is a layer of colored vesicles and granules, which can be seen through the skin, giving it the often very beautiful colors which are observed in many species. The various divisions of the cutaneous skeleton, of which the number is quite limited, have been so thoroughly studied in zoology, that they may well be passed over here without notice. The Cephalothorax sends off from its inner surface, especially with the Opilionina, and Araneae, various processes, which serve, as with the Crustacea, as points for the insertion of muscles, and as septa between certain, organs. With the Araneae, they form, at the bottom of the cephalothorax,. a solid horizontal plate, -a kind of internal skeleton, which, before and behind, is attached to the sternum by two tendinous ligaments. This plate is deeply indentated on its anterior border, and furnishes points of insertion for the muscles of' the extremities, as well as for several other parts. (4) CHAPTER II. MUSCULAR SYSTEM AND ORGANS OF LOCOMOTION. ~ 298. The voluntary muscles of the Arachnoidae are of a dirty-yellow color, and, like those of the Crustacea, are distinctly striated transversely. () Their general disposition agrees, also, with those of Crustacea.(2) The principal muscular masses are found in the cephalothorax, for here arise, not only the muscles of the parts of the mouth, but also those of the first article of the tactile organs and legs. With those species having an unarticulated abdomen, the muscles of this part of the body differ from those of Crustacea. For, directly beneath the skin, is a thin layer, composed of numerous short, riband-like fibres, interlaced in various directions, and frequently anastomosing with each other.(3) Moreover, with many species, there are, on both the dorsal and the ventral surface of the abdomen, depressions of the skin, from which pass off small muscular bands, which penetrate into the interior of the abdomen, and pass among the viscera. With the Araneac there is, generally, on each side of the ventral median 4 This plate, already recognized by Lyonet (loe. Meclcel, Syst. d. vergleich. Anat. III. p. 47; and cit. p. 405, P1. XXI. fig. 26), and by Treviranus for the muscles of Phalangium and Mlygale, see (Bau d. Arach. Taf. II. fig. 23), has been described Tulk, and Wasmann, loc. cit. The very complimore exactly by Wasmann (loc. cit. p. 2, fig. cated muscular system of the Tardigrada is quite 2-4). A similar, but rudimentary plate, exists, apparent from the transparency of these animals perhaps, with Phalangium., and, as it lies under see Doyire, loc. cit. p. 335, Pi. XVII.-XIX. the ventralcord, the muscles have the appearance 3 This cutaneous layer, already observed by of rising from this last; see Tulk, loc. cit. p. 325, Treviranus (Verm. Schrift. I. p. 9, Taf. I. fig. 3, or in Froriep's neue Notiz. XXX. p. 136. a. n.), and by Brandt (Mediz. Zool. I. p. 88, Taf. 1 The Tardigrada form an exception in this re- XV. fig. 8, a. a., or Ann. d. Sc. Nat. XIII. p. 180, spect, their muscles being smooth; see Doyire, P1. IV. fig. 1, a. a.), with Epeira, has been conloc. cit. p. 336. firmed by Tulk (loc. cit. p. 154) with Phalan2 For the disposition and arrangement of the gium, and described in more detail by Wasmann. muscular system of Scorpionidae and Araneae, see (loc. cit. p. 8, fig. 7, 8) with Mygale. 370 THE ARACHNOIDAE. 6 299. line, a tendinous ligament, on which are inserted several of these muscular bands.(4) It is very probable that these animals' can, by this apparatus, compress their abdomen in various directions. ~ 299. The locomotive organs of the Arachnoidae are situated exclusively on the cephalothorax. They consist of only four pairs of legs, of which the first may, perhaps, be regarded as the posterior pair of metamorphosed maxillae. (1) Some Mites, only, when young, have six feet, andthe young of the Pycnogonidae have, also, only four. With Phrynus, and Thelyphonus, the first pair considerably resembles two multi-articulated tactile organs; but with Galeodes, these same organs have wholly the appearance of legs, excepting they are without claws. With Mygale, the maxillae of the first pair have the form of feet, and their extremity is not only unguiculated, but also provided with a tarsus. The other Arachnoidae have usually nails on all their feet, and, with some, each foot may have four nails.(2) With many Araneae, the nails have, on their convex side, a pectinated appendage.(3) As to the types of the articulations of the legs, they are usually as follows; first, a movable Coxa; then a short Trochanter; then a longer, stiff Femur; then a Tibia, divided by an articulation into two unequal parts; and, finally, a Tarsus, composed of a long ltnd a short article. With the Phrynidae, not only are the first and antenniform pair of feet already mentioned, different from this type, but the three other pairs have a great number of articles, each tarsus having four. But the Phalangidae differ the most, — the tarsi of all the feet having an extraordinary number of articles. On the other hand, among the lower Arachnoidae, and especially with the Acarina and Tardigrada, there are species with which the seven articles just mentioned cannot be easily distinguished, for the articulations are less in number, or wholly indistinct. With many of these species, some of the pairs of legs, or even all, are reduced to real foot-stumps.(4' Numerous parasitic Acarina have, between the nails, a small organ (Arolium.), by which, as with a sucker, they can attach themselves to foreign bodies.1() These organs are most developed with Sarcoptes and allied genera, which are without nails, for they here consist of a long, pedunculated disc upon all, or only upon some of the feet.(6) With the aquatic Htydrachnea, the swimming feet have no other peculiarities than that one of their sides is thickly pilose. 4 For these muscles, the cutaneous insertions of all the eight legs of Tyroglyphus and Glyciphawhich, with the Araneae, with Chelifer and PIha- gus, but with the anterior legs, only, with Sarcoplangium, have been taken by Trevirasnus (Bau tes. The posterior legs of this last genus, and all d. Arach. p. 23, Taf. II. fig. 17-19, Taf. III. fig. of them with the Tardigrada, and with Demodex 28, and Verm. Schrift. I. p. 18, 33, Taf. II.) for the folliculorum, are only simple stumps. stigmata, see Brandt, Mediz. Zool. loc. cit. p. 88, 5 For example, with Ixodes, Argas, DermanysTaf. XV. fig. 8, c. c., and Ann. d. Sc. Nat. loc, cit., sus, Pteroptus, &c. and Wasmann, loc. cit. p. 3. fig. 1, 6, 24. 6 With Sarcoptes ovis and cati, this arolium is 1 See Dug/s, Ann. d. Sc. Nat. I. p. 7, and absent with the penultimate pair of legs; and with Erichson, Entomogr. Heft. I. p. 7. Sarcoptes equi, with the last pair. With Sar2 Most usually there are two nails to each foot; coptes cynotis, rupicaprae, and scabiei, it is but Phalangium, Hoplophora, and Danmaeus, wanting with the last two pairs. With Sarcoptes have only one; while Segestria, Lachesis, and hippopodes, Glycyphagus prunorum, and Melislotho, as well as Demodex, Pelops, Zetes, and chares agilis, all the legs have long pedunculated. Oribates, have three, and Emydium and Macro- organs of this kind; see Hering, Die Krstzmilben biotus have even four. der Thiere, in the Nov. Act. Nat. Cur XVIII. 3 See the figures of Savigny,-loc. cit. part II. Tab. XLIII.-XLV. 4 The articulations are few and indistinct with ~~ 300, 301. TIIE ARACINOIDAE. 871 CHAPTERt III. NERVOUS SYSTEM. ~ 300. The grades of development of the Nervous System with the Arachnoidae are very different, being connected with the divisions of the cutaneous skeleton. For, when these last disappear, those of the nervous system belonging to them, and often the ventral cord, are concentrated, as with the'brachyurous Decapoda, into a single ganglionic mass, occupying the ventral portion of the cephalothorax; while, if the body is multi-articulate, this system resembles that of the macrurous Decapoda. In both cases; with only.a few exceptions, there is a cerebral ganglion situated above the oesophagus, and connected with the ventral cord by two short commissures surrounding this canal. From this ganglion pass off nerves to the eyes, and the maxillary palpi or so-called mandibles; while the first pair of maxillae, changed into tactile organs, receive their nerves from the anterior extremity of the ventral cord. The intimate structure of the nervous system, with the Arachnoidae, consists of primitive fibres much finer, and ganglionic globules much smaller, than those of Crustacea.(1) As to the direction and disposition of these fibres, those of the Scorpionidae almost exactly resemble those of the _Myriapoda. (2) ~ 301. The nervous system is most simple in its organization with the Acarina. In those species where, as yet, it has been found,(1) it consists only of a simple abdominal ganglion, from which pass off, from all sides, the peripheric nerves; and, upon the upper surface of which, is detached a simple transverse band, under which the Eosophagus passes. With the Tardigrada, this system is a little more developed, although the brain is still wanting.'~2 It consists of four ganglia, corresponding to the four segments of the body, and connected together by double longitudiinal commissures. Between each of the ganglia, the commissures are connected by a transverse filament. The nerves which proceed from the ganglia belong to the muscles; butthe first ganglion sends, moreover, in front, four larger trunks, which are the nerves of sense, and are distributed to the eyes and palpi.(3) I Hannover, loc. cit. p. 71, P1. VI. fig. 83, 84. confirmed with this genus and with Limnochares, 2 See ~ 271, and Newport, Philos. Trans. 1843, by Dujardin (Ann. d. Sc. Nat. III. p. 19). Subloc. cit. sequently, Treviranus (Zeitsch. f. Physiol. loc. 1 With many small Acarina, particularly Sar- cit. p. 189, Taf. XYI. fig. 7. c.) has also concoptes and Demodex, no traces of a nervous sys- firmed, with Ixodes, this passage of the cesophagus tern have been found, notwithstanding the most through the principal ganglionic mass. With careful researches; but this is not sulprising, con- Trombidium, whose ganglion is somewhat reddish, sidlering the minuteness of these animals. the cerebral comomissure is quite distinct. 2 Treviranus (Verm. Schrift. I. p. 47, fig. 32) 3 See Doydre, loc. cit. p. 343, PI. XVII. (Milnehas investigated the nervous system of Trom- siusm). bidium, and the results he obtained have been 372 THE ARACHNOIDAE. ~ 301.. The ventral chain of the Pycnogonidae is composed likewise of four ganglia, but these, which send off, each, a nerve from its side to the corresponding foot, are contiguous, and the first connects with the ovoid cerebral ganglion by two lateral commissures.(4) With the Araneae, the central portion of the nervous system consists of a large sub-cesophageal ganglion, and another, smaller and above the (esophagus. They are separated from each other only by a narrow fissure through which the (esophagus passes. The super-cesophageal ganglion, which is somewhat emarginated in front, corresponds to the brain, and sends off nerves to the eyes and cheliceres. The sub-cesophageal ganglion, situated in the middle of the cephalothorax, sends off, on each side, four larger processes, from which arise the nerves of the feet. Its anterior border supplies, moreover, the nerves of the two palpi; and from its posterior margin pass off two nerves for the abdominal viscera.(5) The nervous system of Galeodes,'(' Phrynus, and Thelyphonus,'7' has a, like disposition. The central mass of the nervous system of the Phalangidae begins by two conical, contiguous cerebral ganglia, which connect with a subaesophageal, fused ganglion, by two short lateral commissures. This ventral ganglion is composed of a transverse portion, which is situated in the centre of the cephalothorax, and of two lateral portions which consist, each, of an anterior or larger, and a posterior or smaller lobe. These lobes send& off nerves to the eight legs, and in front, others to the palpi; while from the posterior border of the transverse portion pass off several nerves to the viscera of the abdomen.(8) With the Scorpionidace, the nervous system is very highly developed. The brain, which is not large, is composed of two spheroidal, superoesophageal ganglia fused together. Above, and in front, they send off nerves to the eyes and the cheliceres; and below, they connect with the first ventral ganglion by two short, large filaments, which embrace the cesophagus. The first ventral ganglion is pretty large, being the result, probably, of the fusion of several ga.nglia. It is situated in the middle of the cephalothorax, and sends nerves to the palpi and to the eight legs. Iai the rest of the body there.are three ventral ganglia, smaller, and followed. by four others situated in the tail. All these ganglia are connected by double, longitudinal commissures, and the posterior seven give off, fromn each side, two nerves; while from the last garnglion arise also two others, which, passing backwards, soon unite and extend to the very extremity of the tail, sending off nerves right and left.t9) 4 Qseatrefages, loc. cit., 77, P1. I. fig. 1& 21; also 8 The nervous system had already been partially P1. II. fig. 2, 3 (Ammothea and Phoxichiluts). described by Treviranus (Verm. Schrift. I. p. 38, 3 Treviranus, Ueber d. inn. Bau d. Arach. p. Taf. IV. fig. 24) * but especially, and with full de44, Taf. V. fig. 45, and Zeitsch. f. Physiol. IV. p. 94, tails, by Tulk, loc. cit. p. 324, Pl. V. fig. 31. Taf. VI. fig. 4 i Lyonet, loc. cit. p. 405, Pl. XXI. 9 For the nervous system of the Scorpionidae,. fig. 22; Brandt, Mediz. Zool. II. p. 90, Taf. XV. see Treviranus (Bau. d. Arach. p. 14, Taf. I. fig. fig. 3, 4, or Ann. d. Sc. Nat. XIII. p. 184, P1. IV. 13, and Zeitschrift f. Physiol. IV. p. 89, Taf. VI. fig. 4. Duges, Ibid. VI. p. 174; Grube, loc. cit. fig. 1-3, and Miiller, loc. cit. p. 60, Taf. I. fig. 5, p. 302, and finally Owven, Lectules, &c., p. 253, fig. 7); but especially Newport's excellent description. 109. This last author has represented, in a very (Philos. Trans. 1843, p. 260, P1. XII.); he has instructive manner, the nervous system of a Mygale traced, with Androctonus, the nerves of the exseen in profile. tremities even into the tarsal articles and tkrminal 6 Blanchard, loc. cit. p. 1384. hooks.* 7 Van der Hoeven, Tijdschrift. loc. cit. IX. 1842, p. 68, and X. 1843, p. 369. * [~ 301, note 9.] See also Dufour (Ann d. behind the thoracic mass, from which passes Sc. Nat. XV. 1851, p. 250). This anatomist has off a pair of nerves to the pulmonary organs found a fourth abdominal ganglion, situated just (Scorpio occitanus). -EoD. .~ 302. THE ARACHNOIDAE. 373 ~ 302. A Splanchnic nervous system has been observed with only the higher.Arachnoidae; but here it is highly developed. The odd stomachic nerve has been the part most difficult to discover; it is observe4, however, with some Araneae, - the posterior border of the brain sending off two small filaments which traverse the central opening of the stomach but unite on'its dorsal surface.(') _ The Scorpionidae have a similar stomachic nerve which also arises firom the brain by two'filaments which have a small ganglion at the point of their union. (2) With the Phalangidae, Araneae, Galeodea, and Phrynidae, the splanchnic nerves are very distinct. They arise from the posterior border of the ventral nervous mass situated in the cephalothorax, and are distributed to the digestive, respiratory, circulatory, and genital organs, and have, sometimes, ganglia on their course. With Phalangiunm, there are three of these nerves arising firom the posterior border of the transverse portion of the ventral mass. The middle one of these nerves divides into two branches, which dilate into two ganglia connected together by a transverse anastomosis. From these two ganglia arises a nervous plexus, which is distributed to the internal genital organs, and to the corium. The lateral nerves, directly after their origin, likewise divide into two branches, each of which forms a ganglion; the external nerves after a shorter, and the internal after a longer course. The two external ganglia thus formed send filamnents to the terminal portion of the genital organs, while those of the two internal ganglia are distributed to the digestive tube and neighboring organs.'3~ With the Araneae, the Galeodea, and Phrynidae, the posterior extremity of the principal ventral ganglion sends off two considerable nervous cords, contiguous, which pass into the abdominal cavity where they are distributed, radiatingly, to the digestive organs, to the pulmonary sacs, to the genital organs, and to other abdominal'viscera. Sometimes, before dividing, they unite in a common ganglion.(4) 1 This Nervus sympathicus recurrens was dis- IV. fig. 24, and Tulk, loc. cit. p. 325, PI. V. fig. covered by Brandt, with Epeira; see Mediz. Zool. 31, 33. II. p. 90, Taf. XV. fig. 4, d., and fig. 6, c., or il 4 This ganglion has been observed by Trevirathe Isis, 1831, p. 1105, Taf. VII. fig. 6, b., and Be- nus (Bau d. Arach. p. 45, Taf. V. fig. 45), with the merk. ib. d. Mundmagennerven, loc. cit. p. 15, or indigenous Aranleae, and by Dugds (Ann. d. Sc. Ann. d. Sc. Nat. V. p. 94, and XIII. p. 185, PI. Nat. VI. p. 175), with Mygale. According to IV. fig. 2, c. This same nerve has been refound by Brandt (Mediz. Zool. II. Taf. XV. fig. 3, and Grube (loc. cit. p. 302), with other indigenous Ann. d. Sc. Nat. XIII. p. 185, P1. IV. fig. 4), this Araneae. With Mygale, according to Dughs (Ann. ganglion is wanting with Epeira, and Trevid. Sc. Nat. VI. p. 175), there are, instead of two ranus (Zeitsch. f. Physiol. IV. p. 95), has vainly simple filaments, two lateral ganglionic net-works, sought for it in a Brazilian spider. Blanchard from the brain to the stomach. (loc. cit. p. 1384), has found it with Galeodes, and 2 See Newport, loc. cit.* Van der Hoeven (Tijdsch. X. p. 370), with Thely3 See Treviranus, Verm. Schrift. I. p. 38, Taf. phonus. *[ [ 302, note 2.] See also Dufour, loc. cit. p. 251. -ED. 32 374 THE ARACHNOIDAE. 5~ 303, 304, 305CHAPTER IV. ORGANS OF SENSE. ~ 303. The multi-articulated antennae with which the Crustatea and Insecta areendowed, are absent with the Arachnoidae, or, more properly speaking, they are changed into prehensile and masticatory organs.(l) The palpi, which are absent with only a few Arachnoidae,(2) must be regarded as the principal seat of the sense of Touch. These tactile organs always receive two considerable nerves arising from the anterior extremity of the ventral ganglionic mass.(3) A very delicate sense of touch exists,. also, in the extremity of the feet, which are well supplied with nerves; and, for this object, the feet of the Opilionina and Phrynidae have the form of multi-articulated antennae. With the Araneae, this point admits of no doubt, for these organs (the feet) are especially used in the formation of the web. ~ 304. Although we must grant to the Arachnoidae the sense of Taste, and that of Smell; and although many facts show that they have the sense of Hearing highly developed, yet, at present, nothing satisfactory has been discovered either as to the locality or the structure of the organs which are the seat of these senses. (1) ~ 305. The organs of Vision of the Arachnoidae consist always of simple eyes (Stemmata); but among the lower Arachnoidae, there is a complete series, namely, the parasitic Mites, and allied groups, which are entirely deficient in these organs.() The stemmata of the Arachnoidae have exactly the same organization as the simple eyes of the Crustacea. They are composed of a simple and convex cornea, of a spherical lens, and of a concavo-convex, vitreous body, which is surrounded by a Retina. Each of these eyes is enveloped, before and behind, by a pigment tunic corresponding to the Chorioidea; its color 1 See ~ 306. Latreille (Rggne anim. IV. 1829 Obisium, Chelifer, Phrynus, and Thelyphonus, p. 207), has regarded these mandibles as trans. the palpi are forficulate, and are used as prehensile formed antennae, but usually they have been con- organs. sidered as the first pair of maxillae. This view 3 See Treviranus, Zeitsch. f. Phys. IV. p. 94, of Latreille is the correct one, since the nerves of Taf. VI. fig. 4, No. 4 (a Brazilian spider), and those organs do not arise from the abdominal Doypre, loc. cit. p. 349, P1. XVII. fig. 1, n. a. ganglia, but directly from the brain, as those of (Milnesium). the antennae of Crustacea and Insecta. 1 According to analogy, the sense of taste, with 2 These palpi are wanting with Pycnogonum, the Arachnoidae, is seated probably at the entrance Phoxichilus, Phoxichilidium and Pallene; see of the cesophagus. Savigny, Mim. loc. cit. I. P1. V. fig. 3 * Johns 1 The eyes are wanting with Demodex, Sarton, Mag. of Zool. and Bot. I. P1. XItI. fig. 1-8; coptes, Pteroptus, Dermanyssus, Gamasus, Milne Edwards, I-Iist. Nat. d. Crust. P1. XLI. Thyroglyphus, Glycyphauzes, Acarus, Argas,. fi. 6. With the Scorpionidae, as well as with Ixodej &c. ~ 205. THE ARIACIrOIDAE. E.75 is very variable, a.d, in front, it terminates between the lens and the vitre — ous body by a ring which resembles an Iris. When two of these stemmata. are contiguous, the pigment tunic is common between them.(2) The number, the situation, the disposition, and the direction of the eyes, present so many variations, that they have been used by zoologists to characterize the genera. Chelifer, Er'ythraeus, Smaridia, Tetranychus, Arrenurus, and the Tardigrada, have two of these organs on the anterior portion of the back, while with many Oribatea, they are lateral and anterior. With Trombidium, there are two eyes also, but they are situated directly above the first pair of legs, on clavate peduncles.'3) With the Pycnogonidae, and with Obisirum, there are four eyes situated on the first segment of the body; there are the same number, also, with Bdella, Rhyncholophus, Eylai's, Atax, Diplodontus, Hydrachuna, and Limnochares, situated on the anterior part of the back.(4) With the Opilionina, there are two median, larger, and two lateral,. smaller eyes. The first of these are situated on a tubercle, and their corneae face right and left..' With Galeodes, there are six eyes on the anterior border of the first segment of the body; of these, the middle or largest pair is directed upwards; another, situated in front of these last, forwards; and the remaining pair, inserted above the anteriorlegs, laterally.(6) The Araneae have, usually, eight eyes; only a few have but six.(7) These eyes, always situated on the cephalothorax, are generally of different sizes with the same individual, and are either grouped symmetrically upon the anterior median line of the cephalothorax, or scattered on its lateral border.(8) The dorsal eyes are directed upwards, and the marginal ones, forwards or laterally. The disposition and direction of these organs are conformable with the animal's mode of life; some species watch their prey in crevices, fissures, or tubes; while others remain motionless in the centre of their webs, or lurk from side to side,- a kind of life requiring them to look in all directions. The color of the pigment of the eyes is based also upon the same relations; for, with the diurnal species, it is green, reddish, or of a 2 For the structure of the eyes of Arachnoidae, in pairs, so that each pair would easily be taken see Soemmering, De ocul. hoem. animal. sect. hor- for a single eye. With Atax, Diplodontus, and izont. p. 74, Tab. III.; and Gaede, Nov. Act. Nat. Hydrachna, the two pairs of eyes are widely sepCur. XI. p. 338 (Mygale); but especially Miil- arated. But with Eylais, and Limnochares, ler, Zur. vergleich. Physiol. d. Gesicht-sinn. p. 316, they are closely approximated. With the young Taf. VII. fig. 8-11, or Ann. d. Sc. Nat. XVII. of these aquatic mites, their position is often differ1829, p. 234, P1. XII. fig. 1-4 (Androctonus and ent (Dugis, Ann. d. Sc. Nat. I. p. 144, P1. IX. Galeodes). Brants (Tijds. &c. V., or Ann. d. Sc. X.). Nat. IX. 1838, p. 308) has confirmed AliMller's oh- Wagner's attributing (Lehrb. d. vergleich. servations for the eyes of Buthus and Mygale; Anat. p. 431) compound eyes to certain Hydrachbut he observed, also, tubes situated behind the nea,, is due, without doubt, to his regarding as vitreous body, and analogous'to those of the eyes of such the approximated simple eyes. Dujardin Crustacea and Insecta. AIiiller, however (Arch. (Ann. d. Sc. Nat. III. p. 19), however, affirms 1838, p. 139), has been unable to find them, but he that Penthaleus has a single eye, composed of observed that the fibres of the optic nerve, after eight to ten facets, while some of the species of having entered the eye, are separated by the long Oribates and 7Molglus have only a single stemma filamentoid pigment bodies * and he adds, that situated on the back. these fibres should not be confounded with the 5 See Treviranus, Verm. Schrift. I. p. 24, Taf. vitreous cones of the faceted eyes, the first becoming II. fig. 10. The two lateral eyes are wanting with opaque in alcohol, while the second preserve their many Opilionina. According to Tulk (loc. cit. p..transparency. 326, P1. V. fig. 32), there is a pair of muscles in3 These pedunculated eyes, already figured by serted on the two middle eyes, by which their conDegeer (loc. cit. p. 57, Taf. VIII. fig. 15, y. y.), tents can be displaced. have been described by Hermann (loc. cit. p. 19, 6 See Miuler, Zur vergleich. Physiol. &c. p. Pl. III. fig. E. G.), as Oculi inferi see, also, 332, Taf. VII; fig. 11. Treviranus, Verm. Schrift. I. p. 49, fig. 31, 33, 7 There are six eyes with Scytodes, Segestria, 34, o. o. Dysdera, and Uptiotes. 4 With Bdella, the eyes are wholly lateral. With 8 See Savigny, Descript. de l'lgypte, loc. cit. the Hydrachnua, above named, they are united P1. I.-VII. and Walckenaer, loc. cit. P1. I.-IV., &c. 376 THE ARACHNOIDAE. g 306.'brownish black, as with the other Arachnoidae; but with the nocturnal;spiders, it is replaced by a membrane which has a splendid lustre.'9) With the Phrynidae, there are also eight stemmata, of which two are situated on the middle of the cephalothorax, and the remaining six form a triangle composed of three on each of its sides. With the Scorpionidae, the eyes are the most numerous. There are two large eyes on the middle of the cephalothorax, then a row of from two to,five smaller on each side of its anterior border. The number of optic nerves depends, usually, upon that of the eyes. But the Scorpionidae form an exception in this respect; for their brain:sends off, at the side of the two median optic nerves, two other nerves,.common, and belonging to the two rows of marginal stemmata, but which,do not divide until they have reached these organs.(10) On account of the usually deep position of the brain, the optic nerve is generally of consid-,erable length; but the Pycnogonidae alone differ in this respect from the.other Arachnoidae, for, with Phoxichilus, the four eyes are situated directly on the brain, and, with Ammothea, this last sends off, as a common optic -nerve to the four eyes, a large, short prolongation.(l) CHAPTER V. DIGESTIVE APPARATUS. ~ 306. The entrance of the digestive canal is surrounded by very variable organs, but, with all, the Mandibles are always wanting. The organs usually called such are only antennae metamorphosed into prehensile and masticatory parts. This is shown not only fromn the cerebral origin of their nerves, but by the fact that they, or more properly the Cheliceres, never act, like the mandibles of the other Arthropoda, in a horizontal direction. Most of the Arachnoidae live on liquid food, and, therefore, the basilar article of the maxillae is more or less abortive, and is rarely used in mastication, while the succeeding articles are changed into a usually very large tactile or prehensile palpus. In general, the organization of the parts of the mouth with the Arach-;noidae may be divided into the following five types: 1. With the Tardigrada, there are real organs for suction.'These consist of a kind of sucker, situated on the end of a fleshy proboscis which can be retracted into the head. On each side of this proboscis there are two:stylets (teeth) which, by means of a special muscular apparatus, can be protruded into the former. (') 2. With most of the Acarina, the two cheliceres are sometimes forficulate or unciform, sometimes cultrate or styliborm, and by their use, these 9 Duggs, Ann. d. Sc. Nat. VI. p. 175. 11 Quatrefages, loc. cit. p. 77, P1. I. fig. la,, 10 Treviranus, Zeitsch. f. Physiol. IV. p. 92, 2a.. Taf. VI. fig. 3; and Miiller, Zur vergleich. Phys- 1 See Doyire, loc. cit. p. 319, Pl. XIII.-XV. iol. &c. p. 321, Taf. VII. fig. 10, or Ann. d. Sc. Nat. XVII. p. 238) PI. XVII. fig. 3. Q 306. THE ARACHNOIDAE. 377:snall animals can pierce or cut as may be required. These cheliceres are free, or lodged in a sheath out of which they may be protruded; sometimes they are covered, above or below, by a fiontal or chin-like process. In a few instances, these processes are united, forming a proboscis out of which the cheliceres may be protruded.(2) The first pair of maxillae, which are inserted on the sides of the cheliceres, are wholly unfit for masticatory organs, and, being destined for tactile parts, they have the form of palpi. These palpi are sometimes multi-articulated, sometimes uni-articulated, and, from their various modifications, have received the names of Palpi rapaces, anchorarii, fusiformes, filiformes, antennijbromes, valvaeformes, and adnati.03) 3. -The Oribatea, which, from their herbivorous nature, hold a distinct place, not only amongthe Acarina, but also among the Arachnoidae in gen-,eral, are distinguished also for the organization of their buccal organs.'Their cheliceres are protractile, and the first pair of maxillae, situated under them, forms a complete masticatory apparatus, their basilar article being developed at the expense of the rest into a large denticulated piece. The other articles form only a very short palpus.(4) 4. The Pycnogonidae, Opilionina, Pseudoscorpii, Galeodea, and Scor-.pionidae, all, have tri-articulated cheliceres. Under these last are situated the first pair of maxillae which have no masticatory character.(' With the Scorpionidae, and Pseudoscorpii, they are long-forficulate, while, with the Galeodea, the Pycnogonidae and Opilionina, they are antenniform. With the Phalangidae, only, there is observed on their basilar article, a hairy, obtuse appendage, comparable to a rudimentary maxilla.(6) With the Scorpionidae, the two basilar articles of the pincers are so approxinlated by their flattened internal surfaces, that they may well be used for the bruising of soft animal substances. (7) 5. With the Phrynidae, and Araneae, the cheliceres have the form of bi-articulated, uncifborm antennae. The basilar article of these so-called mandibles is always very thick, and the terminal article consists of a small, very sharp hook.t( When at rest, this last lies folded on the inter2 For the cheliceres of the Acarina, see the de- 4 I have satisfied myself of the presence of;scriptions and figures of Hermann, Dugas, and horny denticulated maxillae, fitted for mastication, Dajardin,(loc. cit.). These organs are forficulate with Hoplophora, Pelops, Zetes, Oribates, Dawith the Acarea, Gamnasea and 1Bdellea see Du- maeues, and with other Oribatea. jardlin, Observ. au Microsc. Pl. XVII. fig. 10, 11 5 Some Pycnogonidae form the only exception in (Acarsus). They are unguiculate with Trombidi- this respect. With Pariboea, the cheliceres are urn, Erythroaeus, Sm.aridia, Atax, atd Eylais; simple, bi-articulate and clavate; but with Endeis, see'Treviranous, Yerm. Schrift. I. Taf. V. fig. 29 Pycnogonuma, and Phoxichilus, they are wholly (Trsombidium). They are styliform with the Ix- wanting; see Philippi, in Wiegmann's Arch. odes, Tetranychus, Rhyncholophus, Rhaphig- 1843, I. Taf. IX. fig. 1-3; also Savigny, Johnsnathozs, and Hydrachna. The frontal prolonga- ton, and MIilne Edwards, loc. cit. tion is regarded by some authors as an under lip. 6 Savigrnsy, M3lm. &c. I. PI. VI. fig. 2, d. It is found with Dermanyssus and Rhaphigsna- 7 It is well known that the Scorpionidae and.thus; while, with Ixodes, it belongs to the chin, the other rapacious Arachnoidae, merely suck and thus forms an under lip. With Smaridia, their prey; but it is said that Galeodes devours and Sarcoptes, the cheliceres are encompassed by completely the insects which it has caught, seizing a kind of tube; see Dujardin (Observat. &c. PI. them with their cheliceres, and eating theln piece XV[I. fig. 1-1 (Sarcoptes). With Ixodes, the by piece. I)uring these processes each chelicere.cheliceres are cultrate and denticulate on their acts separately (Iltton, Ann. of Nat. Hit. XII. external borders 7 see Savigny, Descript. (le 1843, p. 81, or Elroriep's neue Not. XXVIII. p. 1'Eigypte, P1. IX. and Audouin, Ann. d. Sc. Nat. 49). The Phalangidae have probably the same XXV. P1. XIV. The brevity and inequality of hahlbits, for firagments of insect, which they have these organs, as noticed by Audouin with Ixodes eaten are found in their digestive canal (Tulk,.erinacei, were due to the circumstance that they loc. cit. p. 248). were imperfectly and unequally protruded from 8 See Roesel, loc. cit. Taf. XXXVII., and Satheir sheath. vigsny, Descript. de l'Egypte, P1. I.-VIII., also Ly3 This classification of the palpi belongs to Du- onet, loc. cit. P1. XiX. XXI..gas; see Ann. d. Sc. Nat. I. p. 11. 32* 378 TIIE ARACINOIDAE., C37. nal side of, or underneath the basilar article. It is erected when t.hl animal, for defence, or for the seizure of its prey, inflicts a poisonous wound; and, for this purpose, the excretory duct of a poison-gland opens at the apex of each of these hooks.(9) The first pair of maxillae is changed, with the Araneae, into3 very long tactile, and with the Phrynidae, into prehensile organs. Their basilar articles form two upwardly directed prominences, which are contiguous at their bristly, internal borders, and thereby cover the entrance of the oral cavity.(10) As the Araneae bruise, by means of these prominences, their prey which they have seized and taken into their mouth, these parts may be regarded as rudimentary maxillae. The entrance of the Oral cavity is surrounded, with most Arachnoidae,. by a soft, unequal border. This may be regarded, in part, as an upper and under lip, and partly as a tongue. (l) The orifice and cavity of the mouth are often provided with small hairs pointing inwards, among which are sometimes observed horny ridges, which serve, probably, as teeth. The Araneae have this peculiarity, that their large oral cavity has a groove on. the median line of the palate, which is continuous into the cesophagus.(12)' Its lateral borders may be so approximated that it is changed into a canal. This apparatus is certainly very serviceable to these animals in sucking their prey, after it has been punctured repeatedly, and taken into the mouth. With very many Arachnoidae, the food, before reaching the proper digestive tube, traverses a very short esophagus.(13) With the Araneae, this canal is geniculate, of a horny consistence, and, at the point where it enters the stomach, it presents a prismatic muscular enlargement on which is inserted a large muscle arising from the centre of the dorsal shield and passing through the central opening of the stomach. (14) This serves probably as a sucking apparatus during the prehension and deglutition of food.(1o) With the Tardigrada, the cesophagus terminates also by a muscular apparatus of this kind, which, with Macrobiotus, and Emydium, is spheroidal, and with Milnesium, cylindrical.("l ~ 307. The Intestinal canal of the Arachnoidae'is formed after two different types. 1. With the Tardigrada, Acarina, Pycnogonidae, Opilionina, Solpugidae, and Araneae, the stomach has a greater or less number of caecal 9 See ~ 315. cesophagus of the Pycnogonidae; but, subsequently, 10 See Treviranus, Bau d. Arach. Taf. II. fig. he found that he was deceived, and that vibratile 14-16, r., and Brandt, )lediz. Zool. II. Taf. XV. organs were wanting here as with all the Arthrofig. 9, 18, b. poda. 11 With the Araneae, and Scorpionidae, the 14 Brandt, Mediz. Zool. I. p. 89, Taf. XV. fig. entrance of the mouth has a tumid, pilose upper 6, b., or Ann. d. Sc. Nat. XIII. p. 183, P1. IV. fig. lip. With the Opilionina, there are several such 2. b. tumefactions, but with the Pycnogonidae, the oral 15 This suctorial apparatus appears to have been orifice is prolonged, snout-like, between the max- well described and understood by Wasmann (loc. illae. cit. p. 10, fig. 13, i. m.) i but, already before this, 12 See Lyonet, loc. cit. p. 401, P1. XXI. fig. 4, Lyonet (loc. cit. p. 402, PI. XXI. fig. 4, C D E.)) 5, and Duges, Ann. d. Sc. Nat. VI. p. 178. had rightly perceived it: while Brandt (Med. 13 With the Acarina, Pycnogonidae, and Araneae. Zool. II. p. 87) had taken it for an os hyoides. Quatrefages (Compt. rend. XIX. 1844, p. 1152) 16 Doydre, loc. cit. p. 322, P1. XIII.-XV. thinks he has observed a ciliated epitheliurm in the ~ 307. TIIE ARACHINOIDAE. 379 diverticuli, of the most varied form and size. It is continuous into a short, small intestine, which passes, in a straight line, to the anus situated usually at the posterior extremity of the body. Before reaching this point, the intestine has, usually, a dilatation bounded by a constriction, which may be regarded as a rectum, or better, perhaps, as a cloaca. With the Tardigrada, the stomach is oblong and occupies a large portion of the body. It is divided throughout by numerous constrictions into many irregularly disposed caeca.(l) With the Acarina, whose anus is placed nearer the middle of the belly, there are, nearly always, three short caeca at the anterior part of the stomach, and two, longer and more or less constricted, in the lateral regions of the abdomen. With some species of parasitic Mites, these appendages of the stomach are bifurcated. (2) With the Pycnogonidae, the stomach is short, but has five pairs of very long caeca, some of which penetrate into the two cheliceres, and others into the eight long legs, even to the extremity of the tibiae. 3) With Galeodes, also, these appendages penetrate the legs, and the base of the cheliceres and palpi.(4) With the Phalangidae, the stomach is spacious and has thirty appendages of varied size. Thus, at its upper part, there are four rows of short caeca, and, upon the sides, three pairs, very long and extending over nearly the whole length of the visceral cavity; the middle pair of these last has, nloreover, short sacculi. (5 With the Araneae, the stomach is situated in the cephalothorox, and presents a very remarkable disposition. At the posterior extremity of the thoracic cavity, and directly behind the sucking apparatus, it is divided into lateral halves which extend arcuately in front, and, uniting, form a ring from which are given off laterally five pairs of caeca extending towards the points of insertion of the legs and palpi. The intestine arises from this annular stomach, opposite the sucking apparatus. It traverses the abdomen on the median line, and terminates, before reaching the anus, in a cloacal dilatation.'6 2. With the Phrynidae,(7) and Scorpionidae,(8) the intestinal canal is very simple compared with that just described. It consists of a straight 1 Doy~re, Ibid. p. 324, P1. XV. 6 For the annular stomach of the Araneae, and 2 See Lyonet, loc. cit. P1. XIII. fig. 11, 12; on which, with Tegenaria, Treviranus (Ban d. Dugds, loc. cit. I. P1. I. fig. 27. II. P1, VII. (Ery- Arach. p. 30, Taf. II. fig. 24, v. b.) has found only thraeus, Dermanyssus and Ixodes); also, Tre- four caeca, see Brandt, Mediz. Zool. II. p. 89, Taf. viranus, Zeitsch. f. Physiol. IV. p. 189, Taf. XTI. XV. fig. 6, or Anp. d. Sc. Nat. XIII. p. 182, P1. Ixodes has dichotomous stomachic appendages, of IV. fig. 2, or Isis, 1831, p. 1105, Taf. VII. fig. 6; which the posterior, at the extremity of the body, also Owen, Lectures, &c., p. 257, fig. 110; and Wascurve first downwards, then forwards with a long mann, loc. cit. p. 11, fig. 17, 18. According to course. These various caeca of the Acarina often this last observer, the four pairs of stomachic caeca, appear, especially when filled with food, clearly de- with Mygale, bend downwards to the base of the fined, through the skin. But when empty, they eight legs, in order to pass into the thorax where are frequently overlooked in the small species, they ramify and interanastomose. from the tenuity of their walls. However, I have With Argyroneta, and some species of Epeira, always succeeded, even with the smallest Oribatea, according to Grube (Miiller's Arch. 1842, p. 208), in distinguishing the walls of the intestine, especially the lateral halves of the stomach are not united in when it contained food. I must, therefore, consider a ring at their anterior extremity, but are only conas wholly erroneous, the opinion recently advanced tiguous. by Dujardin (Ann. d. Sc. Nat. III. p. 14, or With the Araneae, the walls of the stomach conCompt. rend. loc. cit. p. 1159), that the food eaten tain finely-granular cells which, by reflected light, by the Acarina does not pass through a distinct have a milky aspect, and secrete perhaps a kind digestive tube, but is freely effused in the interstices of gastric juice. of the viscera. 7 Van der Hoeven, Tijdschr. &c. IX. p. 68 3 Milne Edwards, Hist. Nat. d. Crust. III. p. (Phrynus). 531, and Quatrefages, loc. cit. p. 72, P1. I. II. & Meckel, Beitrige, loc. cit. p. 107, Taf. VII. 4 Blanchard, loc. cit. p. 1384. fig. 13; Treviranus, Bau d. Arach. p. 6, Taf. I. 6 Ramdohr, Abhandl. ib. d. Verdauungswerk. fig. 6, and.Mlller, loc. cit. p. 45, Taf. II. fig. p. 205. Taf. XXIX.; Treviranus, Verm. Schrift. 22. I. p. 29, Taf. III., and Tulk, loc. cit. p. 246, P1. iv. 380 TIlE ARACHN01DAE. ~ 308. tube,. of nearly equal size throughout, without a stomachic dilatation and without caeca, which opens by an anus at the posterior extremity of the body.(9) ~ 308. The Salivary glands exist with, perhaps, all the Arachnoidae; for, they are found even in many of the lower forms, where their presence would be least expected. With the Tardigrada, there are on each side of the sucking apparatus, large, lobulated glandular tubes, which appear to be organs of this nature, although their outlets have not yet been distinctly traced.(1) With the Oribatea, there is at the anterior extremity of the body, a pair of' similar tubes, but simple and colorless, which extend to the mouth, and have undoubtedly a salivary function.(2) With Ixodes, these organs are extraordinarily developed, consisting of two large masses of vesicles situated on the sides of the anterior part of the body, and opening by short ducts into two multiramose excretory canals. These last, whose walls are traversed by a solid spiral filament, open into the buccal cavity at the base of the lip-like process.(3) With the Araneae, a slit in the upper lip leads into a cavity situated above the palate, and at the base of this cavity is a transparent, glandular mass, which, very probably, secretes the saliva; this flows up through the slit in question, and moistens the substances from which the animal extracts its food.(4) As salivary organs should also be considered the two pairs of glandular tubes, which, with the Scorpionidae, are situated on the sides of the anterior part of the body, and extend forwards to open into the oesophagus.t~) With the Araneae, and Scorpionidae; there is a Liver distinct from the digestive tube, which, for a long time was regarded as an adipose mass. With the Tardigrada, Acarina, Pycnogonidae, and Opilionina, the walls of the stomachic appendages are of this nature, for they are glandular and compcsed of granular and usually yellowish-brown cells.(") With the Araneae, the brown or dirty-yellow liver is very voluminous, filling a large portion of the abdominal cavity, and enveloping most of the other viscera. At first sight, it appears to be a compact mass, but, further examined, it, is found composed of numerous multiralqose, closely-aggregated caeca. The walls of these are thick, and crowded with hepatic cells, and they open into the digestive canal near its middle by four short hepatic ducts.t7) 9 With the Scorpionidae, the anus is situated on 5 See Miller, loc. cit. p. 52, and Newport, the penultimate caudal segment. Philosoph. Trans. 1843, P1. XV. fig. 39. 1 See Doylre, loc. cit. p. 321, P1. XIII.-XV. 6 With the Tardigrada, Acarina, and Opilionina, 2 I have seen these glandular tubes with Hoplo- at least, I have seen, distinctly, hepatic cells in phora, Zetes, and Oribates. the walls of the stomachic appendages. See also 3 Tle salivary glands of Ixodes ricinus resem- Doyere, loc. cit. p. 327, Pl. XV. ble exactly the botryoidal ones of many of the In- 7 Treviranus (Bau d. Arachnid. p. 30, 47, Taf. secta. II. fig. 24, dd., and Taf. V. fig. 47) had already The secretory vesicles of the saliva are filled with observed the communication between the liver and transparent nucleated cells and surrounded by the digestive organs. The remaining points in the numerous ramified tracheae with which it is im- structure of this organ have been rightly estimated possible to confound the excretory ducts of these by Dugds (Ann. d. Sc. Nat. VI. p. 179), Grube glands; for with these last the spiral turns of thin (loc. cit. p. 299), and Wasmann (loc. cit. p. 13, fig. filament are very wide apart, while, in the tracheae, 17, m. n., 20-22). See also Owen, Lectures, &c., the spiral windings are very close together. p. 258, fig. 110, i. i. 4 This glandular apparatus has been seen by Wasmann (loc. cit. p. 8, fig. 16) with Myg-ale I have found it also with other Araneae. ~ 309. THE ARACHNOIDAE. 381 With the Scorpionidae, the liver is also very large, and composed of many lobes. It occupies the two sides of the abdominal cavity even to the base of the tail, and closely encompasses the intestine, the heart, and the genital organs. The ramifications of the biliary canals traverse, in groups, the parenchyma of this liver, and the bile is poured into the intestine by five pairs of short, excretory ducts, equally, but very widely separated forom each other.(8' x CHAPTER VI. CIRCULATORY SYSTEM. ~ 309. With many Arachnoidae, the circulatory system consists only of a Heart or an articulated dorsal vessel. With the higher formrs, there is, in addition, a system of more or less developed blood-vessels; while with the lower species, such as the Tardigrada, the Acarina and the Pycnogonidae, not only all these vessels, but the heart, also, is absent. There is, therefore, in these last, no regular circulation, but the nutritive fluid fills all the interstices of the body, and, by the aid of the muscular movements and the contractions of the intestinal canal, is transferred in an irregular manner hither and thither in the visceral cavity and in the extremities.(l) The Blood of the Arachnoidae is entirely colorless, and has a slightly milky aspect only when in considerable quantities. It contains a few granular blood-cells of a pretty regular, spheroidal form, and some very small, isolated granules, derived perhaps frorm broken blood-cells.(') 8 See Meckel, Beitr. &c. p. 107, Taf. VII. fig. Beneden has observed, in the extremities of these 13, 15; this autllor has seen four pairs of hepatic animals, regular blood-currents produced apparducts. See, also, Treviranass, Bau d. Arachn. p. 8, ently by contractile membranes at the base of the Taf. I. fig. 6, A. v., and lIiller, loc. cit. p. 35, 46, legs; see Institut. No. 627, or Froriep's neue Taf. II. fig. 22, D. D.; finally Newport, Philosoph. Notiz. XXXVII. p. 72. Trans. 1843, P1. XIV. fig. 32. 2 Forl the blood of the Arachnoidae, see Wagner, 1 C. A. S. Schultze (in his memoir "Macro- Zur vergleich. Physiol. d. Blutes, Heft. I. p. 27, fig. biotus IHufelandii ") thinks he has observed blood- 11 (Scorpio elzropaeus) Horn, Das Leben des vessels in the Tardigrada; but neither Doysre Blutes, p). 10, Taf. I. fig. 12 (Tegenaria domes(loc. cit. p. 310) nor I have been able to find tica), and Doysre, loc. cit. p. 309, P1. XV. fig. 5 them. For the interstitial circulation of the Pycno- (Tardigrada.) gonidae, see, Qzatrefages, loc. cit. p. 76. Van * [~ 308, end.] See, for some researches upon thereby of the nature of the alleged hepatic appendthe hepatic organs of the Arachnoidae by means of ages of the alimentary canal of these animals, chemical agents, and the positive determination Will, 3iiller's Arch. 1848, p. 50. - ED. 282 THE ARACHNOIDAE. ~ 310. ~ 310. With the Arachnoidae, the circulatory organs, when present, are disposed in the following manner: With the Phalangidae, they consist only of a Dorsal Vessel, which is three-chambered, and attenuated at both extrenzities.(l) WTith the Araneae, the dorsal vessel is fusiform, and has many constrictions. It is situated principally in the abdomen, being attached to its dorsal wall by triangular transverse muscles. This heart, which extends also into the cephalothorax, sends off from each extremity and from its sides, many ramified, vascular canals, which are certainly Arteries. The two of these last arising directly behind the peduncle of the abdomen, are distributed to tthe pulmonary sacs, while those following penetrate chiefly the liver. All these vessels gradually disappear in the parenchyma of the body, and the blood, after its effusion, continues to circulate in the lacunae, and, without the intervention of veins, is returned to the heart, or more properly into the blood-reservoir which corresponds to the dorsal sinus of the Crustacea. Thence it enters the heart through its lateral, valvular openings.(2) The vascular systehm is most highly developed with the Scorpionidae. For, here, not only is there an articulated Heart and Arteries, but also a Venous system.(31 The cylindrical heart whose walls contain transverse and longitudinal muscular fibres, is retained in place between the diaphragm of the cephalothorax and the last abdominal segment, by several transverse triangular muscles. It has eight chambers whose size diminishes from before backwards. At each extremity it is prolonged into an I See Tulk, loc. cit. p. 249, PI. IV. fig. 17, H., heart above the points of origin of the arteries. and Treviranus, Verm. Schrift. I. p. 31, Taf. IMI. The analogy between the heart of Crustacea and fig. 16, k., and lig. 18.* of Araneae has been especially pointed out by 2 For the vascular system of the Araneae, see Straus (Considerat. &c. p. 345, and Traitdl'Anat. Meckel, in his translation of Cuvier's Lecons comp. tI. p. 251), and since confirmed by Grant d'Anat. comp. Th. IV. p. 261; Treviranus, Bau (Outlines, &c., p. 452) and Grube (loc. cit. p. d. Arach. p. 28, Taf. III. fig. 28-31, also his Verm. 300).t Schrift. I.p. 4, Taf. I. fig. 1; Gaede, Nov. Act. Nat. 3 Treviranus (Bau d. Arachn. p. 9, Taf. I. fig. Cur. XI. p. 335, Tab. XLIV. fig. 3 (lMygale), and 7), and Miiller (loc. cit. p. 38, Taf. II. fig. 22), Brandt, Mediz. Zool. II. p. 89, Tar. XV. fig. 16, were acquainted with only the heart and larger vas17. See also Duay s (loc. cit. p. 181), who has been cular trunks of the Scorpionidae; but Newport unable to find the venous system with the Araneae, has given of the blood system of these Arachnoidae but, at the same time, traced the heart even into a complete and masterly description accompanied the cephalothorax. Was?nann (loc. cit. p. 16, fig. with very beautiful figures; see Philos. Trans. 21), on the other hand, alfirnms that he has observed, 1843, p. 286, Pl. XIV. XV., or Froriep's neue with Mygale, venous trunks which entered the Notiz. XXXIX. p. 81, fig. 38-40. * [ ~ 310, note 1.] Blanchard (loc. cit. Ann. t [ ~ 310, note 2.] According to Blanchard d. Sc. Nat. XII. 1849, p. 333) has extended our (loc. cit.), the blood, in the Araneae, passes to the knowledge of the circulatory system of this family. respiratory organs, which it penetrates by a kind The dorsal vessel terminates behind in a small yes- of infiltration; from the lacunae of the walls of the sel which runs to the extremity of the body. In lungs it is taken to the heart by means of the pulfront it passes into an artery of considerable size, mono-cardiac vessels which have hitherto been which passes under the brain and sends off small taken for arteries. There are six pairs with Epeira branches to the cesophagus. At the base of this diadema. But with those Araneae which have aorta the ophthalmic artery is given off, which both lungs and tracheae, such as Segestria, Dysbifurcates behind the eyes. From this portion of dera, &c., there is some modification, although the ishe heart also pass off branches to the stomach. arterial system resembles that of the Araneae This naturalist declares the existence here of his essentially pulmonary i the heart is smaller and peritrachean system, which, together with the heart, has fewer chambers, and'the true arteries seem to he says he has injected through the lacunae. - lose their importance and give place to the peritrar ]ED. chean system of circulation. - ED. ~ 310. THE ARACHNOIDAE. 38, arterial trunk. The anterior of these arteries very soon ramifies, and distributes blood to the feet, the pincers, the cheliceres, and to all the organs in the cephalic extremity. Two of its branches, bending downwards, embrace the cesophagus, and then join in a large common vessel called the Supra-spinal artery, which lies upon the ventral cord and accompanies it to the caudal extremity, giving off, in its course, numerous lateral branches.