OS- 
 
 *3 
 
 REESE LIBRARY 
 
 ,.' OF THK * '''' 
 
 UNIVERSITY OF CALIFORNIA. 
 
 Accessions No. 
 
 Shelf No. 
 
 > 
 
A GUIDE 
 
 TO THB 
 
 MICROSCOPICAL EXAMINATION 
 
 OP 
 
 DRINKING WATER 
 
 WITH 
 
 Hn 
 
 MICROSCOPICAL EXAMINATION OF AIR 
 
A GUIDE 
 
 TO THE 
 
 MICROSCOPICAL EXAMINATION 
 
 OF 
 
 DRINKING WATER 
 
 Mftb an 
 
 . ON THE 
 
 MICROSCOPICAL EXAMINATION OF AIR 
 
 BY 
 
 J. D. MACDONALD, M.D., R.K, F.R.S. 
 
 UfSPECTOH-GEXEBAL OF HOSPITALS AND FLTJBTS 
 EX-PBOFESSOR OF NAVAL HYGIENE, ARMY MEDICAL SCHOOL 
 
 WITH TWENTY-FIVE LITHOGRAPHIC PLATES 
 
 EDITION 
 
 LONDON 
 
 J. & A. CHURCHILL 
 
 11, NEW BURLINGTON STREET 
 
 1883 
 

 
 
: TO 
 
 REAR-ADMIRAL THOMAS BRANDRETH, 
 
 ONE. OP THE 
 LORDS COMMISSIONERS OF THE ADMIRALTY 
 
 AND 
 
 CONTROLLER OF THE NAVY, 
 
 WHO HAS ALWAYS ESPOUSED THE PRINCIPLES OF HYGIENE 
 
 AS APPLIED TO SHIPS, 
 THE SECOND EDITION OF THIS WORK 
 
 WITH FEELINGS OF RESPECT AND ESTEEM, 
 
 BY ONE WHO HAS HAD THE 
 PLEASURE OF SERVING UNDER HIS COMMAND, 
 
 THE AUTHOli. 
 
PREFACE 
 
 TO 
 
 THE SECOND EDITION. 
 
 THE author of this work cannot say with many, that the 
 demand for the first edition has been so great as to call speedily 
 for a second. It has, notwithstanding, enjoyed a steady sale ; 
 and if slow it is only what might be expected, when the special 
 nature of the subject is taken into account with the little 
 progress science had made in relation to it when the book was 
 first published. 
 
 The practical utility of the method and arrangement employed 
 in this guide has been tested by its adoption in the Army 
 Medical School for several years, and it has been found that, by 
 its aid, even persons little acquainted with Micro-zoology and 
 Phytology have very readily arrived at the nature and name 
 of objects they had never seen before. 
 
 It is hoped, however, that the identification of forms will be 
 rendered still more easy by the changes that have been made 
 in the general classification, one of the boldest of which is the 
 
Vlll PREFACE. 
 
 removal of the whole of the FLagellata of authors from the- 
 Protozoa to the Protophyta. It is full time that this change 
 should be made. Indeed, all modern research and experience 
 would seem to show the propriety of it. In accordance with 
 the views here expressed, the consecutive order of the figures 
 has been somewhat altered, while some have been newly drawn 
 to facilitate reference, and others added to render the work 
 more complete, though, of course, it cannot still profess to be 
 exhaustive. 
 
PREFACE 
 
 TO 
 
 THE FIRST EDITION 
 
 OFFICERS OF HEALTH, as well as Naval and Military Medical 
 Officers, have often to determine the nature of the suspended 
 matters in water used for drinking. In an Hygienic point of 
 view, the import of these suspended matters must vary with 
 their properties, whether mechanical, chemical, or vital. 
 
 Mineral particles may affect health, on account of their 
 mechanical action, as, for example, when mineral silt of clay, or 
 fine sand causes diarrhoea. Dead animal and vegetable sub- 
 stances may have more important effects, as, when suspended 
 fecal matter produces irritation of the whole alimentary tract. 
 On the other hand, living things, such as the ova of Entozoa, 
 the nematoid worms, and small leeches, may give rise at once to 
 certain grave disorders, or Alga3 may act on sulphates, and dis- 
 engage sulphuretted hydrogen. There are, however, numerous 
 living creatures, both animal and vegetable, found in drinking- 
 water, to which no special effect on health can be at present 
 assigned ; they may be important only as showing the presence 
 of organic impurities, which serve as their pabulum, or as 
 
X PREFACE. 
 
 indicating putrefaction. Farther observation may, neverthe- 
 less, prove them to be of deeper sanitary significance, and 
 even now, though there is no good evidence of their hurtful 
 action, no one would hesitate to condemn a water containing 
 Bacteria or fungi, or swarming with the lower forms of life. 
 At any rate, whatever may be the conclusions hereafter arrived 
 at, as to the sanitary import of the innumerable suspended 
 matters, it cannot be doubted that Medical Officers of Health 
 should be able to state what they are. This must be done 
 chiefly by the microscope ; but, as it is often difficult for those 
 who are unacquainted with Natural History, even with a 
 voluminous work of reference in their hands, to determine the 
 nature of the various objects that may present themselves, the 
 design of the following synopsis is to furnish a number of 
 figures of those objects, with such a commentary as may 
 enable them to be identified. No attempt has been made to 
 link particular forms with special effects ; it is doubtful, 
 indeed, if this be possible at present, beyond a limited extent, 
 being rather a point for the inquiry of future times, which 
 this little work can merely purport to aid. 
 
 The Tables and figures may also prove useful to young 
 naturalists, who are beginning to investigate the world of 
 waters, that wonderful world, in a single drop of which we 
 may behold varieties of form, almost as numerous as those 
 upon the surface of the great globe itself. Many books have 
 been published with a similar object in view ; but one more 
 may find a place, to facilitate the study of a very interesting 
 department of Natural Science. 
 
PREFACE. XI 
 
 In reference to the Plates, by way of apology, it may be 
 mentioned that, with the view of lessening the expense of 
 publication, the figures have been drawn with pen and ink, 
 but, though they cannot pretend to the fineness and delicacy of 
 steel engravings, some artistic effect has been preserved, and 
 it is hoped that they will answer, equally well, the purpose for 
 which they are intended. 
 
 To Professor Parkes, F.B.S., the thanks of the author are 
 
 especially due, for his valuable advice and guidance, in 
 
 rendering the treatment of the subject as practical as 
 possible. 
 
 WOOLSTOX, SOUTHAMPTON, 
 October 1, 1875. 
 
CONTENTS. 
 
 PAGE 
 
 INTRODUCTION. MODE OF COLLECTING SEDIMENTS AND 
 PLACING THEM UNDER THE MICROSCOPE. MICRO- 
 SCOPICAL POWERS. IMMERSION-LENSES. CAUSES OF 
 
 DISCOLORATION AND TURBIDITY ....... 1 
 
 SECTION I. MINERAL MATTERS ....... 8 
 
 SECTION II. DEAD, OR DECAYING ORGANIC MATTER . 10 
 
 A. DEAD VEGETABLE MATTER. . . 10 
 
 B. DEAD ANIMAL MATTER. ... 11 
 
 SECTION III. LIVING FORMS ........ 13 
 
 A. LIVING PLANTS ...... 15 
 
 B. LIVING ANIMALS ...... 43 
 
 MICROSCOPICAL EXAMINATION OF AIR ...... 69 
 
 .B. The numerals placed opposite the genera indicate the 
 corresponding figures in the Plates. 
 
MINERAL MATTER. 
 
 PI 
 
 ,, i 
 
PLATE I. 
 
 Mineral Matter. 
 
 1. Carbonate of lime, finely divided, with vesicles of atmo- 
 spheric air, between the glass slip and cover ; the vesicles 
 invested with minute particles. 
 
 2. Also carbonate of lime, but with the evolution of carbonic 
 acid gas by the addition of an acid ; the vesicles are clear and 
 beautiful. 
 
 3. Fine green mineral particles, cohering as a microscopic 
 breccia, or conglomerate, are here and there mingled with 
 larger and probably more recent sandy granules, preserving 
 their angularity and roughness from fracture ; taken from the 
 debris of a well-sinking, at the Eoyal Victoria Hospital, 
 Xetley. 
 
 4. Silicious or flinty granules taken from road-side stream- 
 lets, (a) more recent, and (b) of earlier date, having been 
 rounded off and smoothed by rolling and attrition, like 
 microscopic boulders. 
 
VEGETABLE PRODUCTS. 
 
 Fi.n 
 
PLATE II. 
 
 Vegetable Products. 
 
 1. Pollen of Grass. 
 
 2. of Water-lily. 
 
 3. of Water-plantain. 
 
 4. of Eush. 
 
 5. of Pine. 
 
 6. Epidermis, parenchyma, and fibre-vascular tissue of straw. 
 
 7. Cuticle of Grass,* with the mycelium of Oidium moni- 
 
 lioides. 
 
 8. Epidermis or cuticle of Water-plantain. 
 
 9. Ditto of the lesser Duck- weed. 
 
 10. Cuticle of Carex, with stomata, and some of the round 
 subjacent parenchyma cells seen through it. 
 
 11. Section of the stem of Carex, showing the large pith 
 or medullary cells, and a bundle of pitted tissue and spiral 
 
 vessels. 
 
 12. Stellate tissue of the pith of the Eush. 
 
 * The epidermis and other tissues of grasses, as of hay and straw, derived from 
 stable manure which is being constantly dried and powdered on every road, and 
 widely dispersed by the wind, are very frequently present in water to which they may 
 find access. 
 
PI. 11 1 
 
 VEGETABLE PRODUCTS 
 
PLATE III. 
 
 Vegetable Products indicative of Contamination icit/i 
 House Refuse. 
 
 1. Linen fibre. 
 
 2. Hemp. 
 
 3. Cotton. 
 
 4. Chip of deal or pine, with the so-called discoidal tissue. 
 and the silver grain of carpenters passing at right angles to 
 the woody fibres. 
 
PL IV. 
 
 ANIMAL PRODUCTS. 
 
 V- 
 
PLATE IV. 
 
 Animal Products. 
 
 1. (a) Ventral hooklet of Nais (a fresli-water annelid) ; (&} 
 liberated ova of the same, often visible when the body of the 
 parent has broken down so as to be indistinguishable. 
 
 2. Spiny spicula of Spongilla lacustris, (a) straight ; (5) 
 curved. 
 
 3. Spicula of Spongilla fluviatilis, (a) birotulate ;* (b) simple.. 
 
 4. Part of the leg of a Cockroach. 
 
 5. Fore leg of Male Dytiscus. 
 
 6. Hind leg of Gyrinus natator. 
 
 7. Foot of a Spider. 
 
 8. Tail of Cyclops quadricornis (male). 
 
 9. Eight superior antenna of the same. 
 
 10. Inferior antenna of Daplmia pulex. 
 
 11. Cast skin of Macrobiotus (Tardigrada). 
 
 12. Head and trophi of Gnat (Culex). 
 
 13. Portion of the Polypiduin of Plumatella (Polyzoa). 
 
 14. Egg of Cristatella Mucedo. 
 
 * The corresponding spicules of the Bombay Tank Sponge, Spougilla Meyeui r 
 form very good objects for the microscope. 
 
P1V. 
 
 ANIMAL PRODUCTS. 
 
PLATE V. 
 
 Animal Products foreign to the Fresh Water. 
 
 1. Fibres of silk. 2. Woollen fibre. 3. Human hair. 
 
 4. Eabbit's hair, (a) the shaft ; (b) the apex. 
 
 5. Nucleated scale-like epithelium from the mouth, &c. 
 
 6. Cuticular epithelium, angular and irregular, without 
 apparent nuclei. 
 
 7. Striped muscular fibre. 
 
 8. Tip of a feather. 
 
 9. Barblets of ditto, more highly magnified. 
 
 10. Scales of Insects. Besides the Lepidoptera namely, the 
 Moths and Butterflies, numerous other insects are furnished 
 with scales. Thus they form a velvety coat on the Anthracidse 
 and Bombylidse, but are more distinctly scaly on the bodies of 
 many of the Curculionidse, Melolonthidae, Clavicornes, Lepis- 
 midae, Poduridae, and on the wings of the Culicidse (Siebold). 
 
BACTERIA. 
 
 Fl VI 
 
 MICRCCOCCUS 
 
 d 
 
 \** : , 
 
 . s . *^* jy. ,**** 3 ~ o 
 
 **:: (HI sVi 
 
 E A C T E R I U M 
 
 tV- 
 
 BACILLUS 
 
 VIBRIO 
 
 S PIRf LLUM. 
 
 SPIROCH/ETA. 
 
PLATE VI. 
 
 Bacteria. 
 
 Micrococcus. 
 
 a. M. prodigiosus. 1. M. vaccinie. c . M. crepusculum. 
 d. M. ureas, e. An allied species. 
 
 Bacterium. 
 
 f. B. termo, free. y. Ditto in the zoogloea form. li. Ditto in 
 linear series. 
 
 I. B. lineola, free. i. Ditto in the zoogloea form. k. Bacteria 
 with highly refracting point. 
 
 Bacillus, 
 m. B. ulna, n, B. subtilis. 
 
 Vibrio. 
 
 0. V. rugtila. p. V. serpens ; 1. free, or in twin spirals, 
 2. felted together. 
 
 Spirillum. 
 
 q. S. tenue ; 1. free, 2. felted together, r. S. undula. 
 s. S. volutans. 
 
 Spirocliccta. 
 
 1. S. plicatilis. 
 
Hf > 
 
 UNIVERSITY 
 
PI VII 
 
 FRONDS WITH BACTERIA. 
 
 or 
 
 AfinuJe Bacteroids in clauate simple 
 brant tied fronds on a spray of pond wed. 
 
PLATE VII. 
 
 V 
 
 Fronds with Bacteria. 
 
 This Plate represents exceedingly minute gelatinous fronds, 
 with embedded bacteroids growing upon a decaying portion of 
 pond weed (Potamogeton). An encrusting layer is seen at 
 the base from which the little fronds spring. 
 
 The great number and extreme minuteness of the mole- 
 cular forms of vegetable life must still claim the attention of 
 Hygieists, from their possible connexion with certain subtle 
 types of disease, until our knowledge has made sufficient 
 progress, either to accept, or reject them as efficient causes. 
 
PI .VII!. 
 
 OSCI LLATORIACE/E. 
 
 NOSTOCHACE> 
 
PLATE VIII. 
 
 Oscillator iacece. 
 
 1. Oscillatoria autumnalis and allied species. 
 
 2. Microcoleus repens. 
 
 3. Lyngbya muralis. 
 
 4. Scytonema Myocrous. 
 
 5. Eivularia Boryana. 
 
 Nostocliacccc. 
 
 1. Xostoc commune. Several fragments showing vesicular 
 cells to the left, and a filament in a gelatinous sheath to the 
 right. 
 
 2. Trichormus musicola. The longer portion to the left 
 exhibiting spermatic and vesicular cells, and the smaller seg- 
 ments to the right, the effect of treatment with acid. 
 
SIPHON A CE/E. 
 
 ZYGNEMACE/E. 
 
PLATE IX. 
 
 Siphonacece. 
 
 1. Vaucheria Ungeri. 2. Portion more highly magnified. 
 
 3. Sporange and antheridium. 4. a and 1} stages in the 
 development of c, the ciliated spore of Vaucheria. 
 
 5. Achlya prolifera, with its mycelioid rootlets growing 
 upon the dead body of a small fly. 
 
 Zygnemaceoe. 
 
 1. Spirogyra. 2. Zygnema. 3. Zygogonium. 
 
 In all three cases the simple filament is shown at a, and the 
 mode of conjugation at b. 
 
 4. Mesocarpus. 5. Staurocarpus. 6. Rhynchonema. a and 
 b in the two latter figures merely indicate different species. 
 
FIX 
 
 CONFERVACE>(a&l))CEDOGONIACE>e(c&<l) CH>CTOPHORACE>E(e) 
 
PLATE X. 
 
 Confervacew, (Edogoniacece and Chcetophoracecc. 
 
 a. Conferva floccosa, I. Cladophora crispata. c. Species 
 of CEdogonium. d. Bulbochaete setigera. c. Chaetophora 
 elegans. Amongst the Diatomacese introduced in this Plate 
 may be noticed Long prismatic Synedne, Tabellaria floccosa, 
 wedge-shaped and stalked Gomphonemse, with the little bent 
 frustules of Achnanthes minutissima. A spray of pond weed 
 forms the theatre of this microscopic vegetation. 
 
FLACELLATA 
 
 Pl.XI. 
 
 MONADACE/E 
 
 EUGLENACEXE. 
 
 THECAMONADACXE. 
 
 
PLATE XI. 
 
 Monadacece. 
 
 1. Monas (a) gutula, (5) fluida, (c) cunillus. 2. Pleuro- 
 monas granulosa. 3. Cyathomonas (a) turbinata, (5) viridis. 
 4. Ohilomonas (a) destruens, (5) obliqua. 5. Cyclidium (a) 
 .abscissum, (5) distortum. 6. Trichomonas (a) vaginalis, (&) 
 minima. 7. Trepomonas agilis. 8. Amphimonas clispar. 9. 
 Cercomonas (a) longicauda, (&) lobata. 10. Heteromita exigua 
 in two positions. 11. Hexamita noclulosa. 
 
 JHuglenacece. 
 
 1. Colacinm vesiculosum. 2. Distigma (a) proteus, (&) 
 viride. 3. Euglena (a) spirogyra, (&) viridis, (c) longicauda. 
 4. Amblyopliis viridis. 5. Peranema globulosa. 6. Astasia 
 iuflata. 7. Chlorogonium euchlorum. 8. Zygoselmis insequalis. 
 9. Polyselmis viridis. 
 
 Thecamonadaccce. 
 
 1. Trachelomonas volvocina. 2. Cryptomonas globnlus. 3, 
 Tliaciis pleuronectes. 4. Crumenula texta. 5. Anisonema 
 sulcata. 
 
PLACE LLATA . 
 
 PI. XII 
 
 PERIDINIACEXE. 
 
 a 
 
 DINOBRYONACEXE. - 
 
 ANTHOPHYSACEXE 
 
 PROTOCOCCUS. 
 
PLATE XII. 
 
 Peridiniacece. 
 
 * 
 
 1. Chsetoglena sp. 2. Chsetotyphla armata (a) end, and (I) 
 side view. 3. Glenodinium cinctum. 4. Peridinium cinc- 
 tum. 
 
 Dinobryonacece. 
 
 1. Epipyxis utriculus. 2. Dinobryon sertularia, 3. Stylo- 
 bryon insignis. (Fro.) 4. Pycnobryon socialis. (Fro.) 
 
 A nthopJi ysacece. 
 
 1. Anthophysa Miilleri. 2. Uvella virescens. 3. Tetra- 
 baBna Dujardini. (a) side view, (&) end view. 
 
 Volwcacece. 
 
 1. Gonium pectorale. 2. Volvox globator. 3. Pandorina 
 morum. 4. Allodorina irregularis. 5. Diplodorina Massoni. 
 
 Transitional form, Protococcus mridis. 
 
 (a} Single motile cell ; (I) stationary cell undergoing cleavage ; 
 (c) two resulting cells ; (d) cleavage into four, &c. ; (e) into eight 
 new cells within the primary one. 
 
PI XIII. 
 
 PALMELLACE/E. 
 
 16 
 
PLATE XIII. 
 
 Palmellacece. 
 
 1. Microhaloa ichthyoblabe. 2. Palinella cruenta. 
 
 3. Coccocliloris Brebissonii. () Development and cleavage 
 of a cell resulting in two new cells, each enclosed in a new 
 gelatinous coat within the primary one. (b) Multiplication 
 in the absence of the moisture necessary for the production of 
 the gelatinous . coat, (c) Approximation, union, and coales- 
 cence of two endochromes, to form a new cell, with the capa- 
 bility of repeating the process with a similar cell. 
 
 4. Hormospora (a) mutabilis, and (b) transversalis ; which 
 latter makes a near approach to some of the humbler Des- 
 midiaceae. 
 
 Types of Desmidiaceae. 
 
 1. Closterium (a) lunula, (b) momliformis. 2. Peniuni 
 Brebissonii. 3. Spirouenia condensation. 4. Docidium 
 baculum. 5. Tetmemorus Brebissonii. 6. Micrasterias sp. 
 (Fiji.) 7. Euastrum didelta. 8. Cosmarium margaritiferum. 
 9. Arthrodesnms convergens. 10. Xanthidium fasciculatuin. 
 11. Staurastrum gracile. 12. Didymocladon furcigerus. 
 
 13. Didymopriuin Grevillii (a) front, and (b) side-view. 
 
 14. Desmidium Swartzii (a) front, and (b) side-view. 
 
 15. Sphserozosma vertebra turn. 16. Hyalotheca dissilens. 
 17. Aptogonum desinidium. 18. (a and b) Scenedesmus 
 quadricornis. 19. (b) Scenedesmus obtusus, (c) S. obliquus. 
 20. Ankistrodesmus falcatus. 
 
 For the Pediastrece, see Plate XV. 
 
PI XIV 
 34 TYPES OF FRESH WATER DIATOMACEXE. 
 
 m ^-Lj-t 
 
 'tPgZfaiS** X \^7 
 
PLATE XIV. 
 
 Thirty-four Types of Fresh- Water Diatomacece. 
 
 1. Epitliemia turgida. 2. Eunotia tetraodon. 3. Himanti- 
 dium pectinale (a side, and I front view). 4. Meridion circulare. 
 5. Eragilaria capucina. 6. Denticula elegans. 7. Odontidium 
 turgidmn (a side, and b front view). 8. Diatoma vulgare (a side, 
 and 1} front view). 9. Astrionella forinosa. 10. Cyclotella oper- 
 cula. 11. Melosira varians. 12. Campylodiscus spiralis. 
 13. Surirella splendida. 14. Sphynctocystis elliptica. 16. Sy- 
 nedra (a splendens, b capitata). 17. Cocconeis pediculus. 
 18. Achnanthes minutissima. 19. Aclinanthidium microee- 
 phalum. 20. Cymbella Ehrenbergii. 21. Cocconema lanceola- 
 turn, a and I (a, single frustule highly magnified). 22. Gom- 
 phoneina acuminatum. 23. Pinnularia grandis. 24. (a) Navi- 
 cula cuspidata, (1) 1ST. sphserophera. 25. Stauroneis acuta. 
 26. Gyrosigma attenuatum. 27. Amphora ovalis. 28. Tetra- 
 cyclus lacustris (a side, "b front view). 29. Tabellaria floccosa 
 (a side, b front view). 30. Terpsinoe musica (a side, b front 
 view). 31. Mastogloia lanceolata. 32. Frustulia saxonica. 
 33. Colletonema vulgare. 34. Encyonema paradoxum. 
 
Pl.XV. 
 
 PEDIASTRE/E. 
 
 HYDRODICTYON 
 
 APIOCYSTACE/C. 
 
PLATE XV. 
 
 Pediastrece. 
 
 1. Pediastrum tetras. 2. Pediastrum simplex. 3. Pedias- 
 trum liexactis. 4. Pediastrum tricyclium. 5. Pediastrum 
 lunare. 6. Pediastrum granulatum. (a) shows a disc from 
 which gonidia are still escaping, the greater number of the cells 
 having been already emptied in this way. (I) a new family just- 
 forming, (c) more advanced stage, the gonidia beginning to 
 take a definite form. Hydrodictyon utriculatum. (a) portion 
 of H. utriculatum showing its general structure, (&) two of the 
 component cylindrical cells separated from the organism, 
 (c) three of the same connected at one end and showing the 
 gonidia within, preparatory to their union so as to form a new 
 colony, as seen at (d), which is one of the cells more advanced 
 in development and more highly magnified. 
 
 Apiocystacecc. (Provisional.) 
 
 1. Apiocystis Brauniana (a young, I zoospore). 2. Hydro- 
 cytium acuminatum (, b stages of growth, c shedding zoospores). 
 3. Ophiocytiuin majus. 4. Sciadium arbuscula (a stages of 
 development, I complete form). 5. Chytridium Olla, on a 
 filament of (Edogonium, one dehiscing and discharging monad- 
 like zoospores. 6. Pythium entophytum (a an immature 
 cluster in a cell of Chlorosphsera, b one perforating the cell- 
 wall and discharging its contents). 7. Codiolum gregarium. 
 
PI XV i 
 
 RH IZOPODA. 
 
 RADIOLAR1A. 
 
 l.A canthocy&tis 3 . C 
 
 RETICULARIA 
 
 Pleuraphrys 
 
 ^ rnph itr 
 
 LOB OS A 
 
 <? 
 
 tuberculafa. Q.E.a 
 
 \ l)nrft"./ia, fa'o I'tintm. 5. . !///// \ ///yww. from 
 alwve.Q.Cvpltiduim. 7 Angela .several lorm* 
 
PLATE XVI. 
 
 Ehizopoda. 
 
 Radiolaria. 
 
 1. Actinophrys ; (a) Eichornii ; (1) sol. ; (c) ditto young. 
 
 2. Acanthocystis turfacea ; (a) full grown, (I) young. 
 
 3. Clathrulina elegans. 
 
 Rcticidaria. 
 
 1. Groniia fluviatilis. 2. Pleurophrys amphitremoides. 
 3. Amphitrema Wrightianum. 
 
 Lobosa. 
 
 1. Triuema acinus. 2. Euglypha tuberculata, 3. E. alveo- 
 lata. 4. Difflugia () spinosa, (&) proteiformis. 5. Aroella 
 vulgaris. 6. Cypliidium aureolum. 7. Amosba, (a) ramosa, 
 (&) radiosa, (c) young of diffluens. 
 
CIL1ATA 
 
 ENCHEL1A. 
 
 PL XVII. 
 
 TR1CHODINA 
 
 KERONIA. 
 
 EUPLOTA. 
 
PLATE XVII. 
 Ciliata. 
 
 Enclidia. 
 
 1. Acornia vitrea. 2. Gastrochseta fissa. 3. Enchelys nodu- 
 losa. 4. Alyscum saltans. 
 
 Trichodina. 
 
 1. Pelecida rostrum. 2. Dileptus folium. 3. Trachelius 
 anas. 4. Acineria* incurvata. 5. Triclioda angulata. 
 
 Keronia. 
 
 1. Halteria grandinella. 2. Oxytricha gibba. 3. Urostyla 
 grandis. 4. Kerona polyporum. 5. Stylonychia histrio 
 (lanceolata ?). 
 
 Euplota. 
 
 1. Himantophorus cliaron ; () front, and (6) side 
 view. 2. Euplotes vannus, () front, and (&) side view. 
 
PI XVlll 
 
 PAR AM ECI A. 
 
 // 
 
 VORTICELLIIMA. 
 
 
 
PLATE XYIIL 
 
 dliata. 
 
 Paramccia. 
 
 J. Chilodon cucullulus. 2. Nassula elegans. 3. Prorodon 
 teres. 4. Glaucoma scintillans. 5. Colpoda cucullns. 
 G. Paramecium aurelia (three-quarter-view). 7. Panophrys 
 crysalis. 8. Holophrya ovum. 9. Trachelocerca olor. 
 10, Laciymaria proteus. 
 
 BuTsarina. 
 
 1. Opliryoglena acuminata. 2. Bursaria vorticella. 
 
 3. Leucophrys (a) patula, (&) spatliula, Ehr. (Spathidium 
 hyalinum) Du. 4. Spirostomum ambiguum. 
 
 Urceolarina. 
 
 1. Ophrydium versatile, showing an animal in the extended 
 state, and (a) encysted, (b) the supposed Acineta form. 
 
 2. Urceolaria pediculns (Trichodina). 3. Stentcr cceruleus, 
 with internal germs. Urocentrum turbo. 
 
 Vorticellina. 
 
 1. Vorticella microstoma. 2. Carchesium polypinum. 
 
 3. Epistylis crassicollis. 4. Opercularia articula. 5. Zoo- 
 thamnium arbuscula. 
 
PI. XIX 
 
 SYMMETRICAL FORMS. 
 
 CCELENTERATA. 
 
 HYDRIDA. CORYNIDA A 
 
 SCOLECIDA 
 
PLATE XIX. 
 
 Ciliata. 
 
 Symmetrical Forms. 
 
 1. Ichthydium Podura. 2. Chsetonotus Larus. 3. Coleps 
 hirtus. 4. Planariola rubra. 
 
 Ccelenterata. 
 
 1. Hydra viridis. 2. H. vulgaris. 3. Cordylopliora 
 lacustris. 
 
 Turbellaria. 
 
 1. Derostoinum. 2. Prostomum. 3. Mesostomum. 
 4. Planaria. 
 
ID 1 W 
 
 NEMATODA. 
 
 ANARTHRQPODA 
 
 3a 
 
PLATE XX. 
 
 Nematoda. 
 
 1. Anguillula (from bilge water). 2. A. aceti. 
 3. A.-fluviatilis. 
 
 Rotifem. 
 
 % 
 
 1. (Ecistes crystallinus. 2. Megalotrocha flavicans. 
 3. Monostyla quadridentata. 4. ^loscularia ornata. 5. Hyda- 
 tina senta. 6. Eotifer vulgaris. 7. Braclrionus amphiceros. 
 
 Annelida. 
 
 1. Naiad ; (a) conformable with the Pro to of Oken ; (6) 
 setse, and ventral booklets. 2. Xephelis, sp. 3. Glossiphonia 
 bioculata ; 3. a dorsal chitinous tooth-like process directed 
 backwards from the eleventh segment, over a little pit in the 
 twelfth. 
 
ENTOMOSTRACA. 
 
 OSTRACODA. 
 
PLATE XXI. 
 
 Entom ostraca. 
 Ostracoda. 
 
 1. Cypris tristriata. 2. Candona reptans. 3. Cythere 
 inopinator. 
 
 Copepoda. 
 
 1. Cyclops quadricornis. 2. Canthocamptus minutus. 
 3. Diaptomus castor. 
 
 Pkyllopoda. 
 
 1. Branchipus stagnalis. 2. Lepidurus, Zeac/^=Monoculus 
 
 Apus of Linnceus. 
 
 Cladocera. 
 
 Lynccidm. 
 
 1. Chydorus sphsericus. 2. Camptocercus macrourus. 
 
 3. Alona quadrangularis. 4. Pleuroxus trigonellus. 
 
 DapJinidce. 
 
 5. Daphnia pulex. 6. Bosmina longirostris. 
 
 7. Sida crystallina. 8. Daphnella Wingii. 
 
ffcP 
 
 OF 
 
 UN? ; TY 
 
MALACOSTRACA. 
 ISOPODA. 
 
 PI. XXII 
 
 \ AMPHIPODA. 
 
 ARACMN1DA. TARDIGRADA. 
 
 ACARiNA 
 
PLATE XXII. 
 
 Malacostraca. 
 
 Isopoda. 1. Asellus aquaticus. 
 
 Amphipoda. 2. Gammarus pulex. 
 
 Arachnida. 
 
 Tardigrada. 
 
 1. Emydium testudo. 2. Milnesium tardigrada. 
 
 . 3. Macrobiotus Hufelandii. 
 
 Acarina. 
 1. Hydrachna globula. 2. H. geographica. 
 
 3. A more globular form in which, quite exceptionally, six 
 eyes are present. 
 
 4. Limnochares holocericus, a crawling water mite. 
 
N S E C TA 
 
 PI. XXIII. 
 
 OVA OF ENTOZOA. 
 
PLATE XXIII. 
 
 Insecta. 
 
 Coleoptera. 
 
 1. Larva of Acilius sulcatus. 
 
 2. Larva of Gyrinus natator. 
 
 Trichoptera. 
 
 3. Phryanea grandis in its composite case. 
 
 4. The form named Tkelidomus by Mr. Swainson, who 
 mistook the little built-up case for a genuine shell, and gave it 
 a place among the Helices (snails), arranged in ac3ordance 
 with the " quinary system." 
 
 The case figured, from the Isle of Pines, S. W. Pacific, was 
 made of granules of ironstone, but in some of the streams of 
 ISTew Caledonia, the retreat of probably the same species, is 
 constructed of little amethysts. 
 
 Hccmiptera. 
 
 5. Pupa of Nepa (water scorpion). 
 
 NcuropUra. 
 
 6. Pupa of Agrion puella. 
 
 7. Pupa of Calepteryx virgo. 
 
 8. Pupa of Ephemera vulgata. 
 
 Diptcra. 
 
 9. Larva of the Gnat Culex pipiens. 
 
 Ova of Entozoa. 
 
 10. Of Tsenia rnediocanellata. 
 
 11. Of Fasciola hepatica. 
 
 12. Of Ascaris dentata. 
 
 13. Of Bilharzia hsematobia. 
 
 14. Young of Filaria medinensis. 
 
PL XXIV. 
 
 WELL-WATER (NETLEY). 
 
 a. eansjus fronds e. 
 
 with Bacteria. f . 
 
 b . Monaduwt, . g\ Thecvmoiutdina. 
 
 c . DiafoTtiac&E. h. Pabnetta ,fa 
 
 d. Star shaped cells i . Euglena 
 
 k. Spore of Septoria, (funyusj. 
 
 I . OsciUatoria-. 
 
PLATE XXIV. 
 
 Well-Water (Netley). 
 
 The suspended matters represented in this Plate were 
 obtained by setting aside a tall glass litre measure full of the 
 water, with a disc of glass attached to a long wire at the 
 bottom. During the first twelve hours a deposit of grosser 
 particles was formed, with a delicate coating here and there 
 of the gelatinous matter and bacteroids shown at a. In twelve 
 hours more this coating had become more consistent, and at 
 the end of forty-eight hours was so firmly adherent as to 
 require some force to remove it, with the mineral particles, 
 resting-spores of algse, and organic debris of different kinds 
 embedded in it. 
 
 In the little bays and creeks of this gelatinous- substance 
 the loosened and detached Bacteria were in active motion, and 
 interspersed with Monads (b) of minute size. 
 
 Navicula, Synedra, and other Diatoms (c), were free in the 
 field, or often projecting from the amorphous debris. The 
 little green star-like bodies (d) probably allied to the Tetra- 
 pedia, have also been noticed in other specimens obtained from 
 a deep source, and are evidently identical with those figured 
 in Plate IV., illustrating the Eeports made to the Directors of 
 the London (Watford) Spring- Water Company by Drs. 
 Lankester and Piedfern. 
 
 The remaining objects are sufficiently explained in the 
 references attached to the Plate. 
 
Pi.XXV. 
 
 BOG-WATER. 
 
 a . Particle of boy j&oss. 
 b . 
 
 c . 
 
 d . CbsmaPium. 
 
 e . Closterium. 
 
 1 . 
 
 o. Brown Veyetabl& 
 
PLATE XXV. 
 
 Bog Water. 
 
 Tli3 specimen of water here represented was taken from the 
 swampy ground near Miller's Pond, Sholing, Southampton. 
 It was very rich in Ehizopoda, Infusoria, Oscillatorians, and 
 Desmids large and small, and the beautiful Pinnularia grandis, 
 which is so plentiful in all the surrounding district, but 
 chiefly in stagnant and impure water. 
 
MICROSCOPICAL EXAMINATION 
 OF DRINKING WATER. 
 
 INTRODUCTION. 
 
 ALTHOUGH the microscopical examination of drinking water 
 may, in one sense, be regarded as an abstract question, if any 
 important deductions are to be drawn from the study, not 
 only the nature of the source of the samples, and the mode 
 of collection, but the vessels used for their conveyance, should 
 be taken into consideration. 
 
 Just as the mineral debris would afford us a clue to the 
 nature of the strata or soil through which the water may pass, 
 so the known habitat of certain organisms detected should 
 enable us, in a general way, to determine whether the water 
 had been taken from a river, stream, lake, pond, or well source. 
 Indeed, if we were more perfectly acquainted with the natural 
 history of the forms occurring in a sample of water, even in 
 the absence of more definite information, we would have little 
 difficulty in forming a conclusion as to the source from whence 
 the water was derived. 
 
 It is always important that we should guard against every 
 shadow of fallacy in our conclusions drawn from microscopical 
 observation, to whatever hygienic purpose it may be subservient. 
 Indeed, as. absolute purity and cleanliness are required in all 
 
 B 
 
2 INTRODUCTION. 
 
 delicate chemical operations, so all our apparatus for microscopy 
 should be microscopically clean, so to speak. 
 
 In relation to the apparatus just mentioned, some few 
 remarks may be of use to the beginner. 
 
 As it is only in the mode of collecting the objects for 
 observation that any essential difference exists in the method 
 of examination applicable to air and water, the reader is 
 referred to the Appendix for the means to be employed in the 
 case of air. 
 
 Collecting bottles for water. When a sample of water is 
 received for chemical analysis, it is usual to reserve a portion, 
 with the sediment at the bottom of the bottle, for microscopical 
 examination. It will therefore be seen how necessary it is 
 that bottles in which samples are conveyed should be perfectly 
 clean in the first instance, and in every other particular suitable 
 for the purpose. In the laboratory of the Army Medical 
 School, where a large amount of water analysis is continually 
 carried on, it has been decided not to examine any samples sent 
 in ordinary wine bottles or stone jars closed with corks and 
 sealing-wax, corn-cobs, or other adventitious materials, with 
 which there must always be some fallacy associated. Clear 
 glass-stoppered Winchester quarts, so called, which are cheap 
 enough, are therefore recommended for this purpose, and 
 commonly used, with others of a larger size if available. 
 
 Tall glass vessels for the deposit of suspended matters'. Though 
 a litre or half-litre measure glass would answer very well, 
 there can be no doubt that a special vessel closed with a glass 
 stopper would be more suitable for this purpose. The mouth 
 of the vessel, however, should be sufficiently large to admit of 
 its being easily and thoroughly cleaned before use. 
 
 Moderately tall conical glasses for the further concentration of 
 sediment. Such glasses as are used for the collection of urinary 
 deposits will answer this purpose, but the interior of the 
 
INTRODUCTION. 3 
 
 bottom, though small, should be rounded, and not acuminately 
 conical, which in some instances will scarcely admit of being 
 cleaned, especially if a former sediment has been permitted to 
 dry within it. When glasses of this kind are only carelessly 
 rinsed out, the tabulated results of a subsequent examination 
 cannot be reliable. 
 
 Dipping tubes or pipettes. These tubes should be quite 
 cylindrical in form in fact, simple glass tubing cut in lengths 
 of eight or ten inches. The lumen or bore should be compara- 
 tively small say, the eighth or tenth of an inch in diameter. 
 ,If the tube is too large, and with a small aperture below, the 
 contained air will materially affect the ascent of the fluid with 
 the sediment. On this account it is often difficult to manage 
 the pipettes that are made with the greatest care. The ends 
 of a piece of glass tubing cut in the usual way should be 
 smoothly ground or slightly fused, and rounded by means of 
 a blowpipe, to obviate the minute chipping of the glass, which 
 is often a source of fallacy. 
 
 It may be well to mention here, as a good precaution, that 
 every separate sample of water for observation should have a 
 separate pipette for taking up the sediment. When the 
 same pipette is used for every purpose, even with what might 
 be thought to be a clean rinse for every new occasion, any 
 evidence deducible from the last, or indeed any observation 
 under such circumstances, would be inadmissible. In this way, 
 for example, striped muscle and fibrous tissue have been 
 reported as occurring in drinking water, which had otherwise 
 been found to be quite free from organic impurity ; the fact 
 being that the pipette employed had been previously used in 
 the examination of a certain form of beef-tea, from which even 
 the clean rinse had not entirely divested it. 
 
 TJie slides and covering glasses required for more immediate 
 examination of specimens need no special remark in this place. 
 
 B 2 
 
4 INTRODUCTION. 
 
 further than to say that for rough materials it will be more- 
 convenient to use thick covers that may be easily cleaned 
 without breaking them ; while for finer materials, and especially 
 for immersion purposes, they should be proportionately thin. 
 
 Mode of Collecting Sediments and placing them under the Micro- 
 scope Microscopical Powers Immersion-lenses. 
 
 When water is very turbid, from an obviously impure source,, 
 it is easy enough to obtain a sufficient amount of sedimentary 
 matter for microscopical examination, and a just estimate of 
 the unfitness of such water for drinking purposes may be thus 
 readily formed. But it more frequently happens that the 
 deposit, even after long standing, is but slight, and when this 
 is the case, we must have recourse to special means, by which 
 the whole, or a large amount of the matters in suspension, may 
 be concentrated, or collected together, within a small compass.. 
 In the first place, one of the tall glass vessels above described 
 should be filled with the water to be examined, and a circular 
 disc of glass, resting on a horizontal loop at the end of a long 
 aluminium wire lowered to the bottom, when the whole 
 arrangement, lightly covered, must be set aside for twenty-four 
 or forty-eight hours, as the case may be. 
 
 At the end of the specified time, the water should be 
 siphoned off with a piece of india-rubber tubing, so as to leave 
 only a thin stratum of the liquid over the glass disc. This 
 should now be carefully raised and laid upon blotting-paper 
 to dry its under surface and remove the surplus moisture, 
 when it may be at once transferred to the microscope, with a 
 large piece of covering glass so placed upon it as to exclude all 
 air-bubbles. An ordinary watch-glass may in some cases be 
 substituted for the disc alluded to, with advantage, as being 
 less likely to permit the loss of sediment by overflow, which is- 
 
INTRODUCTION. 5 
 
 certain to happen with a plain surface. The operator must be 
 cautioned not to use iron wire, which rusts so rapidly that it 
 ^will soon throw down a flocculent precipitate. Another good 
 plan, which is perhaps the better of the two, is to siphon off 
 the water until only a sufficient quantity remains to permit 
 the sediment to be shaken up with it, and poured into a tall 
 conical glass, from which, after standing again for a short time, 
 portions may be taken up by means of a pipette, and placed 
 on slides for examination. If the subsidence is observed to be 
 complete, it is rather an advantage to have a good body of 
 water in the glass, or, at least, so much as will permit the 
 pipette to be used with ease and facility. It may be observed 
 here, that it is very inconvenient to have too much fluid at a 
 time on a slide. The covering glass will be unstable and 
 liable to have its upper surface wetted, while the objects them- 
 selves will be tremulous, if they do not quite run out of the 
 field. To obviate this, the pipette, when taken out of the 
 water, should be held in a vertical position for some little time, 
 until the suspended matters gravitate to the bottom of the 
 tube, when a well charged droplet might be placed on a 
 number of separate slides and examined seriatim. This is, in 
 fact, the only way in which a large sediment can be thoroughly 
 inspected. 
 