(4) The posterior arterial trunk is distributed in like manner to the posterior extremity, and gives off; right and left, numerous branches. The middle chambers of the heart send off, each, laterally, shorter arteries, which are distributed to the neighboring organs. Beside these arteries of the muscles and viscera, these animals have, also, a special Visceral artery, arising from the anterior arterial trunk before it divides into the two branches which form the supra-spinal artery. The visceral artery runs backwards towards the digestive tube, and sends branches to the liver. ) The terminal ramifications of these various arteries are directly continuous, it is said, with a venous systemn.'6' In this last may be noticed, especially, a Sub-spinal vein, by which the blood is carried to the pulmonary sacs; thence to be borne to the heart by special vessels. These last open, probably, into a sinus, from which the blood passes into the heart through lateral openings, two of which exist in each of its chambers.t 4 This supra-spinal artery had been seen, it cisely this point, and has not distinctly indicated it would appear, by Miiiler (loc. cit. p. 62, Taf. I. in his plates otherwise so beautiful, I demur admitfig. 5, r. r.), but he took it for a ligament. ting that, with the Scorpionidae, the arteries pass 5 According to Newport, this visceral artery, directly into the veins, and therefore. that these which is simple with AAndroctonus, is divided into animals have a system of capillary vessels. This two trunks with Buthus. direct communication between these two systems 6 Newport speaks in his memoir of various an- does not exist with the other Arachnoidae, neither astornoses occurring between the arteries and veins with all the other Arthropoda in general.* with Scorpio. But, as he nowhere describes pre" [ ~ 310, note 6.] In regard to the question of pulmono-cardiac vessels, wholly analogous to those capillaries with the Scorpionidae, a remark of we have described with the Araneae." - ED. Blanchard (loc. cit.) may be given. He says, " I t [ ~ 310, end.] For further details on the cirhave proved with an entire certainty that the blood culatory system of the Arachrdoidae, see the memoir is distributed in all the cavities of the body, as with quoted above of Blanchard. This naturalist has all the Articulata, and that it is conveyed to the sought to extend his doctrine of the peritracheau lungs simply by means of the lacunae. Most of the circulation, to the different sections of the Arachvessels which arise from the sides of several of the noidae. - ED. chambers of the heart have appeared to me to be $384 THE ARACHNOIDAE. $~ 311, 312. CHAPTER VII. RESPIRATORY SYSTEM. ~ 311. The higher Arachnoidae respire by tracheae, or by lungs; but in thea lower, namely, the Tardiorada,(1 ) the Pycnogonidae,(2) and some parasitic Acarina,(3) no traces of respiratory organs have yet been found. With these animals therefore the respiration must be cutaneous. Many Acarina, the Opilionina, the Pseudoscorpii and the Solpugidae,. breathe by tracheae, while the Araneae, the Phrynidae and the Scorpionidae breathe by lungs. On this account, these animals have been divided,. in zoological systems, into the Arachnidae tracheariae and pzulmonariae. But this classification is valueless, since it has been shown that the Araneae possess both lungs and tracheae. ~ 312. With the Acarina, the Tracheae are exceedingly tenuous, and it is only in, the larger species that the spiral filament of these organs can be observed. They arise usually by a simple tuft from two stigmata which are sometimes concealed between the anterior feet, as with the Hydrachnea, the Oribatea, and the Trombidina, sometimes very apparent above the third pair of legs, as with the Gamasea, and sometimes behind the last pair of legs, as with the Ixodea. (1) With the IIydrachnea, which live in the water and never come to'the surface to take in air, the tracheae possess, probably, the power to extract from the water the air necessary for respiration.(2) With the Pseudoscorpii, there is, on the ventral surface of the two first abdominal segments, a pair of lateral stigmata, with four short but large trachean trunks from which arise numerous unbranchecl tracheae spreading through the entire body. (3) With the Solpugidae, whose tracheae 1 See Doyere, loc. cit. p. 316. tracheae of the Acarina, see, moreover, Dujardinz 2 See Quattrefoaes, loc. cit. p. 76. (Ann. d. Sc. Nat. III. p. 16, or Compt. rend. loc. 3 Demodex, Sarcoptes, Acarsts, &c. cit. p. 1160). It will be difficult, I think, to prove 1 With Trombidiumnz, there arise two simple the assertion of Dujardin, that, with these animals,. and very distinct trachean tufts from the two the trachean system serves exclusively for the act stigmata situated behind the second pair of legs of expiration, inspiration being performed wholly (Treviranus, Verm. Schrift. I. p. 47, Taf. VI. fig. by the skin. 32, t. t.). These tracheae do not proceed directly 2 DitsLs (Traits d. Physiol. II. p. 549) is cerfrom the stigmata, but from two large, short trunks tainly right in placing the tracheae of the Hydrachunobserved by Treviranus. nea in the category of Branchiae tracheales, whichWith Gamasus, and Uropoda, there are given are so widely spread with the aquatic larvae off, from the two ramified trachean tufts, two un- of Insecta (see below). branched tracheae which, remaining of the same 3 According to Ausdouein (Ann. d. Sc. Nat. size, describe a slightly arcuate course along the XXVII. 1832, p. 62), the tracheae of Obisium are lateral borders of the cephalothorax and terminate ramified, a statement which I have been unable to in caeca at the base of the parts of the mouth. The verify. It has already been stated that the scartwo lateral stigmata of Ixodes have been described like fossae on the abdomen of Chelifer have been by Lyonet (loc. cit. p. 288, Pl. XIV. fig. 3, 5), erroneously taken for stigmata (~ 298, note 4). Treviranus (Zeitsch. f. Physiol. IV. p. 187, Taf. The tracheae of the Pseudoscorpii are so easily XV. fig. 2,f.f.), and Audouin (Ann. d. Sc. Nat. seen by the microscope that it is incomprehensible XXV. p. 419, PI. XIV. fig. 2, q. r. s.). For the how anatomists should have remained so long. ~ 312. THE ARACIINOIDAE. 385 ramify through the whole body like those of insects, there are three pairs of stigmata.~4) With the Phalangidae, the trachean system is highly developed, arising from two stigmata concealed under the coxae of the posterior legs, each of which has a horny valve. The two large trunks given off from these stigmata, run obliquely to the cephalic extremity; they intercommunicate by a transverse anastomosis, and give off, in all directions, numerous branches which are spread over the abdominal viscera, and penetrate even the palpi and legs.(5) With many of the Araneae, there are, on the under surface of the abdo-. men, two orifices which lead into two pulmonary sacs, beside two other openings belonging to the trachean system. With Segestria, Dysdera,(6) and Argyroneta,(') there arise from these two stigmata two large trunks surrounded by a kind of horny trellis-work. From the extremity of these, trunks are given off innumerable, very small tracheae, which are unbranched and without the spiral filament. They are disposed in tufts, and are distributed, some in the abdomen, and others in the cephalothorax, penetrating even to the extremity of its members. With Salticus, and Mlicryphantes,~(t the two stigmata are situated at the posterior extremity of the body, far removed from the pulmonary sacs, and send off, directly, two tufts of unbranched tracheae, which are distributed exclusively to theabdominal viscera.0) There is, with the other Araneae, a tracheanr system, very imperfect it is true, which has hitherto been overlooked by anatomists. Directly in front of the spinnerets, there is, with most species, a transverse fissure difficult to be seen, which leads into a very short. trachean trunk. From this trunk are given off four simple tracheae which, singularly, are not cylindrical, but are flattened, riband-like, and without a trace of a spiral filament; these extend, with a gradual attenuation, to the base of the abdomen. These riband-like, silvery tracheae are, composed of a thin, but solid, homogeneous membrane, which is enveloped by a soft, transparent pellicle corresponding to a peritoneum. The air received into these organs is separated into as fine porfions as that of the lungs. These tracheae differ therefore, prominently, from those of the other Arachnoidae.('0) ignorant of their existence, and even lately, that finely divided, while that in the cylindrical traTulk (Annals of Nat. Hist. XV. p. 57) should cheae given off from these trunks, forms a continuhave failed to see them with Obisium. ous column. 4 See Mziller, Isis, 1828, p. 711, and Milne Ed- 10 I have found this trachean system with wuards, Rdgne anim. Illustr. Arachnides, PI. II. Epeira, Tetragnathus, Drassus, Clubiona, 5 Treviranus, Verm. Schrift. I. p. 32, Taf. IV. Theridion, Lycosa, Diomedes and several fig. 19, and Tulk, loc. cit. p. 327, PI. V. fig. 33. others. I have been unable to perceive it in 6 Dugis, in "Le Temps," 1835, No. 1942, individuals escaping from the egg. Thomisus ZFeuilleton, Acad. d. Sc. Seance du 9 FEvrier. or viaticus is the only species in which the four Froriep's neue Notiz. XLIIT. p. 231, or Aun. d. flattened trachean trunks are ramified, and thus Sc. Nat. VI. p. 183, and R.gne animal, Atach- serves as the passage to the most highly developed nides, PI. III. fig. 4, V. fig. 4. See also Owen, tracheart system of Salticus. By dilect light, Lectures, &c., p. 259, fig. 112. they appear black, and thus it is possible that they' 7 Grube, loc. cit. p. 300, and Menge, loc. cit. p. may have sometimes been taken for urinary canals.. 22, Taf. I. fig. 6-14. But this- error is unnecessary, for these last vessels: s Menge, loc. cit. p. 23, Taf. I. fig. 15. burst from the slightest pressure and effuse granu9 I have had an opportunity to satisfy myself of lar contents, while the tracheae under such treatthe existence of this interesting trachean system ment become transparent, their contained air withSegestria, Argyroneta, Salticus, and MI2icry- making its escape, and when the pressure is with-. phantes. I should also add that the principal drawn they resume their black color.* trunks are flattened, and that the contained air is,[ 312, note 10.1 See also for these anomalous elongated pulmonary sacs; but especially Leuc — tracheae, Blanchard (loc. cit. Ann. d. Se. Nat. kart (Ueber den Bau und die Bendeutung der sog.. XII. 1849, p. 345), who regards them as only Lungen bei den Arachniden, in Siebold. and' Kdlli-' 33 886 THE ARACINOIDAE. O 313 ~ 313. The Lungs of the Arachnoidae consist of round sacs situated near the lower surface of the abdomen and communicating, externally, by transverse fissures. Their internal surface has numerous thin solid lamellae, triangular or rhomboidal, and connected together like the leaves of a book. By reflected light these lamellae have the same silvery lustre as the tracheae, although, seen by direct light, they appear of a deep-violet, nearly black color. Each of these is formed by a membranous fold, between the two leaves of which the air enters from the general cavity of the lung and is divided into very minute portions. No traces of blood-vessels have been found in these Pulmonary lamellae. It is therefore very probable that the blood of the pulmonary arteries is effused into the parts surrounding the lungs, and in this way bathes the lamlellae.'l' With the Scorpionidae, the four anterior segments have, each, on their under surface, a pair of stigmata. These animals have eight pulmonary sacs, in each of which there are twenty fan-shaped lamellae.(') The genus Phrynus has only two pairs of pulmonary sacs, the stigmata of which are placed between the first and second, and the second and third abdominal segments. But each sac has eighty lamellae.~31 With the Araneae, there are only two lungs occupying the base of the abdomen. The number of their lamellae is considerably less than in the preceding groups. But with the Mygalidae only, there is a second pair of lungs directly behind the first. The place occupied by these organs, is indicated, with the Araneae, by a triangular horny plate, at the posterior border of which is a stigma.(4) 1 These organs, with which no motions have been act. 1843, p. 295, P1. XIV.) is probably mistaken in discovered, have been called Branchiae by many saying that unnucleated cells and a; very fine' Zootomists. But the name of Lungs is very ap- capillary net-work exist between these plates, and propriate since the respiration is aerial and not that the net-work arises from a branch of the pulaquatic. monary artery situated on the free border of each 2 For the lungs of the Scorpionidae, see Meckel, lamella. Translat. of Leqons d. Anat. comp. of Cuvier, Th. 3 See Van der Hoeven, Tijdsch. loc. cit. IV. p. 291; Treviranus, Bau d. Arach. p. 7, Taf. 4 The lungs of the Araneae have been studied I., and Beobacht. aus d. Physiol. p. 25, fig. 4042; by Meckel (Translat. Leqons d'Anat. comp. of A3iiller, Isis, 1828, p. 708, Taf. X. fig. 1-3, and in Cuvier, loc. cit. p. 290), Treviranus (Bau d. MIeckel's Arch. loc. cit. p. 39, Taf. II. fig. 11-13. Arachn. p. 24, Taf. II. and Beobacht. &c. p. 29, fig. Muller has very correctly, and in the above-men- 43-47), Gaede, Nov. Act. Nat. Cur. XI. p. 335, tioned manner, understood this respiratory appara- (Mlygale); but especially by Miller (Isis, 1828, p. tus, while, on the other hand, Treviranus and 709, Taf. X. fig. 4-6). See also Menge, loc. cit. other anatomists, think that the air, instead of p. 21; Taf. I. fig. 6-9. I am unable to say by entering between the leaves of the pulmonary what means the blood returns to the heart, whether lamellae, passes over their external surface, and by a direct course, or, more or less circuitously that the blood penetrates between the two plates through the interstices of the parenchyma, for composing the leaves. Newport (Philos. Trans- there are no veins..ker's Zeitsch. 1849, I. p. 246) who, contrary to view put forth together with the general doctrine Blanchard, advances the view that these organs that the pulmonary sacs of the Arachnoidae are, are only a form of tracheae, infra-formed, and likewise, but modifications of the tracheal type, which are without the spiral filament, because has many facts deserving the attention of anatotheir simple, unbranched condition does not re- mists, and especially the developmental relations quire, like the ramose tracheae, a spring-like of the spiral thread as observed in the embryos of structure, to prevent them from collapsing. This these animals. —ED. 314. THE ARACHNOIDAE. 387 CHAPTER VIII. ORGANS OF SECRETION. I. Urinary Organs. ~ 314. With most Arachnoidae, there are small, usually multiramose, glandular tubes, which open into the cloaca. By their structure and the nature of the fluid they secrete, they exactly resemble the Malpighian vessels of the Insecta, and like them, also, they have, for a long time, been regarded as hepatic organs; but now, they are known to be positively those of an urinary nature. The urine is usually accumulated in the cloaca, and consists of a troubled, dirty-white liquid, rarely reddish; and, by direct light, is found to hold in suspension innumerable dark molecules. These organs appear to be absent with the Tardigrada, and Pycnogonidae. But, on the other hand, they are easily observed with many Acarina, where they consist of simple or ramose white tubes, situated between the appendages of the stomach.(') With the Phalangidae, there are two pairs of urinary canals which wind between the stomachic caeca.(2) With the Araneae, these organs are numerous, multiramose, and of a white or xeddish color. Their very small branches penetrate between the different portions of the liver, and end in two principal trunks or ureters, which open into a cloaca provided with a kind of diverticulum.(3) With the Scorpionidae, the organization in this respect is quite similar, and the canals, ramified in various ways, enter, some the interstices of the hepatic lobes, while others surround the digestive canal. They pour their product into the cloaca by two ureters which are situated back of the biliary canals. (4) 1 I have discovered without trouble, these 3 Ramdohr (loc. cit. p. 208, Taf. XXX. fig. 2), canals with the IHydrachnea, Gamasea, Trombi- and Treviranus (Bau d. Arach. p. 30, Taf. II. dina, and Ixodea. Treviranus (Zeitsch. f. Phys- fig. 24) were only irperfectly acquainted with the iol. IV. p. 189, Taf. XVI. fig. 8, n. n.) had already urinary canals of the Araneae. They have been observed their insertion into the cloaca with Ix- more exactly described by Brandt (Mediz. Zool. II.,odes. With Ixodes ricinus, where they are p. 89, Taf. XV. fig. 6, 17, or Ann. d. Sc. Nat. XIII. simple and flexuous, I have seen them ascend p. 183, PI. IV. fig. 2, 3); but see, especially, Waseven to the anterior extremity of the cephalo- mann, loc. cit. p. 17, fig. 17, 21-23 (Mygale). In thorax; this is entirely so with Ixodes ameri- most species, the urine is of a dirty-white color - -canus. The canals, whichwith Nigua, Treviranus but with Mygale, it is reddish. In several indi-(loc. cit. fig. 7, g. g.) has regarded as salivary or- viduals of a large species of Mygale preserved in gans, are certainly only the anterior extremities of alcohol, I have found, in the ureters, hard, reddish the urinary vessels. The two species of Ixodes concretions which Dugis (Ann. d. Sc. Nat. VI. p. just mentioned have their cloaca filled with a 180) had already observed. Treated with nitric white urine. acid and ammonia, I obtained purpuric acid. 2 See Treviranus, verm. Schrift, I. p. 31, Taf. 4 See Treviranus, Bau d.i Arach. p. 6, Taf. T. III. fig. 167 17. Tulk (loc. cit. p. 249, P1. IV. fig. fig. 6, and Miiller, loc. cit. p. 47, Taf. II. fig. 22. 17) who has been unable to trace these canals to This last anatomist says that these glandular canals their points of insertion on the intestine, has taken communicate with the heart, but he has probably a portion of them for salivary organs. confounded them with the blood-vessels. 388 THE ARACHNOIDAE. $ 315. Lr. Organs of Special Secretions. ~ 315. Very many Arachnoidae have Poison-glands, the product of which is excreted through the extremity of a hollow claw. With the Phrynidae, the Araneae, and some Acarina, there are two such glands in communication with the terminal hooks of the cheliceres. They have been often taken for salivary organs. With the Trombidina, there are, on each side of the cephalothorax, two small, flexuous, colorless, glandular tubes, which, at. their anterior extremity, are dilated, each, into a cylindrical, thin-wallecd poison-reservoir. From this reservoir arises a long, narrow canal, which runs to the cheliceres.(11 With the Araneae, the poison-apparatus consists of two tubes, often a little curved, and surrounded by a layer of flattened, spiral, muscular fasciculi. (2) These two glands are situated at the base of the cheliceres, extend more or less into the cephalothorax,~3) and, in front, become suddenly attenuated, forming a narrow excretory duct which terminates at the apex of the hollow claw of the cheliceres.(4) With the Scorpionidae, this apparatus is situated in the last caudal segment; it consists of two oval vesicles, whose excretory ducts open at the apex of the sting situated on the end of the tail. These two glands are surrounded by a layer of flat, circular, smooth, muscular fasciculi.(51 With the Araneae, there is another and very remarkable secretory apparatus, - the Silk organs. Its product is a viscous, transparent liquid which hardens quickly on exposure to the air, forming threads. It escapes by three, rarely by two pairs of spinnerets, situated behind the anus.(6) The glands which secrete it are composed of transparent nucleolated cells, and are of very variable form and disposition, but always situated in the midst of the abdominal viscera. About five kinds of these glands may be distinguished, although not always simultaneously in the same individual. The threads have probably different qualities, according to the glands from which they are secreted. The genus Epeira, containing all these five kinds of glands, will serve as the type for their description. There are observed:(7) 1. Small pyriforin follicles, aggregated in groups of hundreds, and having short excretory 1 The two poison-glands of the Trombidiumr ho- 16, 17; Brandt, Mediz. Zool. II. Taf. XV. fig. 6,. losericeum, and Rhyncholophus phalangioides, or Ann. d. Sc. Nat. XIII. P1. IV. fig. 2; and. have the form of a ring with a small opening. Wasmann, loc. cit. p. 19, fig. 25, 26. For the inTreviranus (Verm. Schrift. I. p. 48, Taf. VI. fig. timate structure of these glands, see Meckel, in; 34) has described only very imperfectly these Miller's Arch. 1846, p. 35. glands with the first mentioned of these animals; 5 Miiller, in Meckel's Arch. loc. cit. p. 52, Tafand not having seen their excretory ducts, he took I. fig. 7, 8. Serres (loc. cit. p. 90) regards tha them for salivary glands. Dugis (Ann. d. Sc. portion of these glands which is surrounded by Nat. III. p. 10), on the contrary, perceived their muscular fibres, as a reservoir of poison, and that, true relation to the cheliceres. this last is secreted by innumerable glandular folli2 It is remarkable that these muscular fasciculi cles enveloping the muscular layer. In fact, with present such different histological characters. I Scorpio europaeus, I have seen this layer covered, have seen them distinctly striated with Lycosa, externally, with a stratum of cylindrical cells. Drassus, Tegenaria and Micryphantes. They 6 The Mygalidae have two pairs of these papillae, are smooth with Epeira, Thomisus, Clubiona or spinnerets, instead of six, the usual number. and Mygale; with Salticus, they present obscure 7 I speak here upon the careful investigations of transverse lines, so that I am undecided whether H. Meckel (Miiller's Arch. 1846, p. 50, Taf. III.. they belong to the first or to the second of these fig. 40-49). For the older descriptions, see Trecategories. viranus, Bau d. Arach. p. 41, Taf. IV. V., and 3 With Mygale, these glands are entirely con- Verm. Schrift. I. p. 11, Taf. I. fig. 4; and Brandt, cealed in the basilar article of the cheliceres. Mediz. Zool. II. p. 89, Taf. X V. fig. 5, or Ann d. 4 Treviranus, Bau d. Arachn. p. 31, Taf. II. Sc. Nat. XIII. p. 184, P1. IV. fig. 5. fig. 21, 22 i Lyonet, loc. cit. p. 397, P1. XX. fig. ~ 315. THE ARACHNOIDAE. 389 canals, which are interlaced in a screw-like manner, and open at the six spinnerets;(8) 2. Six long, flexuous tubes, which gradually enlarge into as many pouches, and are then continuous, each, into an equally long excretory duct which forms a double loop; 3. Three pairs of glandular tubes.similar to the preceding, but which open externally through short excretory ducts; 4. Two groups of multiramose follicles, whose pretty long excretory ducts run to the two upper spinnerets; 5. Two slightly ramified.caeca, varicose at intervals, and which terminate, by two short excretory ducts, in the middle spinnerets. Most Araneae have three pairs of spinnerets, that is, papillae in the form of an obtuse cone; the middle pair of these is composed of two, and the anterior and posterior pairs, of three articles. The apex of these papillae defines the passage of the thread, and is surrounded by. stiff bristles and hairs, and dotted with numerous small, horny tubes, which are only prolongations of the excretory ducts. Each of these tubes is composed of two pieces; one, basilar and thick, the other, terminal and very small, and through the orifice of which the web-liquid escapes in the form,of a very delicate thread.(') The number of these tubes varies according to the species, the age, and the sex.(~) Those belonging to the unbranched glands are distinguished from the others by their size. With some species of Clubiona and Drassus, there are, beside the usual six spinnerets, two others, composed of a single article and joined together. This fourth pair is situated on the belly, forward' of the others, and is connected with a kind of comb (Calamistrum) attached to the metatarsus of the two posterior legs. (11) With Phalangium, there is an S-shaped glandular tube situated on the digestive canal, and ending at both extremities by a narrow duct. Its nature is yet unknown; and although the outlet of these excretory ducts has not been discovered, yet as this apparatus is found only with males, it may well be supposed to have some connection with the genital functions.(l2) With some Acarina, there are certain phenomena indicating that these animals have special secretory organs, whose product, like the web-liquid, is hardened on its evacuation. Thus, with some species of the genus Uropoda, there is formed, by a substance of this kind, a peduncle situated at the posterior part of the abdomen, and by which these animals fix themselves to insects. This stalk, dilated disc-like, was taken formerly for an organ of suction.(3) Many species of Hydrachna fix, by a kind of glue, 8 nJ'ygale has only this one kind of glands; they cording to Blackwell (loc. cit.), with Clubiona form four groups, situated immediately at the base atrox, Drassus viridis. imus, parculus and ~eiof the spinnerets. guus. 9 The spinnerets and terminal tubes have al- 12 See Treviranus, Verm. Schrift. I. p. 37, Taf. ready been very exactly figured by Leeuwsnhoek III. fig. 17, h., and Tulk, loc. cit. p. 252, P1. IV. (loc. cit. p. 326, fig. 5, 6), and by Roesel (loc. cit. fig; 21. Taf. XXXYIII. fig. 4). See also Lyosnet, loc. cit. 13 See Degeer, loc. cit. p. 52, Taf. VII. fig. 16, p. 387, P1. XIX. fig. 6-12 * Wasmann, loc. cit. p. and Dugis, Ann. d. Sc. Nat. II. p. 30 (Uropoda 20, fig. 31-34, and H. Meckel, loc. cit. p. 54, Taf. vegetans). The peduncle is more or less long and III. fig. 43-45. often attached to the hardest parts of the Coleop10 There are more than a thousand of these tera. Its formation is connected with some metatubes on the spinnerets of Epeira; with Tegena- morphosis of these animals, and is without doubt ria, there are about four hundred; with Clubiona due to a secretion produced by some glandular ap and Lycosa, three hundred i with Segestria, one paratus opening near the anus. This view aphundred, and their number is even less with the pears, at least, more natural than that advanced small spiders; see Blackwell, Transact. of the by Dugis (loc. cit. p. 30), and adopted by DujarLinn. Soec. XVIII. 1841, p. 219, and Ann. of Nat. din (Comnpt. rend. loc. cit. p. 1160), that this peHist. XV. p. 221, and Menge, loc. cit. p. 24. duncle is formed by the feces hardening after their 11 This pair of accessory spinnerets is found, ac- escape from the anus. 33* 390 THE ARACHNOIDAE. g 316. the anterior portion of their body on aquatic plants, and in this position, wait the completion of their moulting.'14) The secreting organs of this substance have not yet been discovered. CHAPTER IX. ORGANS OF GENERATION. ~ 316. All tB e Arachnoidae reproduce by a sexual generation, and their male and female genital organs are situated upon different individuals. The eggs are fecundated in the genital organs of the females, and the males have often copulatory organs of a very singular character. The Tardigrada form an exception in this respect, being hermaphrodites, and wanting the copulatory organs. In general, the genital organs of the Arachnoidae are composed of the following parts. The ovaries or testicles are always double, but sometimes blended together on the median line. They are situated in the abdomen, and have two excretory ducts, which usually open at a common genital orifice at the base of the abdomen, or under the thorax. The ovaries, when filled with eggs, have always a botryoidal aspect. Only a few species have an ovipositor or a penis. The excretory ducts of both the ovaries and the testicles sometimes have appendages which, with the females, serve to receive the sperm, or to secrete a viscous substance for enveloping the eggs; and which, with the males, represent an epididymis or the seminal vesicles. Quite often, the males differ from the females in a special modification of their cheliceres, their palpi, or some of their legs. When this is the case, these organs serve, during copulation, to hold the females, or play the part of a penis. The eggs of the Arachnoidae are spheroidal, rarely oval,(1> and composed of a smooth chorion enclosing a vitellus consisting of vesicles filled with a colorless and, also, often highly-colored fat, in the midst of which is concealed the germinative vesicle. The germinative dot is sometimes simple, sometimes composed of a group of small granules.(2) The eggs of Lycosa, Thomisus, Diomedes, Salticus and Tegenaria, are remarkable; for, beside the germinative vesicle, they contain, before being filled with the vitellus, a peculiar, round, finely-granular, solid nucleus.(3) 14 According to Duggs (Ann. d. Sc. Nat. I. p. Clubiona and Salticus; see Wagner, Prodom. 170), Hydrachna cruenta, adult, before moulting,'&c. loc. cit. p. 8, Tab. I. fig. 11 (Epeira). bores into aquatic plants by means of its oral or- 3 This nucleus which appears to contain a cengans. But I have seen it fixed, also, upon smooth'tral nucleolus, is distinguished, with direct light, glass walls, with the parts of its mouth enveloped by its dirty-yellow color, and it has always apin a kind of cement. peared to me that there were detached successive1 The eggs are oval with the Oribatea and Scor- ly from its surface. several layers of granules pionidae. which mixed with the albumen, without the nucle2 The germinative dot is simple and flattened us diminishing in size. At all events, this nucleus with Scorpio, Thomisus, T'heridions, Micry- plays an important part in the development of the phantes, Lycosa, Phalangium, Obisium, Trom- eggs, for it appears very early, and does not disapbidium, Hydrachna, Ixodes, Oribates, Bdella, &c. pear until quite late. It has also been observed'It is composed of a group of granules with Epeira, 316. THE ARACHNOIDAE. 891 The lower Ara hnoidae produce only a small number of eggs at a time, but these are often of a size disproportionately large to that of the animal. (4) As yet, only very incomplete researches have been made on the elements of the Sperm. It appears, however, that the spermatic particles differ considerably in the various groups. Those of the Tardigrada have the; cercarian form; those of the Scorpionidae, on the contrary, are simply filamentoid. But both kinds have very active movements which are suspended by the contact of water.(5) The Sperm of the Araneae always contains spherical or reniform motionless corpuscles.6)) With the Aca — rina, the spermatic particles are motionless and of most varied forms.() by Wittich (Observ. quaed. de Aranearum ex ovo velopment, and that their definite form would be cerevolut. Dissert. Halis, 1845, fig. 1, A.).* carian. But I quickly abandoned this idea when I 4 With the Tardigrada, the eggs are very large, found the same form in the seminal receptacle of as are also those of Oribates, Sarcoptes and De- the females, where, evidently, the spermatic parti-~ modex. cles cannot be present except in their perfect state. 5 See Doydre, loc. cit. p. 354, P1. XVI. fig. 5 7 With Trombidium, Zetes, Oribates, and (Macrobiotus), and K6lliker, Schweiz. Denkschr. Hoplophora, the spermatic particles are developed,. VIII. loc. cit. p. 25, Taf. II. fig. 16 (Scorpio euro- as I have satisfied-myself, under the from of very paeus). I have observed that the characteristic small, rigid corpuscles, in very large cells. With movements of the spermatic particles ceased in- Bdella, they are produced in a similar manner, but stantly from contact with water, and that the par- are fusiform. With other Acarina they are found, tides themselves became twisted and doubled. of remarkable forms. Thus, in the testicles of the 6 With Tegenaria, Salticus, Lycosa and The- IHydrachnea and Gainamasea, I have observed round ridion, the spermatic particles have the form of masses of cuneiform bodies, at the larger extremity round cells, while those of Micryphantes and of which there was an oblong granular spot. I Clubiona are reniform or semilunar. They are have also satisfied myself that these motionless formed in groups in the mother-cells. With Tege- spermatic particles of such large size are preceded naria, a round nucleus is easily distinguished in the in their development by round nucleated cells. In spermatic particles. With Lycosa, this nucleus is the testicles of lxodes ricinus, I have seen countoblong, curved and attached to the wall of the cell- less transparent staff-like bodies, pretty long and and this led me at first to think these cells were large, motionless, but swollen at one of their exthe spermatic particles in their first stages of de- tremities when placed in water.t * [ ~ 316, note 3.] The development and struc- ture have been observed by both Wittich and ture of the eggs of Araneae have recently been Carus; they are composed of concentric layers carefully studied by Wittich (Die Enstehung des around a nucleus. Of their nature and function Arachnideneies im Eierstocke, die ersten Vor- nothing is known. -ED. giange in demselben nach seinem Verlassen des Mut- t [ ~ 316, note 7.] I have studied the developterkdrpers; in Miuller's Arch. 1849, p. 113), and ment and nature of the spermatic particles of the oy J. V. Carus (Ueber die Entwickelung des Spin- Araneae and Acarina, but with results different neseies, in Siebold and Killiker's Zeitsch. II. from those above mentioned. With the first of 1850, p. 97). The structure of the ovary of these these, they are developed, as usual, in special animals is no less beautiful than singular; it re- daughter-cells, and invariably consist of an arcuate sembles a bunch of grapes enclosed in a common staff; to which is attached a short but very, very capsule. The eggs are developed, each, on the ex- delicate tail; indeed, this tail is so tenuous that tremity of a pedicle which is attached to the main only the best and highest microscopic powers can stem or rachis. The details of the development of bring it out. It escaped the watchful eyes of Wagthe ova are briefly as follows: On the extrem- ner and Leuckart, and led them to adopt erroneity of the pedicle appears a delicate vesicle, or cell, ous views of the formation of these bodies (see which contains a nucleated cell. This nucleated Art. Semen, Cyclop. Anat. & Phys. fig. 374). cell is the germinative vesicle, with its dot, and With the Acarina, the particles have the same does not increase so rapidly in size as the vesicle form and character, but are much more minute and in which it is contained; but this last dilates and difficult of examination. It would appear from the expands, and minute cells appear in the liquid, description given above by Siebold, that he must lying between its membrane and the germinative have taken for spermatic particles the peculiar vesicle. These newly-formed cells constitute the granule-like bodies found in the sperm of the vitellus; and when the ovum is completely formed, Araneae. These bodies are very hydroscopic, but it consists of vitellus in which is concealed the are homogeneous, and although I could make out germinative vesicle with its dot. In a word, the nothing further as to their structure, yet it is eviovum is here formed as elsewhere, except that it is dent that they are wholly different from the true developed on the extremity of a pedicle. In regard spermatic particles, and cannot be considered as to the peculiar bodies mentioned above by Siebold, either undeveloped or modified forms of these last. as fould in the vitellus, their presence and struc- - ED. 392 THE ARACHNOIDAE. gq 317, 318, I. ~Hermaphrodite Arachnoidae. ~ 317. The Tardigrada have only a single, but large, ovarian tube, applied on -the posterior half of the digestive canal and opening into the cloaca. This last which is only a dilatation of the rectum, receives, also, two lateral, narrower, seminiferous tubes, together with the excretory orifices of a pyriform seminal vesicle. With Milnesium, Emydium, and Macrobiotus ursellus, the eggs are surrounded by a smooth chorion, and deposited in a solid epidermis which is detached during the moulting, - so that all the:eggs are finally contained in this envelope. But the other species of Macrobiotus shield their eggs in another manner, by surrounding each vith a very solid, granular capsule.(l) II. Female A rachnoidae. ~ 318. The female organs of the Acarina consist of two ovarian sacs, the ovi-,ducts of which open in a common vulva situated in the middle of the belly, or further forwards on the thorax, sometimes between, sometimes behind the last two pairs of legs.(L) With many of these animals, the oviduct opens into a protractile ovipositor by the use of which the eggs are lodged under the epidermis of plants or animals.t(2 A great number of Mites 1 For the genital organs of the Tardigrada, see cation with two short cylindrical glands filled with Doydre, loc. cit. p. 350, P1. XIII. XIV. XVI. transparent cells, and which secrete probably a.Goeze (Bonnret, Abhandl. aus d. Insekt. 1773, p. substance for enveloping the eggs. I have, more374), and 0. F. Miiler (in Fuessly, Arch. d. In- over, found with other Acarina (for example,with the sektenkunde, Hft. VI. p. 27, Taf. XXXVI. fig. 4, 5) Ilydrachnea, Gamasea, and Oribatea) various orhad already observed that the Tardigrada deposit gans belonging to the genital apparatus, but without -their eggs in their cutaneous envelope.* perceiving their relations as clearly as with Ixodes. 1 With the Gamasea, and Ixodea, the vulva is sit- However this may be, I am convinced that Dujar-.uated on the thorax; while, with the Trombidina, din (Ann. d. Sc. Nat. III. p. 20) goes too far in Bdella, lIydrachnea, and Oribatea, it is upon the saying that, with most Acarina, the eggs are develbelly; see Treviranus, Verm. Schrift. Taf. V. oped loosely in the parenchyma of the body, with(Hydrachna and Tromnbidium); Audouin, Ann. d. out the necessity of an ovary with proper walls..Sc. Nat. XXV. PI. XIV. J. Muller, Nov. Act. Nat. According to this same naturalist (Ibid.), the OribaCur. XV. Tab. LXVII.; and Treviranus, Zeitsch. tea are viviparous and have a large vulva which f. Physiol. IV. Taf. XVI. fig. 2 (Ixodes). For the can be closed by two lateral alae, and before which ovaries and oviducts of the Acarina, we have only is an' orifice closed also by a similar apparatus..the works of Treviranus,Verm. Schrift. I. p. 47 Taf. This last orifice belongs to a tube which Dujardin VI. fig. 32 E. q. (Trombidium), and Zeitsch. f. Phys- regards as a penis i so that the Oribatea would be iol. IV. p. 190, Taf. XVI. fig. 7, 8, 10, x.;. (Ixodes). hermaphrodites. As to the first point, - the viviparI have observed with Ixodes ricinus the following ity of these animals, I have verified it for Hoplopeculiarities, which were probably overlooked by phora, Zetes and Oribates; but I cannot say as Treviranus with Irodes americaneus. The two much of the second point, for, as I have satisfied. long ovaries anastomose arcuately at the posterior myself, the posterior orifice is an anus, and the extremity of the abdomen. The two oviducts, here anterior a vulva having an ovipositor. given off, open right and left into a pyriform uterus 2 For example, Hydrachnoa; see Diugis Ann. d. whose neck communicates laterally with a large Sc. Nat. I. p. 165. A parasitic mite long known.caecum coming from the vulva. This caecum is under the name of Hydrachna concharum or Lim-.divided by a septum into a posterior, or larger, and nochares anodontae, and which lives in the cavity an anterior, or smaller, portion. The first receives of the mantle of Anodontae, buries its eggs deeply the sperm which flows from the second during cop- in the skill of that organ; see Pffeifer, Naturg. -ulation, and thence passes into the uterus and even deutsch. Land u. Siisswasser-Mollusk. Abth. II.,into the oviducts. The anterior portion represents p. 27, Taf. I.; and Baer, Nov. Act. Nat. Cur. XIII. the vagina properly speaking, and is in communi- p. 590, Tab. XXIX. * [ ~ 317, note 1.] See also Kaufmann (loc. eggs from their first stages, in the ovary of Macro -it. in Siebold and KellikeI's Zeitsch. III. 1851, liuLs Dujardin. - ED.,p. 220), who has studied the development co" the ~ 318. THE ARACIINOIDAE. 393 surround their eggs, grouped together, with a tough coagulable substance, and glue them to various bodies. It is, therefore, very probable that there are special organs for the secretion of this substance.'3) As yet, we have no observations on the internal genital organs of the Pycnogonidae, although, for a long time, the females have been recognized by their filiform oiphores, composed of nine to ten articles, and situated in.front of the first pair of legs. (4) With the Phalangidae, the two ovaries are blended together, and form a flexuous tube occupying a large portion of the abdomen and continuous anteriorly into two short oviducts. These last unite in a large oviduct situated, loop-like, in the posterior extremity of the abdomen, between the -convolutions of the ovaries. Its anterior extremity receives a second ovi-,duct, which, after describing numerous convolutions, opens in a horny, articulated ovipositor. This last can be protruded between the posterior legs by means of a special muscular apparatus, on the under side of which,are two caeca opening into the oviduct at the base of the ovipositor. These organs are either seminal receptacles, or the secretory organs of a viscous substance.(5) rTith most Araneae, the two oblong ovaries are concealed between the hepatic lobes, and open by the intervention of two short oviducts, into a vagina situated between the two pulmonary sacs. This vagina is supported by a horny plate, and opens externally through a transverse fissure, after having previously received the excretory ducts of the two contiguous Beceptacula.semninis. These last are pyriform and nearly always composed of a deep-brown, horny substance; they are attached to the cutaneous envelope, and have, each, an equally horny excretory duct which is more,or less long and interlaced with the corresponding one on the other side.(6) The females surround their eggs in groups, with a web, so that they have ao organs for secreting a viscid substance. The Epeiridae offer a remarkable modification in their external genital organs. The entrance to their vagina is covered by a horny process, directed from before backwards, and at the base of which there are pyriform, pedunculated, seminal reservoirs. (7 It is yet undetermined whether this process is connected with the act of copulation, or with the deposition of the eggs. The Scorpionidae have three ovaries consisting of as many longitudinal *tubes united by fofr pairs of transverse ones. ThQ two external of the former tubes are continuous anteriorly as oviducts, and unite in a short vagina which opens at the base of the abdomen. Before their junction, the oviducts dilate into a round pouch, which, as it sometimes contains the sperm, may be regarded as a Receptaculum seminis.(s') 3 For example, Eylais, Limnochares, and Di- paid no attention to these organs. The seminal plodontus. receptacles are short and pyriform with Lycosa, 4 See Johnston, Magaz. of Zool. I. p. 370 P1. Theridion, and Micryphantes; but they have a XIII.; ]Milne Edwards, Hist. Nat. d. Crust. P1. long excretory duct entwined with its opposite, with XLI. fig. 7 i and Philippi, in Wiegmann's Drassus, Salticus, and Thomisus. Arch. 1843, I. p. 177, Taf. IX. With Phoxichi- 7 This process is S-shapedwithEpeira diademna. lidium, the two o8phores are only five articled. It has been described and figured by Leeuwen5 See Treviranus, Verm. Schrift: I. p. 34, Taf. hoek, loc. cit. p. 336, fig. 8 5 Roesel, loc. cit. p. IV. fig. 20, 23 i also Tulk, loc. cit. p. 318, P1. V. 253, Taf. XXXVII. fig. 1, b. and Taf. XXXVIII. fig. 26-29. fig. 1, 3; and by Degeer, loc. cit. p. 85, Tat 6 Treviranus (Bau d. Arachn. p. 37, Taf. IV. XII. fig. 10. See, also, Treviranus, Bau d. fig. 32) has figured very correctly the ovaries and Arachn. p. 39, Taf. II. fig. 18, c.- and Savi;ny, their oviducts. He has even seen the Receptacula Descript. de l'Egypte, loc. cit. P1. II. fig. 8 m. With seminis, but he mistook them for cartilaginous Nephilafasciata, this process is tongue-shaped. bodies (Ibid. p. 38, Taf. II. fig. 20, o. and Taf. IV. 8 The female organs of the Scorpionidae have fig. 40, o. 41). The anatomists who succeeded him been described by MIeckel (Beitr. loc. cit. p. 113, 394 THE ARACIiNOIDAE., 319. II. Macle Arachnoidae. ~ 319. From the few observations hitherto made upon the male organs of, the Acarina, it appears that they are formed after very different types. With Trombidium, there are twenty red, testicular vesicles, attached by short peduncles to the annular Vas deferens which opens between the posterior legs. This last. before its termination, receives also two brown, longpedunculated vesicles, whose nature is yet unknown.(1) With Ixodes, the testicles consist of a group of four to five pairs of longer or shorter follicles, which unite in the middle of the abdomen, and send off two small Vasa deferenria to the base of the chin-like process. This last, together with the cheliceres, these animals introduce deep into the vagina during copulation, while their two palpi, separated at a right angle, are applied upon the thorax of the female.(2) With Gamasus, there appear to be only two simple, isolated, testicular follicles, each having a deferent canal. With many Acarina, there is a short penis situated at a point corresponding to that of the vulva of the females, and sometimes concealed within the body.t3) With other Acarina, the males are distinguishable from the females, by the larger size of their cheliceres, and some of the legs which serve to retain the females during copulation.(4) With the Phalangidae, the testicles consist of numerous small caeca, all united at one point into a long, flexuous deferent canal. This last is continuous into a Ductus ejaculatorius which traverses a muscular penis; this terminates with a hook-like gland, and its body is horny and surrounded by a muscular sheath out of which it can be protruded under the thorax.(5> With many Opilionina, the posterior legs have remarkable spines and excrescences which, undoubtedly, are used during copulation.'6) With the Araneae, the testicles consist of two long, simple, interlaced caeca, concealed between the hepatic lobes.) From them pass off two Taf. VII. fig. 18-20); Treviranus (Bau. d. dorsal shield covering the whole body, palpi shorter, Arachn. p. 12, Taf. I. fig. 12), and Miiller (loc. cit. and teeth less numerous upon the also shorter chin p. 53 Taf. II. fig. 14-19). This last naturalist has like process. found, with the large African scorpions, eggs in the 3 The penis is sub-ventral with Bdella, sub-tholateral long, varicose and caecal appendages of the racicwith Gamasus, ahd behind the genital orifice ovaries. These appendages do not increase in size with Oribates. With.4rrenurus, it is inserted except in proportion as the eggs are developed; on a tuberosity of the abdomen, giving the males a while, with the small European scorpion, the eggs very singular appearance (Duges, loc. cit. I. p. produce only simple pyriform folds on the ova- 155, P1. X. fig. 20). rian tubes. I have found sperm and very active 4 With the males of certain species of Gamasus, spermatic particles in the seminal receptacles of the two cheliceres are perforated, and the second living females of Scorpio europaeus. pair of legs is very stout and provided with spines 1 I have proved this complicated disposition of and excrescences. With Dermaleichus, it is the the male organs with Trombidium. holosericeum, third pair of these organs which is sometimes very where it had been wholly misapprehended by large and armed with robust nails. With SarcopTreviranus (Verm. Schrift. I. p. 48, Taf. VI. fig. tes, the posterior legs are long and armed with 35). nails and discs, while with the females these same 2 This singular mode of coition had already been legs are abortive. observed by Degeer (loc. cit. p. 45, Taf. VI. fig. 5 Treviranus, Verm. Schrift. I. p. 36, Taf. IV. 6) with Ixodes ricinus, and subsequently by Ph. fig. 21, 22 i and Tulk, loc. cit. p. 250, P1. IV. fig. W. J. Miiller (Germar's Magaz. d. Entomnol. II. 21-24. 1817, p. 281) but it remained wholly unobserved 6 With Eusarcus, Gonyleptes, &c. The very by the other entomologists. It appears that the large cheliceres of the Phalangidae are not used in male of Ixodes ricinus, which differs considerably the act itself of copulation, but are employed to from the female, has been mistaken for a different fight with on these jealous occasions; see Latreille, species and named Ixodes reduvius (Audouin, Hist. Nat. d. Fourmis, p. 380. loc. cit. XXV. p. 422, P1. XIV. fig. 4), or Irodes 7 For the testicles of the Araneae, see Treviramarginalis (HIahn, Die Arachn. II. p. 63, fig. nus, Bau d. Arachn. p. 37, Taf IV. fig. 33, and 153). The characters peculiar to this sex are, a Brandt, Vlediz. Zool. II. p. 89, Taf XV. fig. 7. { 319. THE ARACINOIDAE. 395 deferent canals to the base of the abdomen where, between the two pulmonary sacs, there is a genital opening in a small horny plate. This opening is only a simple transverse fissure which, in copulation, does not come in contact with the vulva of the female. These animals always use their hollow, spoon-shaped palpi, which often have a very complicated structure. They are filled with sperm and applied to the entrance of the vulva. For this purpose, the last article of the palpi, which is always hollow and much enlarged, contains a soft spiral body terminated by a curved, gutter-like, horny process. Beside this, there is an arched, horny filament, and several hooks and other appendages of the most varied forms.'These appendages are protractile, and serve, some to seize the female, and others as conductors of the sperm.(8) Vlrith the Scorpionidae, each of the two testicular tubes forms.a loop enveloped by the substance of the liver, and connected with its mate by two transverse canals. The anterior border of each of these loops sends off a short Vas deferens which opens at the base of the abdomen, receiving in its track two caeca of unequal length. Of these, the longer contains a granulo-vesicular substance, and is, perhaps, an accessory gland.; while the shorter, from the character of its contents, is evidently a Vesicula seminaZis. (9) A deeply crenated, small papilla projects out of the genital orifice, and, as it is wanting with the females, may be regarded as a 8 For a long time, the excretory point of the Vasa ranus, Ban d. Arachn. p. 37, Taf. IV. fig. 35deferentia was undetermined, because the two 37; Brandt, Mediz. Zool. II. p. 87, Taf. XV. fig. sexes of these animals had never been seen to place 1; Savigny, Descript de 1'Egypte, Pl. I.-VII.; in contact these genital orifices during copulation. Menge, loc. cit. p. 35, Taf. III. fig. 13-27But when it was discovered that only the palpi of Treviranus (Bau d. Arach. p. 33) has made an the males touch the vulva, the excretory ducts of exposition of the older opinions of Lister, Lyonet, the testicles were sought in these palpi. It is only Clerk, and Degeer, on the copulation of these ali recently, however, that it has been perceived, that mals; but he regarded the act as only a prelude with these animals, as with the Libellulidae (see my for exciting the sexual desires, and which would ba memoir in Germar's Zeitsch. f. d. Entomol. II. p. followed by a real copulation, consisting of the con 423), the copulatory organ and the Vesicula semi- tact of the male and female genital orifices. Morenalis are entirely removed from the male genital over, Treviranus had never observed this last act. orifice. In order to be convinced that the applica- The more recent observers, such as.Duges (Ann. tion of the male palpi against the female vulva d. Sc. Nat. VI. p. 187), Menge (loc. cit. p. 36), and constitutes really the act of copulation, it is only Blackwall (Annals of Nat. Hist. XV. p. 225), have necessary to examine the palpi under the micro- naturally only confirmed the views of the older natscope and compress them. From the last article a uralists. According to Menge. the males of Linlarge quantity of sperm will be seen to escape. yphia and Agelena evacuate a drop of sperm from Then again, after copulation, the Receptacula sem- their genital orifice, which is then received and inis of the females will be found filled with the absorbed by the last article of their palpi.* fluid. The form of the palpi with the males varies 9 For the male organs of the Scorpions, which almost infinitely according to the genera and spe- have been very imperfectly described by Treviracies. They are very simple and slightly swollen nus (Bau d. Arachn. p. 22, Taf. I. fig. 11), see with Clubiona and Lycosa, while, with Epeira, Meckel (Beitrag. loc. cit. p. 114, Taf. VII. fig. 14), Tegenaria, Linyphia, Micryphantes, Salticus, Serres (loc. cit. p. 89) and Miuller (loc. cit. p. 59, lArgyroneta, &c., their last article is so complicated Taf. I. fig 8). I have seen distinctly with living that the most minute description would be inade- individuals of Scorpio europaeus, spermatic parquate in giving an exact idea of it; see the figures tides in motion in the small caeca which I have of Lyonet, loc. cit. p. 383, Pl. XIX. XX.; Trevi- called the seminal vesicles. * [~ 319, note 8.] I have made a microscopic 316, note 7). As the most repeated and carefdl examination of this curious palpus-structure in examinations showed no spermatic particles in this connection with the general structural relations of palpus-capsule, I was led to advance the view that the internal genital organs, in some of the common the palpi were only excitatory and not intromittent Araneae (Tegenaria, Agelena, &c.) where this organs, in the copulatory act (see Proceed. Boston formation is most marked. In Agelena, the pecu- Soc. Nat. Hist. IV. 1851, p. 106). But the question liar, corkscrew-like, horny process, situated in is still open, and especially as some recent investithe last, spoon-shaped article of the palpus, con- gators of the economy of these animals have observec tains a canal throughout, which commences in facts that would indicate the intromittent function a kind of receptaculum at the base of the pro- of these organs; see particularly, Blackwall, Ann. cess. This receptacle is filled with the peculiar Nat. Hist. passim, for several.years past. -ED. granule-like bodies mentioned above (Note to ~ 396 THE ARACHNOIDAE. ~ 320. rudimentary penis. It is yet undetermined if the two external, lateral, pectiniform appendages situated near the genital orifice in both sexes, serve any purpose during copulation.