 By the second method above mentioned, the specimen of 
 well-water sediment represented in Plate XXIV. was prepared. 
 The gelatinous matter, developed round the bacteria-like cells 
 Sit the lower part of the drawing (a) was only loosely adherent 
 at the close of the first day; but, subsequently to this, or 
 during the next forty-eight hours, it formed a delicate but 
 perfect incrustation at the bottom of the vessel. Many of the 
 little bodies detached from the gelatinous frond were seen in 
 active motion in the immediate vicinity. More definite fronds, 
 with still more minute bacteriform bodies growing upon a 
 
6 INTRODUCTION. 
 
 i 
 
 decomposing spray of pond-weed, are shown in Plate VII., as 
 seen with a sixteenth of an inch immersion-lens. The first of 
 these forms, at least, would seem to exhibit an alliance with 
 the Palmellaccce, while others, which are very readily confounded 
 with them, show a marked affinity to the Oscillatorians (see 
 further remarks on this subject under the head of Bact&riacece). 
 It will be apparent, from the foregoing observations, that the 
 sediments of comparatively clear water require the very highest 
 microscopical powers for their investigation, and the employ- 
 ment of immersion-lenses if available. 
 
 Filamentous Algae, as narrow as true bacteria, may be thus 
 frequently brought into view, as well as the delicate flagellse, 
 or locomotive organs of monads, whose bodies alone would be 
 scarcely visible with lower powers. It is also important to 
 mention that, by these means, even in the absence of ordinary 
 amoebae, particles of protoplasm of bacterium size, exhibiting 
 amoebiform movements, are often discernible. Lastly, very 
 finely-divided mineral matter in suspension, giving rise to 
 milkiness or haze, can only be studied with immersion-lenses, 
 though certain cases may occur in which no objective cause of 
 this condition can be detected microscopically. 
 
 Mineral matters of various hues in the soil, through or 
 over which water percolates or flows, are the more usual 
 causes of discoloration and turbidity. Peroxide of iron, in 
 particular, may be mentioned as the source of the "brown 
 cloudy appearance of water from the blue clay, as also, 
 frequently, of the brown colour of pools in bog-lands, though 
 this more usually arises from organic matter passing into 
 decay. In the coarser sediment under such circumstances, the 
 microscopic forms of animal and vegetable life are likely to be 
 abundant (viz., Rotifera,, Infusoria, Ilhizopods, Oscillatorians r 
 Nostocs, Desmids and Diatoms). In ferruginous bog- water 
 also the twin-spiral filaments of Didymolielix, invested with a 
 
INTRODUCTION. 7 
 
 yellowish -brown gelatinous matter, and Leptotlirix ochrea, a 
 rather ill-defined myceloid structure, may add to the general 
 effect. By reflected light, moreover, the fine amber tint of the 
 Diatomacece, floating or resting, is quite brown. Some of the 
 heterogeneous materials usually occurring in bog-water are 
 represented in Plate XXV. 
 
SECTION I. 
 
 MINERAL MATTERS. (Plate I.) 
 
 MINERAL matters in suspension in water often give a turbidity 
 of a colour and character indicative of their nature. When 
 the particles are large, they will descend more rapidly ; but 
 when very subtle or minutely divided, the suspension being 
 more complete, a longer time will be required for their sub- 
 sidence. Looking down through a considerable depth of the 
 water, with the glass vessel containing it resting on a white 
 ground, will afford some preparatory information ; especially 
 when compared with a stratum of pure water in a second 
 vessel observed in a similar way. 
 
 Haziness, or peculiarity of colour, may be thus detected, 
 which would be quite inappreciable in a thin layer. With a 
 long glass tube, a stratum of two or more feet might be obtained ; 
 a method also valuable in observing the effect of reagents or 
 tests in water. In the light of preparatory information, it 
 may be stated, moreover, that sandy particles or clay in sus- 
 pension give a yellowish-white turbidity ; and on boiling the 
 water, as Professor Parkes observes, " sand, chalk and heavy 
 particles of the kind will be deposited." If it be a chalk 
 water, the calcium carbonate will carry down suspended 
 sewage or vegetable matter, effecting a change of colour. 
 Under such circumstances, the sense of smell may afford con- 
 firmatory evidence. 
 
 Silicious particles, as of flint or sand, are usually angular ; 
 and though often much rounded by rolling and attrition, a 
 vitreous-looking fracture will be observable in many of them, 
 
INORGANIC MATERIALS. 
 
 as shown in Plate I. Fig. 4, a. It should be mentioned here 
 that a little source of fallacy may be occasioned by the very 
 frequent detachment of minute scales or chips from the 
 margins of the covering glass, or, as before mentioned, the 
 extremity of the pipette, when not properly ground, or even 
 from the glass stoppers of bottles in which specimens are kept. 
 On carefully inspecting the more minute particles of silicious 
 matter, which are so easily diffused and suspended in water, 
 their thin or scale- like character will be apparent. Particles 
 of chalk, clay and marl, on the other hand, are usually more 
 rounded, but the former will be at once recognized by their 
 solubility in acids, with the evolution of carbonic-acid 
 bubbles. The crystalline forms of numerous substances are 
 frequently visible in the smallest molecules. Indeed, the 
 study of the inorganic matters in the sediments of fresh water 
 is a kind of microscopical mineralogy which is of growing 
 interest and importance to the water 'analyst. It would of 
 course include goniometry, spectrum analysis, and the 
 behaviour of definite particles amongst others, under the action 
 of reagents. In the latter connection, besides the effect of 
 adding a little mineral acid, a useful micro-chemical experiment 
 is to introduce a solution of the mixed prussiates of potash 
 beneath the covering glass, when any ferruginous matter 
 present will be indicated by the blue colour produced. 
 
 ISTessler's fluid, used in the same way, will often show the 
 presence of organic sources of 'ammonia, even in an amorphous 
 state. Organic substances, such as the bodies of infusoria, &c., 
 are darkly discoloured by the permanganate of potassium ; and 
 by boiling the sediment with solution of the chloride of gold, 
 interesting results may be obtained under the microscope. 
 Altogether there would appear to be great promise in the kind 
 of research here indicated. 
 
SECTION II. 
 
 DEAD, OR DECAYING ORGANIC MATTER. 
 
 ANY of the forms described in the succeeding section, as living 
 plants and animals, may be found in the sediment of drinking- 
 water, either whole or fragmentary, in a dead and more or less 
 decayed state. Their recognition will, in many cases, be difficult, 
 in consequence of the accumulation of debris of different kinds 
 about them, as well as their own altered condition ; but when 
 the more unyielding structures remain intact, a little practice, 
 with the help of figures, will enable the observer to determine 
 them with sufficient accuracy for all practical purposes. 
 
 A. Dead Vegetable Matter. (Plates II. & III.) 
 
 When the higher plants die down, those of a more humble 
 kind seem to nourish with greater vigour, so that however 
 shapeless the decaying masses may be, minute Oscillatorians, 
 Bacteria, and their allies will usually be found in their vicinity. 
 The breaking down of vegetable cells is of course attended with 
 the discharge of the contained sap, endochrome, &c. ; and these 
 will soon assume an amorphous, or irregular granular appearance, 
 in which the original green colour is here and there very evident. 
 Its further change, however, is usually into an olivaceous, or 
 yellowish-brown tint. In some instances, the albuminous 
 inner coat of the vegetable cells, known as the primordial 
 utricle, is seen much contracted within the cellulose coat, 
 passing into an indigo-purple tint in a more advanced stage of 
 decay. With a little care the collapsed and crumpled cell-walls 
 
ORGANIC MATERIALS. 11 
 
 may be recognized casually. But very characteristic of decaying 
 vegetable matter, if it appertain to vascular plants, is the 
 occurrence of spiral vessels, or even the spiral fibres drawn out 
 of the cells ; annular ducts, dotted and pitted tissue and hairs, 
 which, from their comparative indestructibility, are sometimes 
 very beautifully dissected out, as it were, by maceration. 
 These at once afford a clue to the nature of the amorphous 
 matter in connection with which they are found. 
 
 The little scales of " bog moss" (Sphagnum} with their 
 porous or fenestrated cells, the discs and roots of " duckweed" 
 (Lemna), sprays of " pond- weed" (Potamogetori), or of the " stone 
 worts" (Cham and Nitella), and segments of the numerous 
 filamentous Algae may be met with, more or less altered in 
 colour, or otherwise. 
 
 Amongst the vegetable products (Plate III.) not properly 
 belonging to the fresh water, but rather indicating contamination 
 from house refuse, may be mentioned the fibres of fabrics, such as 
 linen (1), hemp (2), cotton (3), and the discoidal tissue of 
 ordinary deal or pine (4), swept from the floor. It may be 
 mentioned, in passing, that this well-marked structural particular 
 is assumed to be characteristic of coniferous woods as a whole. 
 
 B. Dead Animal Matter. (Plates IV. & V.) 
 
 Decaying animal, as well as vegetable, matter may consist of 
 materials proper to the fresh water, or foreign to it. To the 
 first class belong, in particular, the dead bodies of Entomostraca 
 (water-fleas, &c.), and the numerous forms of segmented or 
 annulose animals, including the water-bears and mites, the 
 larvae of aquatic insects, and the Annelida (Naiads and leeches). 
 The Naiads are often only to be recognized by their inde- 
 structible setae and ventral booklets, which may ultimately 
 become quite isolated in the field. Animal products not 
 
12 ORGANIC MATERIALS. 
 
 proper to fresh water may embrace the bodies or exuviae of 
 terrestrial insects, house-flies and others, often overgrown with 
 Achlya* and numerous other matters, such as are represented 
 in Plate V., to which the following references will apply : 
 1. Fibres of silk; 2. Wool; 3. Human hair; 4. Hair of rabbit 
 a. the shaft, and 1. the extremity 5. Epithelium from the 
 mouth or mucous surfaces ; 6. Ditto from the cutaneous sur- 
 face ; 7. Striped muscular fibre ; 8. A feather ; 9. Portions of 
 the same more highly magnified ; 10. Scales of Lepidoptera. 
 The scales of moths and butterflies are usually flat, with fine 
 longitudinal fluting and a serrated extremity. Hairs, properly 
 so-called, have commonly a soft central axis of cells, often 
 absorbed so as to form a medullary cavity. Wool, on the 
 other hand, is much smaller than hair, as a rule ; more compact 
 in the centre, while the superficial imbrication of the com- 
 ponent cells is more open and clearly marked. Nucleated 
 epithelial scales are broad and flat, and much more easily 
 recognized than the non-nucleated, and much smaller epithelium 
 from the skin. The nucleus is oval, highly refringent, and it 
 is usually surrounded with minute scattered points spreading 
 towards the margin of the scale. They resist maceration for 
 a considerable time, and thus frequently percolate with other 
 impurities, from latrines into wells culpably sunk in the imme- 
 diate neighbourhood. It may not be out of place here to call 
 the attention of the observer to the possible presence of the 
 ova of Entozoa in the water under examination. All spherical 
 and ovoid bodies with albuminous-looking and segmented con- 
 tents should be looked upon with suspicion, until their real 
 nature is determined ; accurate measurements of them should 
 be taken, and drawings, if possible, for future recognition. 
 (See Plate XXIII. Figs. 10-14.) 
 
 * A colourless parasite, more like a fungus than a siphonaceous plant, which it is 
 supposed to be, on account of its flagellate zoospores. (Plate IX. Fig. 5.) 
 
SECTION III. 
 
 LIVING FOKMS. 
 
 THE simplest grades of plants and animals, or the Protophyta 
 and Protozoa, possess so many characters in common, that it is 
 by no means easy for the uninitiated to determine the true 
 nature or position of numerous minute organisms which 
 constantly present themselves in the field of the microscope. 
 The most reliable means of distinguishing them is founded 
 upon physiological grounds, and more especially their mode of 
 nutrition. For it is quite admitted that no structural par- 
 ticulars can be named, in the a-bstract, as characterizing the 
 one more than the other. Of course, where the life history of 
 any form has been satisfactorily traced out, the determination 
 must be certain ; as, for example, when a zoospore, furnished 
 with motile organs or flagella, is found not only to have origi- 
 nated from a bona-fide plant, but ultimately to grow into one 
 itself. Of such organisms, either losing the motile organs 
 spoken of at an early stage of their existence, or retaining 
 them as a permanent character, the Flagellata of authors 
 mainly if not altogether consists, forming up to the present 
 time, an order of Infusoria. To the casual observer, the 
 equivocal movements executed by the forms of doubtful position 
 are more striking than their intimate structure, while the 
 other parts of their history are quite out of the question. In- 
 deed, in many cases a claim to belong to the animal kingdom 
 has been raised alone upon the exhibition of animal-like move- 
 ments. The liability to error is therefore all on one side, and 
 
14 MOVEMENT OF PLANTS AND ANIMALS. 
 
 as far as we know, not a single genuine protozoon has yet been 
 classed by the botanist in his domain ; while our greatest diffi- 
 culty at the present time is to eliminate the protophyta from 
 the realm of zoology. It will be scarcely doubted that the 
 numerous species of Difflugia Arcella and Euylypha, for example, 
 are veritable animals ; but the equally numerous naked Amceboe 
 are so wonderfully imitated both in appearance and movement 
 by truly vegetable Amoeboids, that falling into error in relation 
 to them might be very excusable. 
 
 The following kinds of movement may be noticed and com- 
 pared in the two kingdoms : 
 
 Protophyta. Protozoa. 
 
 r Without special organs .... BACILLUS, &c GREGARINA. 
 
 / By pseudopodia . Amoeboids of VOLVOX . AMCEBA. 
 
 J By cilia .... Spores of VAUCHERIA . PARAMECIUM. 
 
 { Byflagella . . . EUGLENA.&C. ... NOCTILUCA. 
 
 The pliant Vibrio and the rigid Diatom exhibit the pheno- 
 menon of spontaneous movement, connected probably with the 
 play of the same, or similar nutritive processes, developing 
 dialytic currents which are on this account quite invisible, 
 while they operate as a moving cause or movable bodies. In 
 this way the diatom moves without change of form, and shall 
 we say that by the same law the extensile plasma of Arnceba 
 and Amoeboid alike is drawn out into Pseudopodia, with the 
 semblance of active and even voluntary motion ? 
 
 Above the lowest grades of plants and animals, or such as 
 are notified in the' above table, no difficulty can arise in assign- 
 ing to every form its true position ; and when the Flagellata, as 
 a whole, are placed with the Protophyta, as in the following 
 arrangement, nearly all the uncertainty and misunderstanding 
 at present existing will be at once removed. 
 
CLASSIFICATION OF THE AQUATIC ALG^J. 15 
 
 A. Living Plants. 
 
 COMPRISING THE MORE USUAL AQUATIC ALGM OCCURRING IN 
 THE EXAMINATION OF DRINKING WATER. 
 
 Though our knowledge of the fresh-water Algae has become 
 greatly extended of late years, we are still only in possession 
 of fragmentary particulars in relation to many of the more 
 humble forms ; and until the whole life history of each has 
 been satisfactorily traced out, it would be quite impossible to 
 group them so as to "be altogether free from objection. The 
 classification here adopted cannot, therefore, purport to be 
 perfect, but it is hoped that it may serve as a guide to the 
 leading characters of the vegetable products usually presented 
 to the observer in the microscopical examination of drinking- 
 water. 
 
 All observation and experience of late years would go to 
 show that the Flagellata, as before intimated, should no longer 
 be classed with the Protozoa, but, even pending the possible 
 elimination of any specia] forms, be at once removed to the 
 ProtopJiyta. 
 
 The fresh-water Algse are so diversified in form and 
 character that it would be much easier to point out the parti- 
 culars in which they differ than to group them in accordance 
 with their natural affinities. On surveying them as a whole, how- 
 ever, some will be seen to preserve the cell form and character 
 more or less distinctly, while others are rod-like, or filamentous, 
 jointed, or tubular. It so happens, perhaps, as a something 
 more than a mere coincidence, that all the families admit of a 
 very similar distribution in these two sections, and may be 
 thus arranged : 
 
16 
 
 CLASSIFICATION OF THE AQUATIC ALG^E. 
 
 OEDEE I. EOD-LIKE OR FILAMENTOUS ALG^E. 
 
 GROUP I. Filaments without articulation, free or embedded in 
 a gelatinous frond ; Spores simple, minute. 
 
 Distinctive Characters. Families. 
 
 (a) Without distinct segmenta-N Microscopically minute,punc- 
 tion of the endochrome; f tiform, elongated, rod-like 
 exhibiting very active f" or filamentous, straight or 
 movements. ) spiral BACTERIACEJE. 
 
 (J) With regular segmentation^ gtrai ^ gom Qr - n bun _ 
 of the endochrome, exhi- ( dle | Q J. mQre ^ legg curved 
 biting spontaneous move- 1 in a gelatinous stratum . . OsciLLATORiACEvE. 
 
 GROUP II. Filaments distinctly articulated ; Spores simple or 
 
 flagellate. 
 
 Distinctive Characters. 
 
 (Simple or forked and con- 
 torted in a gelatinous stra- 
 ^ co ,uu e i ~~. - 
 
 (6) Terete, 
 
 all 
 
 cleav- 
 age 
 trans- 
 
 I dochrome 
 
 f Cells cleaving in the middle 
 Trunks&branches ] without persistent rings . 
 of nearly equal-! Cleavage at the upper or dis- 
 size. tal end of special cells, with 
 
 V persistent rings .... 
 Branches smaller^ BrancH lternatel ^ _ 
 the trunks, l, Branches w } lor i ed , plain or 
 
 than 
 
 ends acumiuate- 
 
 Families. 
 
 NOSTOCHACEJE. 
 ZYGNEMACEJE. 
 
 COXFERVACEJE. 
 
 EDOGONIACEJE. 
 CH^ETOPHOEACETE. 
 
 ly produced. 
 
 moniliform BATRACHOSPERMACE^: 
 
 GROUP III. Filaments tubular, continuous, only sparsely 
 branched ; Spores ciliated. 
 
 SIPHONACE.3E. 
 
 OEDEE II. CELL^EFORM ALG^E. 
 
 GROUP I. Component cells flagellate (equivalent to the Flagellata 
 
 of authors). 
 
 Distinctii'e Characters. Families. 
 
 (a) Integument not distinguishable from the body substance MONADACEJE. 
 
 (&) Integument not only distinct but striated and contractile EUGLENACE^E. 
 
 (c) Integument more or less rigid and non-contractile . . THECAMONADACEJE. 
 
 (rf) Cell sheathed in a bipartite carapace, with an inter- 
 vening ciliated sulcus PERIDINIACEJE. 
 
 (e) Outer envelope urceolate, cells separate or definitely 
 
 aggregated DINOBRYOXACEJE. 
 
 (/) Outer envelope wanting ; cells united by their base . . ANTHOPHYSACE^E, 
 
 (</) Outer envelope gelatinous ; cells separate or definitely 
 
 united VOLVOCACEJE. 
 
CLASSIFICATION OF BACTEEIACE^E. 17 
 
 GROUP II. Component cells non-flagellate, but fissiparous and 
 conjugating. 
 
 Distinctive Characters. Families. 
 
 (a) Cells plain, with a gelatinous investment ; plane of fission 
 
 indefinite PALMELLACE^E. 
 
 (6) Cells or frustules ornamented with rich green endo- 
 
 chrome ; fission definite, margins plain .... DESMIDIACEJE. 
 (c) Frustules silicious, with amber endochroine, fission 
 
 definite, with overlapping margins DIATOMACEJE. 
 
 GROUP III. Component cells non-flagellate, simple or gemmi- 
 parous, with green or colourless contents. 
 
 Cells usually fixed capsular, tubular, straight or curved, and 
 
 discharging zoospores by rupture or dehiscence . APIOCYSTACEJE. 
 
 Definition of the foregoing Families, and the Characters 
 of their -more important Genera. 
 
 OEDEE I. EOD-LIKE OR FILAMENTOUS 
 FAMILY I. Bacteriaceai. (Plates VI. & VII.) 
 
 Under the head of Bacteria, Cohn has included all the very 
 minute spherical, elongated, dumb-bell shaped, chopped-hair and 
 rod-like, straight and spiral filamentous plants endowed with 
 more or less active spontaneous motion, and now found to be 
 associated with putrefactive and other conditions of hygienic 
 importance. The annexed table, applicable to Plate J3J is in 
 accordance with Dr. Colin's classification, which he admits 
 must be only provisional, until something more definite is 
 known of the nature and affinities of these interesting or- 
 ganisms. Though the species are not separately described, it 
 was considered advisable to retain them in the table to facili- 
 tate further reference, should such be found necessary. 
 
 The three first genera viz., Micrococcus, Bacterium, and 
 Bacillus, are sufficiently defined ; but a few remarks on the 
 distinguishing features of the three remaining genera viz., 
 
 c 
 
18 BACTEBIACE^E, TABLE OF COHN. 
 
 Vibrio, Spirillum, and SpirocTioeta, might be added in further 
 elucidation of the table. In the passive state, Vibrio is nearly 
 straight, slightly flexuous, or obscurely spiral, while Spirillum 
 and Spirochccta are perfectly spiral ; but when in motion Vibrio 
 exhibits only a progressive lateral flexure or undulation, while 
 Spirillum, though rigid, in itself progresses by rotation on its 
 long axis, just as a corkscrew enters a cork, and lastly, Spirochceta 
 combines lateral flexure with rotation. 
 
 Clathrocystis ceruginosa is a plant of doubtful position, con- 
 sisting primarily of green cells embedded in a solid gelatinous 
 matrix or frond, but after a while, by rapid development of the 
 cells, the interior becomes hollow ; finally, after the separation 
 of certain bud-like projections, a f enestrated body remains. 
 Cohn has lately placed it with Bacteria, near Clathrocystis roseo- 
 persicina, a plant which forms purplish-red films on decaying 
 algse along the American coast, but which in Europe is also 
 found in fresh water. In Germany, where it is known as the 
 " Wasserbliithe," it has been destructive to fish, but there is no 
 record of its having any injurious effect upon the human system 
 (Farlow). 
 
 Bacteria (Cohn.) (See Plate VI.) 
 
 GENUS AND SPECIES. 
 
 A. SPHJEROBACTERIA .... Micrococcus. 
 
 (Minute jostling Zymogenous. (c) crepusculum (Ehr.) 
 
 spherules). (Ferment producing.) caudidus (Cohii) 
 
 (d) ureoe (Colin) 
 
 The ferment of am- 
 moniacal putres- 
 cence. 
 
 Chromogenous. (a) prodigiosus (Ehr.) 
 (Colour producing.) The blood stain in 
 
 bread. 
 
 luteus (Schroeter) 
 
 ,, aurantiacus (Sch.) 
 
 ,, chlorinus (Sch.) 
 
 cyanus (Sen.) 
 
 3, violaceus (Sch. ) 
 
 Pathogenous. (6) vaccinas (Cohn) 
 (Disease producing.) diphthericus (Dartnel) 
 
 septicus (Klebs) 
 
 bombycis (Be'champ) 
 
RELATIONSHIPS OF BACTERIACE^E. 
 
 19 
 
 JB. MlCROBACTERIA 
 
 Chromogenous. 
 
 GENUS AND SPECIES. 
 
 Bacterium, 
 (f, g, ft, k) termo (Ehr.) 
 
 Producing putrefac- 
 tive fermentation. 
 (i,l) lineola (Ehr.) 
 
 In brooks, &c. 
 xanthium 
 syncyanum 
 seruginosum 
 
 C. DESMOBACTERIA . . 
 (Straight, flexible 
 or rapidly un- 
 dulating fila- 
 ments.) 
 
 Bacillus, 
 (n) subtilis (Ehr.) 
 
 Producing butyric fer- 
 
 mentation. 
 (m) ulna (Cohn) 
 
 Similar to the former, 
 anthracis (Cohn) 
 In the blood, in ma- 
 lignant pustule. 
 
 D. SPIROBACTERIA . . 
 
 (Spiral filaments, 
 
 rigid or flexible.) 
 
 Movement lateral, undulatory 
 
 Vibrio. 
 
 (o) rugula (Ehr. ) 
 (p) serpens (Ehr.) 
 
 rotatory, spiral . . . Spirillum. 
 (g) tenue (Ehr.) 
 (r) undula (Cohn) 
 (*) volutans(Ehr.) 
 
 both lateral and rotatory Spirochata. 
 
 (t) plicatilis (Ehr.) 
 
 While there is little doubt of the intimate relationship 
 existing between the larger forms of the preceding table and 
 the Oscillatorians, Bacterium termo and its immediate allies are 
 involved in much obscurity as to their real nature, and bo- 
 tanical affinities, seeing that their supposed position in the 
 animal kingdom is now no longer tenable. The slightly 
 dumb-bell shape of the true putrefactive (Bacterium) manifests 
 a very significant correspondence with the form represented in 
 Plate XXIV., developed in the sediment of well water, and 
 with many others, such as that shown in Plate VII., occurring 
 amongst decomposing Algae. 
 
 All analogy would go to indicate that the Zooglcea form of 
 Bacterium termo may be regarded as the primary or normal 
 state of this organism, the surrounding gelatinous matter 
 being simply the representative of that which forms the in- 
 definite frond of MicroTialoa or Pcdmdla for example. 
 
20 BACTEBJACE^E OSCILLATORIACE^E. 
 
 Further, when the matrix breaks down, and the separate 
 little Bacteria detach themselves from it, they often commence 
 those active movements which are in some intimate way con- 
 nected with their nutrition. Even many Diatomacece which 
 are normally fixed to, or included in, a gelatinous frond, are 
 motionless until they have become free from it, when the 
 'movements they exhibit are known to bear a certain relation 
 to the shape of the frustule, being rectilinear, when the latter 
 is narrow, as in Na/owula, but more irregular when it is of a 
 different form. The subsequent history of Bacteria has been 
 variously represented by authors. The carbon of the higher 
 aquatic plant is derived from the carbonic acid present in the 
 water, or liberated by the decomposition of carbonates, while 
 that of the molecular and more filamentous Alg?e (MicrococcuSr 
 Bacterium, &c.), is usually derived from the vegetable acids that 
 may be in combination with a base, as for example, the I of 
 Tartrate of Ammonia. 
 
 Dr. Cohn's researches go to show, that not only will Bacteria 
 nourish in solutions of the salt just mentioned, or in the 
 absence of organic matter, but that even in this case the 
 genuine putrefactive odour is evolved. Indeed, it may be said 
 that the putrefaction of animal and vegetable matter cannot 
 take place without Bacteria, while simple decay is more es- 
 pecially associated with fungous life. 
 
 FAMILY II. Oscillatoriacece. (Plate VIII.) 
 
 These very simple plants consist of cylindrical or tapering 
 filaments, with or without a gelatinous investment, and having 
 faint or rich bluish-green, or purple-coloured contents, or en- 
 dochrome, in which, as the filaments elongate, a transverse 
 segmentation takes place, giving rise to the deceptive appear- 
 ance of true articulation or cells in linear series. The filaments 
 
CLASSIFICATION OF OSCILLATOBIACE^E. 21 
 
 may be quite free, or disposed in bundles or strata. In the 
 free state, their peculiar animal-like movements render them 
 objects of interest to the microscopist. Branching, in the true 
 sense of the term, is quite foreign to these plants, which, like 
 the Bacteria, multiply by transverse fission ; but their sexual 
 reproduction has been only imperfectly made out. They are 
 divided into several sub-families, which are easily distinguished 
 in the manner shown in the following table, with illustrative 
 genera : 
 
 Classification of the Oscillatoriacece. 
 
 Distinguishing Characters. Sub-families. Genus. 
 
 Like Oscillatoria, \ 
 
 but in tufts or \.Lyngbye.(z (3.) LYNGBYA. 
 
 strata. . . ,j 
 ^ i Motion- J l Invested 
 
 less . ] Having a proper \ singly . (4.) SCYTOXEMA. 
 
 gelatinous in- s. Scytonemece 
 
 vestment . .) I Invested in 
 
 V bundles . (2.) MICROCOLEUS. 
 
 Tapering, with a large basal cell Mvulariece (5.) KIVULARIA. 
 
 It is highly probable that many of the supposed members 
 of the Oscillatoriacece are truly referable to the succeeding 
 family (Nostocliacew) . 
 
 On carefully inspecting a fair specimen of water rich in 
 Algae of different kinds, it will usually be easy to trace examples 
 of Oscillatorians ranging from the proportions of ordinary 
 Confervas to the diameter of Bacteria. The same phenomena 
 of spontaneous movement and endochrome cleavage may be 
 observed when the filaments are free in the field, whether 
 normally so or liberated from their gelatinous investment. 
 Moreover, any differences distinguishable in the smaller, as 
 compared with the larger forms, can only be said to be of a 
 relative kind, and apparently in no way centra-indicate a 
 prevailing unity of type. Frequently also the smaller moving 
 points or molecules observable in the field, instead of being 
 
22 RELATIONSHIPS OF OSCILLATOR! ACE^E. 
 
 V 
 
 referable to the genus Micrococcus, are but segments of the 
 more minute filamentary species or varieties, as the case may 
 be ; for, even if their cylindrical form is not demonstrable 
 to the eye, their peculiar refractive, properties will enable us 
 to link them with the less equivocal fragments always .to be 
 found in the same vicinity. 
 
 In the punctiform, fragmentary, on filamentous plants of 
 smaller size than the admitted Oscillatorians, it would be 
 impossible to distinguish a primordial utricle and a cellulose 
 coat, and of course, also difficult to determine the precise 
 nature of the segmentation should such really take place. In 
 the Oscillatorice, however, the endochrome alone is supposed to 
 suffer cleavage, while the primordial utricle and the cellulose 
 tube take no part in the process, being only capable of simple 
 growth and extension. In the Confervacem and the other 
 filamentous Algse, on the contrary, both the primordial utricle 
 and the endochrome are engaged in the segmentation of the 
 filament within the cellulose coat, to which, nevertheless, the 
 transverse septa and new internal layers are added. 
 
 In a very interesting paper published in the Quarterly 
 Journal of Microscopical Science, vol i. 1861, Dr. B. Hicks, 
 F.K.S., describes a lateral expansion by cleavage in Lynglya 
 muralis, thus showing it to be dimorphous, and allusion is 
 made to the extremely small size of its gonidia. The plant 
 in question, though confounded by some with the genuine 
 Conferva, is now generally admitted to be an ally of the 
 Oscillatorians, and as such at least one of its modes of develop- 
 ment or transitional phases presents a suggestive bearing upon 
 all the members of this family, and thereby, it may be fairly 
 presumed, upon Bacteria in general. 
 
 We thus perceive how slender are the grounds upon which 
 we can assume almost any palmellaceous plant, for example, to 
 be a distinct entity, and in this remark may be included some 
 
. OSCILLATORIACE^E NOSTOCHACE^E. 23 
 
 forms reputedly belonging to the Ulvacece. Let us suppose 
 for a moment the minute Spirilla and even Bacterium termo 
 itself to be in the category of the filamentous Algae, then how 
 small must be their reproductive gonidia. From actual obser- 
 vation, the writer must say that the moving particles in 
 which the Spirillum common in bilge -water originates, how- 
 ever small they may have been in the first instance, are not 
 only very minute, but quite shapeless. In the light of this 
 fact, we may again submit the question, if the corresponding 
 particles are visibly so small in relation to the diameter of 
 Lynglya muralis, how small must be their original state in the 
 case of Bacterium termo. They might readily escape the 
 keenest scrutiny of the advocates of equivocal generation. 
 
 The Oscillatoriacece are ubiquitous as a family, though many 
 of them are very definitely distributed ; thus the Rivularice 
 appear to be confined to northern regions; they are often 
 found on the stumps of aquatic plants, on rocks in rapid 
 streams, and sometimes where they arc exposed to the force of 
 cataracts. They frequently also indicate calcareous water, and 
 crystals of carbonate of lime may be deposited in their sub- 
 stance. A pretty little species presents the appearance of 
 minute green stars upon the surface of lakes. In India 
 Oscillatorians ascend to 17,000-18,000 feet above the level of 
 the sea. 
 
 FAMILY III. Nostochacece. (Plate VIII.) 
 
 Plants consisting of microscopic moniliform filaments of 
 cells in series, usually coiled, curved, or entangled in a gela- 
 tinous matrix constituting the frond, which may be rounded, 
 f oliaceous, linear, or formless. They are found in damp places, 
 or in water, floating on the top, or at the bottom attached to 
 stones in rivulets and streams, or in brackish ditches. The 
 
24 FABLOW ON THE NOSTOCHACEJE, ETC. 
 
 characters of the frond afford the readiest means of distinguish- 
 ing the three more important genera, thus 
 
 Frond elongated, curved, linear or spiral ; filaments single . MONORMIA. 
 expanded, globular or irregular ; numerous NOSTOC. 
 formless, often a floating film ; THICHORMUS. 
 
 Besides simple multiplication by fission (which is some- 
 times longitudinal as well as transverse, reminding one of 
 Lynglya in this respect), the Nostochaceos afford indications of 
 the existence of a true reproductive system, in the presence of 
 certain vesicular cells (supposed to be spermatic ?) amongst the 
 ordinary ones ; which latter are, moreover, here and there 
 further developed into sporangial cells, producing true spores 
 from which new filaments arise. This process appears to 
 have been distinctly observed by Thuret in Nostoc verrucosum. 
 
 In reference, more particularly, to the Oscillatoriacece and 
 Nostochacece, Dr. Farlow, Assistant Professor of Botany in the 
 Harvard University, has published some very interesting 
 remarks in the Bulletin of the Bussey Institution, Jan. 1877. 
 Having failed to obtain any precise information as to the 
 cause of a cucumber taste often noticed in the Boston water 
 supply at the fall of the year, he speaks of odours as affording 
 more definite indications. Of these, three kinds are especially 
 mentioned viz., 1. " An indescribably suffocating odour, as in 
 the case of several Lynglym and Oscillatorice. 2. " A sulphurous 
 odour" given off by species of Beggiatoa. 3. " A still more 
 disagreeable odour," resembling that of a "pig-pen or very 
 strong horse- dung," arising from species of Nostoc in a decaying 
 state. " The chemical nature of the stifling odour is not 
 known," nor is it peculiar to nostocs or even to fresh-water 
 plants. " It is marked in several marine plants, as PolysipJionia 
 fastigiata, which forms blackish tufts on the larger rock weed." 
 
 " The Algse which exhale sulphurous odours belong to the 
 genus Beggiatoa, which resembles Oscillatorice, in consisting of 
 
FARLOW ON PLECTONEMA, ETC. 25 
 
 filaments endowed with motion, but which differ in colour, 
 being whitish, the cells being full of opaque granules. They 
 look to the naked eye like white films covering decaying Algae 
 and other plants. They are found on the sea-shore, as well as 
 in fresh water, but are particularly common in hot springs. 
 Cohn has shown that the peculiar exhalations of hot sulphur 
 springs are owing to the growth of species of Beggiatoa, which 
 depend for their existence upon, at least, two conditions ; the 
 presence of a large amount of sulphur in the water, and the 
 absence of iron. Cohn confirms the observation of Cramer, 
 that the dark granules in the species of Beggiatoa consist of 
 sulphur. When Beggiatoa filaments are heated, the granules 
 fuse into large yellowish drops, and a sulphurous odour is 
 developed. If the filaments are treated with sulphide of 
 carbon, the granules are dissolved, and then the cell partitions 
 become, for the first time, visible." Dr. Farlow goes on to 
 describe a new species of Plectonema (of the Order Nostocliinece). 
 The Plectonema Wollei (Farlow) " is a summer plant, and does 
 not attain considerable dimensions before July. It starts on 
 the stems, leaves and old sticks on the bottom, and forms coils 
 several feet in length. On reaching the surface it expands 
 over considerable areas. In the latter part of September it 
 breaks away from its attachments, drifts ashore, and disappears, 
 to return next summer." 
 
 Masses of slimy matter with decaying cell-chains, of some 
 species of Nostocliacious plant, supposed to belong to the genus 
 Anabccna, were found on the margin of the water, or entangled 
 in the meshes of the above-mentioned Plectonema ; and it was 
 noteworthy that while the decaying Anabcena gave out the 
 odour of rotting horse-dung, the living Plectonema, free from 
 the slirne, emitted the suffocating smell of many of the Oscilla- 
 torians, but not the pig-pen odour. This latter odour, however, 
 was developed in decaying Plectonema, proved to be free from 
 
26 CLASSIFICATION OF ZYGNEMACECE. 
 
 Analcena by microscopical observation. Details of this descrip- 
 tion are just what we want, to afford us reliable data for hygienic 
 deduction and consequent good counsel. 
 
 FAMILY IV. Zygnemacecc. (Plate IX.) 
 
 Plants consisting of cylindrical articulated filaments with 
 green contents, usually disposed in elegant patterns. Eepro- 
 duction is effected by the phenomenon of conjugation, the 
 whole contents of each pair of united cells being converted 
 into a spore. The particulars of the manner in which this 
 process takes place will be seen in the definitions of the 
 following genera : 
 
 Classification of the Zygnemacece. 
 
 DUtinyuisli'uiy Characters. Genera. 
 
 I Endochrome spiral . (1.) SPIROGYRA. 
 
 (By transverse 
 tubes between 
 the neighbour-- 
 ing cells of 
 different fila- 
 ments 
 
 Wtbep^tW 
 
 cells. 
 
 or stellate M2.) ZYGXEMA. 
 
 ( masses . . . .J 
 / Endochrome in two \ 
 
 Spores formed in I "^ r Dilate Us.) ZY 
 the connecting; \ c , .. * , *-, ',.' \ 
 
 ZYOOGONIUM. 
 
 1 Spores rounded, en- 
 ^ dochrome diffused . 
 Spores square or") 
 
 ~.o- V (5.1 
 
 cruciate, endo-;>(5.) STAUROCARPUS. 
 
 5 
 
 chrome diffused . J 
 
 I kJJJV^J-CO AWA1J.1CVA 1X1 
 I 4.1 !. 
 
 between 
 
 By an arcuate ( Spores formed in 
 tnh hpf.wm, one of the parent. 
 
 j cells. 
 
 I Hlt3 
 
 V tube. 
 
 Endochrome 
 fused 
 
 rome dif -| (7 .) PLEUBOCABPUB. 
 
 The Zygnemacece are found in rivers and running waters. In India, amongst the 
 Himalayas, they reach a height of 15,000 feet. 
 
 FAMILY Y. Confervacece. (Plate X.) 
 
 Plants composed of cylindrical cells forming articulated 
 filaments, simple or branched, with a very delicate gelatinous 
 coat. The cell contents are usually green, rarely brown or 
 
CONFER VACE^E CEDOGONIACE^E. 27 
 
 purple, often assuming peculiar patterns, and ultimately con- 
 verted into zoospores, with two or four flagella, from which 
 the filamentous fronds are reproduced. 
 
 From a fresh-water point of view, only three genera appear 
 to be of importance viz., Cladopliora, Ehizodonium, and 
 Conferva ; and even these may all be yet included in the 
 succeeding family. 
 
 All the species with branching filaments may be referred 
 to the genus Cladopliora ; for though many species of Ehizo- 
 donium have root-like branches, it so happens that those found 
 in fresh water have simple filaments, which are best distin- 
 guished by their decumbent habit from the simple filaments of 
 Conferva. 
 
 Cladoplwra glomerata occurs in dark green wavy skeins in 
 pure running water, and C. crispata (b) in yellowish or dull 
 green strata, commonly in fresh though frequently also in 
 brackish water. 
 
 Renzodonium rividare is found in fine, bright, green bundles, 
 23 feet long, in streams and rivers, while E. implexum occurs 
 on mountain rocks. 
 
 Conferva bombycina, in which the cells are four or five 
 times as long as they are broad, is met with as a yellowish 
 green cloudy stratum in stagnant water, while C. floccosa (a) 
 with cells once or twice longer than broad, with circumcissile 
 dehiscence, is to be found everywhere in pools and still waters. 
 
 The Confervacece and Zygnemacecv flourish in similar situa- 
 tions, as a rule, but the habitat of the Confervacece is more 
 varied. 
 
 FAMILY VI. (Edogoniaceoc. (Plate X.) 
 
 Articulated filamentous plants, simple or branched, exhibit- 
 ing much variety in their means of reproduction. Thus the 
 whole contents of a cell produce zoospores with a rich growth 
 
28 CILETOPHOBACEJE. 
 
 of cilia, and sporangial cells develop large resting spores ; while 
 antheridial structures are present either on the ordinary fila- 
 ments, or on dwarf parasitic plants. The filaments grow by a 
 rather peculiar process, commencing with circumcissile division 
 of the cellulose coat of the interstitial cells, which thus permits 
 of the growth or extensions of the primordial utricle, or under- 
 coat, and the formation of a new septum. A cementing band 
 of cellulose repairs the gap between the divided borders of the 
 parent cell, leaving an annular impression to record the fact, 
 and the repetition of the process produces a repetition of the 
 rings, which always characterize even fragments of these 
 plants. 
 
 The two genera are easily distinguished, the filaments of 
 (Edogonium (c) being simple, and those of Bulbocliwte (d) 
 branched, and bearing bristle-cells with a bulbous base. 
 
 The -species of (Edogonium abound in fresh water under 
 almost all conditions, in lakes, ponds, pools, ditches, streams, 
 and in tanks and cisterns. Bulbochcete sctigcra (d), -apparently 
 the only reliable species of the genus, grows luxuriantly upon 
 other fresh- water plants. 
 
 FAMILY VII. Chcetophoracece. (Plate X.) 
 
 These are very beautiful, branched and articulated plants 
 enveloped in gelatinous matter, and made up of cells in single 
 series. Some are free, with a straight central axis ; while 
 others are fixed with depressed radiating branches, or forming 
 a discoidal frond. The tapering extremities of the branches, 
 in some instances, are quite bristle-like, affording one of the 
 distinctive characters of the family. Bristles of an inarticulate 
 kind, however, arise from the articulations in certain genera. 
 Finally, spores and four-ciliated zoospores are formed from the 
 contents of the cells. 
 