(10) ~ 320. Te have, as yet, only insufficient observations on the Development of the Arachnoidae. However, those that we possess upon its first stages,(1) show that, with few exceptions,t2) here as with the Crustacea, the disappearance of the germinative vesicle is followed by a superficial and partial segmentation of the vitellus. There is thereby formed a thin embryonic layer, composed of molecular corpuscles retained in a transparent viscid liquid, and distinguished from the rest of the vitellus by its white color. While this oval blastoderma, whose longitudinal axis corresponds to the ventral or nervous side of the embryo, extends towards the sides and the back, it divides into an external or serous, and an internal or mucous lamella, the last of which gradually covers the remaining portion of the vitellus, and becomes changed into the digestive tube and its appendages. In the mean while, there appear, on the external surface of the serous lamnella, various symmetrical prominences and projections, which in time become the segments of the body, the parts of the mouth, the tactile, and the locomotive organs. With the exception of the Scorpionidae, and Oribatea, which are viviparous, the embryos of all the Arachnoidae are developed subsequent to the deposition of the eggs.(3) With the majority of Arachnoidae, the embryos, at their escape from the egg, have the form of the adult.(4) The lower orders, only, form an exception in this respect, for they acquire their definite form after several moultings, and a true metamorphosis. With the Pycnogonidae, these I0 Tulk (Ann. of Nat. Hist. XV. p. 56) has that the same phenomena occur as with most of the lately expressed the opinion that these combs serve other Arachnoidae.* to clean the palpi, the tarsi, and the extremity of 2 I have distinctly seen, in the eggs of Macrobithe tail. He adduces, as proof, the presence of otus Hutfelandii? the segmentation involve the entransparent combs of exactly identical form, with tire vitellus. Kblliker (Miiller's Arch. 1843, p. 136) Obisium, between the pincers of the cheliceres, and has madeithe same observation with Pycnogonum.t which are used for this purpose. 3 The relations of the Scorpionidae in this respect 1 The first phases of development have not are very remarkable, for their embryos are devel been observed as yet except with the Araneae and oped in the ovaries at the spot even where the eggs Scorpionidae; see Herold, De Generat. Aranear. are formed * see ]Iiiller, loc. cit. p. 55, and Rathki., in ovo, 1824; RatfLhk, Zur. Morphol. Reisebemerk. Zur Morphol. loc. cit. It is evident that the sperm aus Taurien, 1837, p. 17, and in Burdach's must ascend from the two seminal reservoirs into Physiol. II. 1837, p. 242; the same in Froriep's the ovaries to fecundate the eggs. With the Orineue Notiz. XXIV. 1842, p. 165 (Lycosa sac- batea, the embryos appear to be developed in a cata) ); also Kolliker, in Mliiler's Arch. 1843, p. kind of uterus situated immediately behind the 139 (Scorpio europaeus); finally, Wittich, Observ. ovipositor. quaed. de Aranear. ex ovo evolut., Halls. 1845, fig. 4 With the Araneae, the sexual differences which 1, A. As to the development of the Acarina, I are so striking io not appear until after the first have satisfied myself upon the eggs of the Oribatea, moulting. [~ 320, note 1.] See, also, Wilson, Researches Tardigrada, see Kaufmann, loc. cit. in Siebold into the structure and develop. of a newly-discov- and Koilliker's Zeitsch. III. 1851, p. 220. The ered parasitic Animalcule, &c., in the Philos. Trans. type of development is like that of the Articulata in 1844, p. 305 (Entozoon (Demodex)folliculorum), general, and this would seem to clearly settle the and Van Beneden, Recherches sur l'Atax upsilo- position of these animals in this class. Kaufphora, in the M4m. de PlAcad. Roy. de Bruxell. mann confirms the observation of Siebold as to XXIV. Wilson's details are imperfect, and throw the segmentation of the entire vitellus. After this but little light on the real character of the develop- process has occurred, the mulberry like mass is ment of the follicle-parasite. It would appear, -hanged into the embryo, exactly as is observed however, to be truly one of the Arthropoda. - ED. with the eggs of the Araclmoidae in general. - ED. t [ ~ 320, note 2.] For the embryology of the ' 320. THE ARACHNOIDAE. 897 changes should be most prominent, for their embryos have a short unarticulated body, and, beside the cheliceres, are provided with only four bi- or tri-articulated feet. There is, however, a very long lash, attached, sometimes to the two cheliceres, sometimes to each of the four legs. It is not until after successive moultings, that the other legs, the divisions of the body, and the extremities, appear.t) With Ernydizumn,(6 and most of the Acarina, the embryos have only six legs, when hatched; but as they otherwise resemble the adults, their metamorphosis consists only in the appearance of another pair of legs. A true metamorphosis is observed only with Hydrachna. Here the embryos have a very long and large snout which might easily be taken for a head distinct from the trunk.(7 This disproportion between these two parts is subsequently reversed, when the young pierce with their snout the bodies of insects, while their own bodies, gorged with food, become of a monstrous size. These young have six legs, and, during their parasitic life, were for a long time described as distinct species under the generic name Achlysia, until it was discovered that they possessed eight legs after their first moulting. (8 Similar metamorphoses occur with the Trombidia which, as red, hexapod larvae, are attached to flies, grasshoppers, plant-lice and various other terrestrial insects. These, also, have been formed into proper genera under the names of Astoma, Leptus, and Ocypeta.'8) * / See Kroyer, Naturhist. Tids. III. 1840, p. found these red Achlysiae with monstrous bodies on 299, or Isis, 1841, p. 713, Taf. III. Tab. III. or the dorsal surface of the abdomen of Dytiscuts and Ann. d. Sc. Nat. XVII. p. 288, P1. XIII. B. Hydrophilus. Others, smaller, were observed even 6 See Doyere, loc. cit. p. 358. The embryos of more frequently upon the segments of the body and the other Tardigrada have four pairs of legs. the articles of the extremities, with Nepa, and Ra7 See Dug-s, Ann. d. Sc. Nat. I. p. 166, P1. XI. natra. The true nature of these epizoa has been fig. 47. It follows clearly from the position of the cleared up by Burmeister (Isis, 1834, p. 138, Taf. eyes, which are situated not upon this snout, but I. fig. 1-6), and by Duses (Ann. d. Sc. Nat. I. upon the cephalothorax, that this snout is only a 1834, p. 166, P1. XI. fig. 49-55). support of the parts of the mouth, and not a head. 9 See Gervais, in Walckenaer, Apteres, &c., III. 8 See XAudouin, Mim. sur l'Achlysie in theMim de p. 178. la Soc. d'Hist. Nat. de Paris, I. p. 98, Pl.V.No. 2). He * [~ 320, end.] There is some ground for the the Icarus muscarum of Degeer, and the Hlypoopinion that alternation of generation, so called, pus of Dugis. It has neither mouth nor digestive occurs with some of the Arachnoidae. Dujardin apparatus, but simply adheres to the animal on (Ann. d. Sc. Nat. 1849, XI. p. 243) has examined which it lives, by a sucker. It may be the nurse the wall-mite found on the house and other flies - of a Gamasus.- ED. 34 BOOK FOURTEENTH. INS ECTA. CLASSIFICATION. ~ 321. As anatomists have been able to examine, with few exceptions, nearly all the orders and families of the Insecta, their anatomical researches have not been restricted, as. in the preceding classes, to isolated genera or species, but have embraced entire families. With such abundant materials, we should go beyond the limits of our work in enumerating here all the genera, or even all the families, whose organization has been studied. A. INSECTS WITHOUT METAMORPHOSIS. (Insecta ametabola.) ORDER I. APTERA. FAMILIES: PEDICULIDAE, NIRMIDAE, PODURIDAE, LEPISMIDAE. B. INSECTS WITH INCOMPLETE METAMORPHOSIS. (Insecta hemimetabola.) 1. M O U T H S U CTO R I A L. ORDER II. HEMIPTERA. FAMIIJES: COCCIDAE, APHIDIDAE, PSYLLIDAE, CICADIDAE, CERCOPIDA;, NAUCORIDAE, NEPIDAE, COREIDAE, PENTATOMIDAE. 2. MOUTH MANDIBULATE. ORDER IlL. ORTHOPTERA. FAMILIES: PHYSOPODA, FORFICULIDAE, PSOCIDAE, PERLIDAE, EPHEMERIDAE, LIBELLULIDAE, TERMITIDAE, ACRIDIDAE, LOCUSTIDAE, ACHETIDAE, PHAShIIDAE, MANTIDAE, BLATTIDAE. 321. THE INSECTA. 399 C. INSECTS WITH COMPLETE METAMORPHOSIS. (Insecta holometabola.) 1. M oUTH SUCTORIAL. a. Two wings. Under lip changed into a suctorial organ. ORDER IV. DIPTERA. FAMILIES: PULICIDAE, NYCTERIBIDAE, HIPPOBOSCIDAE, MUSCIDAE, OESTRIDAE, SYRPHIDAE, CONOPIDAE, STOMOXYDAE, BONMBYLIDAE, ANTHRACIDAE, LEPTIDAE, HENOPIDAE, ASILIDAE, STRATIOMYDAE, TABANIDAE, TIPULIDAE, C ULICIDAE. b. Four scaly wings. Maxillae changed into a suctorial organ. ORDER V. LEPIDOPTERA. FAMILIES: TINEIDAE, PYRALIDAE, GEOMETRIDAE, NOCTUIDAE, BOMBYCIDAE, HEPIOLIDAE, ZYGAENIDAE, SPHINGIDAE, PAPILIONIDAE. c. Four naked wings. Tongue changed into a suctorial organ. ORDER VI. HYMENOPTERA. FAMILIES: APIDAE, ANDRENIDAE, VESPIDAE, FORMICIDAE, SCOLIADAE, MUTILLIDAE, POMPILIDAE, CRABONIDAE, BEMBECIDAE, CHRYSIDIDAE, CYNIPIDAE, ICHNEUMONIDAE, SIRICIDAE, TENTHREDINIDAE. 2. MOUTH MANDIBULATE. a. Two posterior wings only. ORDER VII. STREPSIPTERA. b. Four membranous wings. ORDER VIII. NEUROPTERA. 3FAMILIES: PHRYGANIDAE, SIALIDAE, HEMEROBIDAE, MYRMELEONIDAE, RHAPHIDIADAE, PANORPIDAE, MANTISPIDAE. c. Two upper wings corneous, and two under membranous. ORDER IX. COLEOPTERA. FAMILIES: PSELAPHIDAE, COCCINELLIDAE, CHRYSOMELIDAE, CERAMBYCIDAE, CURCULIONIDAE, CISTELIDAE, MELOIDAE, TENEBRIONIDAE, PYROCdHROIDAE, ELATERIDAE, LAMELLICORNES, CLAVICORNES, EIYDROPHILIDAE, HYDROCAN. THARI, STAPHYLINIDAE, CARABIDAE. 400 THE INSECTA. g 321. BIBLIOGRAPHY. MRaumur. Mlmoires pour servir a l'histoire des Insectes. 1734. Roesel. Insekten-Belustigungen. 1746. Swammerdamm. Bibel der Natur. 1752. Lyonet. Traite anatomique de la chenille, que ronge le bois de saule,. 1762, and Anatomie de differentes especes d'Insectes, in the Mem. dut Museum, &c., XVIII.-XX. 1829-32. Degeer. Abhandlungen zur Geschichte der Insekten. 1776. Meckel. Beitrage zur vergleichenden Anatomie. 1808. Gaede. Beitrage zu der Anatomie der Insekten. 1815. Suckow. Anatomisch-physiologische Untersuchungen der Insekten uncl Krustenthiere. 1818. Straus-Durckheim. Considerations generales sur l'Anatomie compar~e des animaux articules. 1828. Kirby and Spence. Introduction to Entomology, 1816-28, or its translation into German by Oken, 1823-33. Burmeister. Handbuch der Entomologie. 1832. Brandt and Ratzeburg. Medizinische Zoologie. Bd. II. 1833. Ratzeburg. Die Forstinsekten, 1837. Lacordaire. Introduction a l'entomologie. 1834-38. Westwood. An introduction to the modern classification of Insects. 1839. Newport. Article Insecta, in the Cyclopaedia of Anatomy and Physiology, II. 1839. Leon Dufour. Recherches anatomiques et physiologiques sur les Hemipteres, 1833; and, Recherches anat. et physiol. sur les Orthopteres, les Hymenopteres et les Neuropteres, 1841. Both of these are in the Mem. a l'Acad. royale d. Sc. de l'Institut. de France, IV. VII. Nicolet. Recherches pour servir t l'histoire des Podurelles, 1841, in the Neue Denkschr. der allg. schweizer. Gesellschaft, &c. Bd. VI. ADDITIONAL BIBLIOGRAPHY. Dufour. ]tudes anatomiques et physiologiques, sur une Mouche, in the MIem. de l'Instit. IX. 1846, p. 545. - Recherches anatomiques et physiologiques sur les Dipteres, in Ibid. XI. 1851, p. 171. See also his various communications on the anatomy and metamorphosis of different Insecta, in the Ann. d. Sc. Nat. VII. 1847, p. 5, and p. 14; VIII. 1847, p. 341; IX. 1848, p. 91, 199, 205, 344; XIV. 1850, p. 179; XVII. 1.852, p. 65. Blanchard. De la Circulation dans les Insectes, in the Ann. d. Sc. Nat,. IX. 1848; p. 359 -also in extract in the Comp. rend. XXIV. 1847, p.. 870, or in the Ann. Nat. Hist. XX. 1847, p. 112, or in Schleiden and, Froriep's Not. LXVI. 1847, p. 342. Nouvelles observations sur la circulation du sang et la Nutrition, chez les Insectes, in the Ann. d. Sc. Nat. 1851, XV. p. 371. Stein. Vergleichende Anatomie und Physiologie der Insekten. In Monographieen, Erste Monographie: Die weiblichen Geschlectsorgane. der Kafer. Mib. 9 Kupertafeln. Berlin, 1847. g~ 322, 323. THE INSECTA. 401 Siebold. Ueber die Fortpflanzung von Psyche: Ein Beitrag zur Naturgeschichte der Schmetterlinge — in Siebold and K(lliker's Zeitsch. I. 1848, p. 93; see, also, for further researches on the subject, his Bericht fib. die entomrol. Arbeiten d. schles. Gesellsch. in J. 1850, or its transl. in the: Transact. of the Ent. Soc. I. 1851, p. 234. Leydig. Die Dotterfurchung nach ihrem Vorkommen in der Thierwelt und nach ihrer Bedeutung, in the Isis, 1848, Hft. 3. Einige Bemerkungen fiber dei Entwickelung der Blattl;use,, in Siebold and K(lliker's Zeitsch. 1850, II. p. 62. - - Anatomisches und Histologisches fiber die Larve von Corethra. pluinicornis, in Ibid. III. 1852, p. 435. - Zur Anatomie von Coccus hesperidum, in Ibid. V. 1853, p. 1. Meyer. Ueber die Entwickelung des Fettk6rpers, der Tracheen und der Keimbereitenden Geschlechtstheile bei den Lepidopteren, in Sieboldi and K lliker's Zeitsch. I. 1849, p. 175; see also the Mitth. d. naturf. Ges. in Zurich, Hft. 2, p. 206. See, also, the various writings referred to in my notes. - ED. CHAPTER I. EXTERNAL ENVELOPE AND CUTANEOUS SKELETON. ~ 322. The cutaneous envelope of the multi-articulate body of the Insecta consists, as with the other Arthropoda, of a kind of external skeleton, of a consistence sometimes leathery and soft, sometimes horny and solid..Its elasticity and flexibility is limited to the points of junction of the segments of the body, and of the articles of the extremities. Its characteristic' chemical substance is likewise chitine, a peculiar azotic matter insoluble inl caustic potass, and with which highly-colored pigments are often chemically combined.( Chitine enters also into the composition of the hairs and the scales of the skin, and the internal processes which "may be regarded as an; Internal Skeleton. ~ 323. Histologically, the cutaneous envelope is so variously and often so ex1 See Odier, MWm. de la Soc. d'IIist. Nat. de cutaneous skeleton is probably due to an oilt Paris, i. loo. cit.; Lassaigne, Compt. rend. XVI. with which the chitine is impregnated, especially 1843, pI. 1087, or Froriep's neue N otiz. XXVII. p. with the -Coleoptera. 7, and Schmidt, Zur vergleich. Physiol. &c. p. See Bernard-Deschamps, Sur les Elytres des 32. Lassaigne has proposed for this substance Colioptires, in the Ann. d. So. Nat. III. 1845i p. the name Entonioderm. The coloration of the 354.* * [ ~ 322, note 1.] Recent researches have and Wiegmann's Arch. 1850, p. 253 i Schultze, shown that the peculiar substance Chitine is not Beitr. zur Naturgesch. d. Turbellarien, p. 33; ands limited in its distribution to the Arthropoda, for it. Leuckart, Morphol. der wirbellosen Thiere, p. 4% has been found in nearly every class of the Inver- in Siebold and KSlliker's Zeitsch. 1851, p. 191s tebrata. See Grube, Miiller's Arch. 1848, p. 461, and in Wiegmann's Arch. 1852, p. 22. —ED. 34* 402 THE INSECTA. ~ 323. traordinarily complicated, that it is very difficult to recognize its elements. When horny, there can always be distinguished an epidermis composed of nnucleated, lamellated cells intimately blended together. These cells, however, are often polyhedral, and so disposed as to form a simple layer; in other cases, they are more or less blended together, giving rise to undulating or imbricated lines in the epidermis. In crder to study the subjacent layer, or dermis, the cutaneous envelope must be macerated and decolored in caustic potass. This layer will then be found to be composed usually of several lamellae superposed in various ways and thereby often producing very elegant markings. In many instances, these reticulated or radiated markings would indicate the presence here of intercellular passages, and porous canals.(' In the thin, membranous portions of the skeleton, for instance, the wings, the structure usually appears wholly homogeneous. On the external surface of this envelope there are o en numerous excrescences, such as tubercles, spines and hairs, which are usually hollow. The hairs are sometimes simple and smooth, sometimes set with small hairs -or barbellate.(2) Many of these cutaneous formations are inserted by a:small peduncle in small fossae, to which they loosely adhere, and from which they are very readily detached. Usually, they are fattened, scale1 Histological researches upon the cutaneous one of which is provided with denticulations pointskeleton have, as'yet, been extended over only a ing upwards, while the opposite one is loosely infew species. I am able to cite only the works of serted in a small fossa, so that they are detached H. Mleyer (Miil/er's Arch. 1842, p. 12 (Lucanus without breaking from their fastenings by the least cervus), and of Platner (Ibid. p. 38, Taf. III. contact. The deep-colored spots observed on the (Bombyx mori). back of the processionary moths, and which are di2 These barbellate hairs are found with the lar- vided into four parts by crucial lines (Ratzeburg, vae of all the Bombycidae (Reaumur, Mim. &c. Die Forstinsekt. loc. cit. Taf. VIII. a fig. 1.L and Tom. I. P1. VI., and Degeer, Abhandl. I. Taf. 1. 1), consist of callosities on which are situated IX.-XIII.). thousands of these small fossae from which arise an They are easily rubbed off, and when brought in infinite number of hairs. With many birds and contact with our skin, they insinuate themselves insectivorous reptiles, the hairs of the moths which by the truncated extremity, and thereby often pro- these animals have eaten, traverse the mucous voke an insupportable itching or even an inflamma- membrane of the stomachs and enter the tissues. tion. The processionary moths are so much feared I should not have thus mentioned this subject, in this respect as to pass for being poisonous; see since for a long time the true nature of the hairy JNicolai, Die Wander-oder Prozessionsraupe, 1833, stomachs of old cuckoos has been understood (see p. 21, and Ratzeburg, Du Forstinsekten, II. p. the discussion on this subject between Brehm, 127, Taf. I. fig. il, 12, and Taf. VIII.a. The Richter, Carus, Oken, and Bruch, in the Isis, -pains which these hairs can produce with man, may 1823, p. 222, and 666, Taf. VIII., also, 1825, p. be judged by the disease which Ratzeburg suffered, 579, Taf. IV.), if, recently the passage of hairs and of which he has given an account (Entom. from the digestive tube into the mesentery of frogs Zeit. 1846, p. 35). had not given rise to a similar error. The mesentery The symptoms spoken of by this excellent ento- of these reptiles very often contains fragments of,mologist may be explained without attributing any hairs and the spines of insects, surrounded by conspecific poisonous property to these hairs, if it be centric layers of connected tissue and thus arrested considered that, like a fine powder, they rest on the in their course. These encysted hairs have been skin and may enter the respiratory organs by described by Remako (Miiller's Arch. 1841, p. inhalation, and penetrating the tissues encoun- 451) under the name of parasitic enigmatical horny ter a multitude of nervous fibres. Their passage fibres, while Mayer at Bonn has gone so far as to into the tissues is the more easy, since they alre take them for Pacinian corpuscles (Die Pacinischen fusiform, very sharp at both extremities, the free Korperchen, 1844, p. 14, fig. 2).* * [ ~ 323, note 2.1 Will (Schleiden and Fro- vided, and in the hairs. These hairs were mostly riep's Not. 1848, Aug. p. 145) has made chemico- hollow, and their cavity was not closed at their microscopical investigations upon the nature of this base, but passed through the skin and appeared peculiar poisoning power manifested in the proces- connected with glands below. These observations sionary moths i his researches were upon Bombyx are the more interesting since this same observer has.processionea. The poisonous material was found shown that the poisonous material of the poisonto be formic acid in a free and highly-concentrated apparatus of the Hymenoptera, consists likewise state; it was met with in all parts of the cater- of formic acid. See my note under ~ 347, note pillar, but especially in the faeces, in the greenish- 11. — ED. yellow liquid emitted by these animals when di %~ 324, 325. THE INSECTA. 403 like, and colored. Their forms vary infinitely not only according to the species, but also according to the regions of the body. They are often ribbed longitudinally, and denticulated or deeply serrated on their borders. These scales are often inserted on the skin perpendicularly, thus fonrming a peltlike covering easily wiped off; sometimes they are imbricated and exactly fitted to each other.'~' ~ 324. The various parts of the cutaneous skeleton of the Insecta have been so carefully studied in Zoology, that they may well be passed over here. As the internal surface of this skeleton furnishes points of insertion to the voluintary muscles, the segments of the body on which these last are attached, would naturally be developed in proportion to their volume. Thus with those Insecta which have powerful masticatory organs, the head is remarkably large,on account of the prominent development of the masticatory muscles; in the same way likewise other fossorial, rapacious, or saltatory Inseeta,indicate their habits of life by the size of their legs, which are endowed with great,muscular power. It is for the same reason, also, that with the species which fly, the mesothorax and metathorax are so largely developed; for these contain not only the muscles of the last two pairs of legs, but also those of the wings. These relations are especially distinct in those families or genera which embrace both winged and unwinged species. On the internal surface of the cutaneous skeleton, are found, in the head and thorax, processes which may be regarded as an internal skeleton. Some of these serve as septa, which separate certain organs, and others furnish points of insertion to muscles, and then are often bifurcated. (1) CHAPTER II. MUSCULAR SYSTEM AND LOCOMOTIVE AND SONIFEROUS ORGANS. ~ 325. The muscular fibres of the Insecta are striated, not only in the voluntary mnuscles, but often also in those of organic life, as in the stomach and intestine. () All are colorless or of a dirty yellow color. This last is especially observed with the muscles of the thorax belonging to the wings, which differ, 3 This covering has a velvety aspect with the Dujardin, Observ. au microscop. p. 121, P1. VII. Lepidoptera, Anthracide, and Bombylidae it is IX. XI. XII.; Nicolet, loc. cit. p. 22, P1. II. scaly on the bodies of many of the Culculionidae, (Poduridae), and H. Fischer, Isis, 1846, p. 401, Melolonthidae, Clavicornes, Lepismidae, Poduridae Taf. IV. (Coleoptera)..and on the wings of the Culicidae, and Lepidoptera. 1 For the internal skeleton of the Insecta, see It has always excited the attention of naturalists, Audouin, Ann. genir. d. Sc. physiq. VII. p. 182, who have figured it in their works. See also or 3Ieckel's deutsch. Archiv VII. p. 435 Riaumur, and Degeer, loc. cit., also Lyonet, Eschscholtz, Isis, 1822, p. 52; Burmeister, MWm. du Musnum, XX. p. 82, P1. VI.-XI.; Ber- 1tandb. &c. I. p. 251, and Newport, Cyclopaed. nard-Deschamps, Ann. d. Sc. Nat. III. 1835, P1. loc. cit. II. p. 909. 11. IV.; Ratzeburg Die F'orstinsekt. II. Taf. I.; 1 NecrophorLts. 404 THE INSECTA.; 326. furthermore, from the others, in their transverse striae being less distinct, and their fibrillae being more easily observed; indeed, with most species, these last show a tendency to separate even from the least pressure, while those of the other voluntary muscles are very compactly united together.(2) The muscles are attached directly upon the cutaneous skeleton, as with the Crustacea. In the extremities, only, do there appear to be tendons; but these are merely very long, flattened processes of the skeleton, situated in the axis of the articles of the extremities. They serve as points of attachment to short muscular fasciculi which are there obliquely inserted, after having arisen from the inner surface of the articles. With adult insects, the segments of the body are only slightly movable, and have but few muscles. But with the larvae, whose extremities are rudimentary, or even wholly wanting, there is a very prominent muscular system situated directly beneath the skin, and composed often of several layers of flattened fasciculi.'(' ~ 326. The Locomotive organs, properly speaking, of the Insecta, are the legs and the wings. The true legs never exceed three pairs, and are inserted upon the first three segments back of the head - Frothorax, Mesothorax, _Metathoraz. Each leg is divided into a Coxa, a Trochanter, a Femur, a Tibia, and a Tarsus. The tarsus is divided into several articles, the: number of which reaches even five. The form of these legs varies infinitely according to the mode of life of each species. The most common are those ~o which are usually given the names: Pedes cursorii, arnbulatorii, gressorii,, 2 This is so with the Diptera, Hemiptera, and Straus, Consid. &c. p. 140, PI. III. IV. (MelolonHymenoptera, with the muscles of whose wings the tha vulgaris). elements may be very easily separated.* Reference may be also made to the works of 3 Lyonet (Trait(, &c., p. 114, P1. VI.-vIII.) has Aleckel (System, &c., III. p. 22), Cuvier (Leons, given a very detailed account of the muscles of the &c. II. p. 64), Burmeister (IHandb. &c. I. p. 267), larva of Cossus. See also Newport, Philos. Lacordaire (Introduct. A l'Entomol. II. p. 249), Transact. 1836, p. 537, P1. XXvII. (the cutaneous and of Newport (Cyclopaed. &c. loc. cit. p. 934). muscles of the larva of Sphinx ligustri), and * [~ 325, note 2.] The delicate and beautiful ially) with the highest and best microscopic powersStructure of the thoracic muscles of some of the In- The discs composing the primitive fibrillae, easilysecta, has been carefully studied of late, and has separate and may be studied by themselves. But,. aided not a little in the elucidation of the histology with the best powers, I have been unable to observe of the muscular tissue. See Lebert, Recherches in them anything but that each disc is a solid,. sur la formation des muscles, &c., in the Ann. d Sc. homogeneous light-refracting body. The fibrillaI Nat. XIII. 1850, p. 182-195, PI. VII. fig. 18-27; appears to be formed by the aggregation of these but especially Aubert, Ueber die eigenthUmliche discs in a linear series and with regular interstructur der Thoraxnmuskeln der Insekten, in Sie- spaces; no sheath, by which these discs would be bold and KSlliker's Zeitsch. IV. 1853, p. 388. retained in a row, was observed. Contraction of This last-mentioned naturalist states that he has the fibrilla takes place by an approximation of the observed a new form of muscle-element in the discs to each other, and the consequent greater or thorax of the Libellulidae, consisting of primitive less disappearance of the interspaces. These phemuscular bands by means of which, with a beaker- nomena can be easily observed, and, it may be shaped apparatus, the wings are moved. These added, there are often seen isolated fibrillae confibres consist of flattened riband-like bands, striated tracting and relaxing, thus showing that the real on their borders as well as on their flat surface. phenomenon of muscular contraction, does not deI have recently studied the elements of the pend upon the nervous system, however much the thoracic muscles of many Diptera (Culex, espec- action of this last may serve as a stimulant. EDu 5~ 326. TIHE INSECTA. 405.natatorii, saltatorii, raptorii, and fossorii.() The tarsal articles are often enlarged, in which case they form, on their under surface, either a naked, fleshy sole, or a thickly-pilose ball of the foot, which is usually cordiform.'With the Dytiscidae, several of these tarsal joints are changed into a disc provided with suckers. The last article of these organs bears usually two movable hooks, which are sometimes deeply bifid or denticulate on their concave border. (2) It is rare that there is a third hook between them. (3) But with the Strepsiptera, and Physopoda, all the hooks are wanting. The Diptera and many Hymenoptera, have, moreover, under these hooks, soft lobules {Arolia) provided with numerous small papillae, by means of which these insects can fix themselves to objects.(4) With a great number of larvae, the six legs are very short or abortive, or even completely wanting. In the first case, they consist, usually, of merely a hook, but these larvae have also many short obtuse processes on the other segments of the body, and by means of the hairy soles on the extremity of these, they can fix themselves on bodies and thereby move along.(5) With many entirely apodal larvae, these processes are replaced by simple tubercles, or by belts of backwardlypointing bristles or spines, which serve as points of support in their loconmotion.'6) The organs of flying are the anterior and the posterior Wings. The first are inserted on the mesothorax, and the second on the metathorax; but in nearly all the orders, there are genera with which these organs are wholly wanting.(7) In other genera, the females alone are wingless,(8) which is also true of the neuters of certain families.(' It is more common still, to see the posterior wings changed into balancers;(10) and this same transformation occurs also, but very rarely, with the elytra.(l) The wings, properly speaking, are only prolongations of the cutaneous skeleton traversed by tracheae and blood-canals. Their forms, their nervures, their folds, &c., as well as their sometimes complete abortive condition, may here be passed over, for all these points belong to the domain of Zoology.* 1 For the marching, leaping, and swimming of steep and smooth surfaces. But this assertion reinsects, see Straus, Consid6r. &c. p. 180. quires further proof, although it is admitted by 2 Thus, the hooks are bifid with Meloe, and den- Spence (Trans. of the Entomol. Soc. IV. p. 18). ticulate with the Pompilidae, Hippoboscidae, Cis- 5 With the Lepidoptera, and Tenthredinidae. telidae, and with Taphria, Dolichus, Calathus, 6 With many Diptera. and Pristonychus, of the Carabidae. 7 Among the Orthoptera. the wings are wanting 3 This third hook is found, for example, with with some Blattidae, Acrididae, Phasmidae, and Lucanus cervus. With larvae of the Meloidae, Psocidae; among the Hemiptera, with Acanthias, the legs are terminated by three very remarkable, and Rhizobius;,and among the Diptera, with straight, lanceolate hooks, known by the name of 3ielophagus, Phthiridium, and Pulex flagelTriungulinus. Many of the Curculionidae can los. grapple objects by means of the immovable hooks on 8 With Lampyris, some Blattidae, Coccidae, their tibiae. Bombycidae, Geometridae, also with the Mutillidae 4 The Tenthredinidae have a lobule of this kind and the Strepsiptera. on each of their legs, and the Diptera have even 9 With the Formicidae and the Termitidae. two to three. For these lobules, as well as for the 10 With the Coccidae and the Diptera. The postarsi of Insecta in general, see the beautiful figures terior wings are entirely wanting with some Ephemgiven by Everard Home (Lectur. on Comp. Anat. eridae. IV. PI. LXXXI.-LXXXIV.). According to Black- 11 The two singularly distorted balancers of the wall (Trans.'of the Linn. Soc. XVI. p. 487, 767; Strepsiptera, situated in front of the wings and in and Ann. of Nat. Hist. XV. p. 115), the papillae of rapid and unceasing motion, are, from their inserthe Arolia secrete a viscid substance which en- tion, only abortive elytra. ables the Insecta having these organs to walk on * [ ~ 326.] Leidy (Proceed. Acad. Sc. Philad. traction of the alary extensors, the spring-like ligaIII. 1846, p. 104) has described a peculiar mechan- ments, or ligamenta spiralia, are stretched in the ism by which the membranous wings of Locusta expansion of the wings, and upon the relaxation or are closed in a plicated manner like a fan. This cessation of the act on of the muscles, the physical mechanism consists of spiral ligamentous bands, properties alone of the ligamenta spiralia, in rewound, like the thread of a screw, around the suming their unstretched state, close the wings. - transverse or connecting veins, which latter are ED. also flexible. By this arrangement, upon the con 406 THE INSECTA. ~ 327 The movements of the wings arc produced by two extensor and several smaller flexor muscles, which arise from the middle and uosterior thoracie" segments, and are inserted on a tendinous process at the base of each wing. The size of these muscles is proportionate to the size of the wings and their mode of use in flight. They are, consequently, all equally developed when the four wings participate equally in the act of flying, as is the case witl the Lepidoptera, Hymenoptera, the majority of the Neuroptera, the Libelludidae, Perlidae, and finally, the Cicadidae, and the Aphididae. The muscles of the anterior wings are comparatively smaller than those of the posterior, when the first are not used, properly speaking, except to cover the latter, as is the case with the Coleoptera, the Bugs, and many of' the Orthoptera.(l2) With most of the Poduridae, and with the young larvae of Xenos sphzecidarum, there is a peculiar, fork-shaped, saltatory organ. It is inserted on the posterior extremity of the body or under the abdomen, and, when at rest, points horizontally backwards. By means of a special muscular apparatus, this fork is bent forwards and applied against the abdomen; it is then returned violently into its original position, thereby tossing the animal a considerable distance.('l) ~ 327. Many of the Insecta produce sounds which we perceive partly as clear tones, and partly as confused noises. These are due, sometimes to particular soniferous organs, but more often to vibrations of the cutanous skeleton produced by special muscular organs, or to the rubbing of certain parts against each other. But in every case, without exception, the sound is due to the action of voluntary muscles,' and has no connection with the respiratory organs.(l) The buzzing produced by many Diptera, and Hymenoptera, during flight, is due, without doubt, to vibrations of the thorax produced by the rapid and successive contractions of the muscles of the wings in this act.(2) Further researches are necessary to show if the sounds produced by certain butterflies are due to rubbings of some parts of the cutaneous skeleton, or to a special soniferous apparatus.(3) But the sharp sounds of many Coleoptera 12 For the flight of Insecta, see Straus, Con- of the wings, for it persists sometimes after the resider. &c. p. 200 but especially the extensive moval of these last. Neither can it be attributed work, illustrated with many figures, of Chabrzer, to the rapid passage of air through the stigmata of ML6m. du Museum, VI.-VIII. the thorax, causing vibrations in that part of the 13 See Nicolet, loc. cit. p. 39, P1. III. * and my body. Burmeister, who has advocated this last Beitrag. zur Naturg. d. wirbell. Thiere. p. 84, Taf. opinion (Handb. &c. I. p. 508, and in PoggenIII. fig. 70. This fork is wanting in the genera dorf's Ann. d. Physik. XXXVIII. 1836, p. 283, Acl/orutes and Anurophorus, as well as with Taf. III. fig. 7-9), compares these sounds to those. the larvae of Stylops among the Strepsiptera. produced by a siren 3 but this theory has been, 1 Some Insecta produce sounds by striking or fully refuted by Goureau, Solier, and Erichson rubbing certain parts of their cutaneous skeleton (see Silbermann's Revue Entomol. III. p. 105,. against the body. The males of Myeterus cusrcu- and Ann. de la Soc. Entom. de France, VI. 1837,. lioides knock with such violence the extremity of p. 31, and Wiegmansn's Arch. 1838, II. p.' 193). their body against the boughs on which they have The various sounds of flies and bees may be imialighted, that they produce a pretty loud sound, tated, moreover, by placing a vibrating tuningdesigned, probably, to call the females. fork in contact with a band of stretched paper,The larvae of Vespa crabro, when hungry, an experiment in which the vibrations of the air scratch the walls of their cells with the point of their take no part. jaws, and thus call the attention of the parents to 3 It is said that, with Esuprepia pudica, the petheir condition. culiar sounds are produced by the rubbing of a 2 The buzzing of these Insecta has been at- callosity of the two posterior hips against the midtempted to be explained in various ways. At die hips (Solier, Ann. de la Soc. entom. loc. cit.). all events, it cannot be due alone to the movements The cry of Acherontia atropos has been attempted. $ 327. THE INSECTA. 40j are caused by the rubbing of their prothorax against the peduncle of the mesothorax, or by grating the ridges of the abdomen against the internal surface of the elytra. Reduvizus stridulus, iAutilla europaea, and ]Mliantis religiosa, produce also certain sounds by the friction of particular portions of their skeleton.(4 The males of many Acrididae produce their creaking sounds by playing, as with the bow of a violin, upon the lateral borders of their Elytra, by their posterior thighs which have a longitudinal granular ridge on their internal surface.(~) The peculiar cry of the male Locustidae and Achetidae is produced by the base of their elytra. The very hard and sharp internal border of one of these elytra rubs against a horny ridge, upon the under surface of the other, close to the tympanitic disc'.( With the males of the musical Cicadidae, there is a very remarkable soniferous apparatus, situated on the under surface of the first abdominal segment. It consists of two spacious drums at the base of which is a dry, plicated membrane, to which is attached a large muscle of conical form, arising from a median, bifurcated process of the second abdominal segment. The entrance of each of these drums is more or less covered by a rounding operculum which is free behind. The muscle draws the membrane inwards, then relaxing, this last returns by its own elasticity, producing, as from the bending up and down of a metallic plate, a loud, clanging sound. This sound is undoubtedly considerably increased by the resonance of the air in the drums and in the neighboring vesicular tracheae.(7) to be explained in various ways, but none of the 6 For this soniferous apparatus, see Goureau causes yet assigned are satisfactory; see Passerini, and Solier, Ann. d. la Soc. Entom. 1837, p. 31; Ann. d. Sc. Nat. XIII. 1828, p. 332 S R. Wagner, Neowport, Cyclopaed. loc. cit. II. p. 928, fig. 394in Miller's Arch. 1836, p. 60; Goureau, Nord- 396; Goldfuss, Symb. ad. Orthopt. quorund. mann, and Duponchel, Ann. de la Soc. entom. VI. oeconomiam, Bonn. Diss. 1843, p. 5, fig. 1-10; and IX., or Wiegmann's Archiv. 183941.* my observations in Wiegmann's Arch. loo. cit. p. 4 See Burmeister, Handb. &c. I. p. 507, and 69. Burmeister (Haundb. &c. I. p. 511) has Goureau, in Silberman's Revue Entom. III. p. sought to explain this sound by referring it to the 101. powerful escape of the air from the stigmata of the 5 See my observations in Wiegmann's Arch. Locustidae and Acrididae i but this is unsatisfac-.1844, I. p. 53. This fiddling movement may be tory. easily observed with the males of Gomphoceros 7 For the soniferous apparatus of the musical and Oedipoda. Pneumora maculata has, upon Cicadidae, see Riaumur, MWm. V. 4th msm. P1. the sides of the second abdominal segment, a very XVII.; Burmeister, Handb. &c. I. p. 513 strongly denticulate, oblique ridge, against which Ratzeburg, Mediz. Zool. II. p. 208, Taf. XXVII. is rubbed, probably, a horny process situated on and especially Carus, Analekt. zur Naturwiss. p. the internal surface of the posterioi' thighs. I am 142, fig. 1-18.t yet unable to account for the way in which the males of Oedipoda stridula produce their hoarse buzzing, during flight. *[ ~ 327, note 3.] Haldeman (Silliman's Jour. European Acherontia atropos may produce its AMay, 1848) states that Lithosia miniata, Kirby, peculiar sound in a similar manner. - En. or an allied species, produces an audible stridula- t [ ~ 327, note 7.] See also my investigations tion by vibrating the pleura beneath the wings, upon this apparatus of the Cicada septendeczm in this part being marked in recent specimens by par- the Proceed. Boston -Soc. Nat. Hist. 1851, p. 72.allel lines, apparently indicating the position of the ED. muscles. According to him, it is possible that the 4)I8 THE INSECTA. ~ 328. CIHAPTER III NERVOUS SYSTEM. *~ 328. The central parts of the nervous system consist, with the Insecta, as with the other Arthropoda, of a Brain and a Ventral Cord.(l The brain is situated in the cephalic segment, and is composed of a dGanglion supracesophageum, connecting with a Ganglion infracesophageum which is smaller, by two lateral commissures which embrace the oesophagus. The first of these ganglia corresponds to the cerebrum of the Vertebrata; and the second is comparable perhaps to the cerebellum or spinal cord. The ventral cord succeeds upon the sub-oesophageal ganglion, and con-.sists, sometimes of a single ganglionic mass, sometimes of a chain of ganglia more or less approximated and connected by double, longitudinal commis-,sures.(2) The number of the ventral ganglia, which is never greater than -that of the segments of the body, as well as the presence and length of the longitudinal commissures, depend often upon the number, the size, and the -mobility of the segments of the body to which they belong. With those Insecta whose segments are very short and rigid, the ganglia are closely.approximated or even entirely blended together; while, in most larvae, where the segments of the body are equally developed and flexible, the ganglia are separate, nearly equal in size, and connected by pretty long.commissures.'These last are rarely united into a single cord, although the.ganglia, not only those of the ventral cord, but also those of the brain, appear, nearly always, to be composed each of two united ganglia. Aside from the differences presented according as the insect may be a larvae, a pupa, or an imago, the nervous system varies so much even in -the same group, that it may be quite dissimilar in species which, in other respects, are very closely allied. These modifications refer to the number,of the ganglia, the length of their commissures, and the more or less complete fusion between certain ganglia. The superior cerebral ganglion, which is often composed of two hemi-,spheres more or less fused together, gives off the two antennal and the two,optic nerves. The simple eyes or steinmata, either when alone, or when coexistent with compound or faceted eyes, always receive their nerves from -the same ganglion; although these last are sometimes given off from a trunk in common with the optic nerve. The sub-cesophageal ganglion furnishes.nerves chiefly to the mandibles, to the maxillae and their palpi. With the perfect Insecta, the three thoracic are much more voluminous than the abdominal ganglia. They send nerves not only to'the legs, but also to the nmuscles of the wings. 1 For the nervous system of the Insecta in gen- 2 Entomotomists are not agreed as to the number,eral, see Burmeister, Handb. &c. I. p. 290 i of the abdominal ganglia, for the sub-cesophageal.Lacordaire, Introd. &c. II. p. 183, Newport, ganglion is sometimes regarded as the first of the.Cyclopaed. 1I. p. 942, and Blanchard, Ann. d. Sc. ventral cord. For the nervous system of the larva Nat. V. 1846, p. 273. L. D)ufour (Mem. pr6s. A. and pupa of Sarcophaga, see L. Dufour, loc. cit l'Acad. d. Sc. IX. 1846, p. 562, P1. I. fig. 16) has Pl. I. fig. 12-15. given a very exact description of this system in Sarcophaga haemorrhoidalis. ~ 329, 330. THE INSECTA. 409 The ventral ganglia:.re usually small, coequal, and give off no nerves,except to the segments of the abdomen. The last ventral ganglion, alone, is larger, for it furnishes, in addition, nervous filaments to the rectum, and to the excretory ducts of the genital organs. Usually, the nerves arise in the ganglia by two or three principal roots. Some nerves, however, arise from the interganglionic cord. In those,species where the ventral ganglia are entirely fused together, the nerves.arise close together, but immediately diverge in different directions. ~ 329. As to the Intimate Structure of the nervous system of the Insecta, both the nerves and the ganglia are always surrounded by a fibrous neuTolemma, and, according to carefully-made researches, are never wanting in the two usual anatomical components. Between the extremely tenuous primitive fibres, are interposed, in the ganglia, very small globules. These last, nucleolated, usually contain also a finely-granular substance, colorless, though sometimes reddish or brownish.(l) There are, with the Insecta, as with the Crustacea, two modes of the dis-:position of the fibres in the ganglia. The first, which form nervous, inferior cords, are disseminated in the ganglia; while the others, which belong to the superior nerves, simply pass through or over these ganglia. These -two kinds of fibres give off, laterally, nervous filaments, which, uniting, -form peripheric nerves of a mixed character. The superior cords corre-:spond, probably, to the motor nerves, and the inferior to the sensitive nerves of the Vertebrata. (2) ~ 330. The Disposition of the nervous system in the various orders of Insecta presents the following differences:(l) Among the Aptera, the ventral cord of the Pediculidae is composed of three contiguous ganglia situated in the thorax. The prothoracic ganglion connects with the brain, and the metathoracic sends nerves to the abdomen.(t2 The nervous system of the Poduridae differs from this, in their three thoracic ganglia, being separated, and their interganglionic longitudiInal commissures being wide apart.(3) More widely different still, is the ventral cord of the Lepismidae; it is composed of eleven ganglia connected by double longitudinal commissures. (4 With the Hemiptera, this system is limited to two thoracic ganglia, of vhich the anterior is the smaller. With Pentatoma, and Cicada, these two ganglia are not separated except by a constriction; while, with Nepa, 1 It was undoubtedly from their extreme deli- p. 389, PI. XIII.-XVII. and Cyclopaed. Ioc. cit. p. tcateness that these ganglionic globules were over- 946). Hagen (Entom. Zeit. 1844, p. 364) has since looked by Treviranus (Beitrag. zur Aufklir. d. observed it with Aeschna grandis and GryllolErscheinung. u. Gesetze d. organisch. Lebens. I. talpa vulgaris. iHft. 2, p. 62). They have been distinctly seen by 1 Various and special accounts of the general iEhrenberg (Unerk. Struct. &c. p. 56,. Taf. VI. fig. disposition of the nervous system of insects may 6 (Geotrupes)), Pappenheim (Die specielle Gewebe- be found in Cuvier, Lecons, &c., III. 1845, p. 334. lehre d. Gehiororg. p. 51), Helmholtz (De fabric. 2 Swamomerdamm, Bib. der Natur. p. 36, Taf. Syst. nat. &c. p. 21), Hannover (Recherch. II. fig. 7. microscop. &c. p. 71, P1. VI. fi'g. 81, 82 (Aeschna)) 3 Nicolet, loc. cit. p. 44, Pi. IV. fig. 1 (Smynand Will (Miller's Arch. 1844, p. 81). thurus). 2 This difference of the nervous cords was first 4 Treviranus, Verm. Schrift. II. IIft. 1, p. 17, pointed out by Newport with the pupa and imago Taf. IV. fig. 3. of Sphinx ligustri (Philos. Trans. 1834, part II. 35 410 TIHE INSECTA. 3 330. they are connected by two long commnissures. From the posterior of these ganglia pass off, in a ventral cord, two main trunks, approximated, which send off, in their course, lateral branches towards the periphery; with Pentacomna, these two main trunks are fused into one.(5) With the Diptera, the ganglionie chain is always connected by simple commissures. The number of ganglia varies with the families, and, usually, is proportionate to the length of the segmients of the body.(6' The ven-l tral cord is most concentrated with the Hippoboscidae,(7) the Oestridae,. and the Muscidae calypterae; it consists of only a single thoracic ganglion, from which pass off nerves in various directions. The Muscidae aecalypterae, on the contrary, the Syrphidae~(t and the Conopidae, have, beside this thoracic ganglion, one or two ventral ganglia; while the Scenopinidae have five, and the Tabanidae, Stratiomydae,(1) Therevidae, Leptidae, Asilidae, and Bolnbylidae, have six. Their number is still larger with the Elmpidae, Culicidae, and Tipulidae; — there being, in the first, three thoracic and five abdominal ganglia; and in the last two, three thoracic and six abdominal ganglia. The larvae of the Diptera usually have one more pair of ganglia than the adults. It is only in those species whose ventral cord is fused into a single mass, that the same concentration is observed with the larvae. (0 The larvae of the Diptera have either a moniliform ventral cord, composed of ten approximated ganglia, or a chain of eleven of these masses, connected by long commissures, which are often double.(ll) With the Strepsiptera, alike in the three states of larva, pupa and imago, the ventral cord consists only of a large thoracic ganglion, from which pass off nerves in various directions.(2) With the adult Lepidoptera, the ventral cord consists of seven ganglia, of which the first two are the largest and belong to the thorax. The connecting commissures are not double except between the thoracic ganglia; those of the others being more or less fused into a single cord. In the Caterpillars, the ventral cord consists of eleven nearly equal ganglia; the two commissures between the first three of these, are quite wide apart; 5 Treviranus, Beitr. zur Anat. u. Physiol. d. intestin. exposit. contin. tertia. p. 28, Taf. III. fig. Sinneswerk. Hft. 1, Taf. II. fig. 24 (Cicada), and 4), and according to which, two long ganglionic L. Dufour, Recherch. sur les Himiptires, p. 259, cords, connected by transversal anastomoses, exPl. XIX. fig. 801-803 (Pentatoma, NYepa and tend the whole length of the body, —is based on inexCicada).* act observations. Inthe larvae of Piophila and Eris6 For the nervous system of the Diptera, see talis, several ventral ganglia fused together form a L. Dufour, Ann. d. Sc. Nat. 1844, p. 245. singleabdominal cord; see Swammerdamm, Bib. 7 L. Dufour, Ibid. III. 1845, p. 64, P1. II. der Nat. p. 279, Taf. XLIII. fig. 7, and Burmeisfig. 12. ter, Handb. loc. cit. Taf. XVI. fig. 10. 8 Burnteister, Handb. d. Entomol. I. 307, Taf. 11 The larvae of Stratiomys have an abdominal XVI. fig. 11 (Eristalis tenax). cord composed of ten contiguous ganglia (Swa7n9 Swammerdamm,Bib. d. Nat. p. 270, Taf. XLI. merdamm, Bib. der Nat. p. 264, Taf. XL. fig. 5). fig. 7 (Stratiomys). With those of Culex, Chironomus, Sintulia, and 10 I have found the ventral cord of the larva of other Tipulidae, the ten ganglia are wide apart, Oestrus bovis concentrated into a single large and connected by double longitudinal commisganglion, situated at the extremity of the thorax. sures.t I think, therefore, that the description of the nervous 12 In the apodal larvae and the larvae-like fesystem of the larva of Oestrus ovis given by J. males of Xenos Rossii, I have found this nervous L. F'ischer (Observ. de Oestro ovino atque bovino. mass in the first segment of the body which correDiss. Lips. 1787, p. 32, or in Werneri, Vermium sponds to the cephalothorax. * [ ~ 330, note 5.] For the nervous system of plumicomis, Leydig found the ventral cord comBelostoma, with all its details, see Leidy, History posed of eleven, instead of ten ganglia; see Anatoand Anatomy of the hemipterous G-enus Belostoma, misches und Histologisches Uib. d. Larve von Corein the Jour. Acad. Nat. Sc. Philad. I. 1847, p. 65, thra plmicornis in Siebold and Klolliker's: P1. X. fig. 13.- ED. Zeitsch. III. 1852, p. 438.- ED. t [ ~ 330, note 11.] In the larva of Corethra ~ 380. THE INSECTA. 411 while those of the others are usually fused together'.(l2) During the pupastate, a remarkable change takes place. The commissures between the first and second, and the third and fourth ganglia, are gradually shortened. The ganglia are thereby gradually approximated, and, in the end, are fused together, forming the two th.oracic ganglia of the adult, which send off nerves to the leos, and to the muscles of the wings. At the same time, the fifth and sixth ganglia entirely disappear or are fused into one.(14 With the Hymenoptera, the ventral cord is composed of seven to eight ganglia connected by double comlnmissures. The first of these, smaller than the second, is, like it, produced by the fusion of several ganglia; and both are situated in the thorax. Of the remaining five or six abdominal ganglia, the last two are closely approximated, or fused into one.