BATRACHOSPEKMUM LEMANIA. 29 
 
 Draparnaldia presents a central axis of large colourless cells, 
 with tufts of smaller branches at the articulations. In Chceto- 
 pliora (c) the filaments are branched and setigerous, indefinitely 
 embedded in gelatinous matter. In Coleochcete the frond is dis- 
 coidal and adherent, composed of radiating dichotomously 
 branched filaments, and the bristles springing from the back of 
 the joints are sheathed at the base. 
 
 FAMILY VIII. Batrachospermacece. 
 
 These plants are evidently very closely allied to the Chceto- 
 pheracece, and the name is derived from the resemblance which 
 their beaded filaments bear to frog's spawn. The central 
 axis consists of a single series of cells, with an investment 
 of expressed filaments descending from joints or nodes, occur- 
 ring at stated intervals, and also giving rise to dense whorls of 
 exceedingly delicate moniliform branches. Some of these latter 
 produce spores at their extremities, whilst others form trans- 
 parent capillary points. The spores are agglomerated at the 
 nodes. 
 
 In BatracJiospermum, the ramuli are moniliform, while in 
 Tfwrea they are cylindrical. These plants are exclusively 
 aquatic, but chiefly found in pure and gently running water, 
 like the ChcetopJwracece. 
 
 The Lemaniacece are usually noticed near the Batrcwhosperms 
 in systematic works, though differing much both intrinsically 
 and in external appearance. They are olive-coloured, tubular 
 and branched filamentous plants, distinguished from the 
 fiiphonaccce, presently to be described, in the compound cellular 
 structure of the tube wall, instead of being simple, and the 
 sprouting of tufted whorls of spores in moniliform series from 
 its inner surface. The genus Lemania is represented by two 
 British species, L. torulosa and L. fluviatilis, and from their 
 natural habit their presence would indicate running water. 
 
30 VAUCHERIA AND ACHLYA. 
 
 FAMILY IX. Siphonacece. (Plate IX.) 
 
 The tubular, simple, or branched frond of the Sipkonacece 
 are composed of a continuous extension of cellulose lined with 
 green endochrome granules, and the reproductive elements are 
 formed within special outgrowths of the tubular membrane. 
 
 Excluding such members of the family as are purely marine, 
 only two fresh- water genera are worthy of notice here viz., 
 Vaucheria and Achlya (Saprolegnid, Klitzing). 
 
 Vaucluria (1 to 4). Most of the species of this genus are 
 inhabitants of fresh water, though they are also to be found in 
 moist, or even in merely damp, localities, as in the clay of 
 flower-pots intermixed with moss. They are frequently to be 
 seen on the borders of roadside streamlets, with their branched 
 tubular filaments almost felted together in fine, silky green 
 tufts. The little granules of chlorophyle in the interior of the 
 filaments are for the most part applied to the walls, embedded 
 in a colourless protoplasm. Zoospores are formed in the club- 
 shaped ends of the filaments. linger observed that these 
 bodies usually made their escape about eight o'clock A.M., at 
 which time the process may be observed in healthy plants, 
 cultivated in fresh water. A true sexual mode of repro- 
 duction also exists in VaucJieria, and the spores are richly 
 ciliated. Of the numerous species of this genus that have 
 been described, it would appear that only two or three are 
 reliable. 
 
 Achlyaprolifera, is a small colourless plant, consisting of clavate 
 erect tubular filaments springing from a mycelium-like minutely 
 ramified base, closely applied to the bodies of dead flies in 
 water, fish and frogs, upon which they grow parasitically. It 
 was originally supposed to be the common fly fungus, or an 
 aquatic form of Botrytis Bassiana, but more recent researches, 
 rewarded by the discovery of ciliated zoospores, and a perfect 
 
CHARACE^E AND ULVACE^E. 31 
 
 sexual system like that of Vauchcria, have given the plant 
 what would appear to be an uncertain position. Apropos of the 
 want of colour in this parasitic form, it will be noticed that 
 Chytridium and Pytliium, which are parasitic members of the 
 Apiocystaeeee, are also without colour. 
 
 The Siplionacece (Vaucheria, for example) are often found in 
 large tufts on mud, whether impregnated with salt or fresh 
 water. Codium ampliibiorum in particular flourishes on turf 
 banks at high water, while other members of the family are 
 altogether marine. 
 
 Though the Ckaracece are not generally admitted to belong 
 to the Algse properly so called, as they are likely to be met 
 with in samples of water, it may be well to give a short 
 account of the family here. In these interesting plants, while 
 the vegetative apparatus is of a very simple type, the genera- 
 tive system is more highly developed than in any of the pre- 
 ceding forms. The plants consist of a number of large tube- 
 like cells, forming a central axis, and whorls of similar, but 
 smaller, cells at the nodal points. So far, this description will 
 answer the genus Nitella, which- may attain a length of several 
 inches ; but in CJiara an additional envelope is furnished to 
 the central stem by closely applied tubular cells passing from 
 the nodes in both directions, and meeting at the middle of the 
 internodes. 
 
 The antheridia and germ cells are here respectively named 
 globules and nucules. Eight triangular valves radially fluted, 
 and numerous conf ervoid filaments with antherozoids in the 
 cells, make up the globule ; while fine spirally-twisted tubes 
 form the investment of the nucule. So short a notice of those 
 organs is only given to facilitate their recognition when 
 detached. 
 
 The Ulvacece are plants composed of a single or double 
 layer of polyhedral cells, multiplying by fission, disposed in 
 
32 CELI^EFOBM ALGJD, MONADACE^E. 
 
 tabular or tubular frondose extensions, chiefly marine, but in 
 some few instances occurring in brackish or fresh water. 
 
 The long tubular fronds of Hjnteromorpfia intestinalis are 
 sometimes found in fresh-water ditches, but more usually ill 
 brackish or salt water. 
 
 OEDEK II. CELUEFOKM ALG^E. 
 
 GEOUP I. Flagellate Forms, or Flagellata. 
 
 FAMILY I. Monadacece. (Plate XL) 
 
 Distinguishing Characters. Genera. 
 
 {General form, and beak rounded . (1.) MOXAS. 
 
 Beak turned to one side . . . (2.) PLEUROMOXAS. 
 . 
 
 Beak abruptly truncated . . . . (3.) CYATHOMOXAS. 
 
 . Beak produced flagellum at its base (4.) CHILOMOXAS. 
 
 pi I 
 
 ' Mobile at the extremity (5.) CYCLIDIUM. 
 
 With cilia also (Parasitic) (6.) TRICHOMOXAS, 
 
 Similar, at the curved angles (7.) TREPOMOXAS. 
 
 One on each side in front (8.) AMPHIMOXAS. 
 
 One posterior (9.) CERCOMOXAS. 
 
 One trailing (10.) HETERAMITA 
 
 
 
 t With six filaments, four in front and two behind . . (11.) HEXAMITA. 
 
 Habitat , &c. The Monads, so called, are especially found 
 in decaying organic infusions animal and A vegetable, in or 
 beneath the pellicle or scum, usually forming on the surface 
 under such conditions. Trepomonas, Amphimonas and Hexa- 
 mita are to be seen in marsh-water undergoing change. 
 Oercomonas intestinalis has been detected in the dejections of 
 typhoid and cholera, and TricJiomonas vaginalis in vaginal 
 mucus. T. limacis is found in the intestine of Limax agrestis, a 
 common slug. 
 
/ 
 
 CLASSIFICATION OF EUGLENACEJE. 33 
 
 FAMILY II. Euglenacece. (Plate XI.) 
 
 Distinguishing Characters. Genera. 
 
 ' Attached (1.) COLACIUM. 
 
 ^ No visible flagellum, two eye spots (2.) DISTIGMA.. 
 
 C with a tail . . . (3.) EUGLEXA. 
 With an eye . .< 
 One fla^el ' (without a tail . . (4. ) AMBLYOPHIS. 
 
 a ' ' j No eye spot, fla- f ri S id at the base < 5 ') TERAXEMA. 
 
 gellum . .. -(mobile to the base (G.) ASTASIA. 
 Two fl a _ ("An eye spot, green or red .... (7.) CHLOROGOXIUM. 
 
 ge a . 
 
 colourless ..... (8.) ZYGOSELMIS. 
 
 ^Several flagella (9.) POLYSELMIS. 
 
 Habitat, &c. The members of this family are often seen in 
 immense numbers, at the surface of pools and ponds, imparting 
 a, rich green colour to the water. Like many if not all the 
 Monadacece, they are only developmental phases of forms 
 distinguished by other names. Colacium is a parasitic genus 
 and of an exceptionally bright green colour. It is not quite 
 clear whether the little currents produced by it are due to the 
 action of vibratile cilia or a flagellum. Colacium vesiculosum 
 and C. stentorium are found on Entomostraca and Rotifera. 
 Of the true nature of Distigma but little is known ; green, 
 yellow and colourless species have been described, all aquatic. 
 Their movements are more leech-like than those of Euglena, 
 but there are just as few grounds for referring them to the 
 animal kingdom. Euglena mridis moves from place to place 
 by the contractile power of its integument, as well as by the 
 flagellum, which is sometimes absent. 
 
 AinblyopJiis is rather like Euglena, but its posterior extremity 
 is rounded, while that of Euglena is acuminate. Peranema 
 much resembles Astasia, but the flagellum is stout and only 
 mobile at the tip in the former, while it is mobile throughout 
 in the latter. Cldorogonium encJilorum is either solitary or 
 united in radiating groups like little fishes united by their 
 
 D 
 
34 THECAMONADACEJE HABITAT, ETC. 
 
 tails, a resemblance which is much heightened by the position 
 of the eye spot. 
 
 It is common, like Glenodinium, of which it is a further 
 stage of development in standing pools and shallow waters ; 
 and when we are told that it is itself but one phase of Proto- 
 coccus, whose zoospores constitute the so-called genus Chlamido- 
 monas ( the green matter of Priestly), and that other genera 
 rightly or otherwise are referable to the same source, whatever 
 that may be, we see how artificial and uncertain all attempts 
 at a natural classification of these forms must be in the 
 present state of our knowledge. For hygienic purposes, 
 however, the recognition of each in the abstract will suffice 
 with the knowledge of its habitat to enable us to form a 
 judgment of the medium in which it lives, or more practically 
 the properties of the water in which it is detected. Zygoselmis 
 is at once distinguished from Polyselmis by the absence of colour 
 and having only two flagella in continual movement. Poly- 
 selmis is supposed to be merely the zoospore of an Algse. 
 
 FAMILY III. Thecamonadacece. (Plate XI) 
 
 Distinguishing Characters. Genera. 
 
 f Form, globu- ( Hard encasing . (1.) TRACHELOMONAS. 
 I lar, integu-< 
 
 "W't.h fl I merit - (Membranous . (2.) CRYPTOMONAS. 
 
 Integument 
 
 distinct, hard 
 
 or fibrous. 
 
 gellum. j Form?depres _ /- With a tail _ 
 
 I 
 
 sed folia- 
 
 (3.) PHACUS. 
 
 ceous. (. Without a tail . (4.) CRUMEXULA. 
 
 With two flagella,. one trailing (5.) ANISOXEMA. 
 
 Habitat, &c. The integument of Trachdomonas is hard and 
 even brittle ; indeed the genus should probably be rather 
 classed with Clicetoglena and Chwtotyphla than with Phacus, &c. 
 By transmitted light in T. volvocina a red ring is seen to sur- 
 round the cell contents. Phacus and Crumenula differ from 
 Euglena and Aniblyopliis, in having a rigid integument, and it 
 may be mentioned to aid the memory that Phacus and Euglena 
 
PEPJDINIACE^E HABITAT, ETC. 35 
 
 represent one another by having a tail-like process, while the 
 posterior end is rounded off in both Crumenula and Am- 
 Uyophis. 
 
 In Cryptomonas the integument is flexible, but the species are 
 ill defined. Anisonema is colourless like the monad Heteromita, 
 from which it would only appear to differ in the consistency of 
 the external covering. Through a small aperture in this coat 
 the flagella of A. sulcata are transmitted. The trailing fila- 
 ment would seem to act as a steer-oar, but it also serves to 
 retract the body under ' an impulse which it is difficult to 
 comprehend. 
 
 The remaining genera, Disclmis, Plceotia and Oxyrrliis, are 
 marine. 
 
 FAMILY IV. Peiidiniacece* (Plate XII.) 
 
 Distinguishing Characters. Genera. 
 
 {Undivided se _ (With an eye spot . (1.) CHJETOGLEXA. 
 
 " tNo eye spot. . . (2.) CH^OT.PHLA. 
 
 Witb a ciliated P - eye. spot (3.) G L EXO_. 
 
 \3To eye spot . . . (4.) PERIDINIUM. 
 
 Habitat, &c. Chcetoglena and GJicetotypJda are supposed to be 
 the spores of Algcc, and as the absorption band of chlorophyll 
 in the case of Peridinium fuscum has been satisfactorily 
 demonstrated by Mr. Angel, of Southampton, there may be still 
 less scruple in referring the genus to the domain of the botanist. 
 
 * For the practical purpose of this work the above classification has been retained, 
 though the following is a more modern arrangement, after M. de Fromentel : 
 
 { With horn-like | rFRATTr]v , 
 / Two halves of the I processes . . J l - /i ' KATI1 - M. 
 carapace nearly -( 
 
 equal. j Without horn-like > PFRTHXITT ,, 
 
 1 processes . . j *>ra- 
 
 With a stout cara- 
 pace divided in- 
 to two parts / 
 
 * 8 
 
 with interposed \ .-^ 
 cilia. 
 
 Two halves of the 
 carapace very- 
 unequal. 
 
 Borclers project- ) DIXOPHYSIS< 
 
 Borders not 
 
 jectiug . . , 
 
 ^Ciliated at the anterior borler PROBOCENTRUM, 
 
 3Iarine forms are of course also included hero. 
 
 D 2 
 
3 6 DINOBHYACE^E ANTHOPH YS ACE^E. 
 
 P. cinctum is an aquatic form, but said never to be present in 
 decomposing water, from which circumstance one would say 
 that its occurrence would not augur badly. 
 
 FAMILY V. Dinobryacew. (Plate XII.) 
 
 "With urceolate 
 outer envelope." 
 
 Cells in com- I 
 inunities. 1 
 
 In close series simple, or 
 sparsely branched . . . 
 
 On distinct foot-stalks . . 
 
 (2.) DlXOBRYON. 
 
 (3.) STYLOBIUOX. 
 
 I Grouped together at the 
 
 V summit of a single stem . (4. ) PTCNOBEYON. 
 
 Habitat, &c. Epipyxis always wants the eye spot and often 
 the flagellum, while both eye spot and flagellum are persistent 
 in Dinobryon. To these two genera M. de Fromentel has 
 added two others viz., Stylobryon and Pycnobryon, but nothing- 
 is mentioned as to their habitat. The better-known genera 
 are aquatic, and generally to be found with other algae in a 
 living state. 
 
 FAMILY VI. Anflwpliysacem. (Plate XII.) 
 
 / In spherical /Fixed at the extremities of a 
 
 In communities clusters, J branched axis .... (1.) AXTHOPHYSA. 
 without a I united j 
 
 common ^ inferiorly. \ Swimming freely .... (2.) UYELLA. 
 envelope. 
 
 V United by their sides (3.) TETRABJEXA. 
 
 Habited, &<;. M. de Fromentel includes this and the former 
 family in his Volwcina, which it is perfectly allowable to sub- 
 divide even for the convenience of description. The branched 
 tubular axis of AntJwpJiysa is often found with other vegetable 
 debris in pond, bog, and marsh water, and the detached flagel- 
 late bodies resemble the genus Uvclla very closely both in 
 appearance and movement. Uvclla m-a especially is a 
 suspicious species. 
 
VOLVOCACEJE HABITAT, ETC. 37 
 
 FAMILY VII. Volvocacece. (Plate XII.) 
 
 I In square tatelets . (1. ) GOXIUM. 
 
 (In spherical exten- 
 
 (2.) VOLVOX. 
 At the centre of this 
 
 gelatinous mass . (3. ) PANDORIXA. 
 
 & v,., t *^,.i a - Disseminated in the mass . . . (4.) ALLODORIXA. 
 
 envelope. 
 
 v Envelope double (5.) DIPLODORINA. 
 
 Transitional form PROTOCOCCUS (6). 
 
 Habitat, &c. The Volvocacece occur in ponds and sheets of 
 clear water on commons and in bog-pools. Uroglena syncrypta, 
 Sphcerosira, and Synura, are very doubtful genera. In Pando- 
 rina the flagellate bodies are united by their base and centrally 
 disposed in the mass ; while in Volvox they are placed peri- 
 pherally. In Allodorina these bodies are independently 
 distributed in the connecting substance, without any special 
 organic union. Gfonium perforate, which is not uncommon in 
 fresh-water pools, is also found in salt water, in both cases near 
 the surface. G. glaucum is more particularly a salt-water 
 species. 
 
 The life history of the genus Protococcus, so far as it has 
 been traced out by Cohn and others, though presenting a 
 variety of conditions and stages, shows a close relationship to 
 the cells of the Volvocacecc. In one of its developmental 
 phases a motile cell encysted after a fashion, breaks up into 
 four by cleavage, but frequently these remain united by their 
 beaked extremity, the segmentation remaining incomplete. 
 This is, however, quite the reverse of what normally takes 
 place in the case of Volvox. The Volvox sphere results from 
 the segmentation of a single mass of endochrome, the ultimate 
 subdivisions of which assume the flagellate motile character, 
 and become organically united by the mutual blending of little 
 stolon-like processes, piercing the hyaline investments, which 
 are hexagonal by contact with each other, and lateral com- 
 
38 NON-FLAGELLATE FORMS PALMELLACE^E. 
 
 pression. A similar union also takes place in the cells of 
 Gonium, and in those of Pandorina, which occupy the centre 
 of the gelatinous frond. Thus while the connection of the 
 four motile cells of Protococcus arises from incomplete cleavage, 
 the communication existing between the cells of Vohox and 
 Gonium is sequential to complete cleavage. 
 
 The union of primarily distinct elements to constitute what 
 must be called the perfect organism is further seen in a 
 representative way in the Pediastrccs, which are generally 
 admitted to be a sub-family of Desmidiacece, and in the 
 remarkable genus Hydrodictyon, supposed to be siphonaceous. 
 
 GEOUP II. CELLS NON-FLAGELLATE, BUT FISSIPAEOUS 
 AND CONJUGATING. 
 
 FAMILY I. Palmdlaceoe. (Plate XIII.) 
 Green cells (though sometimes red), spherical or ovate, in a 
 more or less consistent or definitely formed gelatinous frond ; 
 the cell multiplying by simple fission, without gemmation. 
 
 Of the numerous genera referred to this family, the follow- 
 ing may be taken as good examples': 
 
 Classification of Palmellacece. 
 
 I Mucoid, floating, with minute cells. (I.) MiCROHALOA. 
 Indefinite or 
 
 formless. 1 Slimy, encrusting, with large globu- j ,g , p ALMELLA 
 
 {,. , c ' e ii s s r (3.) COCCOCHLORIS. 
 -> 
 Band-like, simple or branched, with) 
 cells in twos or fours in single >(4.) HORMOSPORA. 
 series J 
 
 Though the precise limits of the Palmdlaceoe are yet but 
 imperfectly defined, these plants are of considerable interest to 
 the water analyst, they so frequently find their way into 
 cisterns and reservoirs, and thus make their appearance in the 
 deposits of drinking water. Several genera would appear to 
 
PALMELLACE^E DESMIDIACE^. 39 
 
 be more correctly referable to the Volvocacece or other families, 
 and the accumulation of synonyms has only added to the 
 confusion. 
 
 To illustrate multiplication by fission in the Palmellacece, 
 the genus Coccocliloris may be instanced ; this will enable us 
 to see what little more is required to meet the conditions 
 observable in the Desmidiacece and Diatomacece respectively. 
 In Coccochloris (3 a and b) binary subdivision, with the 
 successive formation of a cellulose and hyaline investment, 
 seems to go on practically without limit, a fresh impetus to 
 the process being given by the conjugation and blending of 
 two endochromes (c), in which repeated fission goes forward 
 as before. This is, in effect, also what takes place in the 
 Desmids and Diatoms, and the observation is so far correct, 
 even though Coccochloris and its allies should be, as some 
 suppose, but the gonidia of lichens in a certain phase of 
 development. 
 
 These plants are often found under comparatively dry 
 conditions, as on the weather side of trees, or on old walls, 
 forming a greenish efflorescence, in which case the gelatinous 
 coat is much reduced in bulk. On the return of moisture, 
 however, it will swell up again, and in a constant drip it 
 assumes a glairy appearance. 
 
 FAMILY II. Desmidiacece. (Plates XIII. & XV.) 
 
 These are unicellular plants, usually of an exceedingly rich 
 green colour, nearly exclusively confined to fresh water, occur- 
 ring singly, or remaining in contact after binary subdivision, so 
 as to form more or less brittle threads or cells in linear series. 
 
 A sutural line running round the cell wall transversely, 
 marks it off into two symmetrical halves, and cleavage takes 
 place at this line, preparatory to the gemmation of two new 
 half frustules from the old ones thus separated. The forms of 
 
40 
 
 DESMIDIACE^E HYDRODICTYOX. 
 
 these cells are very beautiful and varied, and chiefly characterize 
 the genera, which admit of the following arrangement : 
 
 Classification of the Desmidiacece. 
 
 flam and Curved or crescentic . 
 