(1) Here, as with the Lepidoptera, the number of ganglia in the ventral cord of the larvae, is eleven, as has been specially shown in the false caterpillars of the Tenthredinidae. (16) With the Orthoptera, and Neuroptera, the nervous system is nearly always composed, in their various states, of three thoracic and six to seven abdominal ganglia connected by double commissures and forming a chain as long as the body.'17) With the Coleoptera, the number and disposition of the ventral ganglia present the widest variations of all. The longitudinal comnmissures, always double, are shortened or even wholly wanting at certain points. The ganglionic chain is, therefore, more or less abbreviated, and sometimes the ganglia are almost fused into a single mass. In this respect this system here presents two principal types, the limits between which, however, have 13 For the nervous system of the larvae of Va- Bembecidae, with Larra, and Tiplica; four with nessa urticae and Bombyx mori, see the figures of Tripoxylon, and three with Eucera. Sweammerdamm,loc. cit. p. 387, 230,Taf. XXVIII. 16 The ventral chain of the Tenthredinidae, fig. 3, and Taf. XXXIV. fig. 7.; also for that of the Apidae, Vespidae and other iymenoptera, underlarva and imago of Cossus ligniperda, the works of goes, undoubtedly, with the pupae, a metamorphoLyonet, TraitS, &c., p. 190, P1. IX., and in the sis similar to that occuring with the Lepidoptera. _Mnim. du Mus. loc. cit. p. 191, P1. LI. (17). For 17 Swammerdamm, loc. cit. p. 108, Taf. XIV. that of Gastropacha pinti, pupa and imago, (a pupa of Ephemera); Marcel de Serres, Mim. see Suckow, Anat. physiol. Untersuch. p. 40, du Mus. IV. 1818, P1. VIII. (1.) fig. 1 (Acridium); Taf. VII. fig. 37, 38; but see especially the excel- J. Miiller, Nov. Act. Nat. Cur. XIV. Tab. IX. lent description of that of the larva, pupa, and fig. 4, and XII. p. 568, Tab. L. fig. 1 (Acridiurz imago of Sphinx ligustri, for which we must and Bacteria); Newport, Cyclop. II. p. 950, fig. thank Neswport. Philos. Trans. 1832, p. 383, P1. 409, 410 (Forficula and Locusta); finally, L. DuXII. XIII.; also, 1834, p. 389, P1. XIII.-XVIII., four, Ann. d. Sc. Nat. XIII. 1828, p. 361, P1. and Cyclop. &c. loc. cit. p. 943, fig. 406, 414, 415. XXII. fig. 4 (Forficula), Recherch. sur les Olr. 14 This metamorphosis of the nervous system thopt. &c. p. 281, PI. II. fig. 7 (Oedipoda), and p. was first observed by Herold (Entwickelungsgesch. 561, P1. XI. figs 160 (Libellula). According to d. Schmetterlinge, loc. cit. Taf. II.) with Pontia L. Dufour, there are seven ventral ganglia with brassicae, and has since been confirmed by Ne1w- Libellula and Ephemera, while there are only six port with Sphinx ligustri and Vanessa urticae; with Perla and Phryganea. But Piefete (ReI see Philos. Trans. 1834, P1. XV. XVI. fig. 20-30, cherch. pour servir a Ihist. et l'anat. des Phryand Cyclop. loc. cit. p. 962, fig. 420-423. ganides. P1. II. fig. 33-36) and Burmeister 15 See Swammerdamm, Bib. der Nat. p. 207, (Handb. &ec. II. p. 895, 898) assign to these InTaf. XXII. fig. 6 (Apis mellifica); Treviranus, secta, in both their larva and their perfect state, Biologie, V. Taf. I. (Bombus muscorum), and eight ventral ganglia. There are even nine of Brandt and Ratzeburg, Medizin. Zool. II. p. 203, these ganglia with the Ephemeridae, according to Taf. XXV. fig. 31 (Apis mellifica). For the dis- Burmeister (loc. cit. p. 763). In the very chubposition of the ventral chain of the Lepidoptera in bed larvae of Myrmeleon there are eight contigugeneral, see, moreover, L. Dufour, Recherch. sur ous ventral ganglia beside two thoracic ones (Cules Orthopt., Hymenopt. &ec. p. 381. According to vier, Legons, &c., III. p. 341). Loew (Germari's this last-mentioned naturalist, the number of ventral Zeitsch. IV. p. 424) remarks that the proper Neuganglia is five with Vespa, Scolia, and with most of roptera are distinguished by the separation of their the Apidae and Andrenidae; six with Odynerus, last two abdominal ganglia, while, with all the OrSphex, Pompilus, Chrysis, the I:hneumonidae, thoptera, they are fused together.* * [ ~ 330, note 17.] See also for a description femoratum, Leidy, Proceed. Acad. Sc. Philad, and figures of the nervous system of Spectrums 1846, III. p. 83. - ED. 412 TIE INSECTA. ~ 331. not yet been definitely fixedl.' The first type consists of an absence of all the longitudinal commissures, as is the case with most of the Lamellicornes, the Curculionidae, and the Scolytidae. Here, the ventral cord is limited to three ganglia connected together; of these, the first corresponds to the prothoracic, and the second, the larger, to the second and third thoracic ganglia. This last is succeeded by an oblong, ganglionic mass, representing the concentrated abdominal portion of the cord, and from which arise the nerves of the muscles of the abdomen.(9) In the second type, the abdominal portion of the cord occupies the entire length of the body. This is the case with the Cistelidae, Oederneridae and Cerambycidae, which have five ganglia in the abdomen.(1) With the larvae of the Coleoptera, these two types are more clearly defined, there being no intermediate f)rms.(il) ~ 331. The Splanchnic nervous system consists, with the Insecta, in all their states, of a single and a double nervous cord. Sometimes the first, sometimes the second of these is the more developed. The single Stomato-gastric nerve arises from the anterior border of the cerebral hemispheres, by two short filaments, which, directly in front of the brain, meet in a ganglion (Ganglionfrontale) lying upon the oesophagcus. From this ganglion are given off several nervous filaments which go to the upper lip; while, from the opposite side, arises a simple nerve S8 There has recently appeared a very detailed and composed of eight ganglia with the Elateridae, memoir, accompanied with. beautiful figures, on the Cleridae and Telephoridae. nervous system of the Coleoptera, by Blanchard; 20 See Blanchard, loc. cit. see Ann. d. Sc. Nat. V. 1846, p. 273, PI.VIII.-XV., 21 With those species of the Lamellicornes, and and Rkgne animal. illustr. Insectes, P1. III. III. Curculionidae, whose ventral cord is very much bis. and IV. (Alelolontha, Carabus, Otiorhyn- concentrated, the eleven large component ganglia chus, Cerambyx). are, with the larvae, united into one knotty mass, 19 See Straus, Considor. &c. p. 391, P1. IX. fig. without any trace of Commissures; see Swammer1 (Melolontha vulgaris), and Blanchard, loc. cit. damm, loc. cit. p. 131, Taf. XXVIII. fig. 1 (OrycAn analogous concentration of the nervous system tes); L. DuLfour, Ann. d. Sc. Nat. XVIII. 1842, occurs in the families of Histeridae, tGyrinidae, p. 1;0, P1. IV. fig. 11 (Cetonia) Burmeister, Nitidulidae, and Scaphididae,where the ventral por- Zur Naturgesch. d. Calandra, p. 13, fig. 13, 14; tion forms a single oblong ganglion, while the three Blanchard, Ann. d. Sc. Nat. loc. cit. P1. XIV. fig. thoracic ganglia are connected by double longitudi- 1 (Calandra). With the larvae of the Mel'idae, sal commissures. In most of the other families, the Pyrochroidae, Lucanidae, Chrysomelidae, Tenethree thoracic ganglia are more or less separated, brionidae, as well as of most of the other families and the abdominal portion is modified in various of the Coleoptera, the ventral chain occupies nearly ways. With the Endomychidae, Meloidae and the entire length of the body, and is composed of Cshrysomelidae, there are only four abdominal eleven ganglia having double commissures the ganglia connected by very short double commis- thoracic ganglia exceed but little in size those of sures; see Audouin, Ann. d. Sc. Nat. IX. 1826, the abdomen; see Brandt, Miediz. Zool. II. p. 105, p. 36, P1. XLII. fig. 16 (Lytta); Brandt, Mediz. Taf. XVII. fig. 20, Taf. XIX. fig. 31 (Meloe and Zool. II. p. 103, Taf. XVII. fig. 2, Taf. XIX. fig. Lytta); L. Dufour, Ann. d. Sc. Nat. XIII. 1840, 19 (Meloe and Lytta); NYewport, Cyclopaed. loc. p. 327, P1. V. fig. 8 (Pyrochroa), and XVIII. cit. II. p. 950, fig. 408 (Timrarcha) and Joly, 1842, p. 172, P1. V. fig. 17 (Dorcus); Newsport, Ann. d. Sc. Nat. II. 1844, p. 24, PI. IV. fig. 16 Cyclopaed. loc. cit. p. 943, fig. 404 (Timarcha); (Colaspis). With the Dytiscidae, and with Bytu- Joly, Ann. d. Sc. Nat. II. 1844, p. 24, P1. IV. fig. rtus, tthere are six abdominal ganglia, and the com- 14 (Colaspis), and Blanchard, Ibid. P1. XV. fig. nissures are also very short; see Burmeister, 7, P1. X. fig. 5 (Chrysomela and Tenebrio). It landb. loc. cit. Taf. XVI. fig. 9 tDytiscus). This is only with the larvae of the Carabidae, Silphidae, figure, however, is not fully exact, if compared Staphylinidae and Diaperidae, that the ventral with that of Blanchard (loc. cit. p. 343, P1. X. fig. cord, although composed of eight ganglia, does not 1). With the Staphylinidae, Silphidae, and Hy- extend into the last abdominal segments; while drophilidae, the abdominal portion, although com- that of the larvae of the Dytiscidae, composed of posed of eight ganglia. is not prolonged much seven ganglia, does not reach beyond the middle into the abdomen; it is longer and composed of of the abdomen; see Burmeister, Trans. of the six to seven ganglia with the Carabidae, Lu- Entomol. Soc. Lond. I. p. 239, P1. XXIV. fig. 9 canidae, and Pyrochroidae e see L. Dufour, (Calosoma); Blanchard, Ann. d. Sc. Nat. loc. cit. Ann. d. Sc. Nat. VIII. 1826, p. 27, P1. XXI. his, P1. IX. fig. 3, 5, P1. XI. fig. 4, P1. X. fig. 2 (Silfig. 2 (Carabus), and Ibid. XIII. 1840, p. 332, pha, Staphylinus, Diaperis, and Dytiscus). Pl.;VI. fig. 9.Pyrochroa). It is even still longer g 331. THE INSECOTA. 413 (Nervus recurrens) which passes over the oesophagus to the stomach, giving off branches right and left. Reaching the stomach, it divides, after having formed a ganglionic enlargement, into two principal branches. The double Stomato-gastric nerve consists of one, two, or three pairs of small ganglia, situated behind the brain, on each side of the oesophagus, and communicating with each other, with the posterior extremity of' the brain, and with the Nereus recurrens, by delicate filaments. These filaments send fine threads to the oesophagus, and, at certain points, anastoIlose with the single nerves.(1) With the Hemiptera, a single Splanehnic nerve has been observed, and, for the double system, there has been seen, on each side of the cesophagus, two small ganglia, one behind the other.(3) With the Diptera, the splanchnic system appears to be present; at least, there has been observed on the Chyliferous stomach of the Hippoboseidae, a pair of filaments belonging, probably, to the double system.(38 The Lepidoptera halve a highly-developed Nervus recurrens, which often forms, with the caterpillars, several small ganglia lying behind each other on each side of the brain, and connected together by a double nervous arch. The double system arises on each side of the oesophagus, from two ganglia, situated one behind the other, which, with the caterpillars and pupae, are often approximated to a blending together, and which send off, beside the filaments anastomosing with the recurrent nerve, threads to the dorsal vessel.(4) The Hym6noptcra,(5) Neuroptera, and Orthoptera, also, have the two kinds of splanchnic systems. The double trunks are highly developed with the Acrididae, and the Gryllotalpida, and have two pairs of ganglia at their upper extremity, beside one or two on their course; while, with the Libellulidae, Blattidae, and especially the Phasmidae, the single nerve is the most developed.(') 1 For the Splanchnic nervous system of the In- temns with the imago and larva of Bombyx mori. secta, of which Swammerdamm. had already ob- The works of Neewport (Philos. Trans. 1832, p. served the recurrent nerve, see, beside the gene- 383, P1. XII XIII., and 1834, p. 389, P1. XIII. ral works of Burmeister (IIandb. &c. I. p. 308), XIV.) on the larva and imago of Sphinx li, ustri, and Lacordaire (Introduct. &c. II. p. 214), espe- are very distinguished. cially J. Mliiler, Nov. Act. Acad. Nat. Cur. XIV. 5 See Treviranus (Verm. Schrift. IIT. p. 59), 1828, p. 73; Brandt (Isis, 1831, p. 1103, also his who thinks he has observed the NYervus recur~Bemerk. fiber die Mundmuagen-oder Eingeweidener- renas with Apis mellifica; Brandt, also (Medizin. ven d. Evertebr. 1835, p. 16, or Ann. d. Sc. Nat. Zool. II. p. 203, Taf. XXV. fig. 32, and his BeV. 1836, p. 95), and Newport, Cyclop. &c. loc. merk. &c. p. 22), has described the two systems in cit. II. p. 957). this species, and in the Bumble-bee (Apis terres2 Meckel (Beitr. zur vergleich. Anat. I. p. 4) Iris). has observed the Nerveus recurrens in the com- 6 According to Burmeister (Handb. &c. I. p. mon Cicada, and Brandt (Bemerk. &c. p. 23, Taf. 310, Taf. XVI.' fig. 6 (C?'yllus migratorius)), the II. fig. 1, 2) has observed the same with Lygaeus, recurrent nerve leaving the frontal ganglion, runs and at the same time the ganglia of the double backwards and ends, after a short course, in a system. ganglion which connects by two filaments with the SeeL. Dunfour, Ann. d. Sc. Nat. III. 1845, p. 67. internal ganglia of the double system. These 4 The recurrent nerve was first discovered in the last send off several branches to the cesophagus, silk-worm by Swammerdamnm (Bib. der Nat. p. and connect, through two filaments, with the exter132, Taf. XXVIII. fig. 3, g.). Subsequently, Ly- nal ganglia of the same system. *From these exteronet (Trait6, &c., p. 577, Pl. XII. fig. 1, PI. XIII. nal ganglia arise two lateral tlrnks whllich run fig. 1, P1. XVI. fig. 14, P1. XVIII. fig. 1) de- along the cesophagus and are distributed to the scribed with the larva of the Goat-moth, the gizzard, forming a nervous plexus having four double system and its relations with the dorsal ganglia. See, also, for the some species, Brandt, vessel. Since then, the two systems have been oh- in the Isis, 1831, p. 1101, Taf. ~II. fig. 5. Accordserved in the larvae, pupae, and imagines of various ing to this last author (Bemerk. &c. p. 29, Taf. II. Lepidoptera; see Sackouw (Anatom. physiol. Unter- fig. 7-9), the double system of Gryllotalpa is simsuch. 40, Taf: YII. fig. 33-38, (pupa and imago of i!larly disposed, only the nervous plexus of the gizGastropacha pisni)), who has described the double zard arises friom two posterior ganglia of the two system and the cardiac nerve. See, also, J. Mil- trunks. See, also, for that of G;ryllotalpa, L. ler (Nov. Act. Nat. Cur. loc. cit. p. 97 (the recur- Duefour, Recherch. sur les Orthopt. &c. p. 285, rent nerve of a larva of Sphinx)), and Brandt P1. III. fig. 22. WxAith Phasma fereula, the four (Isis, loc. cit. p. 1104, Taf. VII. fig. 3, 4, and Be- anterior ganglia of the single system are small, but. merk. &c. p. 20), who has described the two sys- for compensation, the double system is very comn 35~ 414 THE INSECTA. ~ 332. The Coleoptera have, in both their larval and their perfect states, a feebly-developed double nervous system arising from two pairs of ganglia, and a highly-developed Nervuzs recurrens which, with a few species, forms, directly behind the Ganglion frontale, a second ganglion. It runs along the cesophagus, and usually forms, posteriorly, still another ganglion, and then divides dichotomously. (7 A great number of the Insecta have, in all their states, another system of nerves, called Respiratory nerves, which, in view of their functions, ought very properly to be classed among the mixed nerves, for they contain not only motor, but also vegetative fibres. This system arises by several single roots from the longitudinal commissures of the ventral cord. Each of these roots divides into two Nervi transversii which deviate from each other at right angles, and anastomose with the ganglia of the ventral chain and with its peripheric nerves, receiving at the same time organic fibres from the ganglia of the double splanchnic system. These respiratory nerves are distributed to the large trachean trunks, and especially to the muscles of the stigmata. The respiratory movements of Insecta cannot, therefore,, be regarded as properly of a voluntary nature.(8) CHAPTER IV. ORGANS OF SENSE. ~ 332. The sense of Touch appears to be seated, with Insecta, in very different parts of the body.('1 It is chiefly located in the palpi of the mouth, which, for this purpose, are usually terminated by a soft surface.(2) The antennae, also, serve as tactile organs, but in a very variable manner, according to their forms, the degree of their development, and the habits of plete; see Brandt, Bemerk. &c. p. 27, Taf. III. IV. fig. 5, P1. IX. fig. 1) had already described this fig. 1-5, and J. Miuller, Nov. Act. Nat. Cur. loc. respiratory system with the larva of the goatcit. p. 85, Tab. VIII. fig. 1, 3. These two anato- moth, under the name of brides epinidres, it is mists have given, moreover, details with figures on Newport who has recently called the attention of the splanchnic nerves of Libellula, Blatta, Man- anatomists to this subject, by furnishing, with adtis and Gryllus. mirable details, the disposition of this respiratory 7 S;wcommerdamm (Bib. der Nat. p. 132, Taf. plexus, in the larva, pupa and imago of Sphina X;XVIII. fig. 2) has observed the Nervus recur- ligustri (Philos. Trans. 1832, P1. XII. fig. 4, rens in the larva of Oryctes nasicornis. Miiler 1834, P1. XIII. &c., and 1836, P1. XXXVI., also (Nov. Act. Nat. Cur. loc. cit. p. 94, Tab. VII. fig. Cyclopaed. loc. cit. p. 947, fig. 400). See, also, 4, 5) has figured it with Lucanus and Dytiscus. Midiler's ideas (Archiv, 1835, p. 82) on the nature Straus (Consid. &c. p. 406, 391, PI. IX.) has ob- of this nervous system. With various Coleoptera, served with Metlolontha, not only the single and Orthoptera, with Locusta, Gryllotalpa, and nerve, but also the double system which, however, Carabus, the single roots arise, according to Nelwhe mistook for the accessory ganglia of the brain; port, from small ganglia, at the points where are Brandt (Mlediz. Zool. II. p. 103, 118, Taf. XVII. given off the NYervi transversi. fig. 3, 4, Taf. XIX. fig. 20) was the first to under- 1 For the senses of the Insecta in general, bestand the true nature of this system with Meloe and side the works of Spence and Kirby, Burmeister Lytta. See, moreover, Burmneister (I-Iandb. &c. and Lacordaire, see Schelver's Yersuch einer Taf. XVI. fig. 8 (a larva of Calosoma)), Newport Naturgesch. d. Sinneswerkz. bei d. Insekten u. (Philos. Trans. 1834, P1. XIII. fig. 4, 5 (imago and WVarmerin, 1798, a work in which are related the larva of Timarcha tenebriosa), and C(yclopaed. opinions of the older naturalists on this subject. &c. fig. 405, 412, 416-418 (Timarcha, Melot and 2 The tactile sense of the palpi is of great service Luecanus)); also Schibdte, in Kriyer's Naturh. to Insecta when they eat; for these organs are used Tidskrift. IV. p. 104, P1. I. Acilius. not only to feel the food but also to retain, and cor 8 Although Lyon et (Trait6, &c., p. 98, 201, P1. vey it between the jaws. a~ 333, 334. TIE INSECTA. 415 the species. These organs receive, each, directly from the superior cerebral mass, a nerve; these nerves perceive the slightest disturbances occurring in the antennal teguments, which are solid and often provided with hairs and bristles. With those Insecta with which these organs are very long, filiform, and movable in various directions, they serve, like the vibrissae of many mammalia, to announce the presence of external bodies. With very many other Insecta, they are very movable, and are distinctly used as tactile organs, like the fingers of the human hand.0( It is also by means of these organs, that insects perceive the various conditions of the atmosphere, especially the temperature, and thereby regulate their movemnents and asctions. With those Insecta whereof the parts of the mouth are changed into organs of suction, it is quite evident that the extremity of the snout or proboscis is the seat of a very delicate sense of touch. Also with those female insects having an ovipositor, which is used to deposit their eggs in holes of various depth, the apex of this organ must be endowed with the same power. Finally, this sense must be ascribed to the extremities of the legs of many Insecta, which, in either their larval or in their perfect state, use these organs for the performance of labors of a special nature.(4) W7ith the Poduridae, there is, upon the ventral surface of the first abdominal segment, a singular organ which is soft, protractile, bifurcated or bi-lobed, and probably of a tactile nature.(5) ~ 333. Undoubtedly the sense of taste, with Insecta, is seated in the tongue, when this organ is present. The tongue, of a soft consistence, is particularly developed with the Carabidae, Locustidae, Acrididae, Libellulidae,:and Vespidae, which are all mandibulated; and with the Apidae, and Muscidae, which lick up their food. With the suctorial Insecta, the tongue is either wanting, or changed into a horny bristle; — a transformation met with, also, in certain species having masticatory organs. ~ 334. The organs of Olfaction with Insecta, have not yet been satisfactorily determined, although most of these animals by their aid, can perceive in a most wonderful manner, the food proper either for themselves or their young. The various hypotheses upon this subject are unsatisfactory, and especially those by which this sense is located in the hard and dry parts of the body, which are quite unfit to recognize odoriferous substances.'l) 38 This may be especially observed with the cherch. &c. p. 42, P1. III. fig. 5, 19-22. I am not deHIymenoptera. termined whether or not should be placed in the same 4 As' such I recollect only the Ateuchidae and category the soft protractile organs, often of a beau-.Phynchites among the Coleoptera, the fossorial tiful red or orange color, possessed by Malachius Ihymeuoptera, and the larvae of the Phryganidae on the lateral portions of the body, by Stenus at among the Neuloptera. the extremity of the abdomen, and by the larvae of 5 With Smynthurus, these organs consist of two various Lepidoptera (Papilio machaon and podalong contractile cylinders; see Degeer, Abhandl. lirisls, Harpyia vinulao, &c.) on the neck or back.* &c. VII. p. 20, Taf. III. fig. 10, and Nicolet, Re- 1 According to Rosenthal (Reil's Arch. X. p. * [ ~ 332, note 5.1 See upon the protractile, with Papilio asterias; I regard them as odorifertentacular organs of the larvae of the Papiliones, ous and defensive. rather than tactile organs. - Karstenl (liiller's Arch. 1848, p. 375). I have ED. carefully and microscopically examined these organs 416 THE INSECTA., 3885 ~ 335. There is the same uncertainty concerning the organs of Audition. Experience having long shown that most Insecta perceive sounds, this sense:has been located sometimes in this, and sometimes in that organ. But in these opinions, it often seems to have been forgotten or unthought of, that there can be no auditive organ, without a special auditive nerve which connects directly with an acoustic apparatus capable of receiving, conducting, and concentrating the sonorous undulations.(l) Certain Orthoptera are the only Insecta with which there has been discovered, in these later times, a single organ having the conditions essential to an auditive apparatus. This organ consists, with the Acrididae, of two, fossae or conchs, surrounded by a projecting horny ring, and at the base of which is stretched a membrane resembling a Tympanum. On the internal surface of this membrane, are two horny processes to which is attached an extremely delicate vesicle filled with a transparent fluid and representing; a membranous labyrinth. This vesicle is in connection with an auditory nerve which arises from the third thoracic ganglion, forms a ganglion upon the tympanum, and terminates in the immediate neighborhood of the: labyrinth by a collection of cuneiform, staff-like bodies with very finelypointed extremities (primitive nerve-fibres?), which are surrounded by loosely-aggregated, ganglionic globules. (2) The Locustidae and Achetidae have a similar organ, situated in the, 136, Taf. VIII. fig. 5, 6), the olfactory organ of the Meatus asuditorius externus and internus, a. Muscidae is a double, oblong fossa, situated under Tympanum, and a Labyrinthus, of all of which the antennae, and covered by a plicated membrane there is not the least trace. The two white convex formed by the cutaneous envelope, which is other- spots at the base of the antennae of Blatta orienwheres solid and dry. Until lately, from the time of talis, and which Treviranus (Annal. d. WetterReaumur, the sense of smell has been located in auisch. Gesellsch. f. d. gesammte Naturkunde, I. the antennae, although they present no trace of a Hft. 2, p. 169, Taf. V. fig. 1-3) has described as humid surface, and have none of the anatomical auditory organs, are, as Burmeister has correctly and physiological conditions requisite for being the stated (Handb. II. p. 469), only rudimentary accesseat of this function. See Lefibvre, Ann. d. la sory eyes. Newoport (Trans. of the Entom. Soc. Soc. entom. d. France, VII. p. 395, or Ann. II. p. 229) and Goureau (Ann. d. 1. Soc. ent. X. po. d. Sc. Nat. XI. 1839, p. 191; and Kaster, Isis, 10) think that the antennae serve both as tactile1844, p. 647. The same objections might be raised and as auditory organs. But this view is inadmisagainst the opinion of Marcel de Serres (Ann. du sible, as Erichson (Wiegmann's Arch. 1839, II. Mus. XVII. p. 426), who locates this sense, with p. 285) has already stated, except in the sense that.. the Orthoptera, in the palpi. Equally groundless the antennae, like all solid bodies, may conduct appears the view of Baster quoted by Straus sonorous vibrations of the air; but, even admittin(Consider. &c. p. 420), that this sense is seated in this view, where is the auditory nerve? for it is. the stigmata of the tracheae. Treviranus seeks to not at'-all supposable that the antennal nerve can avoid the difficulty in supposing that the entire serve at the same time the function of two distinct buccal cavity, which is humid, can receive odorous senses. impressions. Erichson (Diss. de fabr. et usu an- *2 This organ has been taken for a soniferous aptenn. in Insect., Berlin, 1847) has recently appeared paratus by Latreille (1M1m. du Mus. VIII. p. 123) anew in fatvor of the antennae. According to him, and Busrmeister (Handb. I. p. 512). J. Miiller the numerous small fossae of these organs are covy- (Zur vergleich. Physiol. d. Gesichtssinn. p. 439, and ered internally with a delicate membrane sensible Nov. Act. Nat. Cur. XIV. Tab. IX.) was the first to odors.* who fortunately conceived that with Gryllus hiero1 The author who has erred most widely in this glyphus, this was an auditory organ. tie gave, respect, is L. W. Clarke (Magaz. of Nat. Hist. however, this interpretation only as hypothetical F. September, 1838, or in Froriep's neue Notiz. IX. but I have placed it beyond doubt by careful p. 4, fig. 12, a-n), who has described at the base of researches made on Gomnphoceros, Oedipoda, Pothe antennae of Carabus nemoralis, Illig. an disma, Caloptenus and Truxalis (Wiegmann's auditive apparatus, composed of an Auricula, a Arch. 1844, I. p. 56, Taf. I. fig. 1-7). * [ ~ 334, note 1.] See also Burmeister (Zeit. somewhat in their statements upon the intimatefuir Zool., Zoot., und Pallontol. von D'Alton und auditory structure of these organs, and, therefore, Burmeister, No. 5, p. 49, Taf. I. fig. 25-29), who as to the exact mode by which audition occurs. - likewise advocates the auditory function of the ED. antennae. But Burmeister and Erichson differ $ 336. THE INSECTA. 417 fore-legs directly below the coxo-tibial articulation.~i With a part of the Locustidae,(4) there is, on each side at this point, a fossa; while with another portion of this family,~() there are, at this same place, two more or. less spacious cavities (Auditive capsules) provided with orifices opening forwards.~61 These fossae and these cavities have each on their internal surface, a long-oval tympanum. The principal trachean trunk of the leg passes between the two tympanums, and dilates, at this point, into a vesicle whose upper extremity is in connection with a ganglion of the auditory nerve. This last arises from the first thoracic ganglion, and accompanies the principal nerve of the leg. From this ganglion in question passes off a band of nervous substance which stretches along the slightly excavated. anterior side of the trachean vesicle. Upon this band is situated a row of transparent vesicles containing the same kind of cuneiform, staff-like bodies, mentioned as occurring with the Acrididae. The two large trachean trunks of the fore-legs open by two wide, infundibuliform orifices on the posterior border of the prothorax, so that here, as with the Acrididae, a part of this trachean apparatus may be compared to a Tuba Eustachii.(7) With the Achetidae, there is on the external side of the tibia of the forelegs, an orifice closed by a white, silvery membrane (Tympanum), behind which is an auditory organ like that just described.(8) ~ 336. The organs of Vision consist of simple, or of compound eyes.(l) Thec first occur chiefly with the larvae of holometabolic Insecta; and the second with Insecta in their perfect state. There are, however, many species which have both kinds of eyes in their imago state. These organs are wanting with only a few adult Insecta,(1) but are wholly absent with many larvae and pupae of the holometabolic species.(3) 1. The Simple eyes (Ocelli, Stemmata) are composed of a convex, spheroidal, or elliptical cornea, behind which is situated a spherical or cylindrical lens, lodged in a kind of calyx formed by an expansion of the optic nerve, and which is surrounded by a variously colored pigment-layer. as by a Chorioidea.14' These stemmata are sometimes so closely situated 3 See my researches in Wiegmann's Arch. loc. 1 For the eyes of the Insecta, see Marcel de cit. p. 72, Taf. I. fig. 8-17. Serres, Mrnm., sur les yeux comp. et les yeux lisses 4 Meconema, Barbitistes, Phaneroptera, Phyl- d. Ins.; Treveranus, Verm. Schrift. III. p. 147, loptera. and Beit. zur Anat.. u. Physiol. d. Sinneswerkz.. 5 Decticus, Locusta, Xiphidium, Ephippi- Hft. I. p. 84; finally, J. Mailler, Zur vergleich. gera, Saga, Conocephalus, Callinemus, Acan- Physiol. des Gesichtssinn, p. 326, or in Ann. d. Sc,. thodis, Pseudophyllus, &c. Nat. XVII. 1829, p. 242 (in extract), and his Mle6 In his classification of the Locustidae, Bur- moir in Meckel's Arch. 1829, p. 38. meister (Handb. &c. II. p. 673) has made use of 2 The eyes are wanting in many species of Ptilithe different forms of these orifices 5- differences, um which live under the bark of trees (Erichson, however, which had before been pointed out by De- Naturgesch. d. Insekt. Deutschl. III. 1,) 32); with geer (Abhandl. Th. III. p. 285, Taf. XXXVII. fig. Anophthalmues, which live in caverns (Sturre, 5 and 6) Lansdown Guilding (Linn. Trans. XV. Deutschl. Fauna Abth. v. Bd. XV.), and with Cla1827, p. 153). viger, which live in ant-nests. 7 These two infundibuliform orifices of the tra- 3 As such may be cited the larvae of H-lymenocheae, which L. Dufour (Recherch. sur les Orthopt. ptera, excepting, however, those of the Tenthredini&c. p. 279, P1. I. fig. 2) has called vessies aerosta- dae; those of the Diptera, which live in decompostiques, have generally been regarded as the stig- ing animal and vegetable substances; those of the~ mata of the prothorax, although the true stigmata, Elateridae, IListeridae, Lamellicornes, Tenebrioniof the ordinary form and size, are, situated in front dae, and in general the apodal larvae of Coleoof the orifices in question. ptera; finally, the parasitic larvae of the Strepsi8 With Acheta achatina and italica, there is ptera, whose females are also blind in the imag> a tympanum of the same size, on the internal sur- state. face of the legs in question * but it is scarcely ob- 4 For the simple eyes of Dytiscus, see Alitler,. servable with Acheta sylvestris, domestica and in M ec/cel's Arch. loc. cit. p. 39, Taf. III. fig. 1, 2? campestris for those of Cicada, Vespa, Bomzbus, and Libel 418 THE INSECTA. g 336. on the brain that their optic nerves consist only of small papillae on this last;(') but, when further removed from the.brain and grouped together, the optic nerves arise by a common trunk which divides into as many.branches as there are eyes.(6) The number and disposition of the stemmata vary very much in the different orders. When they alone constitute the visual organs, they are always situated on the lateral parts of the head, -- where they may be disposed either, as one on each side, or as several irregularly grouped together (Ocelli gregati), or regularly arranged in rows (Ocelli seriati). There is only one simple eye on each side with the Pediculidae, Nirmidae, Coccidae, the larvae of the Phryganidae and Tenthredinidae, and the aquatic ones of very many Diptera. These organs are in groups of four to eight with the Poduridae,t7) with the larvae of Lepidoptera, the hexopod larvae of the Strepsiptera, the larvae of the Hemerobidae, lymneleonidae, Raphi-, didae, and with the hexapod ones of the Coleoptera. (8) The winged males of the Strepsiptera have the largest number of stemmata aggregated in groups; they here form two lateral, globe-like projections, and constitute the transitionary form to the faceted eyes, for there are fifty to seventy on each side, separated from each other only by hairs.(9) Very many Insecta with two, faceted eyes, have, also, on their front, three stemmata disposed in a triangle. (10) 2. The Compound eyes, or those whereof the cornea is faceted, are composed of simple eyes so thickly set together that their more or less thick, slightly convex, quadrangular, or hexagonal corneae are contiguous.(l) The size of these facets is not uniform even in the same eye, for sometimes those above, or those in the centre, are the larger.(') Behind each cornea is situated, in place of a lens, a transparent pyramid the apex of which'is directed inwards and received into a kind of transparent calyx corresponding to a Corpus vitreum. This last is surrounded by another calyx formed by the expansion of a nervous filament arising from the lula, see Treviranus, Beitr. &c. p. 84, Taf. II. dae, Perlidae, Psocidae, Ephemeridae and some fig. 25-35. Phasmidae); with some Neuroptera (Hemerobius, 5 Bombus, Apis, Vespa; see Treviranus, Bi Panorpa, Phryganea), and Hemliptera (Pentaxlogie, V. Taf. II., and his Beitr. &c. Taf. II. fig. 29; tonma, Coreus, Berytus, Cicada). This is the case and Brandt and Ratzeburg Medizin. Zool. II. Taf. also with many Diptera, such as the Muscidae, XXV. fig. 31, 32. Syrphidae, Stomoxidae, Bombylidae, Anthracidae, 6 With many of the larvae of the Lepidoptera Oestridae, Asilidae, Empidae, &c.; they are wantand the Coleoptera, the optic nerves arise by two ing with Tabanu.s, Haematopota, Conops, Hipmore or less long roots; see Lyonet, TraitS. &c. poltosca, Melophagus, and many of the Tipulidae. p. 581, P1. XVIII. fig. 1, No. 1, and fig. 6 (larva of With the Hymenoptera, they are constantly presthe goat-moth); Suckow, Anat. physiol. Unter- ent except with the neuter ants and with the fesuch. p. 41, Taf. III. fig. 34 (pine caterpillar), and males of Alutilla and Alyrmosa; there are only Burmeister, Trans. Entom. Soc. I. p. 239, P1. two of these eyes with most of Gryllus; Sciophila, XXIII. fig. 7 (larva of a Calosoma). The three Mycetobia and Leja, of the Diptera; Sesia, Eustemmata of Cicada receive their nerves from a prepia, Pyralis and a great number of the Noctucommon trunk arising from the middle of the brain; idae, of the Lepidoptera; Gryllotalpa, Blatta and see Treviranus, Beitr. Taf. II. fig. 24, and L. Termes, of the Orthoptera; and Omalium and ]Dufour, Recherch. sur les IlIemiptires, &c., P1. Anthophagous, of the Coleoptera. XIX. fig. 203. 11 For the intimate structure of the compound 7 See Nicolet, Recherch. sur les Podurelles, loc. eyes, see Straits (Consid. &c. p. 411, P1. IX.),,cit. p. 28, P1. II. III. Dsiges (Ann d. Sc. Nat. XX. 1830, p. 341, PI. 8 Such are the carnivorous larvae of the Cara- XII., or in Froriep's Not. XXIX. p. 257), R. bidae, Staphylinidae, Dytiscidae, Dermestidae, Sil- Wagner (Wie gnann's Archiv, 1835, I. p. 372, phidae, &c., and the herbiferous larvae of the Taf. V.), and especially Will (Beitrtig. zur Anat. d. Chrysomelidae. Those of Cicindela have only zusammengesezten Augen mlit facettirt. Hornhaut. two large stemmata on each side of the head, and 1840). those of Lycus, Meloe, Lampyris and Cantharis, 12 These differences in the size of the facets had have only one. been observed by Marcel de Serres (loc. cit. p. 45) 9 See Templeton, Trans. Entom. Soc. III. p. 54, with Libellula. They exist also in the eyes of Pi. IV. LagriaJlava, gibbosa, atra, Tabanous rusticus, 10 There are three frontal stemmata with many and some other Diptera i see Ashton, Trans. En4f the Orthoptera (Mantidae, Acrididae, Libelluli- tom. Soc. II. p. 253, Pl. XXI. ~ 337. THE INSECTA. 419 ganglion on the extremity of the optic nerve, a short distance from the brain.(l Each lens-like pyramid with its vitreous body and nervous filament is enveloped by a Chorioidea usually of a brown color, which forms, behind the cornea, a kind of pupil, (14) but to which are due, by no means, the beautiful colors so often observed in the eyes of these animals.(l1 ) The size and form of the compound eyes, as also the number of their facets, are very varied.'') The larvae and pupae of the hemimetabolic Insecta have, usually, a less number of facets and consequently smaller eyes, than the perfect forms. With the Libellulidae, and Diptera, the eyes are very large;(17) while with the Formicidae, they are perhaps the smallest of all. With many Diptera, and some Hymenoptera, those of the males are much larger than those of the females, and are often contiguous in front or above.(18) With some Hymenoptera, and Diptera, they are pilose, - the hairs being inserted in the angles of the facets.(l9) The compound eyes are usually spherical or oblong; and, with many Cerambycidae, and with the Vespidae, they are deeply emarginate in front, ~or on their internal border. With Diopsis,(2~) they have a very singular appearance, being supported on two very long, rigid, frontal processes, and their direction cannot, as with other Insecta, be changed without a turning of the head.(21 CHAPTER V. DIGESTIVE APPARATUS. ~ 337. The Insecta very often use their labial and maxillary palpi to seize and -to convey food to the mouth, and even to introduce it wholly within this last. With many species, the fore-legs are used to seize and retain the food, and the first pair is sometimes changed for this purpose even into rapacious organs.(l) With the larvae and pupae of the Libellulidae, there 13 According to Miiller (Arch. 1835, p. 613), 17 The largest eyes are observed with the Heno-these retinae are formed only by a prolongation of pidae, where they cover nearly the whole head; the neurilemma, while the proper nervous sub- see Erichson, Entomographien. Hft.I. p.132, Taf. I. stance does not extend beyond the extremity of the 18 Among the Hymenoptera, the genera Astata, vitreous body; but Will denies this (Mlillers Larra, Tachytes, Apis; and among the Dipteia, Arch. 1843, p. 349). the Muscidae, Syrphidae, Leptidae, Tabanidae, 14 Each- of these pupils, according to Will (Miil- Stratiomydae, and. many other families.,er's- Arch. 1843, p. 350), is moved Ly thirty to 19 With Apis, Tabanius, Anthossyia, Eristalis, thirty-five delicate fibres which arise on the fort; Volucella, and other Diptera. -transparent cylinders surrounding the pyramidal 20 See Linne, Amoenitates academicae. VIII. lenses; but Brants (Tijdsk. voor natuullijke ge- Tab. VI. and Dalman, in Fuessly's Archiv d.:schied. en physiologie. 1844, II.) regards them as Insekt. Hft. 1, Taf. VI. or Isis, 1820, p. 501, Taf. V. trachean branches and not contractile fibres. 21 The Insecta scarcely move their head when 15 The beautiful emerall color of the eyes of they look in different directions. This renders very:many Libellulidae, Tabanidae, I-Iemerobidae, &c., is singular the extended mobility of the head with due to the corneae; for the chorioideae are of the Mlantis religiosa, which, in watching for its prey, -same dead color as those of other Insecta. looks on all sides. 16 There are sometimes several thousands of 1 For example, with Syrtis, Naescoris, Nepa, -these facets in the eyes of large size * see iuiller, Ranatra, Hemerodromia, Mantis, Mlantispa, Zur vergleich. Physiol. d. Gesichtssinn, &c., p. 340, &c. and Will, Beitrag. &c. p. 10. 420 THE INSECTA. ~ 337. is, attached to the under -lip, a peculiar prehensile organ which covers, like a mask, the masticatory organs, and, by means of a double articulation, can. be let down and then returned with the utmost quickness. During this manceuvre, the prey is seized by two acute hooks inserted on the anterior border of this lip, and carried to the mouth. (2) The parts of the mouth of the Insecta may be divided into MIasticatory and Suctorial organs, between which, however, there are many intermediate forms. The second are, properly speaking, modifications of the first, and for this reason, the last should be described first; the special details of these organs, however, belong to the domain of Zoology. These masticatory organs (*) consist of a pair of Mandibles and a pair of Maxillae, which move laterally and are more or less covered by an upper (Labrurm), and an under (Labiunm) lip. The upper jaws (Mllandibulae)} exceed in hardness all the other parts of the masticatory apparatus, and consist of two simple, horny organs, often denticulated at their extremity. The under jaws (Maxillae) are, usually, softer, and composed of several pieces, - of which the most essential are: Palpi maxillares, composed of from one to six articles, and directed outwards; and the stipule, usually denticulated or ciliated, and divided into a Lobus externus and internus. The under lip, which supports two Palpi labiales composed of from one to four articles, may thus be considered as another pair of maxillae the lateral halves of which are more or less fused together on the median line.(4> Such are the oral organs with the Coleoptera, the Neuroptera, and the Orthoptera. It -is interesting to remark that the Orthoptera, in the widest acceptation of the term, have in common, this character, that their under lip is divided by a deep fissure into lateral halves, while that of the Neuroptera and Coleoptera consists of a single piece.~() At the base of the under lip is attached the tongue, which, either fleshy or horny, is single or cleft. Often it is completely abortive, but in other cases, on the contrary, it is very long and changed into a suctorial organ. This last form is most prominent with the Hymenoptera, where the two jaws have, at the same time, ceased to be masticatory organs, and form a sheath enveloping the tongue and labial palpi.(6) The oral parts are changed into suctorial organs with the Diptera,. Hemiptera, and Lepidoptera. The first have a Proboscis, formed by the under lip transformed into a suctorial tube (Theca) which is often geniculate. At its base are from four to six bristles which may be regarded, some as, miaxillae and mandibles, and others as representing the tongue.() With 2 See Roesel, Insektenbelustigungen, II. Insec- holometabolic Neuroptera. This justifies the sepatorum aquatil. Classis II. p. 12, Taf. III. IX., and ration we have made of the first whose pupae take Sueckow, in Heusinger's Zeitsch. d. organ. Physik. food and are active, from the second whose pupae II. Taf. I. are inactive and do not eat. We have placed these 3 Beside the so often cited writings of Straus, last among the Orthoptera, because, like them, they Kirby and Spence, Brandt and Ratzeburg, Buir- have in all their states a bifid under lip. The difmeister, Lacordaire, Neewport, and Westwoood, ferences between the under lip of the Orthoptera. see Savigny, Wim. sur les anim. sans vertAbres, I. and that of the Neuloptera are well shown in Savigp. 1, P1. I.-IV.; also, Isis, 1818, p. 1405, Taf. XVIII. ny's excellent figures of the buccal orgals of these NYees von Esenbeck, Isis, 1818, p. 1386, and insects (Descript. d. l'Egypte, Orthoptires, P1. I.Suckow, in Heusinger's Zeitsch. &c. III. Taf. I.-IX. VII. and Neuroptires, P1. I.-III. 4 This opinion, before advanced by Oken, Savin- 6 See Swammerdamm, Bib. der Nat. Taf. XVII. ny, and Leach, has been sustained with very many fig. 5; Treviranus, Verm. Schrift. If. I-Ift. 2, p, details by Brulle (Ann. d: Sc. Nat. II. 1844. p. 324). 112, Taf. XII.-XIV. * Brandt and Ratzeburg,. 5 On account of these modifications of the under Mediz. Zool. II. Taf. XXV. fig. 8-16; Neuport, lip,,o which Erichson (Entomograph. I-Ift. 1, p. Cyclop. loc, cit. p. 897, fig. 375, 376; but especially 6, and in Germar's Zeitsch. I. p. 150, Taf. II.) has SavigJny, Descript. de l'Egypte, IHymenoptires, P1. especially called the attention, we can distinguish, I.-XX. in their perfect state, the hemimetabolic from the 7 See Savigny, M1m. sur les anim. sans vert6 ~ 3837. THE INSECTA. 421 the Hemiptera, the suctorial apparatus is lengthened into a Rostrum, by the under lip being changed into two quadri-articulate grooves united so.as to form a tube, and enclosing the setiform mandibles and maxillae.~~ With the Lepidoptera, the changes are still greater, for the mandibles are,only very small appendages, while the maxillae are transformed, each, into a semi-canal which can be rolled up spirally, and when united form an organ of suction (Lingua spiralis). At the base of this last are two very short maxillary palpi, bi- or tri-articulate, while the two tri-articulate and very hairy labial palpi conisist of two pretty large appendages between which the.suctorial tube retreats when rolled up.(9) The buccal organs begin to atrophy with the Aptera. The four palpi present with the Lepismidae, are already wanting with the Poduridae;(c0) and with the Nirmidae, they, as well as the maxillae, are very small, while the mandibles are quite large. With the Pediculidae, there are still wider modifications; for here there is a protractile suctorial tube composed of four stiff bristles (rudimentary jaws) which are enclosed in a soft and equally protractile sheath (under lip.) (11) With the Larvae of Insecta, the buccal organs are most usually masticatory; for, not only the larvae of the Coleoptera, the Orthoptera, and many of the Neuroptera and Hymenoptera, have the same organs of this kind (masticatory) as the perfect insects, (21 but also the larvae of the suctorial Lepidoptera,(13) and those with a distinct head of certain Diptera (14) with which, however, the maxillae and palpi are very frequently wanting.(95) But with the acephalous larvae of Diptera, those of the Strepsiptera, as also with the parasitic ones of some Hymehoptera, the mouth is formed rather for sucking than for masticating the food; for, on the inner side of the soft tumid lips, either the horny organs are wholly wanting,(l" or the mouth is armed with two parallel hooks, which are used partly to grapple and partly to puncture the bodies these animals attack.(l) bres, I. P1. IV. fig. 1, and Newport, Cyclopaed. 14 Such are the larvae of Culex, Chironomus, loc. cit. fig. 379-381.* Corethra and Simulia, and many other of the 8 Savigny, Mim. &c. I. P1. IV. fig. 2, 3; aquatic Tipulariae. Ratzeburg, Mediz. Zool. II. Taf. XXVII.; and 15 In the larvae of Sciara, Mycetophila, &ScioBurmeister, Handb. &c. II. Taf. I. phila, Ceroplatus, &c., which live in rotten wood 9 This suctorial tube is pretty long with the Papi- or in fungi; see L. Dufour, Ann. d. Sc. Nat. XI. -lionidae and the Sphingidae; it is very short with 1839, p. 204, PI. V. fig. 23, XII. p. 10. many Bombycidae and Pyralidae; see Savigny, 16 The mouth oF the apodal larvae of the StrepMom. &c. I. p. 1, PI. I.-III.; Ratzeburg, Die siptera (see my researches in Wiegmann's Arch. Forstinsekt. II. p. 2, Taf. I.; and Neiwport, 1843, I. p. 159, Taf. VII. fig. 14), and of the young Cyclopaed. toc. cit. p. 900, fig. 377, 378. larvae of Microgaster (Ratzebutrg, Die Ichneu10 Nicolet, Recherch. p. 34, PI. IV. mon. d. Forstinsekt. p. 13, Taf. IX.) has, in place 11 Burmeister, Linnaea entomologica. II. p. 569, of jaws, soft papillae which, as these larvae apTab. I. proach the end of their development, are changed 12 See Ratzeburg, Die Forstinsekt. I. III.; into horny jaws by means of which these Insecta Hartig, Die Aderfiiger Deutschlands, Taf. I.- make a passage into the skin of the animals ina VIII. Burmeister, Trans: Entom. Soc. I. P1. which they live. XXIII. XXIV. (Calosoma), and Naturgesch. d. 17 With the Muscidae, Oestridae, Syrphidae, and Calandra, fig. 10-12; Waterhouse, Trans. entom. other Diptera; see Swammerdam7n, Bib. der Soc. I. Pl. III.-V. (Rhaphidia, and various Coleop- Nat. Taf. XLIII. fig. 5, and L. Dufour, Ann. d. tera). Sc. Nat. I. 1844, p. 372: P1. XVI. fig. 8, 10, XII. 13 Lyonet, TraitS, &c., P1. II. and Ratzeburg, 1839, p. 4, PI. II. III. Die Forstinsekt. II. Taf. I. * [~ 337, note 7.] See in this connection the me- the mouth of the Diptera presents appendages tnoir of Blanchard (De la Composition de la bouche wholly comparable to those of the other Insecta, dans les Insectes de l'ordre des Dipteres, in the except that these appendages are modified in a. Compt. rend. 1850, XXXI. p. 424), who shows that special manner. - ED. 36 420 TIHE INSECTA. ~ 338. The mouth of the larvae of the Myrmeleonidae, Hemerobidae, and Dytiscidae, is of a very peculiar construction. There is no oral orifice, properly speaking, and the maxillae and mandibles are wholly unfit for mastication, the latter being changed into two curved hooks, hollow and with a narrow fissure at their extremity. These larvae bury these hooks in the insects they have seized, and through the cavity of these organs, which communicates at its base with the Eosophagus, suck the blood.(l8 A considerable number of the Insecta take no food during their perfect; state, the object of their existence being only to accomplish the act of reproduction. Their jaws are often very rudimentary and are fit neither for sucking nor for masticating. (19) In some cases, indeed, not only are these organs wanting, but the oral orifice is closed as with all inactive pupae.("') ~ 338. The Digestive Canal of Insecta and'their larvae, is more or less long, sometimes extending from the mouth directly to the anus upon the median line; sometimes forming in the abdomen loops and convolutions. It is retained in place not by a nulesentery, but by numerous fine tracheae, which envelop its entire extent. It is always wholly invested by a homogeneous peritoneal envelope under which lies a muscular tunic, composed of longitudinal and circular fibres, which are especially developed about the mouth and anus. Internally, it is lined throughout by an epithelium which is extremely thin at the middle portion of this canal, but very solid and composed of chitine at its two extremities. In the middle portion just mentioned, there is a layer of aggreg.-;ecd cells, evidently of a glandular nature, between the epithelium and the muscular tunic. The different parts of this canal in the Insecta may be properly distinguished in the following manner. The first portion is the Oesophagus, muscular, occupying the three thoracic segments and often dilated at its posterior part into a crop (Ingluvies) and muscular gizzard (Proventriculus). Sometimes there is appended to the esophagus a sucking stomach consisting of a more or less pedunculated, thin-walled vesicle, which is multiplicated on itself when empty. The second portion consists of a stomach (Ventriculus), in which the chyle is formed, and which is continuous at the point of insertion of the Malpighian vessels, with the third portion' of the digestive canal. This third portion commences by a small and usually short Ileum, which is followed by a Colon, larger and of variable length. This last often has a Caecum at its anterior extremity and terminates posteriorly in a short muscular Rectum.(l) 18 See Roesel, Insektenbelust. III. Taf. XVII. proboscis of many Bombycidae and TTepiolidae, apXVIII. (AMyitmeleon), II. Insect. aquit. classis I. pears equally unfit to receive food. Finally, the two Taf. I.-III. (Dytiscus); Ratzeburg, Forstinsekt. small, intercrucial maxillae of the males of the III. Taf. XVI. (Hemerobius). With the larva of Strepsiptera, are wholly inadequate for the funcDytiscus, the body of the maxillae is wholly abor- tions of masticatory organs. tive, but always provided with palpi. With those 20 Movable oral organs and an oral orifice are of Hemerobius, the maxillae are small, deficient in wanting with many Oestridae, and HIenopidae, as palpi, and play in a groove on the concave side of well as with the male Coccidae. the mandibles; finally, with those of Myrmeleon, 1 The functions of these different portions of the these organs are wholly enclosed in the cavity of digestive canal do not always correspond to those the mandibles. of those parts having the same names with Verte19 The maxillae are rudimentary and very soft brata. Burmeister (Zur Naturgesch. d. Calandra with the Ephemeridae, and Phryganidae, in the p. 9) is certainly correct in saying that the stomach last stages of their development. The very short is the chylopoietic part, thus combining the fune ~ 338. T:HE INSECTA. 4203 With nearly all Insecta in their perfect state, this colon or large intestine contains from four to six organs of a peculiar structure and doubtful function. These consist of transparent protuberances, disposed in successive pairs, or forming a transverse series. They are round, ovoid, or oblong, their base being sometimes surrounded by a horny ring, and they are traversed by numerous tuft-like tracheae.(2) The Lepidoptera, especially, are remarkable for their numerous organs of this kind.to) It is singular that they are wanting in all insects during their larval and pupa states. The Anus of Insecta, in all their states, is invariably situated on the last segment of the body. With the quiescent and non-feeding pupae, both the anus and the mouth are wanting, but with the larvae of only the Strepsiptera, the Apidae, and the Vespidae, are both ileum and colon wanting at the same time.(4) The form and disposition of the different parts of the digestive canal vary infinitely, according to the habits of life and the states of development of the Insecta in which they are observed. On this account it is very difficult to make any general statement of the various structural relations.(5) But that condition may be taken as the fundamental type which belongs. to those perfect insects whose life is pretty long and which have masticatory organs. Such, therefore, will receive our first consideration. With the Coleoptera,~) the oesophagus is nearly always terminated by a tions of the stomach and small intestines of the their internal structure. They are especially apNIammalia. The crop and gizzard correspond to parent and four in number with the MIuscidae; see parts of the same names with birds. The ileum, Ramdohr, Abhandl. fib. d. Verdauungswerkz. &c. which is usually regarded as analogous to the small Taf. XIX. fig. 2, M. M.; and. Suckows, loc. cit. intestine of the Vertebrata, probably plays a very Taf. IX. fig.. 153. The four with 1Melophagus are subordinate part in the act of digestion. Burrmeis- very singular and different from those of the other ter thin''?at it serves only to conduct the chyme pupiparous Diptera, in that their external surface or chyl,e. with certain species where it is very is covered with small solid scales; see L. Dufour, long, it is probably the seat of a second digestion. Ann. d. Sc. Nat. III. 1845, p. 71, P1. II. fig. 13The caecum often serves to receive the secretory 15. product of the Malpighian vessels, and therefore 3 I have counted, with the Zygaenidae, thirty of belongs rather to the nrinary than to the Chylo- these swellings, aid nearly a hundred with the poietic apparatus (see ~ 346). Papilionidae, Noctuidae and Geomnetridae. Hepio2 It is hardly comprehensible how organs so com- lus, Tinea, and Adela, have, by exception, only mon with the Insecta, should, as yet, be so little six. Treviranus (Verm. Schrift. II. p. 106, Taf. known. XII. fig. 4), and Lyonet (MIem. du Mus. &c. XX. Swammerdamm, however, observed them with p. 184, PI. XYIII. fig. 6) have taken these organs Apis mellifica (Bib. der Nat. Taf. XYIII. fig. 1), for glands with Papilio. and Suckow (Hetesinger's Zeitsch. III. p. 21, Taf. 4 The digestive canal is probably organized in a XI. fig. 121, 128) has mentioned them with Vespa similar manner with the larvae of the Hymenoptera crabro, and Apis smsellifica, under the name of and the Diptera, which are parasitic in the bodies callous swellings. Brandt and Ratzeburg, Mediz. of other Insecta.* Zool. II. Taf. XXV. fig. 29 (Apis mell;fica), as 5 For the digestive tube of the Insecta, beside the well as Burmeister (H1andb. &c. I. p. 149) speak works already cited of Swammerdamm, Gaede, of them very slightly. L. Dufour (Riecherch. Burmeister, Lacordaire, and Newport, see, sur les Orthopt. &c. p. 396, 427), has figured them especially, Ramdohr, Abhandl. ib. d. Verdauungswith various Orthoptera, Neuroptera and IIymen- werkz. &c.; Marcel de Serres, Ann. du Mus. optera under the name of Boutons charnus; XX. p. 48 i and Suckow, in Heusinger's Zeitsch. finally, Newport (Cyclopaed. &c. II. p. 970, fig. III. p. 1. 424, (Carabuts smonilis)) has designated them as 6 The digestive organs of the Coleoptera have Glandular protuberances. All the figures above been especially studied by L. Dufour (Ann. d. Sc. cited give the external form of these organs but not Nat. II. III. 1824, and I. 1834). See, moreover, * [ ~ 334, note 4.] See, for the intestinal canal of same membrane of the intestine commencing caethe larvae of Hymenoptera, Ed. Grzube (Mailer's cally, and, finally, that the intestine serves, during Atch. 1849, p. 50), who, from examinations of the the larval state, only to receive the secretion of the larvae of wasps and hornets, concludes that a Alalpighian vessels which are urinary organs. But straight alimentary canal opening at the posterior it is doubtful if the contents of the stomach are exextremity is always present, but that only the mas- pelled by mouth during the larval state. This closed cular tunic forms the continuous tube, - the lining pyloric end of the stomach is opened during the membrane of the stomach ending caecally, and the transition to the pupa state. -ED. 424 THE INSECTA. ~ 338. crop-like dilatation,(7' which, with the Cicindelidae, Carabidae, Dytiscidae, and Gyrinidae, is followed by an ovoid gizzard. This last is longitudinally plicated internally, and these folds are usually armed on their borders with cilia or horny hooks. The intestinoid stomach is of median length with the carnivorous Coleoptera, but very long and more or less flexuous with *those which are herbivorous.(') Nearly always, its whole external surface is numerously constricted, and covered with small caeca.'~9 The ileum and colon are, usually, rather short.(10 Among the Orthoptera, the families Forficulidae, Termitidae, Blattidae, Achetidae, Locustidae, Acrididae, and Mantidae, are distinguished for their large crop,(l1) which, with Gryllotalpa is completely constricted from the cesophagus. The gizzard is of variable length, and coverel, internally, with rows of horny denticulated plates.(2) The stomach is tubular, of equal calibre, median length, and rarely makes a half or an entire turn.(l3) In most of the families just mentioned, its upper extremity has two, six, or eight caeca, 14) and its posterior part is continuous into an often somewhat flexuous ileum upon which succeeds a short colon. With the Perlidae, the gizzard is wanting, but the upper extremity of the stomach has from four to eight caeca, pointing forwards. (5) With the Phasmidae, and the Libellulidae, the oesophagus is long and large, and protrudes somewhat into the,straight, oblong, constricted stomach, which is without caeca. and is succeeded by a very short ileum and colon.(16) The digestive tube of the Ephem-,eridae, which, in their perfect state, take no food, is feebly developed. Its walls are very thin throughout, and the oesophagus is directly continulous with the stomach which is a bladder-like dilation and succeeded by a -short, straight intestine.17.Ramdohr, Magaz. d. naturf. Freunde zu Berlin, (Fosficula), and his Recherch. sur les Orthopt. 1807, p. 207, Taf. IV. (Carabus); Brandt, Mediz. &c. loc. cit. Pi. I.-V. XIII. Zool. II. Taf. XVII. XIX. (Melee and Lytta); 12 See the figures cited in the preceding note..Straus, Consider. &c. PI. V. (IMelolontha).* According to L. Dufour (Itecherch. &c. p. 608, 7 With Oedemera, this crop is-constricted from P1. XIIT. fig. 196), this gizzard with its dental apthe stomach; see L. Dufour, loc. cit. III. P1. paratus is wanting with Termes; but, according XXX. fig. 7, 8. to Burmeister (Handb. I. p. 137, Taf. XI. fig. 8 The stomach is of the greatest length with the 8-10), it is present being concealed at the base of Mielolonthidae and Hydrophilidae e see Straus, loc. the oesophagus. {cit. P1. V., and Suckow, loc. cit. It. Taf. III. IV. 13 Gryllotalpa and Ephippigera. 9 This constricted stomach is especially observed 14 These caeca are wanting with Forficula and with the herbivorous Coleoptera, as, with Meloe, Termes. There are only two with Acheta, GrylLytta, and Cantharis; bhut is wholly wanting with lotalpa, Locusta, and Ephippigera; six to eight Lycus, Telephorus, Malachius, and Cistela. with the Mantidae, Blattidae, and Acrididae. In WVith the Elateridae, the stomach is smooth, but, at these last, each of these caeca sends off two deverits upper extremity there are two caecal folds, ticula, one forwards, and the other backwards. which, with the Buprestidae, are very long; see 15 See Suckow, in Heusinger's Zeitsch. II. p. L. Dufour, loc. cit. III. P1. XI. fig. 1, 3, 4; 267, Taf. XVI. fig. 7; L. Dufour, Recherch. &c. Meckel, Beitr. &c. I. Hft. 2, p. 129, Taf. VIII. fig. P1. XIII. fig. 198; and Pictet, I-list. Nat. des 5; and Gaede, Nov. Act. Nat. Cur. XI. p. 330, Nivropteles. Famille des Perlides. These caeca Tab. XLIV. fig. 1. are wanting with Nemura. 10 With the Dytiscidae, a pretty long and small 16 See Ramdohr, Abhandl. &c. Taf. XV. (Libel-,caecum extends forwards from the rectum; see lula and Agrion); Suckow, loc. cit. II. Taf. II. Ramdohr, Abhandl. &c. Taf. II.; L. Duzfour, fig. 14 (Aesch/na); L. Dufour, Recherch. &c. p. Joec. cit. III. PI. X. fig. 3, and Burmeister, Hand- 568, PI. XI. (dAeschna and Libellula); and Mdlbuch, &c., I. Taf. X. fig. 4. ler, Nov. Act. Nat. Cur. XII. p. 571, Tab. L. 11 See Ramdohr, Abhandl. &c. Taf. I.; Marcel (Bacteria). These stomachic appendages are de Serres, loc. cit. P1. I.-III.; Gaede, Beitr. &c. wanting with Psocus also; see TNitzsch, in Ger-'Taf. I. II. (Blatta and Ac/ceta); Suckow, loc. cit. mar's Mag. IV. p. 277, Taf. II. fig. 1. III. Taf. VII. fig. 134-136 (Gryllotalpa); Bur- 17 See L. Dufour, Recherch. &c. P1. XI. fig..meister, Ilandb. &c. I. Taf. XI. fig. 1-6; and L. 167, and Pictet, Hist. Nat. des Insect. Nevropt. Dufour, loc. cit. XIII. 1828, p. 350, P1. XX. Famille des Eph6imrines. * [ ~ 338, note 6.] See, also, Leidy, loc. cit., tails of the intimate anatomy of the alimentary Flora and Fauna within Animals, &c., for full de- canal of Passalus cornutus. -ED. 4 338. THE INSECTA. 425 The predatory Panorpidae, which are rapacious, differ notably from the other Neuroptera, and resemble rather the preceding order. Their oesophagus is short and straight, and, in the thorax, is succeeded by a spherical -muscular gizzard which is lined internally with a brown chitinous membrane covered with stiff hairs. The stomach is tubular and straight; the ileumn makes two convolutions before passing into the long colon.5l8) With the other Neuroptera, namely, the Myrmeleonidae, Hemerobidae, Sialidae, and Phryganidae, the cesophagus is long, and dilated, posteriorly, into a kind of pouch; and often there is a long, thin-walled, sucking stomach inserted on,one of its sides. The proper stomach is of a median length, and is more.or less transversely constricted.(19) The two other portions of the digestive eanal are very small and straight. The Hymenoptera, which often sip up their fluid flood, have a long cesophagus which dilates into a thin-walled, sucking stomach.(1~) With the Vespidae, Apidae, and Andrenidae, this stomach is often only a lateral fold of the oesophagus, and with many Crabonidae, it is attached solely by a short and narrow peduncle.(21) Many species of this order have a rudimentary, callous gizzard, enveloped by the base of the stomach. In the genera Formica, Cynips, LeTcospis and Xyphidria, it is very apparent,.and consists of a globular, uncurved organ. Those Hymenoptera which are,engaged during a long and active life (22) in labors for the raising and support of their young, have a pretty long and flexuous stomach and intestine, and the first has, usually, many constrictions. The Cynipidae, Ichneumonidae, and Tenthredinidae, which, after copulation and the deposition of their eggs, take no further care in the act of reproduction, have only a very short small stomach and intestine. But the modifications of each of the various portions of the digestive tubes are most prominent with the sucking Insecta, especially with the HIemiptera.(132 The cesophagus of these last is usually short and small, while the stomach is generally very long, and describes many convolutions in the abdominal cavity. This stomach, as to form and structure, may be divided into two or three distinctly-defined portions. The first consists of a glandular ante-stomach which is straight, large, and divided by several constrictions. The second has the form of a long, flexuous canal, whose. walls are glandular, and which dilates, at its posterior extremity, into an oval pouch. 24) With the Cicadidae, it forms a kind of loop, its posterior extremity being attached to the ante-stomach with Tettigonia, Cercopis, and 18 Ramdohr, Abhandl. &c. p. 150, Taf. XXVI. 21 With Chrysis, and Hedychrum, this sucking dig. 1, and L. Dufour, Recherch. &c. p. 582, P1. stomach consists of two lateral caeca situated at the Xi. fig. 169, lower end of the oesophagus; see Suckow, loc. 19 Ramdohr, Abhandl. &c. Taf. XVI. fig. 2, Taf. cit. III. Taf. IX. fig. 155, and L. Dufour, loc. cit. XVII. fig. 2, 6; L. Dufour, Recherch. &c. P1. P1. IX. fig. 113, 116. XII. XIII.; and Pictet, Recherch. pour servir i 22 The Apidae, Andrenidae, Vespidae, and Larl'hist. et A l'anat. des Phryganides. ridae. The Myrmeleonidae and Hemerobidae, alone, 23 For the digestive apparatus of the Hemiptera, have a spherical callous gizzard situated between see Ramdohr, Abhandl. &c. Taf. XXIL. XXIII.; the stomach and cesophagus. Suckow, loc. cit. III. Taf. VII. VIII.; L. Du20 See Swammerdamm, Bib. der Nat. Taf. four, Recherch, sur les H6miptkres. p. 20, P1. I.XVIII. fig. 1; Treviranus, Verm. Schrift. II. IX.*'Taf. XIV. XVI.; Brandt and Ratzeburg, Mediz. 24 Notonecta, Naucoris, Velia, Lygaeus, CoZool. II. Taf. XXV. fig. 29; Ramdohr, loc. cit. reus, Pyrrhocoris, Pentatoma, Tetyra, SyroTaf. XII.-XIV. Suckow, loc. cit. III. Taf. VI. mastes, &c. VII. VIII.; finally, L. Dufour, Recherch. &c. p. 389, P1. V.-X. * [ ~ 338, note 23.] For the digestive appara- Proc. Acad. Nat. Sc. Philad. I. 1847, p. 62. - ED. tus with all its details of Belostoma, see Leidy, 36* 426 THE INSECTA. ~ 338. Ledra; and with Cicada, it penetrates even under the muscular tunic of this ante-stomach.(25) With the Pentatomidae, and some Coreidae, there is even a third stomach, quite remarkable, consisting of a very narrow, slightlyflexuous canal, on which are inserted two or four rows of closely-aggregated glandular tubes.(26) The ileum and colon are nearly always fused into a pyriform pouch, upon which is sometimes inserted a kind of lateral cae-r cum.(27)- With the Cicadidae, however, the ileum is distinct, narrow, and nearly always very long and flexuous. The Diptera have a. sucking stomach with a more or less long peduncle, inserted upon one of the sides of the short, small oesophagus. This peduncle accompanies the stomach even into the abdominal cavity, where it ternminates in a pouch whose thin walls are composed solely of delicate muscular fibres. This pouch is oblong or round, and often divided, heart-shaped, by a deep fissure.(28) The proper stomach is always long and intestinoid,. except at its anterior extremity, where it is often dilated. It is situated. in the abdominal cavity and makes many convolutions. In some families, only, there are two lateral caeca inserted near its cardiac extremity. (29) The ileum is small, of median length, and is succeeded by a pyriform colon. The Lepidoptera, which, in their perfect state, live only upon the juices of flowers, suck up this kind of food by means of a thin-walled, sucking stomach, situated at the anterior extremity of the abdominal cavity, and opening by a short peduncle into the posterior extremity of the small, long oesophagus.(30) The stomach is pretty long and large, often varicose, and. always straight. The ileum is long, small, and nearly always forms several 25 See Ramdohr, loc. cit. Taf. XXIII. fig. 3; and two backwards. The Diptera fill this sucking Suckow, loc. cit. Taf. VII. fig. 138 * and L. Du- stomach with liquid (honey, blood, &c.), or solid four, loc. cit. P1. VIII. or Ann. d. Sc. Nat. V. (pollen-grains) substances, but which, certainly, are 1825, p. 157, P1. IV. It was formerly thought that only there deposited without being changed, for the second stomach of Cicada opened into the ante- the walls of this organ do not present the least stomach, but the true relation of these organs has traces of a glandular structure. It is, moreover, been pointed out by Doyire (Ann. d. Sc. Nat. XI. remarkable that the Pulicidae and the HIippobosci1839, p. 81, P1. I.) and confirmed by L. Dufour dae, which feed exclusively on animal juices, have (Ibid. XII. p. 287). The annular stomach of Dor- a kind of crop at the posterior extremity of the thesia and Psylla is probably arranged in the oesophagus, but no trace of a sucking stomach same manner; see L. Dufour, Recherch. &c. loc. see Ramdohr, loc. cit. Taf. XXI. XXIII. (Mielocit. P1. IX. fig. 108, 110. phagus and Pulex), also L. Dufour, Ann. d. Sc. 26 There are four rows of these glands with Nat. VI. 1825, p. 303, P1. XIII. fig. 1, and IiI. Pentatoma, and Tetyra, and two, only, with 1845, p. 69, P1. II. fig. 13 (Hippobosca and MeloSyromastes, and Coreus; see Ramdohr, loc. cit. phagus). With Pulex, the crop is provided with p. 189, Taf. XXII. fig. 3, 4 i L. Dufour, Recherch. large cilia on its internal surface, and thus resem&c. p. 21, P1. I. II. bles a gizzard. These two authors have taken these rows of 30 See Swammerdamm Bib. der Nat. Taf. glands for transverse-plicated semi-canals.'re- XXXVI. fig. 1 (Vanessa urticae); Treviranus, viranus (Annal. d. Wetterauisch. Gesellch. &c. I. Verm. Schrift. II. p. 103, Taf. XI., and Annal. d. Hft. 2, p. 175, Taf. V. fig. 4) is still more mistaken Wetterauisch. Gesellsch. III. Hft. 1, p. 147, Taf, in taking the four rows in Pentatoma ruJipes, for XVI. (Vanessa, Sphinx, and Deilephila); Suckas many adjacent, but distinct intestinal tubes. ow, loc. cit. Taf. IX. fig. 161 (Yponomeuta); and 27 Coreus,'Pelogonus, Rsnatra, and Nepa. Newport, Cyclop, loc. cit. fig. 430, 431 (Sphinx 28 The sucking stomach is simple with the Tipuli- and Pontia). This sucking stomach is double dae, and Leptidae; it is cordate with the Tabani- with the Zygaenidae (Ramdohr, loc. cit. Taf. dae, Syrphidae, and Muscidae; see Ramdohr, and XVIII. fig. 1); it is wholly wanting with the HeSuckow, loc. cit.; Treviranus, verm. Schrift. pialidae, Bombycidae, and in general all the imago II. p. 142, Taf. XVII. * and L. Dufour, Ann. d. Lepidoptera which do not eat. See Treviranus, Sc. Nat. I. 1844, p. 376, P1. XVI. fig. 12. Verm. Schrift. loc. cit. p. 107, and Annal. d. 29 With the Tabanidae, these two caeca point Wetterauisch. Gesellsch. loc. cit. p. 158, Taf. XVII.5 forwards; but with the Leptidae and Bombylidae, and Lyonet, MOm. du iMus. XX. p. 208, P1. XIX. backwards; and with the Syrphidae, there are fig. 10.* four of them, varicose, two pointing forwards * [ ~ 338, ncte 30.] See, also, for the intimate ippi, Annali della R. Accad. d'agricoltura di Tostructure of the intestinal canal and its append- rino, V., or Wiegmann's Arch. 1851, Th. II. p. ages of Bombyx mori (both larva and imago), Fil- 217. - ED. ~ 338. THE INSECTA. 427 convolutions. The colon is constantly of a large size, and is often dilated into a caecum at its anterior portion.(83) Among the Aptera, the Nirmidae, Poduridae, and Lepismidae, have, at the posterior extremity of the esophagus, a kind of crop, which, with Lepisma, is succeeded by a globular gizzard provided with six teeth. The proper stomach has the form of a long tube, and is not flexuous as with the Pediculidae. With these last, and with the Nirmidae, which are parasites, it has, at its anterior extremity, two caeca directed forwards. But the intestine which succeeds it, is very short with all the Aptera.(33) With all the hemimetabolic Insecta, or the Orthoptera and Hemiptera, the digestive canal of the larvae and pupae differs but little from that of the perfect insects.(33) With the Coleoptera, the larvae likewise resemble the perfect insects in this respect, - their mode of life being generally the sane, as has already been evinced by the structure of their oral organs. The stomach is usually shorter and larger, and the number of its appendages less, than with the perfect forms.(14) The larvae of the remaining holometabolic Insecta, which differ essentially from the imagines as to their oral organs, beside living upon different food, have also a digestive canal so different, that it must undergo a constant and gradual change during the quiescent pupa state.(33) Most of these larvae have powerful masticatory organs,- such are those of the Lepidoptera, the Tenthredinidae, the Siricidae, Phryganidae, Sialidae, and the cephalous ones of the Culicidae and Tipulidae. The digestive canal here is straight and rarely longer than the body; its greater portion consists of a large and. usually varicose stomach, while the ileum and colon are pretty short. Wlith the larvae of the Lepidoptera, the cylindrical ileum is large and divided into six lateral pouches, by as many longitudinal septa.(36) But with the cephalous larvae of the Mycetophilidae and Sciaridae, and the acephalous ones of the Diptera, the digestive canal is formed upon a wholly different 31 This caecum is found with Hipparchia, Pon- straight stomach, which, at both extremities and tia, Sphinx, Gastropacha, Euprepia, Acidalia, sometimes also in the middle, has a circle of simple Cabera, Adela, Chilo, and Tinea. It is wanting or varicose, thickly-set caeca; the ileum is very with Vanessa, Zygaena, Hepiolus, Cossus, Ypo- short, and the large intestine extremely large and nomneuta, and Pterophorus. always bent forwards; see Roesel, Insektenbelust. 32 See Nitzsch, in Germar's Magaz. d. Entom. II. Taf. VIII. IX.; Suckow, loc. cit. III. Taf. II:I. III. p. 280 (Nirmidae); Nicolet, loc. cit. p. 46, fig. 87 (Melolontha) L. Dufour, Ann. d. Sc. P1. IV. fig. 2 (Poduridae) Swammerdamm, Bib. Nat. XVIII 1842, P1. IV. fig. 8, P1. V. fig. 18 der Nat. p. 33, Taf. II. fig. 3; Ramdohr, loc. cit. p. (Cetonia and Dorcus); finally, the excellent work 185, Taf. XVI. fig. 3, and Taf. XXV. fig. 4, and of De Haan, Sur les metamorphoses des Col6opTreviranus, Verm. Schrift. II. p. 13, Taf. III. fig. tires, M6m. I. les Lamellicornes, in the Nouv. Ann. 1-6 (Pediculus and Lepisma). du iMus. IV. 1835, p. 153, P1. XVI.-XIX. 33 See Suckow, in Heusinger's Zeitsch. II. Taf. 35 For this metamorphosis of the intestinal canal, I. fig. 8 (Aeschna), and Rathke, in Miiller's see Dutrochet, Jour. de Physique, &c., LXXXVI. Arch. 1844, p. 35, Taf. II. fig. 4 (Gryllotalpa). 1818, p. 130, or Meckel's deutsch. Archiv IV. p. 34 With the larvae of Calosoma, the stomach is 285, Taf. III. (Bombyx, itlyrmeleon, Apis,; Polisstraight and without caeca (Burmeister, Trans. of tes, Tenthredo and Eristalis). This metamorthe Entom. Soc. I. p. 236, P1. XXIV. fig. 10, 11). phosis with Sarcopheaga haemorrhoidalis has With Hydrophilus piceus, and Dytiscus mar- been described and figured by L. Dufoler, Miem. ginalis, it is varicose, slightly tortuous, and with- pr6sent6s, &c., IX. p. 580, P1. III. out caeca (Suckow, in Heusinger's Zeitsch. II. 36 See Swammerdamm, Bib. der Nat. Taf. Taf. IV. fig. 26, and Burmeister, Handb. I. Taf. XXXiV. fig. 4; Lyonet, Traite, &c., P1. XIII. X. fig. 3). The larvae of the Lampyridae, Pyrochro- Ramdohr, loc. cit. Taf. XVIII. fig. 5. Many idae, Mordellidae, and. Curculionidae, differ but naturalists have carefully observed the metamorlittle from the imagines as to their digestive canal phoses of the digestive canal with the Lepidoptera; (L. Dufour, Ann. d. Sc. Nat. III. 1824, P1. XI. fig. see Herold, Entwickelungsgeschichte d. Schmetterl. 7 (Lampyris); Ibid. XIII. 1840, P1. V. fig. 5 Taf. III. fig. 1-12 (Pontia brassicae).; Suckow, (Pyrochroa); XIV. 1840, P1. XI. fig. 9 (_ffor- Anat. physiol. Untersuch. p. 24, Taf. II. fig. 1-10 della); and Burmeister, Zur Naturg. d. Calandra, (Gastropacha pini); and Newport, Philos. Trans. p. 8, fig. 3.) The most marked difference between 1834, P1. XIV. fig. 11-13 (Sphinx ligustri). the larvae and the imagines, is observed with the This last author has figured the digestive canal in Lamellicornes. The first have a very spacious, situ in all the three states. 428 THE INSECTA. ~ 339. plan. It exceeds more or less the length of the body, and there is a crop at the posterior extremity of the ccsophagus upon which succeeds a long and tortuous stomach. Upon the cardiac portion of this last there are inserted two to four caeca directed either forwards or backwards, and with some larvae of the Muscidae, there is also a long, sucking stomach upon one of the sides of the oesophagus.<37) With the larvae of the Neuroptera, which suck up their liquid food through tubular mandibles, the posterior extremity of the oesophagus is dilated into a pyriform sucking stomach, which is followed, by the proper stomach, large, of median length, and slightly flexuous. The extremely small ileum is long and makes several convolutions, while the colon is large, vesiculiform, and continuous into a horn5y tubular rectum.(3) ~ 339. As to the grandular appendages of the digestive canal of the Insecta, the Salivary Organs are quite widely distributed, as well with the Imagines as with the Larvae and feeding Pupae. These organs consist of one, or two, rarely three pairs of colorless tubes of unequal length. These are sometimes prolonged into the thorax, while in other cases they accompany the digestive canal into the abdominal cavity where it makes many convolutions. Their excretory ducts are composed of a solid membrane, and are distinctly separated from the glandular portion.(1) This last is composed of three layers, namely: an external, homogeneous envelope,- an intimate tunic accompanying the excretory duct, - and a middle layer composed of colorless, glandular, nucleated cells, which often form very fine excretory tubes opening into the common duct. Frequently, also, these ducts contain a spiral filament like the tracheae; they open, each, at the base of the oral cavity by a distinct orifice, and it is rare (2) that they unite, forming a common duct; sometimes they have, near their excretory openings, special salivary reservoirs.(3) With very many Aptera,(4) Diptera, Lepidoptera, and (oleoptera,('5 the salivary organs consist of two simple tubes, which, with the larvae of the second and third of these orders, often extend a considerable way into the abdominal cavity.(6) With the Cerambycidae, Te37 See Swammerdamm, Bib. der Nat. Taf. XLI. 1 For the intimate structure of these organs, see fig. 6, Tab. XLIII. fig. 5 (Stratiomys and Pio- II. Nleckel, in Meiller's Arch. 1846, p. 25, Taf. I. phila); Ramdohr, loc. cit. Taf. XIX. fig. 1 II. (Musca); L. Dufour, Ann. d. Sc. Nat. XI. 1839, 2 Piophila, Musca, Sarcophaqa, Tabanus, p. 212, P1. V. fig. 23, XII. p. 13, 18, P1. I. fig. 1, Hippobosca, Oestrus, Mordella, Mantis, and 4, and I. 1844, p. 372, PI. XVI. fig. 8 (Ceroplatus, Forficula. Sapromyza, Piophila). 3 With Forficula, Musca, Sarcophaga, and The metamorphosis of this digestive canal, in Hippobosca, each of these excretory ducts is dilated the pupa of Sarcophaga carnaria, is represented into a roundish reservoir; but with the Termitidae, in a suite of figures published by Suckow, in Acrididae, Achetidae, and Mantidae, there is an Heusisnger's Zeitsch. III. Taf. IX. fig. 147-153. oblong, pedunculated reservoir common to both But Suckow has fallen into the same error as ducts. See, for the figures, the various memoirs of Ramdohr (loc. cit. p. 171) in regarding the caecal L. Dufour. appendages of the stomach of the larvae as four 4 With the Nirmidae. tubes connecting the stomach with the salivary 5 Pyrochroa, Lixus, Phyllobius, Diaperis, canals. Lema, Oedemera, Chrysomela, Coccinella. In 38 See Ramdohr, loc. cit. p. 154, Taf. XVII. fig. this last genus, the two salivary vessels are toI and L. Dufour, Recherch. &c. p. 589, P1. XII. rose. fig. 175 (Myrmeleon). The large intestine together 6 See the figures in the works of Swammerdamm, with the rectum, does not serve, with this larva, as Lyonet, Ramdohr, Suckow, Herold, and L. Dua defecating organ, but, as is very extraordinary, four. has the function of a Spinneret (see ~ 347). ~ 339. THE INSECTA. 429 nebrionidae, Mordellidae,(7) and most of the Hymenoptera,(~) they consist of two rather short, ramified tufts, often contained entirely in the head.(') Among the Neuroptera, the Myrmeleoniclae and Sialidac have two simple short salivary tubes, while, with the Phryganidae and Hemnerobidae, they are ramified and highly developed.(10) It is quite remarkable that there is in this respect, a sexual difference with the Panorpidae; the males have three pairs of very long, tortuous tubes, while, with the females, the only vestiges of this apparatus are two indistinct vesicles.('" Amono the O1thoptera, the salivary organs are entirely absent with the Libellulidae, and Ephemeridae. On the other hand, they are highly developed with the Achetidae, Acrididae, Locustidae, Mantidae, Blattidae, Termitidae, and Perlidae, where they consist of two, four, or six botryoidal masses of vesicles, situated in the thorax, and having long, excretory ducts, beside, also, often lonlg-pedunculated pyriform reservoirs.(12) Among the enliptera,(~3) these organs are absent with the Aphididae and the Psyllidae; but, on the other hand, they are very large and of a remarkable structure with the Bugs and (Dicadidae. Here they are nearly always lobulated, and are divided by a constriction into two portions, of which the upper is much smaller than the lower, and often both have long digitiform processes. The excretory duct divides, immediately after its origin, into two special canals of equal or very unequal length, which extend, serpentinely, first, into the abdominal cavity, and then ascend to the imouth,.Ml) Beside these two constricted glands, many Bugs have, also, one, rarely two pairs of simple salivary tubes,"') which are often dilated, vesiculiform, at their extremity.(" The salivary organs of the musical Cicadidae differ in many respects from those of the others of this family; for, beside the two simple tortuous tubes, there is, in the head, another pair of' glands, composed, each, of two tufts of short, cylindrical caeca, situated one behind the other.(l) It is yet undetermined 7 See L. Dutfour, Ann. d. Sc. Nat. IV. 1824, PI. with Ranatra, Nepa,. Naucoris, Corixa, ReditXXIX. fig. 4, 5, XIV. 1840, P1. XI. fig. 16. vius, and Syrtis. One is very long and the other 8 See L. Dz~fozr, iteehlerch. &c. p. 390, fig. 48, very short with Tetyra, Pentatoma, Syromastes,'72, 109, 148 (Apis, Andrena, Philanthus, and Coreus, Lygaeus, Aphrophora and Cercopis Xyphidria. With the Hlydrocorisae, above cited, the two sali 9 With the Coleoptera, the ramified glands end vary glands are, moreover, composed of numerous in long, tortuous caeca; while with the Hymenop- round secretory vesicles. In general, these glands tera, their extremities are vesiculiform, thereby have been regarded as composed of two vesicles giving the whole gland a botryoidal aspect. each of which has a proper excretory duct; hut 10 See L. Doufour, Recherch. &c. p. 563, fig. this view is incorrect. The two excretory ducts 179, 184, 191, 192, 208, 209 (Myrmeleon, Sialis, are always the result of the division of a common Hemerobius, and Phrygasnea). trunk which arises at the constricted point of the 11 See Brants, Tijdschr. voor naturl. Geschid. gland. With Ranatra, alone, the anterior is enen Physiologie, 1839, p. 173; and L. Dufour, tirely separated fioin the posterior portion of the Iecherch. &c. p. 582, fig. 169 (Panorpa). gland.t 12 See L. Dufour., RIecherch. &c. p. 296, P1. I.- 15 There is only one pair of simple salivary glands V. XIII. (Tridactylus, Oedipoda, Gryllotalpa, with Tetyra, Pentatoma, Pyrrhocoris, Lygaens,.Ephippigera, Mantis, Blatta, Termes, and Naucoris, NVepa atnd RanLata; two pairs with Perla).s Coreres and Al lyduls. With NAepa and Ranatra, 13 For the salivary organs of the lIemiptera, see, they dilate into an oval reservoir. beside Ramdohr, loc. cit. Taf. XXII. XXIII. 16 Syrtis, Redcvius, Pelel-onri.s, and Corixa. especially L. Dufour, Recherch. sur les 11iml- 17 See L. Dotfoour Annl. d. Sc. Nat. V. 1825, p. ptdres, p. 118, P1. I. IX. 158, P1. IV. and Recherch. &ce. P1. VIIi. 14 The two excretory duects are of the same length * [ ~ 339, note 12.] See also Leidy, loc. cit. p. domen; while the other two are about one-fourth 82 (Spectreumfemoratun). -ED. as long. Beside these, on each side of the cesopht [~ 339, note 14.] With Belostoma, the agus, there is situated a sigmoid caecal pouch salivary glands are four in number, are of con- which opens by a narrow duct into the commenceglomerate structure and situated on each side of ment of the cesophagus in the vicinity of the termithe cesophagus into the commencement of which nation of the salivary ducts; these are perhaps they empty. Two of them are long and extend reservoirs of.the saliva; see Lel;dy, loc. cit. p). 63. backwards as far as the commencement of the ab- - ED. 430 THE INSECTA. ~ 339. whether'one of the pairs of these glands with these Hemiptera, may not be a poison apparatus. The Insecta have no distinct Hepatic Organs,.but the function of a Liver is performed by the walls of the stomach, the internal tunic of which is composed of closely-aggregated hepatic cells. With many species whose stomach has caecal appendages, the walls of these last have a similar hepatic structure, and must secrete, therefore, a bile-like fluid.(i)~ With some Insecta, the ileum has glandular appendages, whose product is perhaps analogous to a pancreatic fluid. The two or four rows of follicles which, as before mentioned, are situated on the ileum of the Pentatomidae and some Coreidae, would, in the same manner, be regarded as a Pancreas. The same remark applies to the ramified appendages, which, with Gryllotalpa, open into the stomach below the two caeca, as well, also, as to the two or three follicles which, with Pyrrhocoris, are inserted, laterally, on the posterior part of the ileum.(19) There is found, with all Insecta, a Corpus adiposum, - a tissue, composed of adipose cells, which is intimately connected with the functions of digestion and assimilation. This body is especially developed towards the end of the larval state, and it disappears, for the most part, during the pupa period, so that only a few traces of it are found with Insecta in their perfect state. It is usually of a white, or a dirty-yellow color, but is also observed of a green. red, or orange hue. In the larvae, the fat cells generally form pretty large, lamelliform lobes, sometimes ramified or reticulated, sometimes plicated, spread through. the abdominal cavity in all the intervals of the viscera. These lobes are always traversed and retained in place by numerous trachean branches. With the perfect Insecta, the. remains of this body are not usually found except in the posterior portion of the abdominal cavity, where they consist of fat-cells loosely scattered, and not retained by the tracheae.i'0) 18 For these biliary organs, see J. Miiller, De sur les H4miptires, p. 44, Pl. II. fig. 19, 21 (PyrGland. struct. p. 67. The Malpighian vessels rhocoris).t which were formerly regarded as biliary tubes, 20 See L. Dufour, Recherch. sur les Carabiq., in will be treated of in future (~ 346).* the Ann. d. Sc. Nat. VIII. 1826, p. 29 * Recherch. 19 See L. Dufour, Recherch. sur les Orthopt. p. sur les I-iemipt. p. 141, and Recherch. sur les 332, P1. II. fig. 19 (Gryllotalpa), and Recherch. Orthopt. p: 291, 385, 562.+ * [ ~ 339, note 18.] The liver of the Insecta, as closely applied to the intestinum tenue; they join well as that of the Invertebrata generally, has been the intestine at the junction of the duodenum and investigated by Will (Miiller's Arch. 1848, p. 502) ileum. - ED. who has applied the same chemical mode of in- $ [ ~ 339, note 20.] See, upon the Corpus adiquiry, as that of Brugnatelli and Wutrzer upon posum, Mayer (Ueber die Entwickelung. des Fetthe Malpighian vessels showing their urinary char- tkorpers, &c. bei den Lepidopteren, in Siebold acter (see mfra ~ 345, note 2). With the Insecta, and Killiker's Zeitsch. I. p. 175) who has traced he regards as hepatic the caecal and other glandu- its development. lar appendages which, when present, lie upon the These adipose bodies are formed from a great so-called Ventricslus, thus confirming the suppo- number of separate, flattened, usually manysition expressed in the foregoing ppte. For the in- pointed lobes. These lobes consist of pouches with tinmate microscopic structure of the liver of the In- structureless walls, and filled with fat-globules. secta, see Leidy, Amer. Jour. Med. Sc. XV. 1848, Each pouch is originally a simple cell with a large p. 1. — ED. nucleus attached to its wall. In this cell are t [ ~ 339, note 19.] For the hepatic organs of formed daughter-cells, which, when filled with fat, Belostoma, see Leidy, loc. cit. p. 63, P1. X. fig. burst, and thereby the mother-cell becomes the fatz,, 4, i. They consist of four long very tortuous tubes containing sac. — ED. ~ 340. THE INSECTA. 431 CHAPTER VI. CIRCULATORY ORGANS. ~ 340. The Circulatory System is feebly developed with Insecta, consisting of a contractile, articulated Vas dorsale, and a cephalic Aorta. The first serves as a heart, and the second is a simple conductor of the blood frolm the heart into the body. In both of these vessels, the blood moves from behind forwards, and, at its escape from the aorta, traversesthe body ill all directions, forming regular currents which have, however, no vascular walls. In this way, it penetrates the antennae, the extremities, the wvings, and the other appendages of the body, by arterial currents, and is returned by those of a venous nature. All the venous currents empty into two lateral ones running towards the posterior extremity of the body, and which enter, through lateral orifices, the dorsal vessel.(') 1 Swoammerdamrn, Malpighi, and others of.the terungst. Hft. VI. p. 8), "In the perfect Insecta, older anatomists, had already formed a pretty exact whose respiration is performed by a system of idea of the circulation of the Insecta. But, subse- tracheae traversing the entire body, the circulation quently, it was entirely abandoned when it was ob- of blood would be useless." But to this it may be served that the dorsal vessel was a closed tube, and replied, that Carus, by these words, has contraserved only as a simple reservoir of the nutritive dieted his proper observations; for he has shown juices. Carses was the first to demonstrate anew that there is a circulation in many perfect insects, the existence of a circulation which has since been as is stated not only in the Nov. Act. Nat. Cur., loc. confirmed with all the three stages of insects. See cit., but also in the Erltuterungstafeln from which Carus, Entdeck. eines einfachen, vom Herzen aus the above citation was taken. At all events, the beschleuniot. Blutkreisl. in den Larven netefluiglich. proposition of Carus is correct, " that in insects, the Insekt. 1827 * Nov. Act. Acad. Nat. Cur. XV. blood must come in contact with the atmospheric part II. p. 8, Taf. LI.; and Lehrb. d. vergleich. air, which is accomplished by means of the traZoot. 1834, p. 687; R. Wagner, Isis, 1832, p. 320, chean system." But this applies only to the small 478; Bumneister, Handb. &c. I. p. 164, 436; portion of the circulation connected With the respiBowerbanlc, Entom. Alag. I. 1833, p. 239, IV. 1835, ratory process; whereas, the lar e portion, desp. 179 (also in Froriep's neue Notiz. XXXIX. p. tined for the general nutrition of the tissues, does 149); Tyrrell, Philosoph. Trans. 1835, p. 317; not evidently require the plresence of tracheae. The Newport, Cyclop. &c. II. p. 980; Milne Ed- presence of a real blood-circulation by means of the wards, Asn. d. Sc. Nat. III. 1845, p. 278; and Vas dorsate, is so easily observed, that the injecQuatrefages, Instit. 1845, p. 305. This circula- tions of Blanchard are scarcely necessary (Compt. tion carried on by the dorsal vessel, havinr been rend. XXIV. 1847, p. 870). observed by so many distinguished naturalists, it is If, in certain species, although transparent, these truly incomprehensible that L. Dulfosur (Recherch. phenomena are not observable, ve must not be too aur les'lImnipt. p.l 272; Recherch. sur les Orthopt. hasty in denying its real existence, for tile blood, p. 287; Ann. d. Sc. Nat. XVI. 1841, p. 10; HIm. which is not visible except through its globules, is presentes A l'Inst. IX. p. 595, 601) can persist in often so poor in these last, as to elude our observadenying that the dorsal vessel is anything but a tion. Verloren has recently given a very comsecretory organ which, according to him, has no plete resume of what has been done on this sub. opening and therefore nothing in conmmon with a ject, and has added nev and confirmatory olservaheart. He cites the authority of Cuvier svho Was tions; see Holldndische Beitr. zu den anat. und. nunwillin to accord to the Vas dorsale either the physiol. Wissenschlft. I. IHft. 2, p. 220; i and H1name or the functions of a heart (Cuvier, AIm. moire en risponse d la question suivanlte: eclaircir *sur la maniure dont se fait la nutrition dans les In- par des observations nouvelles le ph6nomone de l1 sectes, in the Hilm. d. 1. Soc. d'-Iist. Nat. de Paris, circulation dans les Insectes, en recherchasot si peut VII. 1798, p. 34, or Reil's Arch. V. p. 97). L. la reconnaitre dans les lalrves des diterents orclres Dufour adcluces, moreover, in support of his erro- de ces animausx, in the Aism. comuonn. par l'Acad neous view, the following remark of Caries (Erlu- de Belgique, XIX. 1847.* [ 340, note 1.] The results obtained by good fortune to wvitness, and their character was Blanchard have been very satisfactorily confirmed such as to leave with me no doulbt as to the periby Agassiz (Proceed. Amer. Assoc. Advancem. Sc. trachean circulation. See, also, the additional evi1849, p. 140, also its translation into French in the dence which Blanchard (Compt. rend. Oct. 6, Ann. d. Sc. Nat. 1851, XV. p. 358), who has suc- 1851) has recently furnished of a peritrachean cir-,ceeded in distinctly injecting the tracheae by the culation, which is very important and weighty. ldorsal vessel. These experiments I have had the He took advantage of the well-known fact that silk 432 THE INSECTA. ~ 340. The Blood of the Insecta is usually a colorless liquid, though sometimes yellowish, but rarely red.(') In this liquid are suspended a few very small,. oval, or spheroidal corpuscles, which are always colorless, have a granularaspect, and are sometimes nucleated. (3) The Dorsal Vessel, which is constricted at regular intervals, is always situated on the median line of the abdomen, being attached to the dorsal wall of its segments by several triangular muscles whose apices point outwards. Its walls contain both longitudinal and transverse fibres, and,. externally, are covered by a thin peritoneal tunic. Internally, it is lined by another very fine membrane, which, at the points of these constrictions, forms valvular folds, so that the organ is divided into as many chambers as there are constrictions. Each of these chambers has, at the anterior extremity on each side, a valvular orifice which can be inwardly closed.(4' The returning blood is accumulated about the heart and enters into it during the diastole of each of its chambers, through the lateral orifices.("? It then passes, by the regularly successive contractions of the heart, from behind forwards into the aorta which is only a prolongation of the anterior chamber. This aorta consists of a simple, small vessel, situated on the: dorsal surface of the thorax, and extending even to the cephalic ganglion,. where it either ends in an open extremity, or divides into several short, branches which terminate in a like manner.(6) The length of the dorsal vessel depends, in all the three states of insects, upon that of the abdomen.. The number of its chambers is very variable, but is, most usually, eight.(') The blood, after leaving the aorta, traverses the body in currents which 2 The blood is red in many larvae of Chzrono- constrictions of the dorsal vessel are feebly marked' mus. with the larvae of the Diptera and Hymenoptera. 3 For the blood of Insecta, see Wagner, Zur ver- 5 According to Newport (Cyclop. loc. cit. p. gloich. Physiol. d. Blutes, Hft. 1, p. 26, Hft. 2, p. 977), the space in which the blood accumulates. 39, and Isis, 1832, p. 323; Horn, Das Leben d. about the heart is surrounded by a very thin memBlutes, p. 9, Taf. I. and Newport, Institut. 1845, brane, and may therefore be regarded as a truep. 241, or Ann. d. Sc. Nat. III. 1845, p. 364, or auricle. Froriep's neue Notiz. XXXIV. p. 9. 6 The Aorta is divided at its extremity with 4 For the structure of the dorsal vessel, see Meloe, Blaps, Timarcha, Vanessa, and Sphinx:Straus, Consid. &c. p. 356, P1. VIII. (Melolon- see Newport, Cyclop. loc. cit. p. 978. tha vulgaris); Wagner, Isis, 1832, loc. cit. Taf. 7 With the Orthoptera, Lepidoptera, and their II. (larvae of Diptera and Ephemeridae), and in larvae, as also with various larvae of Diptera. It Aliller's Arch. 1835, p. 311, Taf. V. (larva of is rare that the number of chambers exceeds eight,. Corethra plumicornis); Newport, Philos. Trans. as, for example, with the Poduridae (Nicolet, loc. 1843, p. 272, and Cyclop. loc. cit. p. 976, fig. 433, cit. p. 50, P'. IV. fig. 3). More commonly there A. and 434 (Lucanus cervus and Asilus crabri- are seven, as with Lucanus and Dytiscus (Newformis); finally Verloren, Mem. loc. cit. p. 31, port, Cyclop. loc. cit. fig. 433, A., and Wagner,.. P1. III.-VII. (Chironomus, Sphinx, Rhyncho- Icon. ~oot. Taf. XXITI. fig. 2). Burmeister7 phorus, Pompilus, Syrphus, and Vespa). The (Handb. I. p. 165) has observed only four with the larva of a Calosoma. worms fed on different artificially-colored leaves tails upon the heart, Leydig, Siebold and Ktoproduced correspondingly colored cocoons. He liker's Zeitsch. 1852, III. p. 446 (larva of Cotherefore fed, in the same manner, various larvae, rethra plumicornis). This naturalist has here and, upon dissection, found not only their blood but described a new and peculiar kind of valves, whicel also their tracheae colored like the color used. deserve particular notice. In the last chamber of With the tracheae, this color was deepest at the the heart, there are six or eight pairs of roundish, base, but gradually paled away towards their ex- clear bodies, attached to the inner surface of the tremity. What adds a corroborating value to these heart by a peduncle. They alternate in their posiexperiments is the fact that the muscles here re- tion, one beyond the other, so that, during the sysmained uncolored, thus showing that this special tole, two of them are so opposed that the calibre of trachean coloration was not due to a bathing of the the chamber is completely closed at that point. general fluids of the body. Compare also the re- Each of these curious valves is only a pedunculatecl. cent various notes and papers of Blanchard, in nucleated cell' see loc. cit. Taf. XVI. fig. 2, c. - Ann. d. Sc. Nat. - ED. ED. * I ~ 340, note 4.1 See also, for histological de 341. THE INSECTA. 433; are always extravascular, and in this way bathes all the organs.(8) The newly-prepared nutritive fluid passes through the walls of the digestive canal in which it is found, into the visceral cavity, and thence directly into the bliod. Latterly, this extravascular circulation has been called in question, lut its presence may be easily and directly observed with very many perfect Insecta and their larvae. The vascular walls supposed to have been seen at certain points, are, undoubtedly, the result of some error of observation or interpretation.(9) This is also true of the pulsatile organs supposed to have been observed in the legs of many water-bugs, and whicl were thought to~affect the circulation.(10) CHAPTEER VII. RESPIRATORY SYSTEM. ~ 341. The Insecta respire, in all their conditions of life, by means of a system of Tracheae which are spread through the entire body and penetrate all the organs. This system of air-vessels either opens externally by stigmata through which the atmospheric air is introduced directly, or they have no external communication, but derive the air from the water by means of lamelliform or tubular prolongations with which the tracheae terminate,, and which have often been compared to branchiae. (' In the first case, they are called Pulmonary tracheae, and in the second, Branchial tracheae. 8 In the antennae, the legs, the filaments of the 10 Very dissimilar and contradictory opinions tail, and other appendages, the arterial and ven- have been published on these pulsatory organs. ous currents are contiguous. But in the wings Behn (Miiler's Arch. 1835, p. 554, Taf. XIII. fig. they are are isolated; and although they may be 13, 14, or Ann.. Sc. Nat. IV. 1835, p. 5) has deobserved in the nervures of the wings, yet these scribed them with Corixa, Plea, Naucoris, Nepa,, last should not therefore be regarded as true blood- and Ranatra, as thin, movable lamellae attached vessels, for their cavities are only prolongations of to the inner wall of the tibiae. Verloren (Mim. the visceral cavity, as is shown by the fact that loc. cit. p. 82, P1. VI. fig. 24, 25) has confirmed they are sometimes traversed at the same time by these observations with the Cicadidae, althoughl branches of tracheae. In the memoir of Verloren neither L. Diefour (Ann. d. Sc. Nat. IV. 1835, (loc. cit. p. 76) will be found a very complete ac- p. 313) nor Wesmael (Bullet. de l'Acad. d(; count of all the reasons opposing the presence of Bruxell. III. p. 158) has been able to discover vascular walls in Insecta. them in the water-bugs above cited. It is possible 9 The same should probably be said about the that these apparent pulsations are produced simply thin walls which Bowoerbank-, and Neswport (loc. by the contractions of neighboring muscular fibres. cit;) think they have observed with Ephlemera 1 See Burmeister (Handb. &c. I. p. 179; Laconcerning the two lateral currents which run to- cordaire, Introduct. &c. IL. p. 89; and Newlport, wards the posterior extremity of the abdomen. Cyclop. loc. cit. p. 983). These organs have not the Another vessel which, according to Treviranoes structure of true branchiae, and the blood is not (Zeitsch. f. Physiol. IV. p. 182, Taf. XIV. fig. 13) subjected in their interior to the respiratory act, as, -and Newport (Philos. Trans. 1834, p. 395, P1. XIV. is shown by the small quantity of this fluid which. fig. 9, and Cyclop. loc. cit. p. 980), is found in the traverses them. These false branchiae are evilarvae and imagines of Lepidoptera above the dently designed to receive air, or, to speak more ganglionic chain, and is the analogue of the supra- properly, to act, through endosmosis and exosmosis,, spiral artery of the Myriapoda (~ 284), requires in the transference of air from the water into the further research, for it may be questioned if such tracheaen system. Duoges (TraitS de Physiol. II, an organ, found only in certainl groups of Insecta, p. 549) is therefore correct in terming them Bran-'i really a vessel. chics trach/ales. 37 434 THIE INSECTA. ~ 342. The tracheae are cylindrical tubes of variable size, which often form, in their course, vesicular dilatations and numerous anastomoses. They divide, like blood-vessels, into many branches which gradually decrease in size, ending, at last, caecally, so that the expired air passes out by the same way that it entered. The intimate structure of these organs is remarkable, and has always attracted the attention of anatomists.(2) When filled with air they present a beautiful, silver appearance. Externally, they are invested with a thin transparent, colorless, or very rarely brownish membrane, corresponding to a peritoneal envelope.(3) Internally, they are lined with another membrane still finer, which presents a lamellated epithelial structure.(4) Between these two membranes is situated a solid spiral filament whose turns are usually near together. This filament is sometimes cylindrical, sometimes flattened, usually transparent and colorless, and in a few instances only, of a dark color. (5) Often, its course is unbroken for a long distance, and rarely is its extremity forked. The new threads always begin between the turns of the preceding one, as may be easily observed at the commencement of each trachean ramification. In the ultimate trachean branches, these threads gradually decrease in size, and at last become indistinct. In the vesicular dilatations of the tracheae, with many Insecta, the spiral thread is often wholly wanting.(6) ~ 342. The Branchial tracheae are found only in certain aquatic larvae and' pupae, and never in the perfect Insecta. The absence of stigmata here is compensated by. the existence of false branchiae (Branchiae spuriae seu tracheales), which are cylindrical, or riband-like organs covered by a very 2 For the internal structure of the tracheae, see, be- body of insects, there is no trace of ciliated episide the works of Burmeister, Lacordaire, and thelium, which, indeed, would be incompatible Newport, that of C. Sprenel, Comment. de partib. with the presence of chitine. Peters (Mitller's quibus Insect. spiritus ducunt, 1815; Suckow, in Arch. 1841, p. 233) was certainly deceived when he Heusinger's Zeitsch. II. p. 24, Taf. I. fig. 10; thought he observed ciliary movements in the Straus, Consid. &c. p. 315, P1. VI. fig. 5; New- tracheae of Lampyris, Coccinella, Musca, and port, Philos. Trans. 1836, p. 529; and Platner, in other Insecta. Hie has himself admitted that tMiller's Arch. 1844, p. 38, Taf. III. he was not able to distinguish the cilia. For my 3 This membrane is brown in the Libellulidae part, I have sought in vain for this movement in and Locustidae; this coloration is due to a finely- the tracheae, and Stein (Vergleich. Anat. u. Phys-:granular substance contained in the membrane. iol. d. Insekt. 