 1. CLOSTEEIUM. 
 
 SLti* J (Ends (Contents simple . 
 rounded j Coute nts spiral . 
 I Straight-) 
 Ends truncated 
 
 2. PENIUM. 
 3. SPIROT^ENII. 
 4 DOCIDIUSI. 
 
 \Ends notched 
 
 5. TETMEMOETJS. 
 
 Deeply inc'sed 
 
 6. MlCRASTERIAS. 
 
 Ornamental Siuuated 
 
 7. EUASTRUM. 
 
 short, or of 
 moderate length ( Without spines . 
 
 . 8. COSMABIUM. 
 
 l Simple . .-| With two spines . 
 V With several spines 
 
 9. ARTHRODESMTJS. 
 . 10. XANTHIDIUM. 
 
 Endviewan-j Pr J ectionssin S le 
 gular . .|p ro j ec tions double 
 
 . 11. STRAURASTRUJT. 
 
 . 12. DlDTMOCLADON". 
 
 , Cells oppo- ( Filaments rounded 
 sitely bi- \ 
 dentate . (Filaments angular 
 
 . 13. DlDTMOPRIUM. 
 
 . 14. DESMIDIUM. 
 . 15. SPHEROZOSMA. 
 
 Cells slightly ( J^ction simple . 
 I coustricted (Junction perforate 
 
 . 16. HYALOTHECA. 
 . 17. APTOGONUM. 
 
 
 (18.-) 
 
 & /"SCEKEDESMUS. 
 j' 19J 
 
 
 (20. ANKISTRODESMUS. 
 
 fDiscoidal . . . 
 
 . 21. PEDIASTRUiT. 
 
 - Pediasiriece (Plate X"V.) Frond. . .-1 Spherical . . . 
 
 . 22. CCELASTRUM. 
 
 1 Eeticulated . . 
 
 . 23. HTDRODICTTOX.* 
 
 Igfj'g" 
 
 In Pediastrum (Plate XV.) the form originates in the cleavage 
 of an endochrome into two, then four, and finally some multiple 
 of this, when a radial frondose expansion is formed by the 
 subsequent juxtaposition, and union of the cells in some 
 definite and characteristic manner. In Hydwdictyon, on the 
 other hand, a motile cell breaks up into numerous distinct 
 endochromes, which acquire a cellulose coat, and so arrange 
 themselves as to form a reticulation of minute cylindrical cells, 
 which gradually increase in size, and finally attain the 
 
 * Only placed here provisionally. 
 
DEVELOPMENT OF DIATOMACE^E. 41 
 
 
 
 character and dimensions of the perfect plant. Hydrodictyon 
 would therefore appear to hold a relationship to Pediastrum 
 and Colostrum, similar to that which Volvox bears to Cronium 
 or Pandorina ; the latter organisms being made up of motile, 
 and the former of ordinary vegetable cells. 
 
 FAMILY III. Diatomacece. (Plate XIV.) 
 
 Like the former family, the Diatomacece are unicellular plants, 
 in some instances isolated, in others cohering in chains of fila- 
 ments, or in some definite way. The cell wall, however, is 
 composed of a glassy or silicious material, instead of cellulose, 
 which is found in all other vegetable cells ; and the endo- 
 chrome is usually of a rich amber tint instead of green. 
 They exhibit also much symmetry and beauty in the forms of 
 the frustules, which are often so exquisitely sculptured as to 
 afford excellent test objects for the microscope. 
 
 Each frustule consists of a new and an old half or valve, as 
 noticed in the Desmidiacece, but the margins of the old valve 
 overlap those of the new one, and thus results the so-called 
 cingulum or " middle piece/' which is not only capable of 
 elongation by growth, but also by one portion sliding upon 
 the other, telescope fashion, so as to make provision for the 
 endogenous development of two new half frustules by fission 
 and gemmation combined. From this arrangement it follows 
 that the cells of each successive generation must be narrower 
 than those within which they arise, by at least the whole thick- 
 ness of the cell wall. Here, then, is the explanation of the 
 great disparity of size so frequently observed in members of 
 the same species. Moreover, we thus also see why it is that 
 after the conjugation of two frustules, the resulting sporangial 
 cell, in which the process just described commences, should be 
 so much larger than the parent cell. 
 
 The genera of Diatomacece are too numerous to be sepa- 
 rately defined in this treatise ; but the annexed table, with the 
 
42 
 
 CLASSIFICATION OF DIATOMACE^E. 
 
 figures arranged in the same order, will assist in the recogni- 
 tion of the more usual fresh water forms ; 
 
 {Without terminal nodules . 
 With C Separate . . . 
 terminal < 
 nodules. CIn a filament . 
 
 
 g 
 
 rt"5 
 
 ~-~ 
 
 Merldionece . Cur.eate . 
 
 Fragilarie 
 
 ( Quadri- 
 1 i lateral. 
 
 oidal 
 
 J In a close spiral 
 1 band .... 
 
 } * >*- chain . . 
 
 Stria? ( ! 
 continu- 4 
 ous. ( In a close chain . 
 
 Strise j In a zigzag chain . 
 scarcely 4 
 visible. (In a star-like chain 
 
 Surircllece 
 
 jDisc 
 
 .S Cylindrical, or glo- ) 
 I bose j 
 
 /Subquadrate, ovate, I 
 J or elliptical, with H 
 i marginal furrows 
 
 Mostly single . . 
 In a filament . . 
 Saddle-shaped . . 
 Full border, simple 
 
 | 
 
 If 
 
 cs-2 
 
 \Mnch elongated 
 Cocconeidece. Elliptical . . . 
 Bent . 
 
 Depressed, borders 
 . undulate . . . 
 
 {Compressed, with 
 median puncta . 
 Prismatic, with a 
 pseudo-nodule . 
 
 . Fixed by one surface 
 [ With a stalk . . . 
 ' 1 Without a stalk . 
 
 <**. .f'-SSr 1 ' -tjWithoutasta* 
 
 I. sigmoid . . ( with a stalk . . 
 
 Gomphonemece Wedge-shaped . . With a stalk . . . 
 
 Ends full & rounded Striao continuous . 
 / Striae dotted, with- 
 
 , cu-oio-M out a stauros 
 Ends btiai S*it -, With a sta uros, or 
 
 more -I ( transverse bar . 
 acute 1 Sigmoid { St t r i^ nb ? th . direC ; 
 Ovoid, inflated 
 
 \H 
 
 S. - \ ; Vittse [ A close series . 
 
 JJ- .{jBs-Jfflsa.u 
 
 zigzag chain 
 Vittaa * 
 Capitate, like notes in music . 
 
 1. EPITHEMIA. 
 
 2. EUNOTIA. 
 
 3. HlMAN-TIDIUM. 
 
 4. MEBIDION. 
 
 5. FRAGILAEIA. 
 
 6. DENTICULA. 
 
 7. ODONTIDIUM. 
 
 8. DlATOJIA. 
 
 9. ASTHIONELLA. 
 
 10. CTCLOTELLA. 
 
 11. MELOSIEA. 
 
 12. CAMPTLODISCUS. 
 
 13. SUEIEELLA. 
 
 1 14. SPHINCTOCTSTIS. 
 ! 15. NITZSCHIA. 
 1 1C. STNEDEA. 
 17. COCCONEIS. 
 
 IS. ACHKANTHES. 
 
 19. ACHNANTHIDIUM. 
 
 20. CTMBELLA. 
 
 21. COCCONEMA. 
 
 22. GOMPHONEMA. 
 
 23. PlNJfULABIA. 
 
 | 24. NAVICULA. 
 I 25. STAUEOXEIS. 
 
 | 26. GTEOSIGlTi. 
 
 27. AMPHOEA. 
 
 28. TETEACYCLUS. 
 
 29. TABELLAEIA. 
 
 30. TEEPSINOE. 
 
 ! Hoops ') 
 with [ Frond mammillated 31. MASTOGLOIA. 
 , loculi j 
 
 
 fLike Joculi ) 
 
 Navicula A Hoops J Frond amorphous . 32. FEUSTULIA. 
 
 ( sim P le (Frond filamentous. 33. COLLETONEMA. 
 (l&eCymbeUa 
 
 Frond filamentous. 3i. ENCTOJTEMA. 
 
CLASSIFICATION OF APIOCYSTACB^E. 
 
 43 
 
 GROUP III. CELLS NON-FLAGELLATE, SIMPLE OR GEMMI- 
 PAROUS, WITH GREEN OR COLOURLESS CONTENTS. 
 
 FAMILY 'L-^Apiocystacece. (Plate XV.) 
 
 The members of this family seem to be grouped with the 
 Palmellacece as a matter of convenience. They are, however, 
 quite distinct in their habit and relations. The fronds are 
 composed of single cells, usually fixed at one end, and the 
 reproductive elements are developed in the same cells, appa- 
 rently engaging the whole contents. 
 
 The following genera may be met with amongst other 
 Alf/co : 
 
 Non-parasitic / 
 with green \ 
 contents . 
 
 Dehiscence 
 
 irregular, 
 
 slit-like 
 
 Dehiscence 
 subterminal 
 circumcissile 
 
 Parasitic on Confervoids, with 
 colourless contents 
 
 L.) APIOCYSTIS. 
 
 (2.) HYDROCYTIUM. 
 
 Pyriform, with gonidia' 
 
 in fours, forming 
 
 merous zoospores 
 Fusiform, with 
 
 tal starch gi 
 
 green contt 
 
 ing zoospor 
 ' Cylindrical, curved, with 1 
 
 8 gonidia, which are >(3.) OPHIOCYTIUM. 
 
 dispersed when ripe . J 
 Cylindrical, straight, \ 
 
 with 8 gonidia form- I 
 
 ing an umbel, like the J-(4.) SCIADIUM. 
 
 parent cell, at its ex- 1 
 
 tremity -' 
 
 Globose, with 
 
 growing upon 
 
 and sending their pe- 
 dicle inwards 
 Flask-shaped, growing ' 
 
 within cells and 
 
 piercing the walls to }-(6.) PYTHIUM. 
 
 discharge their go- 
 nidia . 
 
 a lid,") 
 L cells, f ,g 
 icir pe- C\ 
 
 "I 
 
 (5.) CHYTRIDIUM. 
 
 B. Living Animals. 
 
 The smaller, or microscopic Fauna of the fresh water, as 
 might be expected, is rather comprehensive, including repre- 
 sentatives of all the sub-kingdoms and many of the classes of 
 Invertebrata. This will be seen at a glance in the annexed 
 Table, the arrangement of which will be followed in the 
 succeeding pages : 
 
44 
 
 I i 
 
 B 
 
 "3 -? '* 
 
 Radiolaria . 
 (Pseudopodi 
 
 .2 g 
 11 
 
 i3fi8Kfig 
 
 Cory 
 (Cor 
 
 
 
 1 1 
 ITJ 
 
 1 1 
 
 Is 
 
 . 
 ad- 
 
 Nematod 
 (Smooth 
 
 i s^-s.2 
 
 Rotifer 
 (Wheel 
 
 aea . 
 w bristled. 
 
 H 
 (L 
 
 o 
 
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46 INVERTEBRATE SUB-KINGDOMS. 
 
 To facilitate the recognition of objects under examination, 
 the definitions given of the five sub-kingdoms of invertebrate 
 animals should be carefully studied, after which it will be 
 found comparatively easy to refer each organism to its proper 
 position in the Table- noting that the definitions apply more 
 particularly to the fresh-water forms. 
 
 I. The Protozoa (Siebold) are small or minute bodies, more 
 or less partaking of the character of simple cells, furnished 
 with vibratile cilia (for locomotion, or the development of 
 currents in the water) ; or resembling merely the contents of 
 cells, without integument, but capable of throwing out mobile 
 extensions of the " sarcode," or gelatinous substance of the 
 body. The members of this latter class are named Ehizopoda, 
 from the root -like forms of the locomotive processes, while 
 those of the former, in accordance with the arrangement 
 adopted in this work, constitute the ciliated portion of the 
 Infusoria proper, or the Ciliata of authors. 
 
 II. The Codenterata (Frey and Leuckart) are distinguished 
 by having the lining membrane of the stomach continuous 
 with that of the body cavity. The single class Hydrozoa is 
 represented by the Fresli-iuaUr Polypes. 
 
 III. The Annuloida (Huxley) embrace all the worm-like 
 animals which are not true Annelida and the wheel animal- 
 cules. Thus, in the preceding Table, the class Scolecida (a7cwAi?$, 
 a worm) includes the ciliated Flatworms (TurMlaria), the 
 Threadworms (Ncmatoda\ and the Rotifers (Rotifcra). 
 
 IV. The Annulosa are distinctly ringed, or segmented 
 animals. They may be divided into three groups viz. 
 (a), Apoda, without feet or Lceclies ; (b) Anarthropoda, with 
 inarticulate limbs ; other Annelida, and (c) Arthropoda 
 having articulated limbs. The latter are still further divided 
 
PROTOZOA. RHIZOPODA. 47 
 
 into Crustacea, with a variable number of limbs, but typically 
 seven pairs, Araclmida, or spiders with four, and Insecta, with 
 three pairs of legs. 
 
 V. The Mollusca, as the name implies, are soft-bodied 
 animals, usually protected by a crustaceous covering or shell. 
 They are divided into an inferior class (Molluscoida) taking in 
 the Limniades or fresh-water Polyzoa, and a superior one 
 (Mollusca proper), represented by the fresh-water snails and 
 mussels, or shellfish so-called. 
 
 As all the classes have been named and sufficiently 
 characterized in the foregoing definitions, attention may next 
 be directed to the orders and the illustrative, or more usual 
 genera given in the general Table of Classification with short 
 definitions of the technical terms employed. 
 
 I. PKOTOZOA. 
 I. Rliizopoda. (Plate XVI.) 
 
 Besides the sponges, which are represented by the genus 
 Spongilla (found in still or slowly running waters, on stones, 
 old woodwork, &c.), the Rhizopoda admit of distribution into 
 three groups, easily distinguishable by the characters of the 
 pseudopodia, or the motile extensions of the body substance 
 already noticed. In the first group or order (a) (Radiolaria) 
 they are slender and raylike, persistent, or slowly retractile. 
 In the second (o) (Reticidaria) they are firmly branched, more 
 or less intercommunicating, or reticulate ; while in the third (c) 
 (Ldbosa) they are lobose or digitate. These orders, will be 
 better understood on inspecting the following synopsis of the 
 genera. They have the advantage, at least, of being simple, 
 though of course they can only be provisional in the present 
 state of our knowledge of the subject. 
 
48 DISTRIBUTION OF RHIZOPODA. 
 
 (a) Radiolaria. 
 
 Pseudopodia delicate ray-like simple, besetting the spherical 
 surface. 
 
 /-Naked ................... (1.) ACTIXOPHRYS. 
 
 KJ 
 
 'oK r With fine spiculse; free . . (2.) ACANTHOCYSTIS. 
 
 ^ (.With a covering or shell -< 
 
 (Fenestrated; with a pedicle (3.) CLATHRT;LIXA. 
 
 Habitat. Actinoplirys digitata amongst marsh plants; A. 
 UicJwrnii on the surface of infusions, and with A. discus 
 (Tricliodiscus) and the other species, amongst conferva and 
 aquatic plants. Acantlwcystis, and Clathmdina occur in bog- 
 water. 
 
 (b) Retwularia. 
 
 Pseudopodia filiform, reticulate, or finely branched ; localized ; 
 body, globose or ovoid. 
 
 f Closely reticulated; sarcode reflected over the shell . . (1.) GROMIA. 
 
 g * -S r At one end ..... (2 ) PLEUROPHRYS. 
 
 p^ ft ^Finely branched in a bunch -J 
 
 (. At both ends ..... (3.) AMPHITREMA. 
 
 Hcibitat. G-romia fluviatilis on Cemtophyllum, G. liyalina 
 (with a short neck) in rivulets. Pleurophrys and Ampliitrema 
 in bo-water. 
 
 (c) Lobosa. 
 
 
 Pseudopodia lobose or digitate, simple or dividing. 
 
 /Two or three; 7 /-i \ 
 subterminal i' *' 
 Pseudopodia, fine and sim- 
 
 With a 
 shell 
 
 (Shell discoidal (5.) ARCELLA. 
 
 Pseudopodium single . . . Shell subcubical (6.) CYPHIDIUM. 
 Naked . . Pseudopodia, variable (7.) AJKEBA. 
 
 Pssndopodia, stout and di- Slie11 ^sk-like (4-) 
 
LIMITS OF THE INFUSORIA. 49 
 
 Habitat. Trinema acinus and Euglypha tuberculata in 
 stagnant water ; Difflugia proteiformis and dblonga amongst 
 Oscillatoriacece ; numerous other species in moist moss at the 
 roots of trees ; Arcella mdgaris with Lemnce and aquatic plants 
 A. acideata and A. dentata with Confer vce ; CypJiidium aureolum 
 in stagnant water ; Amoeba diffluens on Lemna and A. radiosa in 
 bog-water. 
 
 (d) Spongida. (Plate IV.) 
 
 Spongilla, the only fresh-water genus, occurs in little grey or 
 greenish more or less rigid or friable masses, with a spicular 
 framework. They present a superficial or dermal coat, nume- 
 rous inhalant pores, internal ciliated chambers, and an exhalant 
 aperture. Their grey or green colour is due to the amount of 
 chlorophyll taken into the sarcode or soft substance of the 
 sponge. The silicious spicules which are often present in 
 the sediment of fresh water are 1, birotate ; 2, short cres- 
 centic, and echinate ; or 3, in the form of stout needles rounded 
 at one end and acute at the other. 
 
 2. Ciliata. (Infusoria.) (Plates XVII. & XVIII.) 
 
 Excluding the Flagellata, the Infusoria proper will 
 only consist of the Ciliata of authors, or the ciliated animal- 
 cules, which are furnished with a mouth (Stomatoda), but in 
 other respects exhibit a very rudimentary organization. Here 
 it may be remarked that, as the object of this work is to 
 facilitate the recognition of the forms themselves, it has not 
 been considered necessary to follow any more modern arrange- 
 ment of the Ciliata. The objectionable points of Dujardin's 
 system -are sufficiently known to the well informed, and they 
 can be of little moment to those who can only give, a small 
 share of attention to the subject. 
 
 The Ciliata then, as the name implies, are furnished with 
 
 E 
 
50 STRUCTURE AND HABITS OF THE CILIATA. 
 
 vibratile cilia, variously distributed either as connected with 
 the mouth or the general surface ; and those organs exhibit a 
 great variety of character. Thus we have the terms setce, cirri, 
 hooks, and styles, to express some of their modifications ; their 
 uses may be said to be threefold viz.: 
 
 1. For the production of currents in the water, the pur- 
 
 veyors of food, and fresh air. 
 
 2. For locomotion, swimming, walking, or jumping. 
 
 3. For resistance, offence or defence. 
 
 These animalcules are generally very voracious, notwith- 
 standing the simplicity of their organizations ; and it is note- 
 worthy in a hygienic sense that if the water in which they are 
 found is deficient in organic matter available for food, either 
 from its actual purity, or from the thorough decay of 
 what may have been originally present, the transparency and 
 leanness of their bodies, and the restlessness of their search for 
 aliment will show that they are in a half -starved condition. 
 Solitary Vorticellce are often the only ciliata to be seen in 
 what may be termed exhausted water, or that in which the 
 organic matter is so far destroyed as to leave no assimilable 
 food for other forms. In some waters of this class even bac- 
 teria may be observed to drag out an inactive existence. The 
 notable presence of the Ciliata, however, would indicate not 
 only stagnant water, but such as may contain organic matter 
 in solution to some relative extent not yet precisely determin- 
 ate. 
 
CLASSIFICATION OF THE CILIATA. 51 
 
 General Table of the Ciliata. 
 
 Characters. Families and Illustrative Genera. 
 
 No apparent mouth, cilia | EXCHELIA. 
 
 scattered ..... j (Enclielys; Alyscum.) 
 
 Mouth with {"Without cirri TRICHODIXA. 
 an oblique or J (Trichoda; Traclielius.) 
 
 circular row*) 
 
 of cilia, (.With cirri | KERONIA. 
 With a carapace (diffluent) ..... EUPLOTA. 
 
 (Euplotes ; Hymantopliorus. ) 
 
 rNo oral fringe .... PARAMECIA. 
 /Free (Paramecium ; Glaucoma.) 
 
 2. Integument I (, With an oral fringe . . BURSARIXA. 
 
 with seri-J (Bursaria; Leucoplirys.) 
 
 ally dispos- ] 
 
 ed cilia. j ^Voluntarily ..... URCEOLARINA. 
 
 ^ Fixed (Urceolaria; Stentor.) 
 
 (.By special organs . . VORTICELLINA. 
 
 (Forticella; Epistylis.) 
 
 (a.) Euchdia.Duj. (Plate XVII.) 
 
 ^Partially f Ciliaatoneend (1.) ACOMIA. 
 
 ciliated< (_ Cilia in a longitudinal furrow .... (2.) GASTROCH^ETA. 
 Body 4 
 
 Ciliated f Cilia a11 alike ( 3l ^ ExCHELYS - 
 
 V al1 over -( With retractile filaments also .... (4.) ALYSCUM. 
 