1847, p. 105) has been equally un4 See Platner, loc. cit. _Most anatomists regard successful. this internal membrane as mucous. This being ad- 5 The tracheae of the larvae of the Dytiscidae owe mitted, it was very natural to suppose that it, like their black color to the spiral filaments. that of the lungs of the Vertebrata, is covered with 6 With the Muscidae, Syrphidae, Vespidae, Api-,cilia. But here, as well as in other regions of the dae, and Melolonthidae. * [ ~ 341, end.] See, also, for investigations upon the other hand, Mayer, who has studied the embry-.the intimate structure of the tracheae, Dujardin onic development of these organs, states that the (Comp. rend. 1849, p. 674), and Mayer (Ueber die spiral thread is originally a homogeneous memEntwickelung. des. Fettksrpers, der Tracheen, &c. brane, which ultimately splits up into the threads. &c., bei den Lepidopteren, in Siebold and Kielli- This subject of the structure of tracheae has now eker's Zeitsch. I. p. 175). The views of Dsujardin an additional point of interest, from its relations to are different from those usually received, for he Blanchard's views of a peritrachean circulation in regatis the spiral thread not as a special forma- the Insecta. In this connection see especially FiVon, but only a fold like thickening of the internal lippi (Annali della R. Accad. d'agricoltsbro di membrane, - which membrane is not composed of Torino. V., also Wiegmann's Arch. 1851, Th. II. -cells but is a structure analogous to the wing-mem- p. 145). - ED. brane, and is covered with hairs and points. On ~ 342. THE INSECTA. 435 thin cutaneous membrane, and containing one or several finely-divided trachean trunks. These trachean branchiae are either isolated, or fascioulated; in this last case, they are often digitiform, or penniform, and their ultimate ramifications are usually deficient in the spiral filament. All the air-vessels which these branchiae contain, arise from the larger trachean trunks. These branchiae occur with various Tipulidae, with a Nymphutla, with the Phryganidae, Sialidae, Ephemeridae, Perlidae, Libellulidae, and with the Gyrinidae. This trachean system is most simple with the larvae of Tipulidae of the genera Chirononius, Tanypus, Corethra and Simzulia, as also with some larvae of the Phryganidae, of the genera Rhyacophila and Hydrlopsyche, where the tracheae, instead of forming cutaneous. appacz-Jles, are submutaneous and can therefore extract air from the water. The lta vac of Corethra are distinguished for having in the thorax and abdomen, directly beneath the skin, two adjacent trachean vesicles, by means of which, very probably, the necessary renewal of air takes place.(') With the pupae of Simulia, there are two branchial tufts on the sides of the prothorax, composed, each, of six to eight long caecal tubes, which contain each a single simple trachea deficient in the spiral thread.(2) Of the various larvae of the lepidoptera, living under the water, that of Nymphula stratiotalis, alone, has trachean branchiae. These consist of fasciculate filaments situated on the sides of the abdominal segments.(3) With the larvae of Sialis, each of the six, seven or eight abdominal segments has upon its sides an articulated, filiform thread, containing a trachean vessel, and which may, therefore, be regarded as a trachean branchia.(4) Most of the larvae and pupae of the Phryganidae, have, at the same points, one or two filiform, trachean branchiae, rarely ramified, and united in groups of from two to five, which:stand out towards the back.(5) With those of the Ephemeridae, each of the anterior abdominal segments has a pair of these branchiae which are sometimes ramified in the most varied manner, and sometimes consist of two kinds, some being lamelliform and alternating with the others which are fasciculate.(6) With all the Ephemeridae, these organs have movements which are sometimes slow and rhythmical, and sometimes rapid and,scillatory. With the Perlidae, the branchiae are filiform, ramified, and situated on the three thoracic segments of the larvae and pupfie, or bound together in several short fasciculi which cover the base of the legs.(7) Among the Libellulidae, the larvae and pupae of Agrion and CaZo1 See RiaumuLr, MIm. loc. cit. V. Pi. VI. fig. 7, chiae are ramose with Hydropsyche, and Rhya;-,or Lyonet, MInm. du Mus. XIX. P1. IX. fig. 14, cophila. 15. 6 See Swamomerdnamm, Bib. der Nat. Tat. XIII.2 See Verdat and Fries, in Thon's Entom. XV.; Reac7ntr, M6lm. VI. P1. XLII.-XLVI.; DeArch. II. p. 66, 69, Taf. III. One must becareful, geer, Abhiandl. II. Taf. XVI.-XVIII.; Suclrow, and not confound, as has sometimes occurred, the in Heusinger's Zeitsch. II. Taf. III. fig. 21, 22; hairy tufts of these larvae for the tufts of tracheae. Carits, Entdeck. eines Blutlreisl. loc. cit. Taf. III.; 3 See De-eer, Abhandl. I. Abth. III. p. 85, and the figures of Pictet, Hist. d. Insect. N6vropt. Taf. XXXVI[i fig. 5, 6. Epphfmirines. 4 See Roesel, Insektenbelust. II. Insecta aquat. 7 See the figures of Pictet, Hist. d. Nivropt., Class. II. Taf. XXIII.i; LDeeer, Abhandl. II. Perlides. According to Newport (Ann. of Nat. Taf. XXIII.i Suckoow, in Ileusinger's Zeitsch. tIist. XIII. p. 21, or Froriep's neue Notiz. XXX. II. Taf. II[. fig. 23, 21; and Pictet, Ann. d. Sc. p. 179, or Ann. d. Sc. Nat. I. 1844, p. 183), Nat. V. 1836, PI. III. During the passage into these branchial tufts persist, with Pteronar/ys the pupa state, which occurs with Sialis out of the regpalis, to the ilaygo state. This would be a. vater, these tracheae are cast off. very extraordinary anoinlly, and should be coa5 See the figures of Pictet, Recherch. pour servir firmed, for, from thet observations of Nletport, it d lhist. et {E l'anat. d. Phryganides, PI. II. &c., does not appear that the tufts of hair situated on an Degeer, Abha:tdl. II. Taf. XII. The bran- the thorax of this Perlide really preserve the strsv ture of branchial tufts. 436 THE INSECTA. ~ 343. pteryx are distinguished for having three lbng, lamelliform branchiae, with' a rounded extremity, and situated vertically upon the posterior part of the abdomen. (8) The trachean branchiae of Aeschna, Libellula, and the other Libellu. lidae, are formed upon a wholly different plan. They are situated in the very large rectum, and consist of numerous epithelial folds which are traversed by a great number of very fine branches of many large trachean trunks. The rectum is, moreover, invested by a very highly-developed muscular tunic, and its orifice has three pyramidal valves which regulate the entrance and the escape of the water required for respiration.9) Finally, the larvae of Gyrinzts have a pair of long branchiae upon the sides of each of the first seven abdominal segments, and two pairs on those of the eight.("' ~ 343. The tracheae most universal with Insecta are those termed Pulmonary, which are characterized by the presence of stigmata (Spiracula). These last are round orifices or narrow two-lipped openings, situated at various points on the external surface of the body, and which, with many soft-skinned Insecta, are surrounded by a horny ring. Usually, their borders are fringed with small, short, simple or pinnate hairs,() and can be opened and shut by means of an internal muscular apparatus;. this last is sometimes attached to two inwardly-projecting horny plates. By these means, many Insectna have well-marked respiratory motions, especially of the abdomen.('2 With the larvae of the Lamellicornes, the stigmata have a peculiar organization. They are closed by a horny membrane whose semilunar borders are cribriform for the free passage of air.(3) The larvae of the Oestridae have two large stigmata, covered each by a similar plate or membrane, at the extremity of the abdomen; and with some larvae of the Muscidae, the posterior stigmata are closed in the same manner, excepting that the membrane is perforated by three very distinct. openings. Each stigma is usually the entrance of only a single trachean trunk 8 Roesel, Insectenbelust. II. Insecta aquatica, due to the protractile and retractile movements of' Class. II. Taf. IX. XI.- and Carus, Entdeck. &c. the abdominal segments. Many Lamellicornes Taf. I. make these respiratory movements before flying,. 9 Roesel, loc. cit. Taf. III.-VIII. and Suckow, probably that they may fill their trachean system in Heusinger's Zeitsch. II. p. 35, Taf. 1. II. with air. 10 Roesel, loc. cit. III. Taf. XXXI. and De- 3 Sprengel (loc. cit. p. 9, Tab. I.) has described geer, Abhandl. IV. Taf. XIII. Further researches very correctly the stigmata of the Lamellicornes. are required to decide if the penniform appendages, Treviranus (Die Erschein. und Glesetze d. Organ. situated on the sides of the abdominal segments of Lebens, I. p. 258) thinks that these lamellae are not certain larvae of the Hydrophilidae, are really perforated and that the air enters these tracheae by trachean branchiae. But it appears to me that, endosmose, although Burmeister (Ilandb. &c. I, with these larvae, the pulmonary and trachean p. 172) says he has observed a single central openbranchiae are confounded i see Roesel, Insecten- ing. I have been unable to confirm the statement belust. II. Insect. aquat. Class. I. Taf. IV. and of Spren, el, and think that these perforations; Lyonet, MWm. du Mus. XVIII. Pl. XXIIT. (12), might easily elude the observation, from their being. fig. 47 (Hydrophilus caraboides.) concealed beneath a kind of net-work on the exter — 1 L. Dufour, Ann. d. Sc. Nat. VIII. 1826, p 20, nal surface of these lamrellae. L. Dusfour (Ann., P1. XXI. d. Sc. Nat. XVIII. 1842, p. 173, P1. IV. fig. 7) has 2 The Locustidae, Libellulidae, a-wd other Ortho- also misapprehended the stigmata of the larvae of ptera, make true movements of insriration and ex- Cetonia for that which he has described as a piration, by alternately dilating and contracting transverse fissure is only a fold, due to a pressure the abdominal segments. With the Apidac, Ves- exercised during the manipulation, on the horny pidae, and other Hymenoptera, the alternate conl- lamella which norr -lly is convex and imperforate tractions and dilatations of the a) C'ominal cavity are in its centre. SC 343. THE INSECTA. 437 which ramifies more or less directly; sometimes, however, several trunks arise from the same stigma.(4) WTith perfect Insecta, the stigmata are nearly always situated on the,sides of the body in the membrane connecting the two segments, being always wanting, however, in the membrane which unites the head and prothorax, and that between the last two abdominal segments. In many cases, they are covered by the borders of the segments. With the Coleoptera, the stigmata are often situated so high upon the back as to be concealed by the elytra.(5) The number and position of the stigmata vary infinitely, and are not invariable in the different conditions (larva, pupa and imago) of even the same species. These variations are the least with the henmimetabolic Insecta. But among the Hemiptera, the Naucoridae and Nepidae form a remarkable exception in this respect. They have, excepting those of the thorax, only two stigmata at the posterior extremity of the abdomen, and which alone serve, probably, for respiration when these insects are in the water; with Nepa, and Ranatra, these anal stigmata are situated at the base of a long tube formed by the union of two semicanals.(6' The small-'est number of stigmata, consisting of two situated adjacently at the posterior extremity of the abdomen, occurs with the larvae of the Dytiscidae, Stratiomnydae, Conopidae, and some Tipulidae and Tachinariae. Sometimes these two stigmata are situated at the extremity of a longer or shorter Respiratory tube (Sipho), surrounded by a circle of stiff or penniform bristles. In some cases this siphon is very long and articulated, and can be intussuscepted like the tubes of a telescope.7 When these Insecta become pupae, these stigmata are sometimes remarkably modified. The pupae of Culex lose their anal siphon, and acquire, instead, two others which are infundibuliform and situated laterally between the prothorax and mesothorax.(~) The pupae of Ptychoptera respire by means of a flexible siphon situated in the neck.(9) With the Strepsiptera, the male, as well as the apodal female 4 In the larvae of the Lamellicornes; see mata. In the young age of these insects; these Sprengel, loc. cit. Tab. I. fig. 1 (larvae of Geotru- false stigmata are open and situated in two pilose pes). Some Capricornes present, in their perfect grooves located under the belly at some distance state, a very singular organization in this respect. from the lateral borders, and which are prolonged Their thoracic stigmata send off not only several even to the end of the siphon, where they blend large trachean trunks, but also an infinite number into one. The air is conducted by these grooves.of small branches; see Pictet, M6m. d. 1. Soc. d. into the stigmata. phys. &c. de Genive, VII., 1836, p. 393, fig. 5, 6 7 By this disposition of the stigmata, the larvae (Hammaticherus heros), or Ann. d. Sc. Nat. VII. of the Dytiscidae, Culicidae and Stratiomydae, are 1837, p. 63. obliged, in order to breathe, to rise to the surface 5 From this arrangemelat, the Dytiscidae and of the water, where they emerge only the stigmatic Gyrinidae, which live in the water, must, in order orifices, and the air then adheres to the coronets of:to breathe, emerge the posterior part of their body hairs on the stigmata. Many Tipulidae, such as to draw fresh air under their elytra, whence it is Ptychoptera, communicate even more easily with taken into the tracheae. The Notonectidae, Hy- the air by means of their long, articulated, siphondrophilidae, Parnidae, and other aquatic Coleop- tube; see Swammerdamm, Bib. der Nat. Taf. terarespire under the water by means of a pro- XXXI. fig. 5, Taf. XXXIX. (Culex and Stratiovision of air which, after their immersion, adheres mys); Lyonet, Mim. du Mus. XIX. P1. XVIII. to the hairs of the legs. With Hydrophilus, the (10) fig. 1-3 (Ptychoptera). The parasitic larvae renewing of this air occurs in a very remarkable of the Conopidae, and of Ocyptera of the Tachimanner. They protrude only their antennae out nariae, which live in the cavity of the body of Casof the water, and, bending them backwards, thus sida, Pentatoma, Bombus and Andrena, obtain establish a communication between the external air the necessary air for their respiration by placing and that adhering to the under surface of the body; the posterior extremity of their body, which has see Nitzsch, in Reil's Arch. II. p. 440, Taf. IX. two stigmata, in contact with a stigma or trachean 6 See Roesel, Insectenbelust. III. Taf. XXII. trunk of the insect in which they live: see L. DuXXIII.; and L. Dufour, Recherch. sur les He- four, Ann. d. Sc. Nat. X. 1827, p. 355, VII. 1837, mipt. p. 244, P1. XVII. fig. 195, Pi. XVIII. With p. 16, P1. I. fig. 13. Nepa, it is true there are stigma-like rings on the 8 See Swammerdamm, loc. cit. other abdominal segments, but they are closed, and 9 See Lyonet, loc. cit. p. 4, 5. L.: Dufour has properly called them false stig37* 438 THE INSECTA. ~ 344. pupae, respire by two stigmata situated on the sides of the cephalo-i thorax. (10) Most of the acephalous larvae of Diptera have only four stigmata, of which two are situated on the truncated extremity of the abdomen, and the two others, smaller, upon the sides of the second segment of the body. These last have sometimes a tubular form, and with some species, are even divided digitiformly at their extremity.(l) With the larvae of many Syrphidae and Tachinariae, the two posterior stigmata consist of two siphons, which are often fused into one.(l2) The larvae of the Coccidae have onlyfour stigmata situated on the under side of the middle portion of their body.("3) Most of the larvae of the Coleoptera, Hymenoptera, Lepidoptera, as well as the cephalous ones of the Diptera, have numerous stigmata situated on each side in the middle of the segments of the body, and which are never wanting, constantly, except with the second and third thoracic,, and the last abdominal segments. ~ 344. The numerous differences of the trachean system (1) in the various families of the Insecta may be classed under two principal forms. 1. With the first and most common, there are two large lateral trunks upon the sides of which open trunks which arise from the stigmata. From these lateral trunks branch off tracheae to the various parts of the body. 2. With the second form, the trunks which arise from the stigmata or trachean branchiae, directly ramify over the organs, but give off, both forwards and backwards, branches of communication to the neighboring trunks. The branches of one and the same segment frequently interanastomose by transverse trunks. Often these two forms of tracheae coexist in the same individual. In many cases, the secondary tracheae, in opening into the main trunks, are dilated into a large vesicle, or have upon their course numerous similar vesicles which give the whole system a varicose aspect. Among the Aptera, the trachean system is of the first form with the Pediculidae, Nirmidae, and Poduridae.(2) But the Lepismidae form an exception in this respect, each of their stigmata opening into a trunk, which, without anastomosing with the neighboring trunks, is isolatedly ramified. ()3 With the Hemiptera, the trachean system presents pmany modifications. The trunks arising from the stigmata, sometimes ramif"y without anastomosing, and sometimes open into two lateral trunks. The musical Cicadidae 10 See my Memoir in Wiegmann's Arch. 1843, 2 With the Poduridae, the six trachean branches I. Taf. YII. given off from the two main trunks, have each an 11 See Bouche, Naturgesch. d. Insekt. Taf. V. oval dilatation; see Nicolet, loc. cit. p. 47, P1. IV. VI.; L. Diufour, Ann. d. Sc. Nat. XII. 1839, fig. 3. P1. II. III., and XIII. 1840, P1. III. and I. 1844, 3 Gserin (Ann. d. Sc. Nat. V. 1836, p. 274). P1.XVI.(Tachina, Anthomyia, Helomyza, Sapro- thinks that the trachean system is wanting with myza, Piophila, &c.). Machilis; but this must be incorrect, for Bur12 The siphon is very long, articulated, and situ- meister (Isis, 1834, p. 137) has observed this sysated at the extremity of the body with the larvae of tem with Lepisma, with which it had for a long Eristalis see Riaumur, Mem. loc. cit. IV. PI. time before been sought in vain. I have very disXxx. XXXII. tinctly observed it in Machilis, as well as in Le13 See Burmneister, Itandb. &c. II. Taf. I. fig. pisma, and its organization is the same in both. 10-12. The vesicles which, with liachilis, are situated on 1 See, beside the works or Burmeister and La- the sides of the abdominal appendages, and which cordaire, the work of ]Marcel de Serres, in the Guirin thinks are respiratory organs, must have him. du lMus. IV. p. 313. another function. ~ 344. THE INSECTA. 439 and the Pentatomidae, have varicose tracheae. With Cicada, there are two of these vesicles situated at the base of the abdomen distinguished for their very large size.(4) With NTepa, the primary trunks pass into the two lateral trunks, and form transverse anastomoses which extend from one side of the body to the other. In the thorax, the two lateral trunks form, several large vesicles, between which arise, upon the sides, two other trunks which send an infinite number of very fine branches to the thoracic muscles. (5) With the Diptera, this system is of the first form. It often presents, especially with those having a large and short abdomen, vesicular dilatations of which there are two, situated at the base of the abdomen, very large and distinct, sometimes filling nearly the whole abdominal cavity.(6) It is, moreover, with the larvae of this order, that this form of tracheae is most completely represented. The two lateral trunks are connected by the same number of transverse anastomoses as there are segments of the body.(7) With the Lepidoptera in all their states, this system is also of the first form.(') With the imagines of some Sphingidae, Bombycidae and Noctuidae, whose flight is continual, there are numerous vesicular dilatations and appendages of the tracheae.(9) The tracheae of the Hymenoptera, which, throughout, are of the first form, send off from their two principal trunks numerous transverse anastomoses, and usually present vesicular dilatations at many points.(') Of these last, those situated on the abdominal portion of the two trunks are very large, and often contiguous, so that the trunk to which they belong appears like a large sac constricted from point to point.() Sometimes there are only two of these vesicles, which are distinguished from the rest by their enormous volume, situated at the base of the abdomen.(")2 With the larvae, there are found, pretty commonly, two main trunks connected by transverse communicating tubes.(l3) 4 See Burmeister, IHandb. &c. II. Taf. I. fig. ages is reduced to two large auriferous reservoirs 10-12 (Coccidae); L. DufouLr, Recherch. loc. cit. situated in the thorax see Suckow, Anat. physiol. P1. XVII. fig. 194 (Tetyra), and Carus, Analekt. Untersuch. p. 36, Taf. VII. fig. 30 (Gastropachau. &c. p. 156 (Cicada). pini). 5 See L. Dufour, Recherch. &c. p. 244, P1. 10 These dilatations are wanting with the CynipiXVIII. dae, Chalcididae, and some Ichneumonidae. For 6 With the Muscidae, Syrphidae, Tabanidae, the trachean system of the Hymenoptera in general, Asilidae, Leptidae, &c. For the trachean system see L. Dufour, Recherch. sur les Orthopt. p. of the larva and pupa of Sarcophaga haemor- 374.* rhoidalis, see L. Dufour, M3m. pr6sent6s, &c., 11 With the Apidae, Andrenidae, Vespidae and IX. p. 572, P1. II. Bembecidae; see Brandt and Ratzeburg, Mediz. 7 Swammerdam.m, B*b. der Nat. Taf. XL. fig. Zool. II. Taf. XXV. fig. 30 (Apis melliJica), and 1 (larva of a Stratiomys); Bouchi, Naturgesch..Newport, Philos. Trans. 1836, P1. XXXVI. or d. Insekt. Taf. VI. fig. 1 (larva of an Anthomyia), Cyclop. &c. II. fig. 436 (Bombus terrestris). and L. Dufour, Ann. d. Sc. Nat. XII. 1839, P1. 12 With many of the Tenthredinidae, with MyrI.-III. mosa, Scolia, Crabro, Pompilus, Sphex, &c. 8 Lyonet, Traits, Pl. X. XI. (larva of Cossus 13 See Swammerdamm, Bib. der Nat. Taf. ligniperda). While the Syrphidae and Muscidae XXIV. fig. 1 (larva of a bee). According to the are passing into their pupa-state, the posterior observations of Ratzeburg (Die Ichneumon. d. stigmata disappear, the two anterior ones alone Forstinsekt. p. 63, 81, Taf. IX.), the parasitic remaining active. With the Syrphidae these last larvae of A}icrogaster and Anomalon are very often appear as two short tubes inserted on the cer- singular. When young, they have no traces of vical region. tracheae, and respire, perhaps, by means Of a caun 9 See Sprengel, loc. cit. Tab. III. fig. 24 (Sphinx dal appendage enveloped by a thin membrane. ligustri). Sometimes the number of these append* [ ~ 344, note 10.] See Newport (On the form- vesicles serve chiefly to enable the insect to alter ation and use of the air-sacs and dilated tracheae its specific gravity at pleasure during flight, and in Insects, Trans. Linn. Soc. June, 1847); these thus diminish the muscular exertion required dulrBacs are formed during the metamorphoses of the ing these movements. - ED. insect, and lr: idopts the view of Hunter, that the 440 THE INSECTA. ~ 345. The true Neuroptera, in all their states, have a pretty simple trachean system provided with two lateral trunks. But with the Orthoptera, on the contrary, this system is usually very complicated. It is, indeed, less so with the Blattidae, Forficulidae, Ephemeridae, and Perlidae;(14) but with the Libellulidae, the two lateral trunks are very large and arise from the trachean branchiae together with two other trunks.(l) With the other Orthoptera, the tracheae are very numerous and disposed according to the second type or form, their trunks being connected by a multitude of voluminous, longitudinal, and transverse anastomoses, giving the whole a reti-;culated aspect.l6) With the Acrididae, most of the transverse anastomoses have large air-reservoirs on their course.() With the Coleoptera, the tracheae are always highly developed, and,disposed, with the larvae, after the first type, but with the imagines, after the second.'l8 With these last, the anastomosing canals, which connect the primary trunks, are often double.(19) With the Palpicornes, and Lamellieornes, this system is most highly developed, - the fine as well as the larger tracheae having a multitude of terminal vesicles.(~0) CHAPTER VIII. ORGANS OF SECRETION. I. Urinary Organs. ~ 345. The Malpighian vessels, which are widely spread among the Insecta in ~all their conditions,(l) must now, since uric acid has been detected in their secretion, be regarded as Kidneys.(2) 14 See Swammerdamm, Bib. der Nat. Taf. XIV. sels; see Ramdohr, Verdauungswerk. d. Insekt. -and Carus, Entdceck. &c. Taf. III. (larva and pupa p. 198, Taf. XXVI. and L. Dusfour, Recherch. of an Ephemera). sur les Hemipt. p. 116, fig. 114. I have been 15 Suckow, in Heusinger's Zeitsch. II. Taf. I. unable to find them with the Strepsiptera in their II. (larva and imago of an Aeschna). various stages of development. The male imagines 16 With the Locustidae, Achetidae and Mantidae; of Xenos Rossii, alone, have presented to me, at:see L. Dufour, Recherch. sur les Orthopt. &c. p. the extremity of the digestive canal, a singular 269, P1. I. fig. 1 (Oedipoda), and Marcel de Serres, glandular appendage resembling a cribriform lobe, M1dm. du Mus. IV. p. 331, P1. IV. (16) (Mantis), and which serves, perhaps, as a urinary organ. also in Isis, 1819, p. 627, Taf. IX. 2 For a long time the Malpighian vessels were 17 2Iarcel de Serres, loc. cit. P1. III. (15) regarded as biliary organs, when Rengger ex-;('ruxalis), and L. Dufour, loc. cit. P1. I. (Oedi- pressed the opinion that they were urinary organs. poda). without, however, having demonstrated the pres18 See Burmeister, Trans. Entom. Soc. I. P1. ence of uric acid in their secreted product (PhysXXIV. fig. 9 (larva of Calo~soma sycophanta), iol. Untersuch. fiber die 1Iaushalt. der Insekt. land Audouin, Ann. d. Sc. Nat. IX. 1826, P1. 1817, p. 27). This chemical proof was furnished XLIII. fig. 3 (Lytta vesicatoria). by Brugnatelli and Wurzer (Meekel's Deutsch. 19 See L. Du1foulr, Ann. d. Sc. Nat. VIII. 1826, Arch. II. 1816, p. 629, and IV. 1818, p. 213), with p. 23, P1. XXI. bis. fig. 1, and Pictet, Mem. de Bombyx mori. Subsequently, the existence of this Gendve, VII. p. 397, fig. 6 (Hammaticherus acid has been confirmed by Chevreul with Melo*heros). lontha vulgaris (Straus, Consid. &c. p. 251), $OSwammerdamm, Bib. der Nat. Taf. XXIX. and by Audouin with Lucanus cervus and Polisfig. 9 (Geotrupes nasicornis), and Straus, Con- tes gallica (Ann. d. Sc. Nat. V. 1836, p. 129).;sid. &c. P1. VII. (3lelolontha vulgaris). See, See, also, Meckel, Ueb. die Gallen- und Harnor. also, for the Coleoptera in general, L. Dufour, gane der Insekten, in his Arch. 1826, p. 21, and Ann. d. Sc. Nat. VIII. 1826, p, 22. Groshans, De System. uropo4t., quod est Radiat. 1 As yet only Coccus, Chermes, and the Aphi- Articulat. et Mollusc. Acephalorum. 1837, p. 39. didae, have been found wanting the Malpighian ves ~j 246. THE INSECTA. 441 These always consist of several very long small tubes which, either separately, or by means of one or two common excretory ducts, are inserted upon the posterior or pyloric extremity of the stomach. These ducts are sometimes dilated, bladder-like, at their point of insertion. The opposite extremity of these uriniferous canals either terminates caecally, or passes arcuately into that of another. When, as is usual, they are very long, they embrace the digestive canal with numerous irregular convolutions. With certain species, they creep, by their anterior extremity, between the tunics of the stomach, or by their posterior between those of the colon; this remarkable relation has often led to the opinion that these organs have two outlets into the digestive canal.(3) These vessels are yellowish or brownish in color, and often slightly vari-,cose.(4) They are composed of an external homogeneous tunic filled internally with cells. These last are very large, and are disposed rather in,rows, than adjacently; and nowhere can there be perceived in the interior ~of the vessels a glandular canal defined by a special epithelium. - Each cell contains a clear, colorless nucleus, and a multitude of very fine granules which appear black by direct light, but by reflected light present a dirty-yellow or brown, rarely a green or red, aspect.(3) The granular contents.of the cells, which give to these vessels their peculiar color, are scattered, when the cells are ruptured, through the intercellular spaces, and flow gradually into the digestive canal, Thus excreted, they accumulate in the colon or in its caecal appendage, and are evacuated with the faeces, or separately, as a troubled liquid of a color varying according to the.species. (6) ~ 346. The Malpighian vessels present numerous modifications as to their numher, their length, their points of insertion, and their modes of grouping, in'the different orders of the Insecta. () With the Aptera, they are of median length; with the parasitic species,.and with the Lepismidae, they are four in number; and six with the Pod*uridae. (2) The IHemiptera have never more than four of these vessels, which are pretty long, whose extremities are looped with the Hydrocorisae and many 3 L. Dufour has clearly demonstrated the usual Myrmeleon, it is gradually accumulated to a large caecal terminations of these vessels; see Ann. d. quantity of a rose-color, in the digestive tube, and Sc. Nat. XIV. 1840, p. 231, P1. XI. fig. 11 (larva which the perfect insect immediately discharges on of a Mordella), and XIX. 1843, p. 155, Pi. VI. fig. leaving the pupa-envelope, as a solid or elongate 9 (Hammaticherus heros). ovoid body. Reaumur (Mim. VI. 10 mim. Pl. 4 The uriniferous canals of Melolontha vulgaris XXXIV. fig. 12, 13) and Roesel (Insektenlbelust. and Sphinx ligustri form, in this respect, a re- III. p. 123, Taf. XX. fig. 28, 29) have taken this markable exception. In a great part of their urinary concretion for the egg of this insect. Some-.course, they have on each side short caeca, pecti- times there is precipitated in the urine, red crystals,nately disposed; see Ramdohr, Abhandl. &c. Taf. of a quadra-pyramidal form; for example, with VIII. fig. 1, 2; L. Dufour, Ann. d. Sc. Nat. III. the larvae of Sphinx and Ephemera.:1823, PI. XIV. fig. 4, 5; Straus, Consid. &c. P1. 1 For these modifications in the different orders V. fig. 6, 10 (Melolontha); and Newport, Cyclop. of Insecta, see the figures belonging to Ramloc. cit. p. 974, fig. 432 (Sphinx)..dohr's work (Verdauungswerkz. &c.); those of 5 For the intimate structure of these vessels, see Suckow, in Heusinger's Zeitsch. III. and L. DuHl. Meckel, in Mdller's Arch. 1846, p. 41, Taf. II. Jbur, Sur les vaisseux biliares ou le foie des In6 With the holometabolic Insecta, the urine is sectes, in the Ann. d. Sc. Nat. XIX. 1843, p. 145, evacuated isolately, especially when they approach P1. VII.-IX. the completion of. their pupa-state. It is well 2 See Treviranus, Verm. Schrift. II. Taf. III. known that the. Lepidoptera, when bursting from fig. 1 (Lepisma), Swoammerdamm, Bib. der Nat their pupae, emit a considerable quantity of urine, Taf. II. fig. 2 (Pediculus), and Nicolet, loc. cit. of a variable color. In the larva and pupa of P1. IV. fig. 2 (Podura). 442 TIHE INSECTA. $ 346, of the Geocorisae.(3) With some species, their excretory ducts form one or two vesicular dilatations situated above tie colon.(4) It is only with a few Geocorisae, and with the Cicadidae, that the extremities of these canals are free.(0) With this last group, and with the Cercopidae, they creep with a portion of the intestine, between the tunics of the ante-stomach, before opening into the lower extremity of the true stomach.(') With the Diptera, there are four long uriniferous vessels. The Culici; dae and Psychodae, alone, by exception, have five.(7) With very many species, these canals are united in twos, and open, by a common excretory duct, into the lower extremity of the stomach.(8) Loop-like anastomoses occur only with the Tipulidae, Leptidae, and Bombylidae.(9) WTith the Lepidoptera, there are nearly always six long, free, uriniferous tubes, which open into the stomach by two excretory ducts.l(0) The Hymenoptera are distinguished for their considerable number of these vessels, which are usually short and surround the pylorus in numbers of twenty to one hundred and fifty.(ll) With the Orthoptera, these vessels are inserted. in a similar manner, (12) but are often much more numerous.l3 The Termitidae, alone, form an exception, -having only six.(l4) The true Neuroptera are distinguished from the Orthoptera in that their vessels of this nature are long, flexuous, and only six to eight in number.(") With the Coleoptera, they are usually long, make numerous convolutions, and never exceed four or six in number.(161 When four, they are nearly always joined by twos at their extremity; and when six, they are often attached by their extremities to the colon.(7) The urinary vessels of the larvae and pupae resemble somewhat those of the perfect Inseeta.(18) With the larvae of certain Hymenoptera, and Orthoptera, 3 With the Naucoridae, Nepidae, with Salda, 12 With the Ephemeridae, alone, the form of Capsus and Reduvius. With Dorthesia; the these canals is somewhat different, in that their free four canals form also two short loops * see L. Du- extremities are nearly always thickened, and that four, Recherch. &c. p. 19, P1. I.-IX. the excretory ducts take one or two spiral turns. 4 Pentatoma, Tetyra, Pyrrhocoris, Lygaeus, 13 See L. Dufour, Recherch. sur les Orthopt. Gerris, Stenocephalus. &c. P1. I.-IV. XI. XIII. Gryllotalpa is distin5 Cimex, Ploiaria, Miris, Alydus and Coreus. guished from the other Orthoptera in that the In the last two genera the uriniferous canals, free, urinary canals are disposed fasciculate and termiterminate at the pylorus in a common reservoir. nate in a single excretory duct. With Alydus, Aradus, Aneourus; Cixius, Issus, 14 L. Dufour, Recherch. loc. cit. P1. XIII. fig. and Asiraca, they unite in twos in a common ex- 196. cretory duct. With Psylla, they consist only of 15 L. Dufour, Ibid. P1. XI.-XIII. There are four rudimentary caeca; see L. Dufour, Recherch. six of these vessels with the Phryganidae, Sialidae, loc. cit. Panorpidae, Rhapididae: and eight with the Myr6 It was a long time before there was an exact meleonidae and Hemerobidae. idea of the canals with Cicada. Doy6re (Ann. 16 There are four urilnary vessels with the Carad. Sc. Nat. XI 1839, p. 81, P1. I.) was the first bidae, Staphylinidae, Gyrinidae, Palpicornes, Lawho perceived that they penetrated between the mellicornes, Cantharidae, and Buprestidae; six tunics of the stomach; but he supposed they re- with the Byrrhidae, Nitidulidae, Dermestidae? appeared on its surface after a short course. Ile Cleridae, Meloidae, Pyrochroidae, Bruchidae, Bosdid not, therefore, attribute to these insects, only tricidae, Capricornes, Chrysomelidae, and Coccintwo uriniferous vessels. This last error has been ellidae. rectified by L. Dufour (Ibid. XII. p. 287). 17 For the uriniferous canals of the Coleoptera, 7 See L. Dufour, Ann. d. Sc. Nat. XIX. loc. see, beside RamdohLr, and Suckowo, loc. cit., L. cit. PI. VIII. fig. 26 (Anopheles). Dufour, Ann. d. Sc. Nat. 1824, II.-IV.; 1834, I. 8 With the Muscidae, Oestridae, Conopidae, P1. II. III.; 1840, XIII. P1. V. VI.; XIV. P. XI.; Syrphidae, and Hippoboscidae. With the Stratio- XIX. Pl. VI. With Donacia, the six vessels mydae, the four canals unite into one excretory have a very peculiar aspect. Two pairs unite ducti see Ssvammerdamm, Bib. der Nat. Taf. loop-like at their posterior extremities, and their XLI. fig. 6 (Stratiomys); L. Dufour, loc. cit. Pi. anterior ends unite in a common reservoir * while TIII. fig. 28 (Sargus). the third pair are free and open isolately at the 9 Ramdohr, loc. cit. Taf. XX. pylorus; see L. Dulfour, Ann. d. Sc. Nat. 1824, 10 With Pterophorus and Yponomeuta, Suckow IV. P1. VII. fig. 7, 8, and 1844, XIX. P1. VII. fig. has found only four urhiiferous vessels (loc. cit. Taf. 10. IX. fig. 159, 161). 18 Beside Ramdohr, and Suckow, loc cit., see L. 11 See L. Dufour, Recherch. sur les Orthopt. Dufour, Ann. d. Sc. Nat. XII. 1839, P1. I.- XIII. P1. III.-X. The smallest number of these canals P1. V.; and XVIII. PI. IV. (larva of a Tipulide, a is found with the Formicidae, Cynipidae, and Ich- Sapromyza, a Pyrochroa, and of a Cetonia, &c.); neumonidae. De Haanz, Nouv. Ann. du Mus. IV. PI. XVI.-XIx. ~ 347. THE INSECTA. 443 alone, their number is smaller,(M1) and with those of the Lepidoptera, the extremities of the six tubes of this kind are insinuated between the tunics of the colon; while, with the imagines they are free.(20) With the Buprestidae, the larvae have six, but the imagines only four, of these vessels.'( Il Organs of Peculiar Secretions. ~ 347. A great number of the Insecta, in both their larval and their perfect state, have glandular organs which secrete very varied products remarkable for their specific properties. Many species have a secretory apparatus analogous to the cutaneous glands of the Vertebrata, which have received the name of Glanduiae odor. iferae. These consist of round follicles situated under the skin, whose very short excretory ducts open between the segments of the body, or beetween the articulations of its extremities. Their product emits a powerful odor, and, with some species, is evacuated in the form of droplets,(') or, with others, covers the whole surface of the body, being perceived only by its odor.(2) The disagreeable odor emitted by the Bugs is due to a fluid secreted by a single, yellow, or red pyriform gland, situated in the centre of the metathorax, and opening between the posterior legs.(3) With other Insecta, there are analogous secretory organs, concealed in the posterior extremity of the abdomen, which copiously emit a fetid, troubled liquid, through an orifice situated by the side of the anus. These Anal Glands are usually double, and consist of simple follicles whose secretory product accumulates in round, or oblong contractile reservoirs.(4) With many (larva of various Lamellicornes); and Burmeister, of many Tenthredinidae, emit droplets of fluid from Trans. of the Entom. Soc. I. Pl. XXIV. fig. 10 (larva the surface of their skin from the least touch. Very of a Calosoma), and his Abhandl. z. Naturges- often the odor of this fluid reminds one of fresh chichte d. Calandra, loc. cit. fig. 3. poppy-juice. The fluid emitted from the cephalo19 The larvae of the Apidae and Vespidae have prothoracic articulation, with Colymbetes and only four uriniferous vessels; see Swammerdamm, Dytiscus, has a very nauseating order. I am unBib. der Nat. Taf. XXIV. fig. 6 (larva of a bee); able to decide whether or not the transparent liquid Suckow, in Heusinger's Zeitsch. III. Taf. VI. fig. which escapes with various Aphididae through two 180, and Ramdohr, loc. cit. Taf. XII. (larva of a tubes on their abdomen, belongs to this same cateVespa); finally, Rathkd, in Miiller's Arch. 1844, gory of secretions. p. 36, Taf. II. (larva of a Gryllotalpa). 2 Certain Phl'yganidae, Hemerobidae, Crabron20 See Lyonet, Traite, &c., P1. XIII., and idae, Scoliadae, Ichneumonidae, &c., emit specific Suckow, Anat. u. physiol. Untersuch. Taf II. odors without the secretion of their Glandulae 21 See L. Dufour, Ann. d. Sc. Nat. XIV. 1840, odoriferae being visible. p. 114. Loew (Entom. Zeit. 1841, p. 37, fig. 3) did 3 See L. Dufour, Recherch. loc. cit. p. 266, P1. not, probably, observe these canals in the larva of XVII. fig. 194. Moreover, the opinion that all the Buprestis mariana; for, otherwise, he would not Bugs emit a bad odor is incorrect; for with many, have regarded as such the two caecal appendages as for example Syromastes, the Glandulae odoriat the upper extremity of the stomach, and which ferae exhales a very agreeable odor resembling that the Buprestidae have also in their imago-state (see of a fine bergamot pear.* ~ 338). 4 These anal glands, which Burmeister (HIandb. 1 With Euprepia, and Zygaena, a fluid of this I. p. 151), Grant (Outlines, &c., loc. cit. p. 584) kind, yellowishly transparent, exudes under the and other anatomists have mistaken for urinary collar; and with many Meloidae, Chrysomelidae, organs, consist, with the Dytiscidae and Gyrinidae, and Coccinellidae, it escapes from the knee-joints. of two simple, long and flexuous caeca, whose reThe larvae of these last Coleoptera, as well as those servoirs, having two short excretory ducts situated * [ ~ 347, note 3.] With Belostoma, the odor- abdomen. They open externally between the Iferous glands consist of two pretty long caecal coxae of the posterior legs. See Leidy, loc. cit. p. tubes situated in the metathorax, beneath the other 641. -ED. viscera, and extending into the anterior part of the 444 TIE INSECTA. ~ 347. Coleoptera, these anal glands secrete a caustic fluid which has a penetrating and more or less aromatic odor. They are somewhat ramified, or composed of vesicles disposed botryoidally, and open into one or several long, excretory ducts.(" These last open into two pyriform, muscular reservoirs, whose powerful contractions expel, as a means of defence, the secreted fluid. (6) The Formicidae, also, have, in the anal region, a glandular apparatus from which they eject a caustic, acid fluid. This apparatus is single and composed of one reservoir whose neck opens into a simple tube. (7 The larvae of Harpyia, also, defend themselves by ejecting an irritating liquid secreted by a glandular sac, which opens directly back of the head on the under surface of the first segment of the body. Among the Hymenoptera, the females of the Vespidae, Fossores, Andrenidae, and Apidae, have, in the anal region, a glandular apparatus which secretes a poisonous fluid introduced by means of a hollow sting into the tissues of their prey or enemies.(8) This Poison-apparatus is composed of two long tubes which are sometimes very ramose.0() The intimate structure of these tubes resembles that of the salivary glands.(l'1 The two poison-glands are sometimes isolated, sometimes united into a common canal, and their product is poured into a pyriform reservoir, which has thin but contractile walls, whose longer or shorter excretory duct opens into the sting.(l" This sting is formed by the intimate union of two lateral pieces, and plays in a cleft horny sheath. Often, its extremity is covered with backwardly-pointing denticles. (2) Both the sheath and the sting have, at their base, a peculiar muscular apparatus by which they are protruded and withdrawn. near the arms, ejaculate a highly stinking liquid. wound these last with their sting, that they may be With the Silphidae, where this apparatus is single, mastered, and conveyed the more easily to the the reservoir opens laterally into the rectum; see H. nest. Indeed, some carry their prey into their Meckel, in Miller's Arch. 1846, p. 47, and L. Du- nests transfixed with the sting. (See my Observ. four, Ann. d. Sc. Nat. VIII. 1826, p. 15, III. P1. X. quaed. de Oxybelo atque Miltogramma, 1841, p. fig. 3, 4, 5, Pi. XIII. fig. 5, 7 (Dytiscus, Gyrinus 11.) The wound does not always kill the insect, and Silpiia). With Gryllotalpa, the anal glands but simply disables it, so that they remain fresh consist of small lobular bodies inserted on the re- for several days by the side of the larvae for whose servoir which receives their product: see L. Du- food they are to serve. four, Recherch. sur les Orthopt, &c., p. 346, P1. 9 There are two simple tubes with Vespa, Scolia, II. fig. 19. Crabro, Halictuzs, Apis, &c.; but they are ram5 With the Carabidae, and Staphylinidae; see ified with Pompilus, Philanthus, Larra, BomL. Dufour, Ann. d. Sc. Nat. VIII. 1826, p. 6; bus, &c. II. P1. XX. XXI.- III. P1. X.; and VII. PI. XIX. 10 For the intimate structure of these poisonXX.; J. Miller, De Glandul. Struct. &c. Tab. I. glands, see H. Aleckel, in lMiller's Arch. 1846, p. fig. 13-18; and Stein, Vergl. Anat. u. Physiol. d. 45, Taf. III. Insekt. 1847, Taf. I. fig. 4, g. g. (Dianous) and 11 This poison-apparatus is described more in Taf. III. fig. 3, 1. n. (Oxytelus). detail in the works of Swammnerdamm, Bib. der 6 With Brachinus, as is well known, this prod- Nat. p. 183, Taf. VIII. (Apis); Brandt and uct is so volatile as to immediately become gase- Ratzeburg, Mediz. Zool. II. p. 203, Taf. XXV. fig. ous on its ejection.* 39-42; Ramdohr, Abhandl. Uib. d. Verdauungs7 See L. Dmufour, Recherch. sur les Orthopt. &c. werkz. &c. Taf. XIV. fig. 5 (Pompilus), and p. 413, Pl. VII. fig. 86. Suck-ow, in Heusinger's Zeitsch. II. Taf. XIV. 8 The Bees, which have a poison-apparatus of fig. 358, 46 (Apis and Crabro).t this kind, ought to be regarded as females whose 12 See Stwamnserdamm, loc. cit. Taf. XVIII. fig. genital organs are undeveloped. Many fossorial 3. Hymenoptera, which feed their young with insects, * I~ 347, note 6.] For the peculiar glandular t [ 347, note 11.1 The poison of the poison apparatus for this purpose, with Brachinus, see apparatus in the Hymenoptera has been investiKarsten, in liiller's Arch. 1848, p. 367. Con- gated by Will (Schleiden and Froriep's Not. trary to other Zootomists, this observer regards 1818, Sept. p. 17) who found, with Ants, Bees, and this apparatus as of a urinary nature, for he states Wasps, that this product consisted of formic acid that an analysis of its secretion furnishes a product and a whitish, fatty, sharp residuum, the former analogous to urea. — ED. being the poisonous substance. - ED. 347. THE INSECTA. 145 There is another category of secretory organs which, with many females, open at the base of the ovipositor, but as fhey are intimately connected with the act of oviposition, they will be most properly described with the genital organs.(l3) A very large majority of the holometabolic Insecta have, in their larvaestate, silk-organs, the secretion of which they use, some, to weave a cocoon when about to pass into the pupa-state,.or to close a hcllow refuge they have sought; others to fasten together foreign bodies for the lkbrication of their retreat. These organs are, therefore, most, developed at the period when these insects approach their pupa-state; but with the larvae of the Psychidae, Tortricidae, and Lasiocampadae, they are already active du. ring the first epochs of life. The silk-secreting portion of this glandular apparatus consists of two long, somewhat flexuous, thick-walled caeca, situated on the sides of the body, and continuous, in front, into two small excretory ducts, whose common orifice is on the under lip, and usually at the extremity of a short tubular protuberance.(4) With the larvae of Myrmeleon, the silkapparatus is very remarkable, for the rectum itself is changed into a large sac and secretes this substance, which escapes through an articulated spinneret projecting from the opening of the anus.(5) With the Apidae, there is a very remarkable Wax-secreting apparatus. This wax is elaborated bjy the Workers under the form of thin discs, which are formed between the imbricated posterior legs, without there having been discovered, as yet, in this region, the orifices of any special glands. It must therefore be supposed that it is produced by an exudation firom the thin membranes which connect the different parts of the legs.t6 3) Moreover, many other Insecta have secretory products which transude through the skin without the existence of any special glandular apparatus, and which are hardened by the air like wax. These products are usually whitish, pulverulent, filamnentous, or fioceulent substances, which catch upon the surfaces of bodies."17 13 See ~ 350. Institut. 1843, also in Froriep's neue Not. 14 See Roesel, Insektenbelust. III. Class. I. Pap- XXVIII. XXIX. ilionurm nocturnorum. Taf. IX. (Bomrbyx); Lyonet, It is, moreover, easy to be convinced of the abTraite, &c., p. 498, P1. XIV. XV. (Cossus); sence of these glands with the bee-workers but ~uckow~, Anat. u. physiol. Untersuch. p. 29, Taf. if certain Andrenidae are examined, there will be VII. fig. 31 (Gastropackia) Pictet, Recherch. found, on each side oftheir posterior tibiae, a small pour servir tA ihist. d. Phryganides, Pl. III. fig. 1 pyriform follicle'vith an excretory duct, and which (Phryganea). The decrease of these organs dur- secretes an oily substance. ing the pupa-state has been very carefully detailed 17 These cutaneous secretions are observed with by Herold, Entwickelungsgesch. d. Schmetterl., Taf. various Coccidae and Aphididae, whose entire bodies Ill. and by Suckow, loc. cit. Taf. II. (Pontia, they cover with a powdery or woolly substance. Gastropacha). With the females of Dorthesia, not only the entire 15 See Riaumur, Meim. &c. VI. P1. XXXII. fig. body is covered with a substance which forms a 7, 8; Ramdohr, Abhandl. &c. Taf. XVII. fig. 1. solid white crust, but also the eggs after their depo16 For the intimate structure of the wax-secret- sition are invested with a similar envelope and ing portions of the skin with the workers of bees, thereby glued to the abdomen of the mother. With see Treviranus, Zeitsch. f. Physiol. III. p. 62, many male Coccidae, this secretion forms, at the 225; and Brandt and Ratzeburg, II. p. 179, Taf. posterior extremity of the abdomen, a bundle of XXV. fig. 18. The production of wax with bees has very diverging, long, white and perishable hairg lately been the subject of much research among With some Cicadidae (Lustra and _Flata), tne French naturalists. li'lne Edwards has ad- thorax and abdomen are covered, in places, by a vocated the opinion before rejected by him, that this kind of mould of a similar origin. The larvae of substance is secreted by special glands. But L. many Tenthrediaidae (for example, Tenthredo Duofour, after carefully-made researches, failed to ovata), as well as those of certain Coccinellidae discover them. See the various memoirs on this (Scymnu.s), exude a liquid which, upon drying, question in the Compt. Rend. XVII. and in the forms white flocci.* * [ 6 347, note 17.] See upon the subject of these copique de la cire, in the Ann. d. Sc. Nat. XII. secretions Dujardin (MI6m. sur l'itude micros- 1849, p. 250); his observations were made upon 38 446 THE INSECTA. ~ 348. The Phosphorescent Organs of the Lampyridae and certain Elateridae,l) consist of a mass of spherical cells, filled with a finely-granular substance, and surrounded by many numerous trachean branches.(9) This substance which, by day-light, appears of a yellow, sulphur-like aspect, fills, with the Lampyridae, a portion of the abdominal cavity, and shines on the ventral surface through the last abdominal segments, which are covered with a.very thin skin; while, with the Elateridae, the illumination occurs through two transparent spots situated on the dorsal surface of the prothorax. The light produced by these organs so remarkably rich in tracheae, is undoubtedly the result of a combustion kept up by the oxygen of the air of these vessels. This combustion explains the remission of this phosphorescence observed with the brilliant fireflies, and which coincides, not with the movements of the heart, but with those of inspiration and expiration.(20) CHAPTER IX. ORGANS OF GENERATION. ~ 348. The Insecta always multiply by means of genital organs situated in different individuals,() and, invariably, are provided with copulatory organs.t With certain species, namely, with the Apidae, and Termitidae, the females 18 For the phosphorescene of these Coleoptera, riep's neue Not. No. 583, p. 168, and in Schleiden see Carus, Analekt. &c. p. 168 Burmeister, and Froriep's Not. No. 9, p. 135.* HIandb. I. p. 534, and Lacordaire, Introduct. &c. 1 Hartig has declared that certain species of II. p. 140. Cynips are hermaphrodites; but Ratzeburg and I 19 The intimate structure of these organs has have shown that this assertion is based on an errobeen studied with Lamnpyris italica by Peters neous interpretation of the organization of the (Miitler's Arch. 1841, p. 229), and by Morresn females of Cynips; see Germoar's Zeitsch. f. (Isis, 1843, p. 412). This last author says that this Entom. III. p. 322, Taf. I.; and IV. p. 380, 396. insect contains phosphorus, but adduces no fact in The true hermaphrodites which have as yet been support of this assertion. found in the other orders of insects, notably among 20 Matteuci has made numerous experiments on the Lepiaoptera, ought to be regarded as monsters. the phosphorescence of Lanpyris italica; from Klug (Verhandl. d. Gessellsch. naturf. Freunde in which it appears that the phosphorescent substance Berlin, I. p. 363. and Jahrb. d. Inseckt. I. p. 254), burns by means of the oxygen contained in the Ochsesnheimer (Die Schmetterl. von Europa IV. p. tracheae, without any increase of the temperature, 185) and Lefebvre (Ann. d. I. Soc. Entom. IV. and without any indication of the presence of 1835, p. 145) have given a list of the cases of phosphorus * see Maotteuci, LeQons sur les phi- hermaphroditism with insects. See also Burnseisnom. phys. d. corps vivants, Paris, 1847, p. 151, ter, Handb. I. p. 338.t and Compt. Rend. XVII. 1843, p. 309, also in Frovarious Insecta, among which were Dorthesia, + [ 348.] The copulatory organs of the Insecta Alaerodes, &c. The wax consists of fibres which present wide and manifold variations, as has been are perpendlicular to the secreting surface, and is shown especially by the recent researches of Laa true product of the integument independent of -aze Duthiers, Recherches sur l'Armure ginitale any special glandular apparatus. - ED. des Insectes, in the Annl. d. Sc. Nat. 1849, XII. p. I [ ~ 347, note 20.] See, also, a note by me upon.353, 1850, XIV. p. 17; also his Recherches sur the intimate structure of the phosphorescent organs l'Armure ginitale femelle des Insectes Orthoptires, in Pyrophorus phosphorsus, Proceed. Boston Soc. id Ibid. XVII. 1852, p. 207, and Recherches sur Nat. Hist. 1850, p. 290. -ED. l'armure g6nitale femelle des Tlsectes -I6miptirest t [ ~ 348, note 1.] See, also, for cases of true Ibid. XVIII. 1852, p. 337, finally the same of the hermaphroditism in the Insecta, Wing (Trans. of Insectes NMvroptires, Colioptlres, Dipteres, il the Ent. Soc. London, Y. p. 119) and JWesm.ael Ibid. XIX. 1853, p. 25, et seq. -- ED (Bull. de l'Acad. d. Brux. 1849, II. p. 378).- ED. 348. THE INSECTA. 447 are much less numerous than the males. In the colonies of Bees, Termites, and Ants, there are, beside the males and females, a multitude of neuter individuals known as the Workers or Soldiers. The sexual parts of insects are developed chiefly during the pupa-state; but their rudiments exist already in the youngest larvae, with which the sexes may then be distinguished.(2) The female genital organs persist in a rudimentary germ-like condition with many larvae of Bees, probably owing to the influence of nourishment, for by increasing that of the workers these last may be raised to the rank of females or Queens. (3) The Aphididae are very remarkable in that they prodluce, for several successive generations, only females which, in their, turn reproduce, but viviparously and without the direct influence of the males.(4) The genital organs of the Insecta are composed in general, of two symmetrical Ovaries, or Testicles, situated in the abdominal cavity, and of two oviducts, or Deferent canals (Tubae, or Vasa defeentia) which unite in a common excretory duct (Vagina, or Ductus ejaculatorius) opening back of 2 Herold (Entwickelungsgesch. d. Schmetterl.) vestiges of the ovaries and of the seminal receptacle. has made very interesting researches on this pre- See Ratzeburg, Nov. Act. Nat. Cur. XV. part II. mature development of the genital organs with p. 613, Tab. XLVII. and my observations in GerPontia brassicae, and which accord with the ob- mar's Zeitsch. IV. p. 375. servations of Suckow (Ant. u. physiol. Untersuch. 4 This mode of generation of the Aphididae (see p. 31, Taf. III. V.) on those of Gastropacha pini. ~ 350) quickly reminds one of that which SteenSee, also, Herold, Disquisit. de Animal.Vertebr. car- strup has called Alternate Generation. Certain ent. in ovo format. Tab. I. fig. 9, or Ann. d. Sc. Nat. species of Cynips belong probably to the same catXII. 1839, p. 186, P1. VII. fig. 8. To be con- egory, for their males have yet been undiscovered. vinced that in the other orders of Insecta the geni- Hartig (Germar's Zeitsch. IV. p. 398) has been tal organs are also developed at a very early unable to find any individuals of this sex among period, it is only necessary to cast a glance over thousands of Cynzips folii and divisa. Similar the figure which Suckosw (Heusinger's Zeitsch. observations have been made by L. Dsufour (ReII. Taf. X. fig. 9) has given of Aphrophora spu- cherch. sur les Orthopt. &c. p. 527). It is to me.maria, and L. Dufour (Ann. d. Sc. Nat. XIII. probable, also, that the capacity which many ento1810, PI. III. fig. 5) of Pyrochroa coccinea. mologists attribute to Psyche of laying eggs with3 For the origin of the neuters with the Hymen- out a previous copulation is an example of alternate optera, see Treviranus, Zeitsch. f. Physiol. III. generation.*.p. 220. In all the bee-workers there are found * [ ~ 348, note 4.] The peculiar economical re- Transact. of the Entom. Soc. London, I. 1851, p. 234. lations of certain Ilymenoptera (Cynips) referred In the first of these researches made upon the to above have received some explanation by the genera Psyche and Fumea, there was no evidence researches of Frauendorf (Ilardinger Berichte hib. that, with the individuals of these genera, reproducd. Mittheil. v. Freunden d. Naturwiss. in Wien. IV. tion occurs in an anomalous manner, that is, withp. 247, or Wiegmann's Arch. 1849, Th. II. p. out the aid of the male; on the other hand, the.118), upon Gastropacha lanestris. He gathered facts of the well-developed character of the inter-two nests of the larvae at the end of June, 1836; nal genital organs of the' females, and of the capacity by the middle of August the caterpillars had spun of the male to impregnate the female while she is up, and on Sept. 18, the first imago appeared, and concealed deeply in her case-these precluded the the second on Dec. 14; both of these were males; hypothesis of Lsucisa sine concubitu. But subuin the spring of 1837, some twenty individuals of sequent researches made upon Talaeporia have both sexes appeared; others, likewise, in the autumn shown him that, with the individuals of this genus, of 1837; others still in the following year, and the non-sexual reproduction does occur, presenting sinlast of them on the 4th of March, 1842. The pupa- ilar phenomena and conditions as the generation of -state of the last of the brood was therefore five and the viviparous Aphides. It is proper to remark, howa half years, while that of the first was only as ever, that the carefully-made researches and expermaany weeks. iments of Speyer upon the genital organs and mode In regard to the alleged anomalous reproductive of reproduction of Talaeporia lichenella, several relations of Psyche, they have received the special years before, had shown that two successive generaattention of Siebold, who has quite cleared up the tions here occur without the presence of males; see subject (Ueber der Fortpfianzung von Psyche: Ein his paper in the Entom. Zeit. 1847, p. 18. For the JBeitrag z. Naturgeschichte der Schmetterlinge, in phenomena and their interpretation of the develop-,iebold and Kolliker's Zeitsch. I. 1848, p. 93 i ment of the viviparous Aphididae, see my note at,also in his Bericht fib. die entomol. Arbeiten d. ~ 355, end. - ED. schles. Gesellsch. im J. 1850, or its transl. in the 443 THE INSECTA. ~ 348v the anus. This duct has several double or single appendages, of which one with the females serves as a seminal receptacle (Receptaculum seminis), or as a copulatory organ (Bursa copulatrix), while the others, in both sexes, are true secretory organs. The vagina is often prolonged into a horny ovipositor, and this same organ modified, with the males, is the Penis. The Eggs of Insecta are very varied in their forms and colors. Externally, they are frequently marked by prominences and raised lines, formingin a very varied, and often a very elegant design.') Those of some Cynipidae, Ichneumonidae, and Siricidae, have one of their ends prolonged into a long, straight or curved thread. (6) With some Hydrocorisae they are oblong and their posterior extremity is covered with long, stiff bristles.'7) They have, usually, a very solid chorion, and a thin vitelline membrane. The vitellus is composed of fat-vesicles more or less colored, which communicate their color to the entire egg. The germinative vesicle contains a germinative dot which is often composed of several parts.(8) These eggs are formed after two different types. 1. With the Orthoptera, and various Coleoptera, the germinative vesiclel is formed in the posterior extremity of the tubular ovaries, and is gradually surrounded by a mass of granular vitelline substance. This vitellinea mass continues to increase until, at last, there is formed on its surface a chorion, at first soft, but which finally becomes solid. During the course of this development, the eggs succeed each other in a row, and in this way advance towards the opening of the ovarian tube.(9 2. With the Lepidoptera, Diptera, Hymenoptera, Neuroptera, Cicindelidae, Carabidae, and Hydrocanthari, the mode of formation is wholly different. The vitelline mass which is disposed around the germinative vesicle, increases in the following manner: Between each two vitelline masses, there appear a group of large vitelline cells whose contents are blended with the subjacent vitelline mass; while, the chorion is developed from a. layer of vitelline cells, commencing by its inner portion. It gradually extends over the vitelline mass and cells, and finally, when the vitellus has reached a certain volume, closes at the upper portion of this last. The epoch at which the eggs reach their maturity coincides, with the Lepidoptera, Tipulidae, and Ephemeridae, with the end of their pupa state, so that these insects are able to deposit their eggs as soon as they have cast off their pupa envelope; while, with the Libellulidae, the Locustidae, and especially the Apidae, the eggs are not matured in the ovaries until a long time after.(1~) With all Insecta, the sperm contains very active filiform spermatieparticles which become immediately stiff and looped when put in water., These particles are developed in large cells whose involucrum finally dis5 Kirby and Spence (Einleitung, &c., p. 100, Taf. 8 See Wagner, Prodromus, &e., p. 9, Tab. II. XV.) have figured a great number of eggs of insects of fig. 18-22. various forms. See, also, Burmeister, l1andb. &c.'9 See Wagner, Abhandl. d. physical. mathemat. Taf. I. and Lacordaire, Introduction, &c., P. 1. I. Klasse. der Alkd. zu Munich, II. 1837, p. 554,. 6 See L. Dufour, Recherch. sur les Orthopt. fig. Taf. II. fig. 1 (Agrion), and Stein, Vergl. Anat. 128, 149 (Cynips and Xiphydria); Hartig, in u. Physiol. d. Insekt. I. p. 47, Taf. IX. fig. 4, 8S Wiegmann's Arch. 1837, I. p. 151, Taf. IV. (Try- (Telephorus and Acheta). phon, Paniiscus, and other Ichneumonidae), and 10 Herold was the first who observed this rein Germar's Zeitsch. f. Entom. p. 327, Taf. I. fig. markable mode of the formation of the eggs witlt 5, 6 (Cynips). the Lepidoptera * see his Disquisit. &c. Tab. I. fig. 7 The eggs of Ranatra have two long bristles; 11-18, or Ann. d. Sc. Nat. XII. 1839, p. 195, P1. while, with those of Nepa, these last form a coro- VII. fig. 13-18. Researches even still more de. net; see Roesel, Insektenbelust. III. Taf. XXII. tailed have been made by Stein, Vergl. Anat. &c, XXIII., and L. Dufour, Recherch. sur les HI- p. 52,'rat IX fig. 2, 9, 13 (Pontia and Ptsrosta mipt. Pl. XVI. chus) ~ 349. THE INSE:CTA. 449 appears, while the spermatic particles thus formed remain together for Some time and finally are united in fasciculi of variable forms.("l) With many species, these bundles are disposed one after another, and. then united forming long, vermicular bodies.'l2 Only gradually, as the: sperm mass passes along the deferent canals, are the spermatic particles. separated to unite again under new and remarkable forms. These last consist of long, penniforrn bodies, having very singular movements,?1r their free extremities oscillate to and fro without cessation.(3) A kinkL of spermatophore is also observed in the female organs of many spe(ies belonging to the Lepidoptera, Orthoptera and Coleoptera. It consists of a peculiar hollow body, usually somewhat pedunculate, with pretty solid. albumen-like walls, and filled with spermatic particles.(4) I. Female Genital Organs. ~ 349. The two Ovaries are always composed of a larger or smaller number of tubes, whose free extremities are extremely sinall, but which gradually increase in size to their point of insertion on the oviducts. From their caecal terminations is prolonged a delicate thread, which, bound together with the others, serves to attach the two ovaries to the thorax.(l) The 11 For the spermatic particles of the Insecta and fecundated females of Locusta and Decticus (see; their development, see my memoir in AMiller's Arch. my memoir in the Nov. Act. Nat. Cur. loc. cit. p. 1836, p. 30 5 and Klliker, in the Neue schweiz. 262, Tab. XVI. fig. 14, 15), while those observed. Denkschrift. VIII. p. 24.* in the Bursa copulatorix of many Lepidoptera are 12 See my memoir in Miller's Arch. loc. cit. p. round and long-pedunculated. With the Coleop38, Taf. III., fig. 16-18 (Pontia). These vermiform tera, spermatophores are often found, also, in the bundles are observed not only with all the Lepidop- copulatory pouch of the fecundated females. Their tera, but also with certain Diptera and Coleoptera * forms vary. considerably, and I may ilcention see Loewo, Horae anatom. Hift. 1, 1841, p. 26, Taf. specially those of Clivina fossor, which are elonII. (Scatopse), and Itammerschmidt, Isis, 1838, gate and remarkable for their very long and twisted p. 358, Taf. IV. (Cleonus and various Lepidop- peduncle; see Stein, loc. cit. p. 91, Taf. I. VII. tera). This last mentioned naturalist has, however, VIII. The older entomologists took these spermtaken these cords for gigantic spermatic particles, atophores for the penis which was detached in the to which he has given the name of Pagiura, Spiri- copulatory act -an opinion which I myself for — lura and Cincinnura. merly entertained (Miller's Arch. 1837, p. 399,. 13 I have discovered these penniform bodies 419); but,since, I have learned the true nature of composed of spermatic particles in the Receptaclu- these bodies, and the rectification of this error,. lum seminis of Locusta and Decticus s; see Nov. made by Steins (loc. cit. p. 86), is perfectly correct. Act. Nat. Cur. XXI. 1845, p. 251, Tab. XIV. XV. 1 For the different dispositions of these tubes, see Dujardin (Observ. au Mlicroscop. 1842, P1. XI. J. Miiller, Nov. Act. Nat. Cur. XII. p. 585;. fig. 18, 19) had already perceived similar bodies in Burmeister, Handb. I. p. 199 i and Lacordaire,. the male organs of Tettifonia plebeja and Spho- Introduct. &c. II. p. 329. The ovaries of the drus terricola. Stein (Vergl. Anat. &c. p. 106, Strepsiptera are organized after a wholly different Taf. I. fig. 19 (Loricera)) has also found them in type. The simplicity of the female organs here is the seminal receptacles of the females of various very remarkable, and in this respect they hold an Ca'rabidae. exceptional position. The two ovaries are, at first, 14 Pyriform, short-pedunculated spermatophores two long bodies, composed of innumerable germs. are found in the Receptaculum seminis of the When these last have matured, they are disengaged * [~ 348, note 11.] The spermatic particles of dae, Andrenidae, Vespidae, &c., these particles the Insecta are described above, as well also by have the form of those of the Araneae - an arcuate WYagener and Leuckart (loc. cit. Cyclop. Anat. and staff, to which is attached a delicate tail; while, Phys.), as being invariably filiform. This is incor- with the Phasmidae, they consist of a spoon-shaped rect: it is true they are generally so; as, for head with a very conspicuous tail - indeed, quite: instance, with all the Coleoptera, Lepidoptera, resembling those of many of the Rodentia. It is Diptera, Aptera, Hemiptera; but with some fami- scarcely necessary to add that in this class these lies of the other orders (the Hymenoptera, Neurop- particles are, as is the case with all the other classes tera and Orthoptera) their form is quite different, of animals, developed in special cells. The whole, and I am only surprised that it has not before been subject is deeply interesting, in both a histologicag noticed. Thus, with the Libellulidae, Ephemeri- as well as a zoological point of view. - ED. 38S 450 THE INSECTA. ~ 349, ovarian tubes are, moreover, always enveloped by numerous trachean networks. (2) Upon their length, which is very variable, depends the number of the eggs or germs which are disposed in a single file; and in this way, they may be distinguished as uni-, bi- and multi-locular. The two Oviducts -are usually short and often dilated into a kind of calyx at their upper extremity, if there are numerous ovarian tubes meeting at this point. The Seminal receptacle (Receptaczdum. seminis) is a double or single, solid capsule (Capsula seminalis) of variable form and surrounded by a muscular layer. It opens into the vagina below the point of junction of the two oviducts, by means of a canal of' variable length (Dzectus seminaZis). This duct has sometimes a simple, or a bif'urcated appendage (Glandula appendiculartis). (3) The seminal receptacle never contains spermatic particles with those females which have not rejected their pupa covering, or especially with those, still in a virgin state; but after copulation it always contains a multitude of these particles moving very actively, and these movements are kept up for a long period, as may be observed with those females which live over the winter.(4) The Copulatory pouch (Bursa copulatrix) consists nearly always, of a spacious, pyriform reservoir, which, with only a few exceptions, opens into the vagina below the seminal receptacle. During copulation, it receives the penis, and often, also, the sperm which enters either by portions contained in the spermatophores, or enveloped by a shapeless gelatinous substance. (5) The secretory organs situated at the lower end of the vagina, consist, usually, of two rather long, glandular tubes on each side of the vagina, into which they open, either directly, or through two small special excretory ducts. They often have, on their course, two vesiculiform reservoirs. In most cases, these glandular organs appear to form a Sebaceous or and scattered through the cavity of the body be- mar's Zeitsch. II. 1840, p. 442). Stein, also (loc. tween the fat-cells. The females are apodal, and cit. p. 112), has shown that the spermatic particles the ventral surface of their body, which resembles remain alive a long time in the seminal receptacles that of the larvae, is occupied by a shallow canal of the Coleoptera. The liquid secreted by the ~(Incubatory canal) which terminates caecally in accessory gland serves, probably, to keep the the penultimate segment of the body, and opens spermatic particles fresh, and to prevent them from upon the cephalothorax by a semilunar orifice desiccation. The fecundlation takes place undoubt(Genital opening). From this canal pass off into edly when the eggs pass in front of the orifice of the visceral cavity three to five forward-bent tubes. the seminal receptacle, which is then probably comThe eggs are developed in the visceral cavity, and pressed by an investing muscular apparatus. This by these tubes the young larvae make their exit long preservation of spermn in the seminal receptacle therefrom; see my Beitr. zur Naturgesch. d. wir- explains how the females of certain species can lay bell. Thiere. p. 75, Taf. III. fig. 62, 67; anci Wie - eggs so long after copulation, and at a time when mann's Arch. 1848, I. p. 147. Formerly, I erred the males have all disappeared. The time of the in taking the ventral for the dorsal surface with full maturity of the eggs in the ovary, moreover, these insects. does not always coincide with that of the heat and 2 J. 1Aiiller has taken these filaments for vessels copulation with the muale. The observations which.communicating between the ovaries and the dorsal have been made on this last point have been colvessel; see Nov. Act. Nat. Cur. XII. p. 580. lected by siiller (Nov. Act. Nat. Cur. XII. p. 624). 3 For a long time this Rereptaculum seminis 5 This copulatory pouch, which, from its large remained wholly unobserved, or was taken for a size, was first perceived by entomologists, is even Bursa copulatrix, or an organ secreting a viscous now often taken for a fecundating sac, or a seminal substance for gluing the eggs together and to for- reservoir (Sperlmatheca). The spermuatic particles eign objects. The older descriptions and figures are carried, undoubtedly by their own movegive, therefore, only an imperfect idea. It is only ments, from this copulatory pouch into the Re lately that the constant presence and true nature ceptacullum seeinsis; and very probably they,of this organ have been recognized (see my memoir begin to travel shortly after copulation, for, a long in Miuller's Arch. 1837, p. 392, and Stein, Vergl. sojourn in the Bursa copulatrix does not apAnat. &c. 1847, p. 96). Yet, at this day, the cop- pear advantageous, since those that remain over ulatory pouch and seminal receptacle are frequently become stiff and dead-like in the midst of the semiconfounded together and L. DujbtLr, in particu- nal fluid, which is granulous and viscid. J. Hunlar, persists in his old error in designating this sem- ter (Philos. Trans. 1774), in his experiments on inal receptacle as a Glande sebiJiqtLe. artificial fecundation, was successful only when he 4 See my observations made upon Vespa (Wieg- took the sperm from the copulatory pouch of the macnn's Arch. 1839, I. p. 107) and Culte (Ger- females which had just come from copulation. 350. THE INSECTA. 451 Mucous apparatus (Glacnduz ae sebaceae or colleteriae), for they secrete a viscous, coagulable substance, which serves to envelop and glue the eggs together, and to fix them to foreign bodies. With the females of the Ichneumonidae, this apparatus secretes a kind of cement with which these insects close the wounds they have made in the bodies of the Insecta in which they have depositedl their eggs. It is probable, also, that, with those Insecta which deposit their eggs by means of an ovipositor in the tissues of plants, thereby producing galls, these same organs serve as a kind of Poison-apparatus causing this diseased formation of the vegetable parenchyma. ~ 350. The different parts of the female genital apparatus present, in the vari-;ous orders and families, countless modifications as to number, form and disposition. The most important of these are the following: With the Aptera, the two ovaries consist each of only four to five tubes, which, with the Pediculidae, open, all, at the top of the corresponding oviduct; while with the Lepismidae, they are separately inserted on the aide of the moderately long oviduct. In both of these families, there are two short varicose caeca, which enter laterally the lower end of the vagina, and are probably sebaceous or viscous organs.() There appears to be here no seminal receptacle or copulatory pouch. Witk the Hemiptera, the ovaries consist of four to eight tubes of variable length, disposed verticillate at the extremity of the short oviducts. The Psyllidae and Cicadidae, alone, form an exception in this respect. With the first, the ovaries are composed of ten to thirty unilocular tubes, and with the second, twenty to seventy bilocular ones. These last, moreover, are distinguished by their oviducts being divided into several branches, on the extremity of each of which is a tuft of ovarian tubes. (2 Their Receptaculum seminis consists of two small caeca.(3' The other Hemiptera have only a single seminal receptacle, which is pyriform with the Psyllidae and oviparous Aphididae;() is a long, slightly flexuous caecum with the Naucoridae, an I Nepidae; and a very long, somewhat fiexuous caecum with the iHydrometridae. With many Capsidae, and other Geocorisae, also, it is a pretty long and flexnuous caecum, while, with the Pentatomidae, the rather short Ductus seminalis terminates in a brownish, horny, pyriforml Capsula seminalis, the constrictions and protubetances of which often present a peculiar appearance. Sometimes this tube is dilated into a second vesicle, at whose base is a horny tube containing a second tube which is a direct prolongation of the Capsula seminis. (5 Most Hemiptera have no copulatory pouch, —the Cicadidae, alone, having one which consists of a narrow-necked, pyriform vesicle. (6' With the oviparous Aphididae, 1 See Sioammerdamm, Bib. der Nat. p. 37, Taf. of the oviparous and viviparous Aphididae, in II. fig. 8 (Pedicuelas), and Treviranits, Vetre. Froriep's neue Notiz. XII. p. 308. $chrift. II. p. 15, Taf. III. fig. 8, 9 (Lepisma). 5 For the seminal receptacle of the Pentatomidae, 2 See L. D)lfoltr, Recherch. sur les Hemipt. PI. see H,. Dlfousr, RLecherch. &c. loc. cit. P1. XIV.XIV.-XVII., and Ann. d. Sc. Nat. V. 1825, p. 168, XVI., and Siebold, in Mal/ler's Arch. 1837, p. Pl. IV. (Cicada); and SoCl/ow, in Heitsinger's 410, Taf. X<. fig. 4-6.* Zeitsch. II. Taf. X~. fig. 55, 57 (Nepa and Cer copis). See Neckel and L. Duefour, loc. cit. Accord3 See Meckel, Beitr. &c. I. iflt. I. Taf. I. fi. 6 i. in to D)oyre (loc. cit. l. 203, P1. VIII. fig. 3). i.; L. Difs/br, Ann. d. Sc. Nat. V. 1825, P1. IV. fig. there is, with the female Cicadidae, a special orifice.5, 1. l., and fig. 8, d. d. and Doy/re, Ibid. VII. by the side of the oviduct, which is continuous with 1837, Pl. VII1. fig. 3-7, E. (Ledra and Cicada). the ovipositor, and through which the peDis pro4 See my memoir on the internal genital organs trudes into the copulatory pouch. *[ [ 350, note 5.1 For the female organs of Belostoma, see Leidy, loc. cit. p. 64. -ED. 452 THE INSECTA. ~ 35(. and many Geocorisae, the secretory apparatus consists of two round gland. ular sacs,(7) while, with the Cicadidae, it is a single, long flexuous tube.(s> The viviparous Aphididae differ from those which are oviparous, in that their eight ovarian tubes are multilocular, and their oviducts entirely without appendages; while with the second or oviparous, these eight tubes are unilocular, and there is a seminal receptacle and two sebaceous glands.() With the Diptera,tl~) the ovaries consist, usually, of numerous short, three or four chambered tubes. With only a few species, these tubes are long and have eighteen to twenty chambers.tl(" The disposition of these tubes varies considerably. With some, they are simply terminal to the short oviduct; while with others they form one or more series on the. sides of these organs, which, then, are longer. The Receptaculum serninis presents the most varied forms, (12) it is usually, triple, rarely simple or double,(31) and is lined with a horny, brown substance. It has a round, pyriform, or oblong shape, and, in this last case, is often flexuous or spiral. The seminal ducts, which lead from the receptacles to the vagina, are sometimes isolated, and sometimes united into one or two common ducts before entering the vagina. Directly below them on each side, are the points of junction of the two secretory organs, which, always present with the Diptera, consist of two simple, rarely ramose tubes, whose very small excretory ducts have, exceptionally only, a vesiculiform dilatation. (14) The Bursa copulatrix appears to be wanting with all the Diptera. But, with many Muscidae, the vagina has, as a seminal receptacle or uterus, a spacious, and sometimes two-lobed reservoir in which the fecundated eggs are accumulated in great numbers, and remain until the larvae are sufficiently developed to be hatched, making these animals viviparous.(l5) With certain species of Tachina, this uterus presents a remarkable form; the vagina is very long, spiral, and of equal size throughout; and, at certain periods, is crowded with larvae or small eggs.16) With the pupiparous Hippoboscidae, the female organs are formed on an entirely special type, corresponding with the remarkable mode of the reproduction 7 See L. Dufour, Recherch. loc. cit. P1. XIV. 13 The Receptacsulum seminis is simple with XV. Pulec, Esnpis, Dolichsopus, and Hilara; anda 8 See Meckel, Suckow, L. Dsufour, Doy/re, double with Piophila, Stomoxys and Borborus. loc. cit. 14 See Siebold, a(nd Loesw, loc. cit. These gland9 See my researches in Froriep's neue Notiz. ular appendages secrete with certain Tipulidae a XII. p. 307. Dutrochet (Ann. d. Sc. Nat. XXX. considerable quantity of gelatinous substance which 1833, p. 204, PI. XVII. f. fig. 1), it would appear, envelops the eggs and binds them in a kind of colhas unwittingly figured the genital organs of an lar. These collars, which are deposited in the oviparous Aph.is, by taking the seminal recelptacle water, have for a long time been figured by hotfor a sperm-secreting organ. In this way he was anists among the algae under the name of Gloeoled to regard the viviparous Aphididae as her- nenma. maphrodites. 15 There are viviparous species in the genera 10 For the internal female organs of the Diptera, Alusca, Anthomyia, Sarcophaga, Tachina, see L. Dufour, Ann. d. Sc. Nat. I. 1844, p. 253, Dexia, Miltogramnma, &c.; see my memoir in and especially Loew, lIorae anatom. p. 61. Froriep's neue Notiz. III. p. 337, and in W/ieg11 Ephydr:a and Tachina; see Loeeo, loc. cit. mann's Arch. 1838, I. p. 197; also my Observat. Taf. IV. fig. 3, 10. quaed. Entom. &c. p. 18. L. Dufolur (Ann. d. Sc. 12 For the Receptaculum seminis of the Dip- Nat. I. 1844, p. 261) has designated this reservoir tera, see Siebold, in Me/ller's Arch. 1837, p. 414, as R/servoir ovolarviTere; see also his Hist. d. Taf. XX. fig. 7-10 * and especially Loew, loc. cit. Ailtamorph. et d. I'Anat. d. la Piophila petasioniso p. 89, Taf. IV.-VI., and in Germar's Zeitsch. III. Ibid. p. 382, P1. XVI. fig. 16, g. Loew (fiorae p. 386, Taf. III.; the numerous figures of this anatom. Tab. IV. fig. 9, 11, 14, Tab. V. fig. 13) author will give some idea of the inexhaustible va- has figured analogous uteriform reservoirs with riety of forms of these organs. When L. Dufour MTusca, Dexia, Piophila and Psila. (Ann. d. Sc. Nat. I. 1844, p. 262) would regard the 16 This long spiral-form vagina, which was forseminal receptacle as a reservoir of the neighboring merly described as an ovarium spirale, is found in. secretory organs, it is evident that this distinguished Tachina fera, tessellata, grossa, vulpina, haeentomotomist must have entirely omitted a micro- morrhoidalis, &c.; see my memoir in Yiegscopical analysis of the substances found in the mann's Arch. loc. cit. p. 194, and Reaunmur various glands and other organs of Insecta. eI/m. IV. 10 mim. p. 412, P1. XXIX. fig. 7, 8 350. THE INSECTA. 453,of these animals. The two ovaries are unilocular pouches of unequal size, inserted laterally, by means of a short oviduct, upon the vagina. The upper extremity of this vagina contains sperm, after copulation, and may, therefore, be regarded as a Receptaculum seminis; while the lower portion is widely dilated, and may, therefore, be considered as an uterus. The upper or narrower portion of the vagina receives two small, simple, or somewhat ramose glandular tubes (Glandulae sebaceae).711) Below these glands are situated the two excretory ducts of a double glandular apparatus, very voluminous and multiramose, whose product serves, without doubt, to nourish the larvae which are provisionally developed in the uterus.(") With the Lepidoptera, each ovary is composed of four very long, spiral, mnultilocular tubes. The Receptaculum serminis M') is pyriform, and often has a long, spiral Ductus seminalis.(20) At its base opens a simple or bifurcated accessory gland, and underneath it there is always a large, double, sebaceous gland, consisting of two rather long, flexuous, simple caeca. These last open into the vagina, by means of a short common excretory duct, and each, at their point of union, is usually dilated into a vesiculiform reservoir.(2 Some Lepidoptera have, moreover, two smaller ramose glands, situated near the orifice of the vagina, which secrete, perhaps, an odorous substance that excites the copulatory act.(22) The copulatory pouch, finally, is very remarkable in all the species of this order. It consists of a:arge, pyriform reservoir, sometimes constricted in its middle, and having for the reception of the penis, a canal which opens externally by a special orifice situated below the vulva. In its course this canal sends off a small, flexuous, lateral duct, which passes into the vagina opposite the mouth of the Receptaculurn seminis, and thus forms a communication between this last and the copulatory pouch.(2) With the Hymenoptera, the ovaries(24) vary very much as to the number of their component tubes, of which there are sometimes four to six, sometimes eight to ten, and with some species they range from twenty to a hundred.(i ) These tubes are always multilocular, and never very long. The 17 These tubes are simple with Melophagus, and Taf. VI. K. (indistinct). Moreover, Malpighi (Do ramose with Hippobosca. Bombyce, 1669, p. 81, Tab. XII. fig. 1, J. K. M.) 18 See my researches in IiIller's Arch. 1837, p. had already perceived, with the silk-worm, all tha 426, and those of L. Dufour, Ann. d. Sc. Nat. VI. appendages of the vagina, and specially the copu. 1825, p. 308, P1. XIII., and III. 1845, p. 76, P1. III. latory pouch with its canal of lateral communicaThis last-mentioned naturalist has very well figured tion. With Eunrepia Hebe this canal has a pyrithe female organs of Hippobosca and Melophagus; form deverticulum. only he is deceived relative to the glandular append- 24 For the female genital organs of the Hymenages of the vagina, in regarding the upper pair as optera, see L. Dufour, 1techerch. sur les Orthopt. a Receptaculum seminis, but which never contain &c. p. 406. spermatic particles. 25 Each ovary is composed of three or four ovige19 For the appendages of the female organs of the rous tubes with Xylocopa, Rombus, Anthophora, Lepidoptera, see Siebold, in oliiller's Arch. 1837, Chrysis; of five to six with Yom.ada, Sapyg.a, p. 417. Chalesis, Vespa; of eight to ten with Pimpla, Pa20 The seminal receptacle has been figured in its niscus; of ten to twelve with the Tenthredinidae; various stages of development by Herold (Ent- of twenty to twenty-five with Myrmica, Xiphrytlria wickelungsgesch. d. Schmetterl. Taf. IV. fig. 1, u. y. and Banchus; and of more than one hundred with p. and Taf. XXV.) as a unicornous secreting organ. Apis. With Chelonus the ovaries present a reSee also Suckow, Anat. u. physiol. Untersuch. markable exception; they consist each of two long Taf. VI. g. g. flexuous tubes, which are very widely dilated at 21 See Herold, loc. cit. Taf. III. fig. 1, t. z. their lower extremity. L. Dufour (loc. cit. p. and the following plates; also Suckow, loc. cit. 541, P1. X. fig. 143) regards these swellings as a UTaf. VI. i. I. kind of uterus in which are developed the larvae of 22 Illelitaea, Argynnis, Zygaena, &c. these Ichneumonidae s but this assertion cannot be 23 See Hlerold, loc. cit. Taf. III. fig. 1, x. f. g. admitted without further research. and the plates following; also Suckow, loc. cit. * [~ 350, note 23.] See also for the internal and Kolliker's Zeitsch. I. 1849, p. 182. This female genital organs, and especially their develop- memoir contains many new details. — ED. muent, of the Lepidoptera, Meyer, loc. cit. Siebold 454 THE INSECTA. ~ 350. Receptacula seminis is nearly always simple, round, or ovoid, and necked, and is continuous into a usually short, seminal duct.(2^) A Glanzduia appendicularis is never absent, and consists, usually, of a bifurcate tube, which opens into the DC ctus seminalis, and only rarely into the Capsula seminalis itself. (27) With the Tenthredinidae this apparatus is, moreover, formed after a different type; the seminal vesicle is a simple deverticulum of the vagina, and more or less distinct from it, beside, it is deli: t in the accessory gland.(2S) The copulatory pouch is absent with all the ilymenoptcra as are also the Glandulae sebaceae with those females which have a sting and a poisongland; but these sebaceous glands are highly developed with those species having an ovipositor, into which.last they open, and probably serve some purpose connected with the oviposition, partly as sebaceous, and partly as excitatory organs. This secretory apparatus consists of a simple or a double ramose gland, whose excretory duct receives the neck of a pyriformn receptacle, or, sometimes, is itself dilated into a vesicular reservoir.(29) With the Orthoptera, the two ovaries are nearly always composed of numerous, multilocular tubes, which usually open in a single row upon the internal or external side of two large and sometimes very long ovaries. (0) The seminal receptacle often consists of a simple longer or shorter pedunculated vesicle, whose closed extremity is dilated into a pyriform vesicle with the Psocidae, Forficulidae, Locustidae, Phasmidae and Mantidae.(31) A similar Capsula seminis is often found with the Acrididae on one of the sides of the Ductus seminalis and removed from its extremity. (32) Most of the Blat26 For the Receptaculum seminis see Siebold, long, flexuous, caecal oviducts, have tubes only at Observ. quaed. Entom. loc. cit. p. 6, and in Ger- their lower extremity. The oviducts of Perla bimar's Zeitsch. IV. p. 362, Taf. II. With those caudata are still more remarkable; they are very females which, at short intervals, lay very many long, flexuous, and have ovarian tubes only on one eggs, the seminal receptacle is very large; see side of their upper extremity, and anastomose in a Swammerdamm, Bib. der Nat. Taf. XIX. fig. 3, loop-like manner. For all these differences, see L. t. u. u., where the Receptaculum seminis of a Dufour, Recherch. sur les Orthopt. &c. P1. II.honey-bee is very well represented.* V. and P1. XI. fig. 165, PI. XIII. fig. 206, and 27 The Glandula appendicularis is simple and in the Ann. d. Sc. Nat. XIII. 1828, P1. XXI. XXII. inserted on the Ductus seminalis with the Ptero- (Forficula). malini and Cyn:pidae; it is double, and opens 31 With Forficula, and Acheta, the seminal relirectly into the Capsula seminis, with Vespa ceptacle has a long and flexuous peduncle, which,:rabo and Tiphiafemorata. with the Psocidae, and Locustidae, is shorter. That 28 The seminal receptacle is double, exceptionally, of Psocus pulsatorzus contains several long-peWvith Lyda. dunculated, glandular bodies (Nitzsch in Ger21 This glandular apparatus is simple and has a mar's Magaz. IV. p. 281, Taf. II. fig. 3-5), which lateral pyriform reservoir with various Ichneumon- I formerly regarded as Capsulae seminales idae; see L. Dufour, Recherch. P1. X. fig. 137- (Msiiler's Arch. 1837, p. 410}; but which are prob142 (Pimpla and Bracon). This naturalist calls ably spermatophores. With Perla, the seminal this apparatus Glande sirifique, as distinguishing receptacle is a simple caecum, twisted like a ram's it from the Glande sebifique. With Sirex, I have horn, and the base of which supports several short observed the excretory duct of this single and mul- glandular follicles (Glandulae appendiculares?). tiramose gland dilated into a large reservoir. With For the seminal receptacle of the Orthoptera cited the Tenthredinidae, it is also ramose, but double as in the text, see especially Roesel, Insektenb. Th. well as its vesicular reservoir; see L. Dufour, loc. II. Ileuschrecken-und Grillen Sammlung. Taf. IX. cit. P1. X. fig. 155-157 (Tenthredo and Cimbex). fig. 3, k. (Decticus); L. Dufour, Recherch. sur 30 With the Locustidae, Acrididae, Mantidae les Orthopt. P1. III. fig. 31, P1. IV. fig. 4-3 (Acheta and Libellulidae, the ovarian tubes are inserted and lMantlir a&zcC YS.*ir I: V A A:uat. Cur. upon the internal side, and with the Ihkastrsdae XXI. a.Grt I7, Eg, -1ia ]2[V fig 1 c. (Loand Ephemeridae, on the outer side of the two ovw- cs a';. ducts. Forficula gigantea has, moreover, only 32see Hegetschweiler, De insect. genitalibus five internal multilocular tubes, while with Foryi- dissert., fig. VII. f. e.; and Siebold, in Miiller's cula auricularis, the very long oviducts have on Arch. 1837, p. 409,'af.. XX. fig. 3 (Gryllus). all sides a multitude of unilocular tubes. With The Ductus seminalis is usually very long and ilantis, the ovarian tubes are unilateral, but intertwisted, as, for example, with Gryllus, Truxunited together in several bundles. With Oedi- alis, &c. poda cerulescens and Truxalis nasuta, the two * [ ~ 350, note 26.] See also Longstreth (Proc. tions on the impregnation of the common honey-bee A jadl. Sc. Philad. 1852, vI. p. 49) for some observa- as due to a Receptaculum seminis.- ED. 3 550. THE INSECTA. 455 tidae(33) and Libelluliclae(') have a short, double, seminal receptacle, which, however, appears to bc,holly wanting with the Ephemeridae. There is a round Bursa copulatrix only with the Libellulidae.(35) The glandular appendages of the vagina are also not found with all the Orthoptera. They are wanting with the Forfieulidae, Phasmidae, Perlidclae, Epheeridae, Libellulidae and Acrididae, but with Decticuzs and Locusta, there is a sebaceous organ consisting of a sinpie, pretty long tube,("') which, with the Achetidae, is more or less ramose, and with the Blattidae and MIantidae is comiposed of a considerable number of partly simple, partly ramose follicles. (37) ~With the: roptera, the ovaries consist always of multilocular tubes. With the Hemerobidae, and M3yrmeleonidae, there are ten inserted on the external side of the two large oviducts,, and with the Phryganidae, their number is quite large, but their insertion on the oviducts is the same.(3) The ten with Panorpa, and the much larger number with Sialis, are disposed 9erticillate at the extremity of the oviducts. With Myrmeleon. and Panorpa, the seminal receptacle is a long, pedunculatedl sac; and has, with Henmerobius, a single, and with Raphidia, a double Glandzla appendicudlaris.(39) With the Phryganidae, this receptacle is still more complicated, for, beside a long, tortuous accessory gland, which is inserted on the neck, or at the base of the Capsuza seminis, there is, at the lower extremity of the Ductus seminalis, another and flexuous glandular tube, and a short — pedunculated reservoir which corresponds perhaps to a copulatory pouch.(40) With,Sialis, beside two lateral deverticula serving, probably, as copulatory pouches, the vagina has numerous vesicular appendages filled with a dark liquid, but the nature of these is still not understood.(41) With Myrmeleon, Hemerobius, and Panorpa, the vagina receives two simple, more or less fiexuous, glandular tubes, (42' which are probably sebaceous organs, andl with the Phryganidae, consist of six digitiform follicles.(43) With the Coleoptera, the ovaries consist of trilocular, rarely multilocular tubes,(44) which are inserted on the calyciform upper extremity of the oviducts, in groups of five to ten or even of fifteen to thirty and forty.(45) Beside 33 Blatta orientalis has two short and flexuous 38 For the female organs of the Neuroptera, see seminal receptacles i but Blatta germanica has L. Du.four, Reeherch. sur les Orthopt. &c. P1. two large and two small ones see Siebold, in XII. XIII. Miiller's Arch. 1837, p. 408. 39 L. Dufour, loc. cit. P1. XII. fig. 174, d. 84The seminal receptacles of Libellula, Aeschna (Panorpa). and Diastatomma consist of two small caeca, 40 L. Dufour, Ibid. P1. XIII. fig. 211, 212. which, with Calopteryx, open into the vagina 41 L. Dufour, Ibid. P1. XII. fig. 188, b. * and through a common duct i while, with lgrion, there Suckow, in Heusinger's Zeitsch. II. Taf. XVI. is only a single long receptacle; see Rathki, De fig. 16, d. Libellular. partibus genital. Tab. I. fig. 11-13, Tab. 42 L. Dsufour, Ibid. P1. XII. fig. 174, 194, c. c. II. fig. 12-14, and Tab. III. fig. 9-11, c., and L. 43 L. Dufour, Ibid. P1. XIII. fig. 211. By Dufour, loc. cit. P1. XI. fig. 165, d. d. (Libellula, means of these glands the females of Phryganea Aeschna and Agrion). See also my memoir on envelop their eggs with a gelatinous substance the generation of the Libellulidae, in Germar's which swells in water and often sticks to stones or Zeitsch. I. p. 433. aquatic plants, presenting the appearance of an 35 See Rathei, loc. cit. Tab. I. fig. 11-13, Tab. annular spawn. II. fig. 12, 13, and Tab. III. fig. 9-11, b. 44 The ovarian tubes are multilocular with the 36 See Roesel, loe. cit. Taf. IX. fig. 3, i., and Carabidae, Hydrocanthari, Cyphonidae, TelephoriSiebold, Nov. Act. Nat. Cur. loc. cit. p. 255, Tab. dae, and Curculionidae; in general they are XIV. fig. 1, e. bilocular with the Staphylinidae; see Stein, 37 See L. Dufour, Recherch. &c. P1. III. fig. Vergl. Anat. &c. p. 29. 31, d. (Oecanthus), P1. IV. fig. 43 (osantis). It 45 The ovaries are multitubular with the Carais not surprising that this wax-apparatus is so bidae, Ilydrocanthari, HIydrophilidae, Elateridae, highly developed with the Blattidae and MIantidae, Chrysomelidae,and Coccinellidae; while withIpion, for, as is known, the females of these insects sur- LixCus, and Hyesiobus, there are only two on each round their eggs with very spacious, multilocular side; see L. Dufouzr, Ann. d. Sc. Nat. VI. 1825, PI. capsules, which they carry about with them, or XvIII.-XX.5 Succow, in Heusinger's Zeitsch. II fatsten to foreign bodies; see Gaede, Beitr. &c. Taf. XIII., and Stein, loc. cit. Taf. III.-VIII. Taf. I. fig. 13, 14 (Blatta orienatalis), and Roesel, loc. cit. Th. IV. Taf. XII. (Mantis). 456'THE INSECTA. ~ 350~ these fasciculate, there are, also, here and there, botryoidal ovaries, in which there are numerous imbricated tubes inserted on a large calyx of each of the oviducts.(4') When these tubes are few in number, they are but rarely,disposed in simple or double regular series.(4') With most species, the Receptaculum seminis is cuneiform and often arcuate; its internal walls are brown, solid and horny, and it communicates with the vagina or copulatory pouch by means of a long, flexuous, spiral Ductus seminalis. With many species, this receptacle is invested with a muscular apparatus, composed of striated fibres, and which undoubtedly is a compressor. Usually, ~there is, attached to the base of the receptacle, a simple, rarely bifurcate or multiramose, Glandula appendicularis, which is sometimes provided with.a long, fiexuous excretory duct.(4'- Sometimes the entire Recep/aculum.seminis is composed of only a simple, rarely bifurcate, somewhat long caecum.(49) Most of the Hydrocanthari, and sonle Carabidae, with which the Ductus seminalis is inserted on the copulatory pouch, have the peculiarity that there arises from the Receptaculunm seminis a special Fecundatory canal which opens into the upper portion of the vagina.~5) A Bursa copulatrix exists, generally, in this order. With only a few species, it -consists of a simple dilatation of the vagina,("3) but, usually, it is a rather long, muscular caecum, separated from the upper wall of the vagina, and:sometimes even flexuous when its length is considerable. (5) Very often, the vagina is quite long, curved S-shaped, and passes with the rectum into a cloaca-like canal. It has a complicated special muscular apparatus.(553'The glandular appendages of the vagina are wanting with the Coleoptera, but, with the Hydrophilidae, there are two multiramose appendages on the oviducts, which are probably sebaceous organs.(54) The same function may, perhaps, be attributed to the glandular walls of the upper extremity of the oviducts of the Staphylinidae and Histeridae.'55) 46 With the Meloidae; see Brandt and Ratze- bidae see Stein, loc. cit. p. 99, Taf. I. fig. 12, burg, Mediz. Zool. II. Taf. XVII. fig. 2. Taf. IL. 47 The ovaries are in single rowvs with 1rfacrony i SilphLa, Dromius, Calosoma, and other Cara~hus, Oxytelus, Silpha, and Byrrhus; but they bidae. are in two rows with Stenelmis, Lycus, Oedemne- 52 See Straus, Consid. &c. PI. VI. fig. 2, o. n. ra, and Hydrobius; see L. Dufour, Ann. d. Sc. (Mfelolonth, a); Brandt and Ratzebuzrg, Mediz. Nat. III. 1835, PI. VII. fig. 25, 27 3 and Stein, Zool. II. Taf. XvII. fig. 2, n. m. (iMeloe); Suckloc. cit. Taf. III. fig. 3, 16, Taf. IV. fig. 3, 4, and ow, in Hesusinger's Zeitsch. II. Taf. XIII.; SieT af. VI. fig. 8. There is a very remarkable dispo- bold, in Miiller's Arch. 1837, p. 405, but especially sition, according to Stein (loc. cit. p. 30, Taf. I. Stein, loc. cit. p. 69, and the corresponding fig. 4), with Dianous caerulescens, Myrmedonia figures..caniculata, Hom.alota canaliculata, and a spe- 53 There is a long,, fexuous, muscular vagina cies of Trichopteryx, which, alone among all with the Cerambycidae, Curculionidae, Elateridae, known Insecta, have only a single ovary and a Buprestidae, and most of the I-eteromera - also,:single oviduct, the first being composed of ten to with the IIisteridae, Dermestidae, Parnidae, &c.twvelve tubes disposed in two rows. see Stein's exact descriptions, loc. cit. p. 71, Taf. 48 For the different forms of the Receptaculum VI.-VIII. seminis of the Coleoptera, see L. Dufour, Ann. d. 54 See Stein, loc. cit. p. 33, Taf. IV. fig. 3 Sc. Nat. VI. 1825, and IIt. 1835, &c.; Siebold, in (Hydrobius fuscipes). With Hydrobius piceus,.MWIller's Arch. 1837, p. 404, Taf. XX. fig. 1, and and caraboides, there are even two kinds of analespecially Stein, loc. cit. p. 96, with the corre- oeous appendages. One consists of eight bifurcate spending figures. With the Elateridae, the acces- follicles, the other of simple tubes inserted on the sory gland is distinguished by a very complicated calyx of the oviducts; see L. Dufour, Ann. d. structure and numerous ramifications i see L. Du- Sc. Nat. VI. 1825, p. 445, PI. XVIII. fig. 5, and four; Ann. d. Sc. Nat. VI. 1825, P1. XVII. fig. Suckow, in Heusinger's Zeitsch. II. Taf. XIII.'8-10, and Stein, loc. cit. p. 129, Taf. V. The sem- fig. 34. The bifurcated appendages were overinal receptacle is wholly wanting with Xantholi- looked by this last naturalist. It is well known -nts punctatus, Lathridius porcatus, Notoxus that the females of the HIydrophilidae enclose their monoceros, and Lagria hirta; see Stein, loc. eggs by groups in a cocoon (Lyonet, MOm. du cit. p. 93. Mas. &c. XVIII. p. 454, PI. XXIV.) which those 49 With the Carabidae, and some Staphylinidae. of Spercheus carry about attached to their postsThe seminal receptacle is double with Stenus and rior legs. Paederus; sde Stein, loc. cit. p. 97, Taf. I. III, 55 Stein, loc. cit p. 35, fig. 6. 50 With the Hydrocanthari and sowe Cara - 351. THE INSECTA. 45T ~ 351. The External Genital Organs of the females are pretty simple with the Ap-tera, Hemiptera, Lepidoptera, Coleoptera, with many of the Diptera, Orthoptera, and Neuroptera, and with some Hymenoptera. The orifice of the vagina is supported by an upper, and two lateral horny plates, whose size and form vary according to the species. With only some Coleoptera, Diptera, and Hiymenoptera, the end of the vagina is protractile, appearing as a more or less articulated Vagina tubiformis.(:) These horny plates about the vaginal orifice serve to support the penis during copulation, and to facilitate the escape of the eggs during oviposition.(2' With the Acrididae, these plates are conical, and in two pairs, one upper, and one under, which may be opened and shut in a pincer-like manner. With several genera of the Tipulidae, and Asilidae, the two lateral plates are very long, and form a simple ovipositor (Vagina bivalvis).() With Boreus, and Acheta, this,ovipositor is long, and with Raphidia, it is long and acinaciform. The Locustidae have also a similar and very prominent ovipositous sabre, but more complicated in that each of its plates is divided into three pieces, which are so disposed that the two internal, soft, are surrounded in a sheathlike manner by the four others, which are horny. With the Tenthredinidae, and with Aeschna, Agrion, and Calopteryx, there is an analogous apparatus situated at the posterior extremity of the abdomen, and covered by two valves, only that its pieces are denticulated in a saw-like manner, and therefore is called saw-ovipositor.(4) With the Siricidae, the ovipositing apparatus is likewise composed of two horny, denticulate plates; but is more auger-like in its form, and, with some species, projects far beyond the short lateral valves.(5 The Ichneumonidae, Cynipidae, and Cicadidae have a more or less long ovipositor (Terebra), composed of two lateral groove-like sheaths, between which plays a kind of sting composed of two intimately-united horny.shafts. This sting serves, partly to pierce the substance in which the eggs are to be deposited, and partly to push the eggs along the sheath formed by the groove-like valves.(6) All these different ovipositors have a muscular apparatus at their base, by which their component pieces are moved. With some Libellulidae, there is a peculiar grqove-like appendage on the penultimate abdominal segment. It serves to receive the eggs at the 1 The ovipositor is unarticulated and protractile 9 (Agrion). It is well known that these Insecta with the Cerambycidae, while it is articulated with use this ovipositor to pierce the epidermis of the Chrysididae and many of the Muscidae. In this plants, and to introduce therein their eggs. The last case, its pieces are movable, like the tubes of a deposition of the eggs with the Tenthiedinidae telescope. They are only the terminal abdominal has been described with details by Dahlbom (Isis, segments modified; see L. Dufour, Ann. d. Sc. 1837, p. 76) and by Ratzeburg (Forstinsekten, Nat. I. 1844, p. 383, Pi. XVI. fig. 16 (Piophila). Th. III. p. 65). I have, also, observed this act with 2 For the ovipositor of Insecta, see Burmeister, Agrionforcipula (Wiegmann's Arch. 1841, I. p. Mlaudb. &c. I. p. 209, Taf. XII., and Lacordaire, 205). Introduct. &c. II. p. 353. 5 Hartig and Ratzeburg have given a detailed 3,Limnobia, Ptychoptera, Tipula, Ctenopho- description of the auger of the Siricidae; it is parra. Asilus, ~aphria. Among these Diptera, ticularly long with Xiphydria and Sirex. Ctenophora ru.scornis is particularly distinguished (6 For the ovipositor of the Hymenoptera, see by the length o( the horny plates composing the Hartig, Die Adlerfifiger Deutschl. p. 16; in ovipositor. Wiegmann's Archiv, 1837, I. p. 151, and in 4 For the str cture of this saw-like ovipositor, Germar's Zeitsch. IIM. p. 326; Ratzeburg, MeseeLyonet, M6-:. du Mus. XIX. p. 57, P1. VI.- diz. Zool. II. p. 145, Taf. XXIII. (Cynips). For VIII. (14-16) (I,uches S scie); and Hartig, Die that of the Cicadidae, see Reauonsur, Aim. V. Adlerfliigler De,' schl. p. 37, Tatf. I. u. d. f.; also, 4 minmoire, P1. XVIII.; and Do, r)e, Ann. d. SeRdaumur, MeP VI. 11 mimoire, P1. XL. fig. 6- Nat. VII. 1837, p. 193. 