 Further description and halitat. 1. Acomia vitrea, ovoid 
 minute (length 1-868"), occurring in decomposing infusions and 
 water of a corresponding description. 
 
 2. Gastrochcetafissa, ovoid, colourless, convex dorsally, ending 
 abruptly in front, and in a blunt tubercle behind, length 
 1 400", found in stagnant water. 
 
 3. Enchelys nodulosa, Duj., Pantotrichum Enchelys of Ehr. 
 Other species of Enchelys Duj. are confounded with the genus 
 Cydidium, Hill, and to add to the confusion Duj ar din applies 
 this latter term to a genus of Flagellata. ( See Monadacecc.) 
 E. nodidosa is usually found on the borders of decaying matter 
 in stagnant water, movements sluggish. 
 
52 CILIATA; TRICHODINA. 
 
 4. Alyscum saltans, length 11260", much resembles the last 
 species in general appearance, though longer and possessed of 
 a trailing filament, which is therefore characteristic, as well as 
 retractile cilia, by which a jerking movement is- effected. In 
 river water kept for some time, and vegetable infusions, this 
 form is frequently to be seen. 
 
 (b.) Trichodina. (Plate XVII.) 
 
 (Fore part curved like a hatchet . . . (1.) PELECIDA. 
 
 1- 
 
 Neck long and slender (2.) DILEPTUS. 
 
 Upper lip forming a proboscis ... (3.) TRACHELIUS. 
 
 In front (On each side, in opposite directions . (4.) ACIXERIA. 
 
 c le 3" (In one row, directed forwards . . . (5.) TRICHODA. 
 
 Further description and habitat. 1. Pclccida rostrum of 
 Dujardin, or Loxodes rostrum of Ehrenberg, having a noncon- 
 tractile integument, is thus distinguished from the Paramecia. 
 
 2. Dileptus folium, as its name implies, is leaf-like lanceolate 
 in form, with the mouth at one side of the base of a proboscidi- 
 form extension of the body in front. It is richly ciliated, par- 
 ticularly near the mouth. 
 
 3. Trachelius anas also has a mouth at the base of a trunk- 
 like prolongation; it is distinguished from Ampliileptus by 
 having a branched intestine. It should be mentioned that 
 Dujardin founded his genus Dileptus on those species of Am- 
 pliileptus which do not possess a reticulated integument. Both 
 genera are found in clear running marsh water, and streams 
 amongst aquatic plants and Algre, and their presence would 
 thus rather indicate living than decaying conditions. 
 
 4. Acineria acuta exhibits a row of cilia arising from one 
 side and directed forwards. The only other species, Acincria 
 incurrata, is marine. 
 
CILIATA : KERONIA. 
 
 53 
 
 5. Trichoda anyulata is described as having the body 
 obliquely and irregularly folded or angular. 
 
 Form 
 
 (c.) Keronia. (Plate XVII.) 
 
 Short and rounded, with a row of stout cilia, and) ,-. \ TT. T , 
 fine Bete for jumping j (1.) MALTERIA. 
 
 Oval 
 
 or 
 
 elongated. 
 
 f Creep ing organs in regular rows . . 
 
 / few, or single 
 
 {behind . . . 
 numerous be- 
 hind, with 
 frontal cirri 
 also 
 
 V Without styles . . . 
 
 (2.) OXYTRICHA. 
 
 (3.) UROSTYLA. 
 
 (4.) STYLONYCHIA. 
 (5.) KEROXA. 
 
 Further description and habitat. 1. Halteria arandinclla. 
 This is a small, nearly spherical, animalcule, 1 850" greatest 
 breadth ; it presents an oblique row of stout cilia at the 
 circumference, and very delicate radiating cilia, by which 
 its peculiar jerking movements are effected. Generally found 
 in indifferent water in the neighbourhood of organic debris. 
 
 2. Oxytricha gi~b~ba, length 1-240". Body lanceolate, convex 
 above and flat below, with a double row of setas, often in bad 
 water with the former. 
 
 3. Urostyla grand-is. This form is rounded at both ends, 
 a little larger in front than behind, and altogether proportion- 
 ately more elongated than Stylonychia, but without the same 
 armature. Length 1-120". 
 
 4. Kerona polyporum. Short as compared with the 
 preceding and following, and slightly reniform. Length 1-144". 
 (See note on the Hydrida, p. 59.) 
 
 5. Stylony cliia histrio. At once distinguished by its 
 numerous styles and the regularity of its outline. 
 
54 CILIATA; EUPLOTA, PARAMECIA. 
 
 (d.) Euplota. (Plate XVII.) 
 
 Body depressed with f Without styles (1.) HIMANTOPHOHI*. 
 
 creeping hooks. | With styles also (2.) EUPLOTES. 
 
 Further description and habitat. 1. Himantophorus charon. 
 Length I ISO". No styles or teeth present, but the hooks 
 are long and slender ; the habitat is marine and probably in 
 brackish or fresh water near the sea-side. 
 
 2. Euplotes vannus. Smaller than the former, but aquatic, 
 usually found where there is much material for food, though it 
 is often seen in a half-starved condition, thin and transparent. 
 
 (e.) Pammecia. (Plate XVIII.) 
 
 /"Frontal margin produced 
 
 (Mouth lateral. Body. J on one side - (M CHILODOX. 
 
 Sh} (.Bounded at both ends . (2.) NASSULA. 
 
 ^ terminal. Body rounded at both ends . . (3. ) PRORODOX. 
 
 With- 
 out 
 
 With f Witn vibrating lips . . (4. ) GLAUCOMA. 
 
 appendages. | A proj - ecting inferior lip ( 5>) COLPODA. 
 
 T Within an oblique fold . (6.) PARAMECIUM. 
 
 [impinging on the margin (7. ) PAXOPHRYS. 
 
 Globular by contraction . . (8.) HOLOPHRYA. 
 
 Mouth 
 lateral. 
 
 Mouth terminal. Body- -pi as ^ TPointed behind (9.) TRACHELOCERCA, 
 ( shaped. "| Eounded behind (10.) LACHRYMARIA. 
 
 Further description and habitat. 1. Chilodon cuculhis. 
 Length 11 30", white or colourless, but with a red spot or 
 globule. The species may be readily distinguished by their 
 colour. Thus, C. uncinatus (frontal margin much curved), 
 is white ; C. cucidlus, white with a red spot ; C. aureus, 
 golden yellow, and C. ornatus, golden yellow with a violet spot 
 on the neck. 
 
CILIATA; PABAMECIA. 55 
 
 C. cucidlus and C. ornatus are found in both fresh and salt 
 water, while the other two mentioned have only been found in 
 fresh water. 
 
 2. Nassula eleyans. Though without the lateral frontal 
 process of Chilodon, has the same cone of little rod-like teeth. 
 They are evidently very closely allied. There is, moreover, a 
 yellow Nassula also, JV". aurea. 
 
 3. Prorodon teres. Body terete, slightly truncated in 
 front ; mouth with a little cylinder of teeth. Length 1 140"- 
 
 4. Glaucoma scintilans. Length 1290. Body oval, 
 covered with cilia ; the mouth near the smaller end furnished 
 with vibrating lips. 
 
 This form is usually found in putrid water, and infusions 
 of vegetable matter. 
 
 5. Colpoda cucidlus. Body ciliated below, smooth above, 
 curved to one side in front, with the mouth in the recess so 
 formed. Length about 1-200". In vegetable infusions, and 
 in water with much organic matter present. 
 
 6. Paramecium aurelia. Length 1-1 00". The body 
 terete, more or less depressed, with a very regular distri- 
 bution of the cilia. Two contractile vessels are usually well 
 seen in this species. 
 
 7. Panoplirys crysalis is marine, but distinguished from 
 Paramecium by having the mouth quite marginal. Paramecium 
 is like a scavenger, removing organic debris from clear sur- 
 roundings. 
 
 8. HolopJirya ovum. Body ovate, green within ; cilia dis- 
 posed in longitudinal rows ; length, 1-576 to 1-216". 
 
 9. Trackelocerca olor, and 
 
 10. Laclirymaria proteus are supposed by some to be the 
 same, but the tail- like process of the former is sufficient to 
 distinguish it, while the body of the latter is more globular. 
 
56 CILIATA; BURSARINA, TJRCEOLARIA. 
 
 (f.) Bursarina. (Plate XVIII.) 
 
 (Acuminate fcehind with an eye spot 
 in front (1.) OPHRYOGLENA, 
 
 I oblique mouth,~\ ( Cilia within the buccal 
 
 fringed with Bounded fossa (2.) BURSARIA. 
 
 ,/' cirri. behind, \ 
 
 o \ V no eye spot No cilia within the 
 
 ( buccal fossa. . . . (3.) LEUCOPHRYS. 
 
 I Linear cylindrical mouth near the middle, within the 
 
 l^ curled end of a row of cilia (4.) SPIROSTOMUM. 
 
 Further description and habitat. 1. Opliryoghna aenmi- 
 nata. Colour, brown; eye spot, red. Two other species 
 are also distinguished by their colour viz., 0. flavicans, yellow, 
 but also having a red eye spot ; and 0. atra, black with a black 
 eye spot. 
 
 2. Bursaria vorticella. So called from its resemblance to 
 a vorticella detached from its stalk. Ehrenberg has described 
 numerous species of this genus, many of which are found in 
 stagnant fresh water. 
 
 3. Lcucoplirys (a) patula and (b) spatluda. The length of 
 the former is 1-288", and of the latter 1-144". The body of 
 L. patula ovate, and full resembling Bursaria. It is found in 
 both fresh and salt water ; L. spatliula is more elongated, com- 
 pressed, and slightly pointed behind \spatliidium Jiyalinum, 
 Duj. and is apparently confined to the fresh water. 
 
 4. Spirostomum amliguum, length 112". Covered with 
 cilia and quite colourless, long, narrow and flexible. Some 
 Bursarina are found in the intestine of the frog, and of ISTais. 
 
 (g.) Urceolaria. (Plate XVIII.) 
 
 Clustered vorticella-like animals in a gelatinous mass . . . (1.) OPHRYDIUM. 
 
 / With a crown of cilia at both ends, body short and 
 
 discoidal (2.) URCEOLARIA. 
 
 Solitary.-| ( Bod y trumpet-shaped, ciliated all 
 
 Crown of cilia j over, mouth spiral .... (3.) STENTOR. 
 in front only, j Bell _ sliaped5 smooth> tail gubu . 
 
 \ late (4.) UROCENTRUM. 
 
 
CILIATA ; VORTICELLINA. 57 
 
 Further description and habitat.- 1. Ophrydium versatile. 
 In this interesting form the common gelatinous substance is 
 quite transparent and colourless, but the little animals, which 
 are 1-100" in length, are green. The whole mass, which ranges 
 from the size of a pea to some inches in diameter, bears some 
 resemblance to frog's spawn. 
 
 2. Urceolaria pediculus may be seen gliding over the 
 surface of Planaria (see also the note appended to the table of 
 the species of Hydra, p. 59). 
 
 3. Stentor cceruleus. The species of Stentor appear to be 
 all aquatic, and some of them are large and very beautiful objects. 
 
 4. Urocentrum turbo. Length 1-430 to 1 290", crown 
 only ciliated, tail one-third the length of the body. 
 
 (h.) Vorticellina. (Plate XVIII.) 
 
 f Simple . . (1.) VOIITICELLA. 
 r Stalk spirally flexible 4 
 
 Bodies all J (Branched. (2.) CABCHESIUM. 
 
 uniform. "S 
 
 (.Stalk inflexible ....... (3.) EPISTYLIS. 
 
 Bodies of f stalk inflexible ....... (4.) OPERCULAHIA. 
 
 two shapes. sta lk spirally flexible ..... (5.) ZOOTHAMNIUM. 
 
 Further description and habitat. 1. Vorticella microstoma. 
 Length of body 12000 to 1 250" ; colour greenish-white, rim 
 . narrowed. 
 
 2. Carchesium polypinum. Length 1580 to 1430" ; the 
 little peduncles have separate muscles, and the bodies are quite 
 campanulate, with an expanded rim. 
 
 3. Epistylis crassicollis. The articulations of the pedicles 
 are annular and rather turgid, and the rim, though narrow, is 
 better denned than it is in V. microstoma. Numerous species 
 are found on JEntomostraca and Algce. 
 
 4. Opercularia articidata and 0. berberina are found para- 
 sitic on water beetles. Following the example of Claparede 
 
58 CGELENTERATA ; SPECIES OF HYDRA. 
 
 and Lachmann, the species of Opcrcularia are now usually 
 referred to Epistylis. 
 
 5. Zootliamnium arluscida. Length of the bodies 1-430". 
 The muscle of the trunk ramifies with the branches, so that 
 there is no regular articulation of the latter at their point of 
 origin. 
 
 Symmetrical Forms. (Plate XIX.) 
 
 The genera (1) Ichtliydium, (2) Chcetonotus, (3) Coleps, and 
 (4) Planariola, are placed by Dujardin in an appendix to the 
 Oiliata, though they appear to have no natural affinity int&r se, 
 on account of exhibiting a bilateral symmetry, which, 
 singularly enough, is wanting in all the other ciliated 
 Infusoria. 
 
 II. CCELENTERATA. (Plate XIX.) 
 
 The only Codenterata occurring in fresh water are members 
 of the sub-class Hydroida, the two first Orders of which viz., 
 Hydrida and Corynida are represented by the respective 
 genera Hydra and Cordylophora. 
 
 (a) Hydrida. 
 
 The first Order is distinguished by the Polypites or separate 
 Zooids being single and locomotive, with a sucker disc at one 
 end, and an oral orifice at the other, surrounded with tentacula. 
 The integument never develops a sclerous layer, and the 
 reproductive organs appear as simple external processes of 
 the body. 
 
 TaUe of the Species of the Genus Hydra. 
 
 Cylindrical or / Tenta la shorter than the body,} (1.) H. virldis. 
 insensibly smaller at the base j (Leaf green.) 
 
 ward^the " 1 T entacu ^ a as l ori g as or longer than | (2.) H. vulgaris. 
 "base the body, tapering to the "end .j (Yellowish or red.) 
 
 Attenuated (Tentacula longer than the body . { H " aftemiata 
 
 bfilow in it \ 
 
 . 
 
 below in a < ( Pale ollve reeu> ) 
 
 ^ e Tentacula several times longer than H. fusca. 
 
 iee< ( the body J (Brown or greenish.) 
 
CCELENTERATA ; ANNULOIDA. 59 
 
 Habitat. In ponds and still waters on Lemna and aquatic 
 plants. 
 
 lfote. Parasitic Infusoria are often found upon these 
 Polypes viz., Kerona polyporum on H. mdgaris and H. fusca ; 
 and Urceolaria pediculus on H. vulgaris and H. mridis. Their 
 presence, however, would indicate impurity of the water and an 
 unhealthy condition of the Polypes themselves. 
 
 (b) Corynida, 
 
 In this, the second, Order, the Polyp ites are either single or 
 two or more connected by a common substance or " Ccenosarc" 
 always fixed at the base, and usually developing a firm outer 
 layer or " Polypary" The reproductive organs or " G-ono- 
 plwres" arise either from the Polypites, the Ccenosarc, or the 
 so-called " GonoUastidia.'* 
 
 Genus Cordylophora (Allman). 
 
 Polypary horny, branched, and rooted by a creeping tubular 
 stolon; polypes ovoid, with a small mouth, and scattered 
 filiform tentacula. 
 
 (3.) Cordylophora lacustris was the only species known to 
 Allman, but lately a second, C. rividaris, has been added. 
 
 III. ANNULOIDA. 
 
 1. Scolecida. 
 (a) Turtellaria. (Plate XIX.) 
 
 Non-parasitic ciliated worms. Some of these are bisexual, 
 with a single alimentary or oral opening, and constitute the 
 first sub-order (Planarida), including fresh-water species, whilst 
 others are unisexual, with two alimentary openings, and form 
 a second sub-order (Ncmertida) altogether marine. 
 
60 PLANARIANS, THREADWORMS AND ROTIFERS. 
 
 Planarida. 
 
 Illustrative Genera. 
 
 Straight f Concatenated (1.) DEROSTOMUM. 
 
 Rhabdocvela j 
 
 ) ("Mouth near the fore part . (2.) PROSTOMUM. 
 
 Intestine -\ (.Single -[ 
 
 (. Mouth near the middle . . (3. ) MESOSTOMUM. 
 llamose 
 Dendrocasla (4.) PLANARIA.* 
 
 Habitat : All in ponds and gently moving deep water 
 amongst aquatic plants. 
 
 (b) Nematoda. (Plate XX.) 
 
 The non-parasitic threadworms composing the family of 
 Anguillulidce are very frequently met with in fresh waters. 
 The vinegar eel (Anguilhda aceti), and sour paste eel (A. 
 glutinis), and the Tylenchus (or so-called vibrio tritici), invading 
 the ears of corn, belong to this family. Anguilhda flumatilis is 
 colourless or white, about fifteen times as long as it is broad, 
 with a fusiform oesophagus, expanding posteriorly into a much 
 larger stomach. 1, Anguillula found in bilge-water; 2, A. 
 .aceti; 3, A. fluviatilis. 
 
 The Anguilhdce are readily confounded with the Enoplidce, a 
 family of minute parasitic Nematodes, infesting the intestine of 
 aquatic larvae and other small animals, but often found free in 
 the water. 
 
 (c) Botifera. (Plate XX.) 
 
 The Wheel Animalcules, so called on account of the deceptive 
 appearance produced by the regular and consecutive action of 
 the vibratile cilia fringing the head-lobes. These latter may be 
 simple, sinuated, lobed or divided, and are capable of retrac- 
 tion and protrusion. The alimentary system is usually distinct, 
 with a dental apparatus and two orifices, and the sexes are 
 separate. 
 
 As a whole these little creatures present superficial points of 
 
 * The hair-worms Gordius and Mermis, found in moist places and pools, seem to hold 
 -the same relation to the true thread-worms that the Planarians do to the Nemertians. 
 
CLASSIFICATION OF E-OTIFERA. 
 
 61 
 
 resemblance to the Entomostraca, to which the character of 
 their segmentation makes a nearer approach than that of any 
 Annelida. Indeed they have been rather appropriately named 
 Cilio-crustaceans by Leydig. Dujardin grouped them in the 
 following simple manner : 
 
 Illustrative Genera. 
 
 Moscularia. Melicerta. 
 Brachionus. Furcidaria. 
 
 Albertia. 
 3. Those that both swim and crawl Rotifer. 
 
 1. Those that are fixed . 
 
 2. Those that swim only 
 
 Ehrenberg's arrangement, though perhaps more artificial, may 
 still be found more convenient for the recognition of genera. 
 
 Sections. 
 
 I. 
 
 Monotroclia. 
 "Wheel organ 
 simple. . , 
 
 II. 
 
 Sorotrocha. 
 "Wheel organ * 
 divided . 
 
 Eotifera. 
 
 Divisions. 
 
 1. 
 
 Holotroclia. 
 Margin entire carapace. 
 
 2. 
 
 SchizotrocJia. 
 ^Margin sinuous carapace . 
 
 1. 
 
 Polytroclia. 
 
 Into several parts carapace 
 
 2. 
 
 Zyyotrocha. 
 
 Into two parts carapace 
 
 Families and Illustrative Genera. 
 /"Absent ICHTHYDIXA.* 
 V Ichthydium podura. 
 
 (. Present (EcisxiNA. 
 
 (1.) CEcistes crystallinus, 
 
 f Absent MEGALOTROCH^A. 
 J (2.) Megalotrocha flavicans. 
 
 ^Present FLOSCULARIJEA. 
 (4.) Floscularia ornata. 
 
 /"Absent HYDATIXJEA. 
 J (o.) Hydatina senta. 
 
 (. Present EUCHLANIDOTA. 
 
 (3.) Monostyla quadrideutata. 
 
 f Absent PHILOBIXJEA. 
 j (6.) Eotifer vulgaris. 
 
 (. Present BRACHIOX.'E A. 
 
 (7.) Brachionus amphiceros. 
 
 IV. ANNULOSA. 
 A. Anarthropoda. 1. Annelida. (Plate XX.) 
 
 (a) Hirudinea. 
 
 All the Leeches have a more or less sucker- like mouth, and 
 are also furnished with a disk-shaped caudal sucker; and 
 
 * Ichthydium podura and Chsetonotus larus will be found amongst the symmetrical 
 Infusoria (Plate XIX., 1 and 2),' to which Dujardin has referred them. Their true 
 position, however, has scarcely yet been determined. 
 
62 HIKUDINEA AND OLIGOCH^TA. 
 
 although the body is finely anmilated, it is divided into larger 
 somites or segments like other Annelida. The. nervous system 
 is highly developed, and the sexes are combined in the same 
 individual ; but neither self -impregnation nor reproduction by 
 fission or gemmation has been observed in any case. The 
 fresh- water types may be thus arranged : 
 
 Genera. 
 10 in numtor 
 
 ("With no teeth or proboscis. , . (2.) NEPHELIS and BDELLIA. 
 Less than 10 -I 
 
 (With proboscis, but no teeth . . (3.) GLOSSIPHONIA. 
 