39 458 THE INSECTA. ~~ 352, 353. moment of their escape from the vagina, and in this way the eggs are col* lected in masses to be deposited in places fit for their incubation.7) II. UMagle Genital Organs. ~ 3 52. The Testicles, which are double like the ovaries, consist, sometimes of two simple caeca, which are more or less long and torose, and sometimes of many caeca, very variable *as to their forms and disposition. Their mode of grouping resembles that of the ovaries; indeed, their whole appearance and contour, and the number and composition of their various parts resemble remarkably those of the female organs. With many species, these organs are covered by a lively-colored pigment layer, or enveloped by a special membrane (Tunica vaginalis). The two Vasa deferentia are of variable length, often exceeding that of the body, and therefore making several convolutions in the abdominal cavity. When the testicles are composed of many caeca, there are often the same number of these canals; but they often unite, on each side, into a common duct. Sometimes they have, each, at their lower extremity, a vesicular dilatation which may be regarded as a Vesicula seminalis. At their point of junction on the Ductus ejaculatorius, there are usually situated two, longer or shorter, simple Glandulae mucosae, which secrete a quickly coagulating, granular mucus, which serves, during the copulatory act, partly to fill and distend the Bursa copulatrix together with the penis, and partly to surround portions of the sperm, and thereby form spermatophores. (1) ~ 353. The principal modifications observed with the internal male organs of the Insecta, are the following. Among the Aptera, Lepisma is distinguished in having numerous ovdl, testicular follicles, whose Vasa deferentia, after forming irregular ramifications, unite in two common excretory ducts, which, gradually enlarging, terminate in a Ductus ejaculatorius at the point of insertion of two arcuate accessory glands.(l) With the Hemiptera, the internal genital organs are of very variable form.(2) The Pentatomidae have only two simple, pyriform testicles, often of a beautiful red color; at their free extremity they sometimes have several constrictions, and thus form the passage to the form proper to many Geocorisae, which have seven long testicular tubes united in a fan-like 7 The ovigerous groove is short and triangular 1 For the various forms of the simple and comwith Libellula vulgata and cancellata; long, pound testicles, as well as for the male organs of the acuminate, and perpendicular with Corduzlia me- Insecta in general, see Burmeister, -Ilandb. &c. tallica; long and cordately emarginate and closely I. p. 217, and Lacordaire, Introduct. &c. II. p. applied against the abdomen with Epitheca bimac.- 305. ulata. A. remarkable appendage, deeply exca- 1 See Treviranus, Verm. Schrift. II. p. 15, Taf. vated, situated to the exterior of the female genital IV. fig. 2. The Pediculidae have only two pairs organs of Doritis Apollo and m.nemosyne, and of testicles. upon which, as yet, no lepidopterist has given any 2 See L. Dufour, Recherch. sur los limipt. PL details, is probably an ovigerous sac. X.-XIII. ~ 353. THE INSECTA 459 manner.() Sometimes these seven tubes are gaouped into a bundle at the upper extremity of each of the two deferent canals.' 4)'With the Cicadidae, the testicular tubes are extremely numerous and fasciculate in the same manner; (5 while with Psylla, there are only four, and with Aphis, only three on each side. () The Hydrometridae have only two or four long testicular follicles, on the sides of which arise the deferent canals. With Pelogonus, and Notonecta, there are two pairs of long, spiral tubes, while witlh _Nepa, and Ranatra, there are five onl each side, long and flexuous. The Vasa deferentia are short with most of the Geocorisae, the Psyllidae and the Aphididae; but with the Hydrocorisae, and the Cicadidae, they are long and intertwisted. The glandular appendages are highly developed with most Hemiptera and often open into the two deferent canals above the Ductus ejaculatorizts.(7) But when these glands appear to be wanting, the deferent canals have upon their course, or at their extremity, vesicular dilatations which, perhaps, take their place.(8) With the Pentatomidae, the glandular appendages consist of two to four multiramose fasciculate tubes. The Ductus ejaculatorius is then dilated at its base into a kind of vesicle divided into two or three lobes, which serve probably as mucous reservoirs. ~") With the Diptera, the male organs are much more simple, there never being but two simple testicles,(l) whose external envelope is often brown or yellow. These organs are usually pyriform or oval, but sometimes long or hooked or twisted in various ways.(") The Vasa deferentia are usually of considerable length,(12) and open in the upper end of the Ductus ejacuZatorius,(l3) always in common with two simple and pretty long accessory glands. With the Lepidoptera, the testicles are always composed of two round or oval follicles, often surrounded by a beautifully colored pigment. (4) Very often, also, they are so approximated on the median line of the abdomen, as to appear fused into a single round body.(') The two deferent canals, after a short course, unite with two simple, long and very flexuous accessory glands, and then form a very long and torose Ductus ejaculatorius. (16) 3 Coreus, Alydus, Pyrrhocoris, Acanthia. 10 The male organs of the Diptera have been de4 Capsus, nMiris. Aradus. scribed by L. Dufour (Ann. d. Sc. Nat. I. 1844, 5 L. Dufour, Ann. d. Sc. Nat. V. 1825,P1. VI. fig. p. 250), and by Loew (Horae Anat. p. 9, Tab. 6, 7, and in his Recherch. sur les IIdmipt. P1. XIII. I.-III.), whose account is very detailed and exact. fig. 152-155 (Cicada, Aphrophora, and Issus). 11 The testicles are long and regularly flexuous 6 With Aphis lonicerae, the six testicular tubes with'fyopa' spiral-form with Asilus and Dasyare concentrated on the median line of the abdom- po ron, while those of the IIippoboscidae are exinal cavity, so that they might easily be taken for a tremely long and very torose; see L. Dufour, single body; see my observations in Froriep's Ann. d. Sc. Nat. loc. cit. neue Notiz. XII. p. 307. According to Morren's 12 Stratiomys, alone, has very long and torose description (Ann. d. Sc. Nat. 1836, p. 87, P1. TI.), deferent canals. there would appear to be a real fusion of the testi- 13 These two glands are very long with Hippocular tubes with Aphis persicae. bosca, Dolichopus, Asilus, and Strationys; ra7 With Aradrus, Nepa, Cicada, Aphrophora, the mose with Trypeta and Psila; with Leptis, they two simple glandular appendages, which are extra- are wanting, being replaced, probably, by two swellordinarily long and flexuous with the Cicadidae, are ings situated at the lower extremity of the two definserted on the sides of the deferent canals while erent canals. Empis and Scatopse have two pairs with -Aphis, which has two, and with Notonecta, of glands, one above, the other below. Miris and Capsus, which have four, the glandular 14 The testicles are carmen-red with Argynnis, tubes open into the Ductus ejaculatorius, con- Hipparchia, Pontia and Liparis; green with jointly with the deferent canals. Lycaena and Sphinx. 8 Psylla, Pyrrhocoris, Velia and Gerris. L. 15 Suckoes (Heusinger's Zeitsch. II. Taf. X. fig. Dufour (Recherch. &c.) unhesitatingly calls these 10) has found two separated testicles with Yponodilatations of the deferent canals Vesiculae sem- meuta. The fusion of these organs is complete inates. with the Papilionidae, Sphingidae, Bombycidae, &c. 9 L. Dufour (Recherch. &c. P1. X.) also regards 16 See Herold, Entwickelungsgesch. d. Schmetthis reservoir as a Vesicula seminalis. terl. Taf. IV. XXXII. (Pontia brassicae), and 460 THE INSECTA.' 353. With the Hymenoptera,l7) the testicles present many different forms. Beside two simple ovoid testicular follicles,(8) there are, not unfrequently, also two testicles composed of several long follicles, fasciciilate, and surrounded, together with a portion of the torose deferent canal, by a c&mmon envelope; but, more commonly, these two testicles are contained in a capsule situated on the median line of the body.-'(9 With the Tenthredinidae and the Siricidae, the testicles are separate and distinct, without capsules, and composed of round follicles disposed botryoidally.('') The two deferent canals are usually pretty long, and have, sometimes, at their lower extremity, two vesicular dilatations which, containing sperm, may be regarded as seminal vesicles.(21) The deferent canals with the Hymenoptera have, usually, two pyriform accessory glands, whose excretory ducts unite into a short Ductus ejaculatorius.(22) With the winged Strepsiptera, there are two pyriform testicles provided with very short deferent canals, which dilate above the Ductus ejaculatorius into two seminal vesicles; but nowhere has an accessory gland been observed. With the Orthoptera, the two testicles are nearly always composed of a greater or less number of follicles. With the Acrididae, Locustidae, Achetidae, Blattidae and Mantidae, they are composed of long fasciculated or imnbricated caeca, which, as with the Hymenoptera, are very often surrounded by a common envelope. In some species the two groups of testicular follicles are united into a common mass on the median line of the abdomen, by this Tunica vaginalis.(2n3 On the other hand, the Phasmidae, Libellulidae, Perlidae and Ephemeridae, have a multitude of round follicles, disposed botryoidally around a long dilated portion of each of the deferent canals.(24) These last are usually very short, and with the Achetidae and Locustidae, only, they are quite long, and spiral from beginning to end.(25) Many Orthoptera have highly-developed accessory glands surrounding a short Ductits ejaculatorius, on which they are sometimes disposed in successive groups.(-26 A part of this apparatus, in which are Suckowu, Anat. u. physiol. Untersuch. Taf. IV. 23 See L. Dufour, Recherch. sur les Orthopt. P1. (Gastropacha pini).* I.-V. There are two distinct fasciculate testicles.17 L. D1four (Recherch. sur les Orthopt. p. with Gryllotalpa, Oecanthus, Ephippigera, and 399, P1. V.-X.) has furnished observations accom- two groups of long, imbricated follicles with Tetrix. parnied with very many figures on the male organs Locusta and Decticus. The testicles are fused of the Ilyinenoptera. into one body with Oedipoda and Blatta.t t18 The testicles are simple with Parnopes, Cy- 24 See Susckow, in Heusinger's Zeitsch. II. nips, Diplolepis and Chlelonus. Taf. XII. fig. 25, Taf. X. fig. 8 i Rathkel, De Li19There are two unicapsular testicular bundles bellur. partibus genital. Tab. I. fig. 3, and L. Duwith Apis, Xylocopa and Bonsbus; see L. Dcu- four, loc. cit. P1. II. fig. 164, and P1. XII. fig. 204 four, loc. cit. fig. 53-62. The two testicular fasci- (Perla and Libellula). culi are enclosed in a common capsule with An- 25 See L. Dufour, loc. cit. fig. 25, 36 (Gryllothophora, Anthidium, Odynerus, l'iphia, Scolia, talpa and Ephippigera). Pom.pilus and Crabro; see L. DuJbur, loc. cit. 26 The Perlidae have only two testicular follicles PI. VI.-IX. inserted on the deferent canals. Tetricx, the 20 L. Dufour, loc. cit. fig. 150-154 (Tenthredo, Acrididae, Achetidae and Blattidae, have two long Hlylotoma and Cephus). and large fasciculi - finally, with the Mantidae and 21 The deferent canals terminate each with a Locustidae, there are, besides these fasciculi, one or seminal vesicle with Cynips, Chelonus, Apis and two pairs of shorter bundles; see L. Dufsour, loc. Xylocopa. cit. PI. III.-V..22 See Brandt and Ratzeburg, Mediz. Zool. Taf. XXV. fig. 35 (Apis), and L. DDujbur, loc. cit. * [~ 353, note 16.] See, also, for histological de- ovaries; but this observer shows that the spermatic tails on the internal male organs and their develop- particles are formed, like the ova, while the insect ment, of the Lepidoptera, Meyer, loc. cit. Siebold is in the pupa-state. - ED. and KOlliker's Zeitsch. I. 1849, p. 182. The for- t [ ~ 353, note 23.] See also Leidy, Proceed. mula of the development of the testicles is, of Acad. Sc. Philad. 1846, III. p. 80 (Spectrum culrse, the same as that of the development of the femoratum). - ED. 353. THE INSECTA. 461 situated here and there vesicular reservoirs, secretes, undoubtedly, with the Locustidae, a substance used in the formation of the spermatophores. But with the Phasmidae, Libellulidae and Ephemeridae, the Ductus ejaculatorius is wholly deficient in all kinds of glandular appendages. With the Neuroptera, the various genera present only few modifications in their male genital organs. With Panorpa, the two testicles are very simple and ovoid;(27) but with the other species they consist of two tufts of long cr round follicles.(28) With Mliyrmeleozn, and Hemnerobius, they are oval and surrounded by a distinct envelope. The two deferent canals are short, and always have on their lower extremity two long or ovoid accessory follicles. (2) With the Coleoptera, the male organs vary very much.(30) With the Carabidae, Hydrocanthari, and Lucanidae, the testicles consist of two extremely long, torose caeca, 3t) of which each is sometimes enclosed in two special envelopes.(32) The Elateridae, Tillidae, Cantharidae, very many Heteromera and Coccinellidae, have, on the other hand, a multitude of round or oblong, short follicles, fasciculate, composing the two testicles, which,(33) in some genera, are here also invested by a capsule.(34) With the Hydrophilidae, and Pyrochroidae, these organs are composed of numerous short, aggregated follicles, situated laterally over a wide extent of the posterior extremity of the deferent canals. (35) With the Staphylinidae, and Silphidae, the testicular follicles are pyriform and inserted botryoidally on the posterior extremity of the simple or mnultiramose Vasa deferentia.'36) WVith the Lamellicornes, Cerambycidae, Curculionidae, and Crioceridae, these organs are formed after a wholly different type, their number being two, six, or even twelve on each side. They are usually round follicles, flattened disc-like, and from which pass off pretty short excretory ducts to the extremity of the two common deferent canals.r)3 The V/sa deferentia, with the Coleoptera, are usually pretty long; but with the Carabidae, Hydrocanthari and Cerambycidae they are very long, spiral or torose.(3s) With a few species, only, is each of them dilated in its course into a Vesicula seminalis.j3') The accessory glands are never wanting in this order, and they either open, together with the deferen.t canals, into the upper extremity of the Ductus ejaculatorius, or they pass into these canals before they reach this duct. In very many species this gland27 L. Dufour, loc. cit. fig. 172. 35 See Sonammrerdamnon, Bib. der Nat. Taf. 28 Sialis and Phryganea. XXII. fig. 5 - Secktao, in llenLsise er's Zeitsch. 29 See L. Dufour, loc. cit. P1. XII. fig. 172-210 II. Taf. X. fig. 1, 2 (Hydrophilu/s); L. Dufour, (Panorpa, Myrmeleon, Sialis, Phry-anea), and Ann. d. Sc. Nat. XIII. 1840, P1. VI. A. fig. 18 Suckocw, in Heusinger's Zeitsch. II. Taf. XYI. (Pyrochroa). fig. 15 (Sialis). S36 The two testicles are multiramose with Silpha; 30 For the male organs of the Coleoptera in gen- see L. Duzfour, Ann. d. Sc. Nat. VI. 1825, P1. Vi eral. see especially L. DuLfour, Ann. d. Sc. Natt. fig. 6. VI. 1825, p. 152, Pl. IV.-IX. andc I. 1834, p. 76, 37 Hammaticherus, Anthribus, Lix. is and DoP1. III. IV. nacia have two pairs of testicles Mlelolontha anti 31 Weith Harpalus, the two caeca are united into Prionus six, Trichius nine, and Cetonia twelve. a single clew. Beside L. Deufoeur (loc. cit.), see Satckow, in Heu32 Cybister, Scac3ites, and Clivina. have two sin er's Zeitsch. II. Taf. Xi. and Straus, Considtesticles invested by a capsule. erat. &c. P1. VI. 33 Each testicular fasciculus is composed of from l 35 Tlhese torosities are even surrounded with a three to seven follicles with Dermestes, Heteroce- capsule with Cyt:ister; see L. Dufour, Ann. d. rus, Anthrenus, Oedemera, lielops, Diaperis, Sc. Nat, VI. 1525, Pl. V. fig. 1. Tenebrio; while with Blaps, Pimelia, My/labris, 39 With the Hlydrophiilidae, there is a vesicular Telephorus, )ostrichius, the Elateridae and Coc- dilatation at the lower extremity of the defereln cinellidae, their number is much larger. canals; but with Anthlrib/us, and Lixus, it is situ 34 There is a Tunica vaginalis with Cleruss,Tri- ated at tl.e opposite extremity, ehodes, AIylabris, and which, with Galeruca, is even common to both testicles. 3985 462 THE INSECTA. ~ 354. ular apparatus consists of only two simple, longer or shorter caeca,(40)'which are sometimes quite long and torose.(41) Another series of Coleoptera have four to eight caecal appendages, disposed in pairs, and variable as to length and volume. One of these pairs is probably only a reservoir for the secreted product of the others.(42) The DuTctus ejaculatorius is always very muscular, and with very many species, quite long and fiexuous, and the penis therefore can be widely protruded during copulation. ~ 354. The Copulatory organs of the male Insecta are valve-like or forficulate, horny appendages,(1) which are so variable in their form that the most allied. species differ, in this respect, widely and constantly.(2) Beside these proper copulatory organs, situated at the posterior extremity of the abdomen, there are often on the antennae, the parts of the mouth, the legs and other regions of the body, auxiliary organs used for seizing and retaining the female, and which have long been objects of careful description in zoology. With most Hemiptera, the posterior extremity of the abdomen conceals;a horny capsule which contains a protractile, tubular penis. With very -many Diptera, the copulatory organs project pronlinently in the same region of the body, and consist often of two horny valves of different forms ~which envelop a rather long penis.(3) The Lepidoptera, Hymenoptera, Orthoptera, and Neuroptera, have two pairs of valves, one internal, the other external, which enclose a tubular or groove-like penis.(4) The Ephemeridae and the Strepsiptera, only, are distinguished by their very simple copulatory organs; for with the first there is only a simple penis without a valvular apparatus. This last is replaced by two long, small, triarticulated stylets, situated on the penultimate abdominal segment and curved inwardly; while with the Strepsiptera, the penis, also naked and horny, is so articulated that it can be applied laterally against the abdomen, like the blade of a knife in its handle. With the Libellulidae, however, the orifice of the Ductus ejaculatorius is most simple, being covered only by two very small oval valves. But the penis is not wanting with these Insecta; it is singularly concealed, together with a horny-walled seminal vesicle, in a fossa situated at the base of the 40 With the Carabidae, Hydrocanthari, and with they been well understood, the formation of many Mordella, Anthribus, Galeruca and Coccinzella. bad species might have been prevented. They 41 Melolontha, Cetonia and Lucanus; see L. prevent allied species from producing bastards by Dufour, Strauss, and Szckow, loc. cit. adulterous connections, for the hard parts of the 42 With the Stalphylilidae, Cantharidae, Byrrhi- male correspond so exactly with those of the female, dae,'lateridae, Tilli(dle, Meloidae, Tenebrionidae, that the organs of one species cannot fit those of Pyrochroidae, Dermuestidae, Ceralnbycidae, with another. L. Dufosur has, therefore, properly Donacia, Heterocercts, &c.; see L. Dufosur, termed these copulatory organs as "la garantie Suckow, loc. cit. and Branzdt, Mediz. Zool. II. de la consserevation des types, et la sauvegarde Taf. XVII. XIX. This glandular apparatus is ide la legitemite de I'espIce." specially developed with Hydrlophilits piceus, 8 This horny apparatus, from its large and often where, of the four pairs, one is distinguislhed for its tuni( lateral valves is quite prominent with the length and thickness, and is composed;at its extrem- Dolichopidae, Empidae, with Asi/us, Laphria, ity of numerous small follicles; see Stvanzmer- Ctenophora, Nenatocetra, and other Tipulidae. damn, Bib. der Nat. Taf. XXII. fig. 4 L. Dot- See Sclhummel, Beitr. zur Entomol. Taf. I.-III. four, loc. cit. VI. P1. VI. fig. 7, and Suckosw, loc. (Tipuela). cit. Taf. X. fig. 1, 3. 4 With the Panorpidae, these copulatory organs 1 See Burtmeister, l1andb. &c. I. p. 227, Taf. are changed into very large pincers; while with XIII. Psyche, the very long penis is protractile like the 2 As yet, these differences in form of the external tubes of a telescope, thus enabling these butterflies male organs have been of little service to entomolo- to copulate with their females which remain congists in the distinction of species, although, had cealed in sacks. ~ 355. THE INSECTA. 463 abdomen.() This penis is composed of three articles with Aeschma, Lilel-'ula, and Gomnphus; but of one only with Calopteryx, and Ag'rion, with which it is not directly adherent to the seminal vesicle. The male Libellulidae are obliged, before copulation, to fill their vesicula seminalis, which is situated at the base of the abdomen. This they accomplish by bending the posterior extremity of the abdomen, so as to meet and empty the semen into this vesicle. They then seize the female by the neck, by means of their anal pincers, and she places her genital orifice in contact with the copulatory apparatus of the male.(6) These anal pincers of the males have very distinct specific characteristics, while the females, on their part, have, in the separate species, equally specific sculptured markings on the prothorax. (7) With the Coleoptera, the copulatory organs consist of a imore or less horny sheath enveloped by a membranous prepuce, and containing a broadly-flattened penis which consists of a canal supported by two lateral horny ridges. At rest, these organs are entirely withdrawn into the abdominal cavity, but can be widely protruded out of it by means of a very remarkable muscular apparatus.(8) With the male individuals of Dermestes, there is a median orifi'e on the third and fourth abdominal segments, from which projects a brush of stiff bristles connected with a round muscular body situated on the internal surface of each of these segments. This brush is undoubtedly some way connected with the act of copulation.(8) ~ 355. The development of the larvae of Insecta in the egg, occurs in the same manner as with most of the other Arthropoda. After the unusually early disappearance of the germinative vesicle,(l' there is formed, from a superficial and partial segmientation, a round or oblong-oval blastoderma, whose hyaline aspect contrasts with that of the rest of the vitellus. ) This blas5 For the copulatory organs of the Libellulidae, 1 The'germinative vesicle is never observed in see Rathkei, De Libellar. partibus genital., and my eggs that have been layed; it has disappeared researches in Germar's Zeitsch. II. p. 4:21. even in those still in the oviduct; this disappear6 The act of copulation of the Libellulidae has ance would not appear, therefore, to depend upon been represented by Slwammerdamm, Bib. der the act of fecundation. _Nat. Taf. XII. fig. 3 Riauemur, 2M11m. &c. VI. 2 The first phases of the development of Insecta P1. XL. XLI.; and Roesel, Insectenbelust. Th. have been studied by Herold (Disquisit. de Anim. I. Insect. aquat. Class. II. Tab. X. vertebr. carent. in eve forlmat. 1835-38) with 7 The different forms of these pin ers have been Spinx ligustri and Ml:usca vsomitoria; and by figured in Charpentier, Horae Entomol. Tab. I..: Killiker (Observ. de prima Insect. genesi, 1842, or and Selys Longchamps, Monogr. des Libellul. Ann. d. Sc. Nsat. XX. 1843, Pl. X.-XII.) with d'Europe, P1. I.-IV. Chironomsus, Simulia, and lDonacia. 8 See Straus, Consid6r. &c. P1. III. V. The ulterior phases have been traced by Rathki 9 See my observations in the Entomol. Zeitung. (Meckel's Arch. 1832, p. 3il7, Taf. IV. and Mil1840, p. 137, and Brull, Ann. d. 1. Soec. Entom. ler's Arch. 1844, p. 27, Taf. II.) with Blatta VII. 1838, p. LIII. The golden-coloredl tuft orientalis and Gryllotalpa vulgaaris; and by of hairs situated at the base of the abdomen Nicolet (Recherch. &c. p. 18, P1. I.) with the with the males of Blaps, does not correspond to Poduridae.* that of Dermestes, because it is only external and does not project into the interior of the body. * [ ~ 355, note 2.1 I am not aware that the conditions of formation belonging to the different numerous researches upon the embryology of the groups, and the observation of the details of deInsecta made within -a few years, have added any velopment of different isternal and external organs. new phases to the general type of development of Those anomalies of development and reproduction, these animals as brought out by the earlier inves- which continued research shows to be far from untigators. The type of development with the Arth- common with the Insecta, will ultimately be found, ropoda is essentially the same in all of the classes probably, referable all to the phenomena, we have,of this section. What late observers have done, discussed below, of the Aphididae. - ED. therefore, is the tracing of some of the secondary 464 THE INSECTA., 355. toderma, which corresponds to the ventral side of tfe future embryo, extends gradually in all directions and at last encompasses the whole vitellus, - its; borders meeting on the dorsal surface. It may be divided into an external or serous, and an internal or mucous layer. In the first of these is developed, on the median abdominal line, the ventral cord; while the second forms a semi-canal which gradually surrounds the vitellus and at last completely enveloping it, is changed into the digestive canal. The various ap-. pendages of this canal are subsequently formed by simple constrictions or' deverticula from its cavity; while the other abdominal viscera are directly developed from a special blastoderma. Upon the external surface of the serous layer are formed the parts of the mouth, the tactile organs, the legs, and the other appendages of the body,. whose articulations, like those of the body itself, are produced by constrictions. The dorsal vessel is formed between the two blastodermic layers on the side opposite that of the ventral. cord. This development of the embryo. takes place at the expense of the vitellus, which, enclosed in the digestive canal, is gradually consumed.* *[ End of ~ 355.] The subject, which has been number of such cells enclosed in a simple sac.. frequently alluded to inll this book, -the singular These are the germs of the third generation ormode of reproduction of the viviparous Aphididae, colony, and they increase pari passu with the deis one of so much interest and importance in physi- velopment of the embryo in which they are formed, ology, that I propose to give it something more and this increase of size takes place not by the, than a brief mention. Moreover, I have enjoyed segmentation of the primitive cells, but by the enexcellent opportunities for the study of these phe- dogenous formation of new cells within the sac. nomena in question, and have advanced an inter- After this increase has continued for a certain time, pretation of them, and their like elsewhere, quite these bodies appear like little oval bags of cells, - different from that usually received. all the component cells being of the same size arld My observations were made upon Aphis caryae shape, - there being no one particular cell which(probably Lachnus of Illiger, or Cinara of Cur- is larger and more prominent than the others, andl tis), one of the largest and most favorable species which could be comparable to a germinative vesifor these investigations. This was in the spring of cle. While these germs are thus constituted the 1853. The first colony, on their appearance from formation of new ones is continually taking place. their winter quarters were of mature size, and con- This occurs by a kind of constriction-process of tained, in their interior, the developing forms of the the first germs; one of the ends of these last being second colony quite far advanced in formation. On pinched off, as it were, and so, what was before a this account it was the embryology of the third single body or sac, becomes two which are attached series or colony, that I was able to first trace. A in a moniliform manner. The new germs thusr few days after the appearance of the first colony formed may consist each of a single cell only, as I (A), the second colony (B), still within the former, have often seen; but they soon attain a more unihad reached two-thirds of their full embryonic size; foernm size by the endogenous formation of new cells the arches of the segments had begun to close on the within the sac in which it is enclosed. In this way dorsal surface, and the various appendages of the the germs are multiplied to a considerable number,, embryo were becoming prominent; the alimentary the nutritive material for their growth being, apcanal was more or less completely formed, although parently, a fatty liquid in which they are bathed, distinct abdominal organs of any kind belonging to contained in the abdomen. and which is thence dethe digestive system were not apparent. rived from the abdomen of the first parent. When: At this time, and while the individuals B. were these germs have reached the size of about one not only in the abdomen of their parents A., but three-hundredth of an inch in diameter, there apwere also enclosed each in its primitive egg-like pears on each, near the inner pole, a yellowish,, capsule; at this time, I repeat, appear the first vitellus-looking mass or spot, composed of yellowtraces of the germs of the third colony, C. Their ish cells, which, in size and general aspect, are diffirst traces consisted of small egg-like bodies, ar- ferent from those constituting the gerrc proper. ranged two, three, or four in a row, and attached This yellow mass increases after this period,pare at the locality where are situated the ovaries in the passu with the germ, and at last lies like a cloucd oviparous forms of the Aphididae. These egg-like over and partially concealing one of its poles. IC bodies were either single nucleated cells of one would, moreover, insist upon the point that it does three-thousandth of an inch in diameter, or a small not gradually extend itself over the whole germ 355. THIE INSECTA. 465 mass, and is, therefore, quite unlike a proligerous bathed, and which fills the abdomen of the parent. disc. The conditions of development in this respect, are When these egg-like germs have attained the size here, therefore, more like those of the Mammalia and of one one-hundred-and-fiftieth of an inch in di- the whole parent animal may be regarded in one ameter, there begins to appear distinctly the sketch- sense as an individualized uterus filled with germs, ing or marking out of the future embryo. This — for the digestive canal with its appendages sketching consists at first of delicately-marked re- seems to serve only as a kind of laboratory for the [reatings of the cells here and there; but these last -conversion of the succulent liquids this animal exsoon become more prominent from sulcations, and, tracts from the tree on which it lives, into this fatty at last, the form of an articulated embryo is quite liquid which is the nutritive material of the germs. prominent. Omitting the curious lnd interesting details of During this time, the yellowish, vitellus-lodking the further history of the economy of these Insecta, mass has not changed its eIlace, and although it is as irrelevant to the point in discussion, we will now somewhat increased in size, yet it appears other- turn to seev what view we should take of these prowise the same. When the development has pro- cesses, and what is their physiological interpretaceeded a little further, and the embryo has as- tion. In the first place it is evident that the germs sumed a pretty definite form, the arches of the which develop these viviparous Aphides are not segments, which have hitherto remained gapingly true eggs; they have none of the structural charopen, appear to close together on the dorsal sur- acteristics of these last,-such as a vitellus, a face, thereby enclosing the vitellus-looking mass germinative vesicle and dot; on the other hand within the abdominal cavity. It is this same vitel- they are at first simple collections, in oval masses, loid mass thus enclosed, which furnishes the de- of nucleated cells. Then again, they receive no velopment of the new germs (which in this case special fecundating power from the rltale, which is would be those of the fourth colony, or D0), and this the necessary preliminary condition of all true germ development here commences with the clos- eggs; and furthermore the appearance of the new ing up of the abdominal cavity, and then the same individual is not preceded by the phenomena of processes we have just described are repeated. segmentation, as is also the case with all true eggs The details of the development subsequent to Therefore, their primitive formation, their developthis time, - the formation of the different systems ment and the preparatory changes they undergo of organs, &c., are precisely like those of the de- for the evolution of the new individual, are all difvelopment of true oviparous Arthropoda in genc- ferent from those of real ova. ral; and although the ovoid germ has, at no time, Another point of equal importance is these vivithe structural peculiarities of a true ovum,- such parous individuals of the Aphides have no proper as a real vitellus, germinative vesicle and dot, yet ovaries and oviducts. Distinct organs of this kind if we allow a little latitude in our comparison and I have never been able to make out. The germs, regard the vitellus-looking mass as the mucous, as we have before seen, are situated in mocliliforne and the germ-mass proper as the serous fold of rows, like the successive joints of confervoid plants, the germinating tissue, as in true ova; if this com- and are not enclosed in a specirl tube. These rows parison of parts can be admitted, then the analogy of germs commence, each, from a single germ-mass of the secondary phases of development between which sprouts from the inner surface of the animal, these forms, and true ova of the Arthropoda, can and increases in length and the number of its combe traced to a considerable extent. ponent parts by the successive formation of new These secondary phases of development need not germs by the constriction process as already dehere be detailed, for they correspond to those de- scribed. Moreover, these rows of germs which, at esribed by Herold, Kliliker, of the true ovum in one period, closely resemble in general form, the other Insecta, and which, too, I have often traced in ovaries of some true Insecta, are not continuous various species of the Arthropoda in general. with any uterihe or other female organ, and there When the embryo is fully formed and ready to fore do not at all communicate with the external burst from its capsule in which it has been de- world, on the other hand, they are simply attached veloped, it is about one-sixteenth of an inch in to the inner surface of the animal, and their comlength, or more than eight times the size of the ponent germs are detached into the abdominal germ, when the first traces of development in it cavity as fast as they are developed, and thence were seen. From this last-mentioned fact, it is escape outwards through a Porus genitalis. evident that, even admitting that these germ-masses With these data, the question arises, what is the are true eggs, the conditions of development are proper interpretation to be put upon these repro uite different from those of the eggs of the truly vivi- ductive phenomena we have just described? My parous animals, for, in these last, the egg is merely answer would be that the whole constitutes only a hatched in the body instead of out of it, and, more- rather anomalous form of gemmiparity; as already over, it is formed exactly as though it was to be shown, the viviparous Aphididae are sexless; they deposited, and its vitellus contains all the nutritive are not females, for they have no female organs, material required for the development of the em. they are simply gemmiparousa, and the budding lg, bryo until hatched. With the Aphididae, on the internal, instead of external as with the Polypi anl other hand, the developing germ derives its nutri- Acalephae; moreover this budding takes on some of tive material from the fatty liquid in which it is the morphological peculiarities of cviparity but these 466 THE INSECTA. ~ 355. peculiarities are economical and extrinsic, and do discussion of those many points suggested by these not touch the intrinsic nature of the processes there- studies. One of these, is, the relation of this subject in concerned. Viewed in this way, the different to some of the various doctrines of development, broods or colonies of Aphididae cannot be said to which have been advanced in late years, such as constitute as many true generations, any more than that of Alternation of Generation, by Steeatthe different branches of a tree can be said to con- strup, and that of Parthenogenesis by Owen. I stitute as many trees; on the other hand the whole have there attempted to show that the phenomenasuite, from the first to the last, constitute but t of these doctrines, as advanced by their respective single true generation. I would insist upon this advocates, all belong to those of gemmiparity, and point as illustrative of the distinction to be drawn that therefore Alternation of Generation and Parbetween sexual and gemmipaouns reproduction. thenogenesis in their implied sense, are misnoNlorphologically, these two forms of reproduction, mers in physiology. Another point there treated have, it is true, many points of close resemblance, in extenso, is the identity of this mode of reprobut there is a grand physiological difference, the duction we have just described in the Aphididae,. perception of which is deeply connected with our with that observed in the so-called hibernating eggs highest appreciation of individual animal life. of the Entomostraca (see above, ~ 290) and the like A true generation must be regarded as resulting phenomena observed in nearly every class of the only from the conjugation of two opposite sexes, - Invertebrata. They are all referable, in my opinion, from a sexual process in which the potential repre- to the conditions of gemmation, modified in each sentatives (spermatic particle and ovum) of two op- particular case, perhaps, by the economical relaposite sexes are united for the elimination of one tions of the animal. germ. The germ power thus formed may be ex- See for some recent writings on this peculiar tended by gemmation or fission, but it can be form of reproduction with the Insecta, and which formed only by the act of generation, and its play contain many interesting physiological remarks, of extension by budding or by division must always Leydig, Die Dotterfurchung nach ihrem Vorbe within a certain cycle, which cycle is recom- kommen in der Thierwelt und nach ihrer Bedeu. menced by the new act of the conjugation again of tung, in the Isis, 1848, Itft. 3; also, Einige Bemer. the two sexes. In this way the dignity of the kungen fiber die Entwickelung der Blattliuse, in ovum as the primordium of all true individuality, Siebold and Kslliker's Zeitsch. II. 1850, p. 62 is maintained. also Zur Anatomie von Coccus hesperidum, in Ibid. I have thus treated this subject in some detail, 1853, V. p. 1; Victor Carus, Zur naheren Kenntnot only from its wide bearing in the physiology of niss des Generationswechsels, Leipsig, 1849; and; reproduction, but also from its direct relation to Siebold, as referred to in my note under ~ 348 note many phenomena alluded to in the preceding 4. I cannot here discuss the often similar and' pages. In the memoir from which I have made dissimilar views to those of my own above detailed, this extract (read before the Amer. Acad. Arts expressed by these different investigators. — ED.. and 8c., Oct. 11, 1863) I have entered into a fu1s INDEX. A B B RE V IA TI ON S Ical., Acalephae. Ceph'd., Cephalopoda. Hel., Ilelminthes. Rhiz., Rhizopcda. Aceph., Acephala. Ceph'r., Cephalophora. Inf., Infusoria Rot., Rotatoria. Ann., Annelides. Crus., Crustacea. Ins., Insecta. Turb., Turbellaria.,4rach., Arachnoidae B.h., Echinodermata. Pvi., Polypi. N. B. The Numbers refer to the Paragraphs. A. B..ACALEPHAE, 53. Balancers. Ins. 326. ACEPHALA, 170. Bladders, natatory. Acal. 58. Ceph'd. 256. A4ciculi, Ann. 145. Blood. Pol. 39, 41. Hel. 110. Ann. 156. Aceph Air cavity or reservoir, Acal. 65. 191. Ceph'r. 216. Ceph'd. 251. Crus. 282. Ambulacra, Ech. 77, 91. Arach. 309. Ins. 340. -Ampulla, of Poli, Ech. 92. Brain. Ann. 146, 147. Ceph'r. 206. Ceph'd. 240. ANNELIDES, 142. Crus. 270. Arach. 300. Ins. 328. Antennae, Ann. 149, 152. Arach. 306. Ins. 332. Branchiae. Ech. 89. Ann. 159, 160. Aoeph..Anus, Inf. 15. Ech. 82. Hel. 107. Rot. 136. 193. Ceph'r. 220. Ceph'd. 253. Crus. 285. Aceph. 188, 189. Ceph'r. 214. Ceph'd. 249. Arach. 312. Ins. 342. Crus. 279. Arach. 307. Ins. 338. Bristles. Ann. 145. Aceph. 185. Apparatus, ceraceous, Ins. 347. Bursa Needhami. Ceph'd. 259. digestive. Inf. and Rhiz. 11. Pol. 35. Byssus. Aceph. 179. Acal. 61. Ech. 82. Hel. 106. Turb. 125. Rot. 136. Ants. 152. Aceph. 188. Ceph'r. 213. Ceph'd. 248. Crus. 278. Arach. 306. C. Ins. 337. ejaculatory, of sperm. Ceph'd. 259. Caecum. Ech. 85,86. Hel. 108. Ann. 154. Aceph. masticatory. Ech. 84. Hel. 108. Rot. 189. Ceph'd. 249. Crus. 279. Arach. 307. 136. Ann. 154. Ceph'r. 213. Cepl'd. 248. Ins. 338. Crus. 279. Arach. 306. Ins. 337. Caeca, hepatic. See Liver. -- mucous. Ins. 349. Calamistrum. Arach. 315. -- respiratory. Inf. and Rhiz. 18. Pol. 41. Canal, intestinal. Ann. 154. Aceph. 189..Acal. 63. Ech. 89. Itel. 112. Turb. 126 ph'r. 214. Ceph'd. 249. Crus. 279. Arach Rot. 138. Ann. 158. Aceph. 193. Ceph'r. 307. Ins. 338. 219. Ceph'd. 253. Crus. 285. Arach. 311. stony. Ech. 75. Ins. 341. Canals, aquiferous. See Aquiferous System. - rotatory. Rot. 133. lateral. Hel. 110. -- sebaceous. Ins. 349. -- longitudinal. Hel. 111. - sericeous. Arasch. 315. Ins. 347. Capsule, genital. Ceph'd. 260. -- suctorial. Hel. 103. Arach. 306. Ius. egg. Ceph'd. 258. 337, 338. ovarian. Ceph'd. 258. tentacular. Ech. 83. Cardo. See Hinge. venomous. Arach. 315. Ins. 347, 349 Cavity, branchial. Ceph'r. 220. Appendices, caecal. See Caecum. - incubatory. Crus. 292. cutaneous. Ann. 143. - pulsatile. Inf. 16. AR-aCHn0IosE, 295. respiratory. Aceph. 194. Crus. 285. Arms. Aceph. 185. Ceph'd. 237. Cell, lateral. Ceph d. 254. Arolium. Arach. 299. Ins. 326. Cells, chromatophoric. Ceph'd. 233. Arteries. See Circulatory System. 5 hepatic. See Liver. Audition. See Auditive Organs. -- vitelline. Hel. 115. Turb. 129. 468 IN D E X. CEPHALOPHORA, 201. I Glands, odoriferous. Ins. 347. CEPHALOPODA, 230. poison. Arach. 315. Ins. 347. Cheliceres. Arach. 306. salivary. Ech. 86. Hel. 109. Turb. 125. Circles, of hooks. tel. 103. Rot. 136. Annim. 155. Aceph. 190. Ceph'r. - osseous. Ech. 73. 215. Ceph'd. 250. Crus. 280. Arach. 308. Cirri. Ann. 149, 152. Ins. 339. Cloaca. Arach. 307. sebaceous. Ins. 349. g- genital. Ceph'r. 227. - sericeous. Arach. 315. Ins. 347. Cocoon. Ann. 166. Collar. Ann. 167. Corallum. Pol. 25. Cord,' cacareous. Ech. 75. -- ventral. Ech. 80. Hel. 104. Ann. 146. Heart. Ech. 88. Ann. 156. Aceph. 191. Ceph'r. Ceph'r. 206. Crus. 270. Arach. 300. Ins. 217. Ceph'd. 252, 255. Crus. 283. Arach, 328. 309. Ins. 340. Corpus adiposum. Crus. 281. Ins. 339. IIELMINTnEs, 99. spongiosum. Ceph'd. 255. Hinge. Aceph. 174. Corpuscles, germinative. Hel. 118. HIooks. Ech. 75.. Iel. 103. Crop.: Ceph'd. 249. Ins. 338. CRUSTACEA, 262. Cups, sucking. IIel. 103. I. Ink-sac. Ceph'd. 256. D. INFUSORIA, 3. INSECTA, 321. Dart. Ceph'r. 227. Intestines. Ann. 154. Aceph. 189. Ceph'r. 214. Dart-sac. Ceph'r. 227. Ceph'd. 249. Crus. 279. Ins. 338. See also Development.' Pol. 51. Ech. 98. Hel. 118. Digestive Tube. T'urb. 129. Rot. 141. Ann. 169. Aceph. 200. Ceph'r. 229. Ceph'd. 261. Crus. 294. Arach. 320. Ins. 355. Jo -- of Molusca in Holothurioidea, 229. Disc, vibratile. Rot. 133. JawsCeph'r. 213 Ann.153. Cephr.213. Ceph'd. Drums. Ins. 327. Drums. Ins. 327. 248. Crus. 278. Arach. 306. Ins. 337. E. K.:ECmNODERMATA, 71. Kidneys. Aceph. 196. Ceph'r. 223. Ceph'd. Eggs. Pol. 44, 45. Acal. 67. Ech. 95. HIel. 255. Ins. 345. 115, 116. Turb. 128. Rot. 140. Ann. 163. Knobs, fleshy. Ann. 145. Aceph. 198. Ceph'r. 225. Ceph'd. 257, 258. Crus. 290. Arach. 316. Ins. 348. -- hibernating. Cr. 292., Elytra. Ins. 326. En-elope, cutaneous. Inf. and Rhiz. 6. Pol. 27 Labium. Ins. 337. Acal. 54. Ech. 72. Hel. 100. Turb. 121. Labrum. Crus. 278. Ins. 337. Rot. 131. Ann. 143. Aceph. 171. Ceph'r. Lantern, of Aristotle. Ech. 84. 202. Ceph'd. 233. Crus. 263. Arach. 296. Larvae, nursing. Hel. 118. Ins. 322. Legs. Crus. 268. Arach. 299. Ins. 326. Eyes. See Organs of Vision. Lemnisci. IIel. 110. crabs. Crus. 289. Ligament, elastic. Aceph. 174. Liver. Pol. 37. Acal. 61. Ech. 86. Hel. 109. Turb. 125. Rot. 136. Ann. 155. Aceph. F u190. Ceph'r. 215. Ceph'd. 250. Crus. 280. Arach. 308. Ins. 339. Fins. Ceph'd. 234. Crus. 268. Lungs. Ann. 159. Ceph'r. 221. Crus. 287. Foot. Aceph. 178. Ceph'r. 204. Crus. 268. Arach. 313. Foramina, repugnatoria. Crus. 289. Fossettes, respiratory. Ann. 158. M. GMandibulae. Crus. 278. Ins. 337. Mantle. Aceph. 171. Ceph'r. 202. Ceph'd. 234. Ganglia, radiating. Ceph'd. 241. Crus. 265. pedal. Ceph'r. 208.' Maxillae. Crus. 278. Ins. 337. Generation. See Generative Organs. Membrane, argenteous. Ceph'd. 247. alternation of. PQl. 45. Acal. 70. IIel. natatory. Ceph'd, 234. 118. Ins. 348, 355. Metamorphosis. Pol. 52. Acal. 70. tel. 118. Germs, egg. Hel. 115. Ann. 169. Aceph. 200. Girdle. Ann. 167. Mouth. Inf. 15. Pol. 36. Acal. 61. Ech. 82, Gizzard. Ins. 338. 84. Idel. 107. Turb. 125. Rot. 136. Ann. Glands, albumen. Ceph'r. 227. 153. Aceph. 188, 189.. Ceph'r. 213. Ceph'd. anal. Ins. 347. 248. Crus. 278. Arach. 306. Ins. 837. - of Bojanus. Aceph. 196. Muscles. See Muscular Bystem. ----— genital accessory. IHel. 116, 117. Ann. 166. Ceph'r. 227. Ceph'd. 258. Arach. 315. Ins. 349. N. - hermaphrodite. Ceph'r. 227 muciparous. Ins; 352. Nerves, pneumogasftic. Ceph'd. 241. - nidamental. Ceph'd. 258. - respiratory. Ins. 328. IN D EX. 469 Nerves, splanchnic. Ann. 148. Aceph. 184. Ceph'r. Orifices, respiratory. Ech. 93. 219. Ceph'd. 242. Crus. 273. Arach. 302. Os sepiae. Ceph'd. 235. Ins. 331. Ovaries. Pol. 45, 47. Acal. 68. Ech. 97. Het Nucleus, generative. Inf. and Rhiz. 21. 115, 116, 117. Turb. 128. Rot. 140. Ann. intestinal. Aceph. 189. 166, 168. Aceph. 198. Ceph'r. 228. Ceph'd. Nurses. See Nursing Larvae. 258. Crus. 291. Arach. 316. Ins. 349. Ovipositor. Arach. 318. Ins. 332, 351. 0. Oars, or oarlike organs. Crus. 268. (Esophagus. Ann. 154. Aceph. 189. Ceph'r. 214. Ceph'd. 249. Crus. 279. Arach. o06. Palpi. Cr. 278. Arach. 303, 306. Ins. 332, 337. Ins. 338. Pancreas. Rot. 136. Ceph'd. 250. Ins. 339. Olfaction. See Organs of. Pedicellariae. Ech. 78. Opiercula, branchial. Crus. 286. Peduncle. Aceph. 180. O erculum. Ceph'r. 203. Penis. IIel. 115, 116, 117. Turb. 128. Ann. 166. _ — caducum. Ceph'r. 203. Ceph'r. 227, 228. Ceph'd. 259. Crus. 291, Organs, auditive. Pol. 34. Acal. 60. Ann. 151. 293. Arach 319. Ins. 354. Aceph. 186. Ceph'r. 211. Ceph'd. 246. Penises, secondary. Crus. 293. Crus. 276. Arach. 305. Ins. 335. Perisoma. Ech. 72. bird's-head-like. Pol. 32. Pharynx. Turb. 125. Ann. 153. Ceph'r. 213. o- f the Byssus. Aceph. 179. Ceph'd. 248. copulatory. Ann.'164, 167. Ceph'r. 227. Pinnulae. Ech. 72. Ceph'd. 259. Crus. 291, 293. Arach.. 319. Plates, ambulacral. Ech. 172. Ins. 354.. - cribriform. Ech. 97. -— generative. Inf. and Rhiz. 20. Pol. e43ntal. Ech. 97 Acal. 66. Ech. 95. Hel. 114. Turb. 128. madreporic. 75. Rot, 140. Ann. 162. Aceph. 197. Ceph'r. ocellary. Ech. 81. 225 Ceph'd. 257. Crus. 290. Arach. 316. Plexus, splanchnic. See Splanchnic Nerves. lras. 348. Pouch, cirrous. Idel. 115. - gyratory. Crus. 285. copulatory. Turb. 128. Ins. 349. - iocomotive. Inf. 7. Rhiz. 8. Pol. 31. fecudating. Ceph'r. 227. — _ fecundating. Ueph'r. 227. Acal. 57. Ech. 77. IIel. 103. Turb. 122. incubating. Crus. 292. Rot. 133. Ann. 145, Aceph. 177. Ceph'r. - problematical red. Crus 286. 204. Ceph'd. 238. Crus. 268. Arach. 299. POLYPI, 24. Ins. 326. Polypary. Pol. 25. - muciparous. Ceph'r. 224. Pores ambulacral. Ech. 72, 77. - -nettling. Pol. 27. Acal. 56. Turb. 121. Cephrttling. 224. 2. Acal 56 Trb. 121. Proboscis. Hel. 103. Ann. 149. Crus. 278 --- olfactory. Ceph'd. 245. Crus. 275. Arach. Aracl 306. Ins. 332, 337. 304. Ins. 334. - Propagation. See Organs of Generation. Prostate. Ceph'r. 227. -- phosphorescent. Ins. 347. --- prehensile. Pol. 36. Acal. 56. Ech. 78. Crus. 268. - rotatory. See Rotatory Apparatus. salivary. See Salivary Glands. Rays, branchial. Ann. 152. - of Secretion. Inf. and Rhiz. 19. Pol. 42. Receptaculum seminis. Turb. 128. Ceph'r. 227. Acal. 65. Ech. 94. Hel. 113. Turb. 127. Crus. 292. Arach. 318. Ins. 349. Rot. 139. Ann. 161. Aceph. 196. Ceph'r. Rectum. Ech. 85. Rot. 136. Ann. 154. Aceph. 223, 224. Ceph'd. 255, 256. Crus. 288, 289. 189. Ceph'r. 214. Ceph'd. 249. Arach. 3071. Arach. 314, 315. Ins. 345, 356, 347. Ins. 338. of Sense. Inf. and Rhiz. 9, 10. Pol. 34. Reservoir, egg. Ann. 166. Crus. 290, 292. Acal. 60. Ech. 81. Hel. 105. Turb. 124. -- sperm. See Receptaculum Seminis. Rot. 135. Ann. 149, 150, 151. Aceph. 185, RHIZOPODA, 4. 186, 187. Ceph'r. 210, 211, 212. Ceph'd. Ring, aquiferous. Ech. 92. 243, 244, 245, 246, 247. Crus. 274, 275, 276, cesophageal. Ech. 80. Hel. 104.' Ann. 277. Arach. 303, 304, 305. Ins. 332, 333, 146. Aceph. 183. Ceph'r. 206. Ceph'd. 240..34, 335, 336. Crus. 270. Arach. 300. Ins. 328. - vitellus-secreting. Hel. 115. Turb. 128. -- osseous. Ech. 73. - sericeous. Ins. 347. Rostellum. Hel. 103. soniferous. Ins. 327. Rostrum. Ins. 337. suctorial. Crus. 278. See also Proboscis. ROTATORIA,130. of Taste. Inf. 10. Ceph'd. 244. Arach. 304. Ins. 333. - of Touch. Inf. 10. Pol. 34. Ech. 81. S. IEel. 105. Turb. 124. Rot. 135. Ann. 149. Aceph. 185. Ceph'r. 210. Ceph'd. 243. Shell. Aceph. 174. Ceph'r. 203. Ceph'd. 235. Crus. 274. Arach. 303. Ins. 332. Crus. 265. - urinary. Ceph'r. 223. Ceph'd. 255. Crus. Siphon. Aceph. 173. Ceph'r. 203, 220. Ceph'd. 288. Arach. 314. Ins. 345. 235. Ins. 343. venomous. Pol. 28. See Venomous Appa- Silk. Arach. 315. Ins. 347. ratus. Skeleton, cutaneous. Pol. 25. Acal. 54. Ech. 72. vibratile. Inf. 8. Pol. 26. Acal. 58. Hel. 101. Crus. 263. Arach. 296. Ins. 322. - of Vision. Inf. 9. Pol. 34. Acal. 60. Ech. -- internal. Ech. 73. Aceph. 175. Ceph'd. 81. Iel. 105. Turb. 124. Rot. 135. Ann. 231. Ins. 322. 150. Aceph. 187. Ceph'r. 212. Ceph'd. 247. Skin. See Cutaneous Envelope. Crus. 277. Arack. 305. Ins. 336. Smell. See Olfactory Organs. vortical. Crus. 285. Spermatophores. Ceph'd. 259. Crus. 290. Orifice, cloacal. Rot. 136. Spermatic Particles. Pol. 46. Acal. 67. Ech. Orifices, genital. Ech. 97. Hel. 115. Turb. 128. 95. Hel. 115, 116, 117. Turb. 128. Rot. Ann. 166. Ceph'r. 227. Ceph'd. 258. Crus. 140. Ann. 163. Aceph. 198. Ceph'r. 225. 290. Arach 318. Ins. 351. Ceph'd. 257. Crus. 290, Arach. 316. Ins. 348,. 40 -470 I N D EX. Spinnerets. Arach. 315. Ins. 347. Tube, anal. Aceph. 189, 194.,Stalk, crystalline. Aceph. 189. -- buccal. Aceph. 189, 194. Stemmata. See Organs of Vision. germinative. Hel. 118.,Stings. Ann. 145. Crus. 264. Ins. 347. -- digestive. lInf. 12. Pol. 37, 38. Acal, 51 Stomach. Inf. 12. Pol. 37, 38. Acal. 61. Ech. Ech. 85. Hel. 106,- 107. Turb. 125. Rot,. 85. Rot. 136. Ann. 154. Aceph. 189. 136. Ann. 154. Aceph. 189. Ceph'r. 214. Ceph'r. 214. Cephkd. 249. Crus. 279.'Arach. Ceph'd. 249. Crus. 279. Arach. 307. Ins. 307. Ins. 338. 338. Suckers. Ech. 77. Iel. 103. Tubes, calcareous. Ann. 161. Sucking Cups. Hel. 103. Ann. 145, 153. Ceph'r. genital. lIel. 117. 204. Ceph'd. 238. Arach. 299. respiratory. Rot. 138. Aceph. 193. Ins, Support, calcareous. See Ilternal Skeleton. 343. +System, aquiferous. Pol. 41. kcal. 63. Ech. 91. -- trachean. Ech. 93. Iel. 112. Turb. 126. Rot. 138. See also Tunnel. Ceph'd. 234. Aquiferous Vessels. TURBELLARIA, 120. circulatory. Inf. and Rhiz. 16. Pol. 39. Acal. 62. Ech. 87. Iel. 110. Turb. 126. Rot. 137. Ann. 156. Aceph. 191. Ceph'r. 216. Ceph'd. 251. Crus. 282. Arach. 309. Ins. 340. Uterus. Hel. 115, 116, 117. Aceph. 199. Ceph'r. muscular. Inf. 7. Pol. 29. Acal. 57. Ech. 227, 228. 76. Hel. 102. Turb. 122. Rot. 132. Ann. 144. Aceph. 176. Ceph'r. 204. Ceph'd. 236. Crus. 267. Arach. 298. Ins. 325. V. - nervous. Inf. 9. Pol. 33. Acal. 59. Ech. 79, 80. Hel. 104. - Turb. 123. Rot. 134. Vagina. Hel. 115, 116, 117. Turb. 128. Ins. Ann. 146, 147, 148. Aceph. 181, 182, 183. Veins. See also Genital Orifices. Ceph'r. 206, 207, 208. Ceph'd. 239, 240, 241. Veins. See Circlatory System. Crus. 210, 271, 272. Arach. 300, 301. Ins. Vesicles, pednclated.. 112. 328, 329, 330. Ins. - of Poli. Ech. 92. - respiratory. See Respiratory Apparatus - emil. Hel. 115, 117. Trb. 128. Ann - splanchoyic. See ReSplanctnic Nerves. 166. Ceph'r. 227. Arach. 319. Ins. 352, -- splanchnic. See Splanchnic Nerves. - tegumentary. See Cutaneous Envelope. See also t leceptacla Seminis. -- tentacular. Ech. 83. Vessel, dorsal. Ann. 156. Crus. 283. Aracr. 309. Ins. 340. Vessels, aquiferous. Ann. 159. Aceph, 195. Taste. See Organs of Taste. Ceph'r. 222. Ceph'd. 254. See also AquiferTeeth. Ech. 84. Hel. 108. Rot. 136. Ann. 153. ous System Ceph'r. 213. Arach. 306. - lateral. - Ann. 156. Tentacles. Pol. 36. Acal. 61. Ech. 83, 91. - Malpighian. Crus. 288. Ins. 345. Turb. 125. Ann. 149. Aceph. 173, 177, 185, ventral. Ann. 156. 189. Ceph'r. 204, 210. Ceph'd. 243. Vulva. See Genital Orifices. Testicles. Pol. 44, 47. Acal. 68. Ech. 97. Hel. 115, 116, 117. Turb. 128. Rot. 140. Ann. 166, 168. Aceph. 198. Ceph'r. 228. Ceph'd. WI 259. Crus. 291, 293. Arach. 316. Ins. 352. Tongue. Ceph'r. 213. Ceph'd. 244, 248. Ins. Wax. Ins. 347. 333, 337. Wings. Ins. 32 Tracheae. Ann 159. Crus, 287.'Arach. 312. Ins. 342.