 Habitat. In ponds and lakes and slowly -moving waters. 
 
 (b) Oligoclmta. (Plate XX.) 
 
 The Oligochceta or Setigera, include the Earthworms (Lum- 
 Iricini) and the true water worms (Naiadidce). Their bodies 
 are usually much elongated, and furnished with locomotive 
 chitinous setee or bristles attached in rows to the sides and 
 ventral surface laterally. The Lumlricini are hermaphrodite, 
 and the Naididce unisexual, but the latter also multiply in a 
 remarkable way by gemmation and fission. 
 
 Families. Genera. 
 
 r Two rows of sete, one dorsal and one ven- ") 
 2. Naiadidce. J tral, on each side ; the four first segments V(l.) NAIS. 
 (All aquatic. )"S without dorsal setae . , ...... J 
 
 (, With ventral set only ....... CH^ETOGASTER. 
 
 In Lamarck's genus Stylaria the setre are very long, and 
 the cephalic segment is produced into a kind of proboscis. 
 The genus Proto, founded by Oken, is distinguished by the 
 presence of ciliated tentaculiform processes surrounding the 
 dorsal and subterminal vent, as in Fig 1 a. 
 
 Habitat. All these little worms live amongst aquatic plants, 
 burrow in the mud, or manufacture little tubes into which 
 they retreat for protection. The setae, but more especially the 
 
BIVALVE ENTOMOSTRACA. 63 
 
 ventral uncini (1 b), which are usually bifid at the extremity, 
 are frequently found in the sediment of water in which Algae 
 have been kept for some little time. 
 
 Note. In some instances two speck-like eyes are present, 
 and they may be confounded with the aquatic larvae of insects. 
 They differ, however,- in having the setae implanted beneath 
 the general surface, and the absence of the fine dark ramifica- 
 tions of the tracheae and of oral or cephalic organs of any 
 kind, except the above-mentioned eye-specks. 
 
 B. ArtTiropoda. 
 
 1. Crustacea. 
 
 A. Entomostraca. (Plate XXI.) 
 
 The first four out of the six Orders of Crustacea bearing 
 aquatic genera belong to the sub-class Entomostraca, which 
 may be said to consist of an empirical assemblage of usually 
 very small or minute crustaceans, having either less than 
 seven, or more than ten, pairs of legs. To this it must be 
 added, that the branchiae are either attached to the oral organs, 
 constituting the first section Lophyropoda, or to the legs, com- 
 posing the second section Brancliiopoda. Each of these is 
 still further divided (as in the general Table) into two Orders. 
 
 1. LopJiyropoda. 
 (a) Ostracoda. 
 
 Body completely enclosed in a bivalve carapace or shell. 
 Legs, 2 or 3 pairs. 
 
 Families. Genera. 
 
 (Cypriote f Both pairs of antenna with a tuft of| (L) CYpHIg< 
 
 ,. (Legs, 2 pairs).! l -> 
 
 .2 i~> -I v Inferior antennas without the tuft . . . (2.) CAXDONA. 
 
 * V^Legs* 3 pairs) } Su P erior antennse without the tuft. . . (3.) CYTHERE. 
 
 Habitat. In ponds and lakes. 
 
64 CYCLOPID^E AND WATER-FLEAS. 
 
 (b) Copepoda. 
 
 Shell jointed, forming a buckler enclosing the head and 
 thorax. Legs, 5 pairs, 
 
 Families, Genera. 
 
 Both superior an- \ ( Large and branched ; ) (1 > CrcLOPS . 
 
 tennte in the [ r , ,* (Foot-jaws, I ovaries 2 . . . . P ' 
 male with B [<**** -\ 2 pairs. 1 Small and simple; 1 (2 )CvNTHOCAMPTIJ g. 
 swollen joint J V ovary 1 . . . . j v 
 
 Malewithaswol- 
 
 feht'^fa*^ ..... (3.) 
 
 antenna only . 
 
 Habitat. In ponds and ditches. 
 
 2. Branchiopocla. (Plate XXI.) 
 
 (a) PJiyllopoda. 
 Legs from 11 to 60 pairs ; joints foliaceous, branchiform. 
 
 FamiUes. Genera. 
 
 TTail simply bifid . .. . . ARTEMIA. 
 
 ( Naked . Branchiopodid<B< 
 
 \ (. Tail m two distinct pieces . (1.) BRAXCHIPUS. 
 
 ( In a shell Aspidephora ............. (2.) Aprs. 
 
 Habitat. Eespectively in salt-pans, ditches, and pools. 
 
 (b) Cladocera. 
 
 Body included in a pseudo-bivalve carapace. Legs, 5 or 6 
 pairs. 
 
 Families. Genera. 
 
 Intestine simple, no black 
 spot in front of the e 
 
 black") 
 ye . j 
 
 , - { (7.) DAPHNELLA . . 2 & 2 jointed"") ^ 
 jjejrs, j o 
 
 6 P airs ((8.) SIDA .... 3 &2 jointed LS 
 
 
 
 T f ( 5 -) DAPHNIA . . . , 
 SI 5^1^ M 3 jointed \-S 
 
 !(1.) CHYDOBUS 
 (2.) CAMPTOCEBCI 
 (3.) ALONV .... 
 (4.) PLETTBOXUS . . 
 
 Habited. In ponds, ditches, tanks, and reservoirs ; usually 
 in good water. 
 
ASELLUS, GAMMARUS, AND TARDIGRADA. 65 
 
 B. Malacostraca. (Plate XXII.) 
 
 a. Edrioplitlialmata. 
 
 (a) Isopoda. 
 
 (1) Asellus aquaticus appears to be the only fresh-water 
 Isopod. Its distinguishing features are the following : 
 Superior antennae, at least as long as the peduncle of the 
 inferior ones. The seven pairs of legs of the Order, with the 
 terminal hooks entire ; and two bifid needle-like processes at 
 the posterior extremity of the body. 
 
 Habitat. Plentiful in stagnant pools, passing the winter in 
 the mud, from whence it emerges in the spring. 
 
 (b) AmpJiipoda. 
 
 G-ammarus is the only genus of Ampliipoda occurring in 
 fresh water. A short branch arises from the tip of the third 
 joint of the superior antennae, and the four anterior legs are in 
 the form of small claws with the movable tip folding on the 
 inner side. 
 
 (2) G-ammarus pulex is the type of the genus, and abundant 
 in fresh-water brooks where there is an accumulation of 
 vegetable debris. 
 
 . Gr. fluviatilis. another fresh-water species, is at once dis- 
 tinguished by the presence of a dorsal spine at the posterior 
 border of each abdominal segment. 
 
 Note. In concluding the notice of the Crustacea it must 
 be mentioned that the larvse of some of the Oniscidce or wood- 
 lice are aquatic. 
 
 2. Arachnida. (Plate XXII.) 
 (a) Tardigrada. 
 
 The water-bears are distinguished by having the head 
 marked off from the thorax, while the thorax and the abdomen 
 
 F 
 
66 WATER-BEARS, ACARINA, INSECTA. 
 
 are confluent. The body is faintly divided into four segments, 
 carrying each a pair of obscurely three-jointed legs, with three 
 or four claws at their extremity. They form but one family, 
 including three genera as under : 
 
 Genera. 
 rMouth conical, without sucker or ? , EMYDIUM. 
 
 ^ /-With appendages . J M oSTl!Sr4i^ 'with palpi- I {2<) MlLNESIUM> 
 
 g J C. form appendages > x 
 
 W (Without appendages . { ^^f ^^ without ap-J {3>) MACROBIOTTJS> 
 
 Habitat. Stagnant water amongst water-plants, in wet 
 moss, and even in the gutters of houses, from whence they 
 may be washed into cisterns and water-butts. 
 
 (b) Acarina. 
 
 In this Order we find the HydracJinea or water-mites, with 
 the head, thorax, and abdomen all fused together ; the Palpi 
 with the last joint unguiculate or spinous ; the eyes two or 
 four, and the legs generally ciliated and natatory, the posterior 
 pair the longest. Of the several genera Hydraclina would 
 appear to be the most commonly met with. (1) Hydraclina 
 globida is subovate in form, of a rich deep red colour, with 
 two pairs of eyes at a moderate distance apart, and the skin is 
 covered with minute puncta. The generic name AcJilysia has 
 been given to the hexapod (six-legged) young of this genus, 
 the Nymphs of which are parasitic on aquatic insects. 
 (2) Hydrachna geograpliica. (3) A still more globular form. 
 (4) Limnochares holosericus, crawling, not natatory. 
 
 Habitat. In ponds and permanent lodgments of water. 
 H. globida uses its legs with great activity, as though running 
 through the water, instead of swimming. 
 
 3. Insecta. (Plate XXIII.) 
 
 The more usual aquatic larvae are of the following Orders, 
 as given by Kirby and Spence, and are sufficiently numerous 
 
AQUATIC INSECTS AND MOLLUSCOIDA. 67 
 
 to suggest that they would be more readily determined by the 
 use of figures than by description, however elaborate. 
 
 Families. Genera. 
 
 f DYTISCUS, HYDROPHILUS, G-YRIXUS, LIMXITJS, PARNTJS, 
 ,leoptera | HETEKOCERCUS, ELOPHORUS, HYDR^NA. 
 
 .,, . . f GERRIS, VELIA, HYDROMETRA, KOTONECTA, SIGARA, NEPA, 
 J l Hemi l^ \ EAXATRA, NAUCORIS. 
 
 (c) Lepidoptera A few (as NYMPHULA). 
 
 (d) Trichoptera The majority (PiiRYGANEA, &c.) 
 
 (e) Neuroptera LIKELLULA, ^SHXA, AGRION, SIALIS, EPHEMERA. 
 (/) Diptera . CULEX and TIPULARIJE. 
 
 (f/) Aptera . . ATAX and some 
 
 The smaller species of water beetles, Hydropliilus, Eloplwrus, 
 Hydroena, Parnus, Limnius, and also Ncpa, walk upon the 
 water. The swimmers generally have the posterior legs fitted 
 for the purpose. Thus, in Dytiscus and Notonecta they' are 
 furnished with a dense fringe of hairs on the shank and foot, 
 and in Gyrinus the terminal joints are very much dilated. 
 
 Some insects walk and swim upon the surface without 
 diving, as Gerris lacustris,> the water-bug, which can walk, run, 
 jump, or swim upon the surface. 
 
 Hydrometra stagnorum, very slender in form with prominent 
 hemispherical eyes, apparently in the middle of the body, 
 though really on the head, rambles over stagnant water, and 
 Velio, rivulorum courses rapidly over running streams and 
 rivers. 
 
 V. MOLLUSCA. 
 A. Molluscoida. 
 
 The Limniadesox fresh-water Polyzoa are thus characterized. 
 Polyzoarium fleshy, spongy, or coriaceous ; apertures angular 
 or round, closing when the zooids recede. Tentacula ciliated 
 in a single series, fringing a more or less crescentic lophophore 
 (Pliylactolcematd) , or an orbicular one (Gri/mnolcematci), in both 
 cases including the mouth. The genera Cristatella and 
 
 F 2 
 
68 MOLLUSCA, BIVALVES AND UNIVALVES. 
 
 Plumatella are examples of the former group, while Paludicdla 
 and Urnatella represent the latter. 
 
 The Polyzoarium in the Cristatdlidce is membranous, 
 sacciform and free, or floating, while that of the Plumatdlida? 
 is fixed, fistular, and confervoid. 
 
 Habitat. Ponds and lakes. 
 
 B. Mollusca (proper). 
 
 The simple recognition of the shell, univalve or bivalve, will 
 suffice for the Mollusca proper, or the fresh-water shell-fish, so 
 called ; conchological works may be consulted if necessary. 
 The following genera occurring either in this or other countries 
 are merely cited as examples. 
 
 1. Lamdlibrancliiata (Bivalves). 
 
 (a) Asiplionida, Anodon, Unio, (b) Siphonida, Cyclas, Pisidium,. 
 
 Cyrcna. 
 
 2. Gasteropoda (Univalves). 
 
 (a) Prosobranchiata (Operculate). 
 
 Ncritina, Navicella, Paludina, Ampidlaria, Hydrobia, Valvata,. 
 
 Melania. 
 
 (b) Pulmonifera (Inoperculate). 
 Limncea, Physa, Planorbis, Ancylus. 
 
MICROSCOPICAL EXAMINATION OF AIR 
 
 THE study of the aquatic Infusoria and Algce is more 
 particularly associated with the microscopical examination of 
 drinking-water, while the smaller Fungi, including also the 
 Bacteria and other minute and specifically light bodies, apper- 
 tain especially to the examination of air. There is, however, 
 so much in common between the two branches of inquiry, and 
 as the ultimate mode of observing the objects obtained is 
 precisely the same in both cases, a short section on the micro- 
 .scopical examination of air may be profitably appended to the 
 foregoing pages. 
 
 From an early period the record of the nature and character 
 of suspended matters in the air ha's usually claimed attention 
 as a supplement to its chemical analysis ; but the large share 
 supposed to be taken by the protophyta in the production of 
 specific forms of disease, and improved means of observation 
 have, of late years, given a great impetus to this important re- 
 search in the interests of Hygiene. 
 
 Numerous schemes have been suggested from time to time 
 for the more efficient collection of suspended matters for 
 examination, but only a cursory glance at the more important 
 of these can be given here. There is (1) the Aeroscope of 
 Pouchet, in which the air is brought by aspiration through a 
 small funnel and made to impinge upon a glass slide armed 
 with glycerine. 2. The Aeroconiscope of Maddox* which is a 
 
 * See Monthly Microscopical Journal for June'l, 1870. 
 
70 EXAMINATION OF AIR. 
 
 larger and more complex contrivance than the last, on the same 
 principle, but requiring no aspiratory arrangement. In connec- 
 tion with the use of this instrument Dr. Maddox employed his 
 well-known cultivation test, with the view of determining the 
 true nature of the spores obtained. 
 
 3. Staff Surgeon Watson used glass threads soaked in 
 glycerine, or even dry powdered glass, through which the air 
 was drawn by means of an aspirator. 
 
 4. Professor de Chaumont, F.K.S., employs a bent glass tube 
 surrounded with ice or a freezing mixture, the water of the air 
 itself as it passes through the tube is condensed, w r hile any 
 solid particles present are arrested in it. 
 
 5. The last-mentioned authority, however, considers it the 
 best plan to carry the air through a succession of bottles con- 
 taining pure distilled water, and in this the author fully concurs ; 
 for while the sediment may be readily placed under the micro- 
 scope, the liquid part can be used for the chemical determina- 
 tion of organic matter, &c. 
 
 The quantity of air submitted to experiment will be in- 
 dicated either by the capacity of the chambers used for aspira- 
 tion or by measuring the quantity of water drawn off; one 
 fluid ounce being nearly equivalent to 1728 cubic inches, so 
 that 1000 ounces would represent 1 cubic foot. (Parkes.) 
 
 It may be necessary to examine (1) the external air ; (2) 
 the air of apartments ; or, (3) the air of the soil. The first of 
 these objects may be answered by the Aeroconiscope of Dr. 
 Maddox ; the second by any other of the foregoing processes ; in 
 addition to which the examination of cobwebs should be men- 
 tioned as likely to afford useful results. Every spider is the 
 unconscious preparer of interesting experiments for the hygieist, 
 for, whatever may be the nature of the suspended matters in 
 the air, whether of an ordinary or special character, they are 
 sure to be entangled in the adhesive matrix of the web. 
 
EXAMINATION OF AIR. 71 
 
 Mineral particles, products of combustion, the heterogeneous 
 materials of dust, so called, debris of animal or vegetable origin ; 
 the down of feathers, epithelium, hair, wool, and silk ; linen, 
 cotton, and woody fibre ; starch granules, mycelia and spores 
 of fungi might be called the staple objects. The two latter, 
 however, should be especially sought for and determined, if 
 possible, with any forms of bacteria that may be present, either 
 free or in their gelatinous frond. 
 
 In all workshops where trades and manufactures are 
 carried on, the prevalent suspended matters are sure to be 
 found in- the cobwebs, though of course a quantitative deter- 
 mination would be quite out of the question. It is curious 
 to remark that in bed-rooms, linen and cotton fibres are 
 more generally diffused than the wool from the blankets, the 
 latter being usually covered with a quilt. 
 
 Lastly, for the collection of materials from the soil air, tubes 
 must be sunk to the required depth, and the air drawn up in 
 the usual way by aspiration. 
 
 Some excellent samples of soil air products were thus 
 obtained at Netley several years ago, the tubes having been 
 inserted near the outer opening of the main sewer of the Eoyal 
 Victoria Hospital. A considerable amount of epithelium and 
 other organic debris, both animal and vegetable, with fronds of 
 bacteria were observed on that occasion, and great promise was 
 afforded of the results of further investigation in this new 
 field of research. Some light also appeared to be thrown 
 upon the occasional appearance of specific diseases, without 
 any obvious clue to their mode of origin. We are now 
 aware that the epithelia cast off in the ordinary exanthems 
 may be regarded as so many little cartridges charged with 
 contagia, and that they may remain dry or moist for a 
 lengthened period and still retain their integrity as anatomical 
 elements. 
 
72 EXAMINATION OF FUNGI. 
 
 In reference to the Microscopic Fungi constituting the 
 smuts, mildeivs, and moulds the following particulars may be 
 useful. These belong respectively to the Conomycetes Hyplio- 
 mycetes and Physomycetes, so called. They all agree in having 
 a more or less tufted and interlaced filamentous Mycelium (the 
 plant proper), and a fructifying part bearing the spores, which 
 latter are either simple or septate. In the two first orders 
 the spores are naked, either grouped together (Conomycetes), or 
 solitary (Hyplwmycctes), while in the remaining order (Physo- 
 mycetes) they are enclosed in little sacs. Even where the 
 thallus or mycelium is aquatic, the fructifying part shoots 
 up into the air, at once distinguishing the fungus from any 
 algal it might otherwise resemble. 
 
INDEX. 
 
 A. 
 
 ACANTHOCYSTIS, 48 
 
 habitat of, 48 
 Acarina, 45 
 
 habitat of, 66 
 Achlya, 12 
 
 supposed to be a form of Bo- 
 trytis Bassiana, 30 
 
 sexual system of, as in Vau- 
 cheria, 30 
 
 prolifera, characters of, 30 
 Achlysia, 66 
 Achnantkece, 42 
 Achnanthes, 42 
 Achnanthidium, 42 
 Acineria, 52 
 Acomia, 51 
 Actinophrys, 44 
 
 digitata, habitat, 48 
 
 discus, habitat, 48 
 
 Eichornii, habitat, 48 
 
 Sol, habitat, 48 
 Aeroconiscope of Maddox, 69 
 Aeroscope of Pouchet, 69 
 JEshna, 67 
 Agrion, 67 
 Air of apartments, 70, 71 
 
 the soil, 70, 71 
 Albertia, 61 
 Allodorina, 37 
 Alona, 64 
 Alyscum, 51, 52 
 Amblyophis, 33 
 Amoeba, 14, 44, 48, 49 
 
 diffluens, habitat, 49 
 
 radiosa, habitat, 49 
 
 Amoebae, 14 
 
 of minute size, 6 
 Amoeboids of Volvox, 14 
 Amphileptus, habitat, 52 
 Amphimonas, 32 
 Amphipoda, 45, 65 
 Amphitrema, 48 
 
 habitat, 48 
 Amphora, 42 
 Ampullaria, 68 
 Anabcena, 25 
 Anarthropoda, 44, 46, 61 
 Ancylus, 68 
 Anguillula, 44 
 
 acefo', 60 
 
 fluviatilis, 60 
 
 glutinis, 60 
 
 tritici, 60 
 
 found in bilge water, 60 
 AnguUlulce, confounded with the 
 
 Enoplidee, 60 
 
 Anguillulidce, species of, 60 
 Anisonema, 34, 35 
 AnJcistrodesmeoe, 40 
 Ankistrodesmus, 40 
 Annelida, 11, 44, 46, 61 
 Annular ducts, 11 
 ANNULOIDA, 44, 59 
 
 definition of, 46 
 ANNULOSA, 44, 45, 61 
 
 definition of, 46 
 Annulose animals, 11 
 Anodon, 68 
 
 Antheridia of Chara, 31 
 Anthophysa, 36 
 AntliopliysacecB, 16 
 
INDEX. 
 
 ApiocystacecB, grouped with Palmel- 
 lacece for convenience, 43 
 
 classification of, 43 
 Apiocystis, 43 
 Aptera, 45, 67 
 Aptogonium, 40 
 Apus,..64s 
 Aquatic Algce, 15 
 
 systematic arrangement of, 15, 
 
 16,17 
 
 Araclmida, 45, 65, 66 
 Arcella, 14, 48 
 
 aculeata, habitat, 49 
 
 dentata, habitat, 49 
 
 vulgaris, habitat, 49 
 Artemia, 64 
 Arthrodesmus, 40 
 Arthropoda, 45, 46, 63 
 Asellus, 65 
 
 aquaticus, characters of, 65 
 habitat of, 65 
 
 (bivalves), 68 
 Aspideplwra, 6A 
 Astasia, 33 
 Astrionella, 42 
 Atax, 45 
 
 B. 
 
 BACILLUS, 14, 17 
 
 species of, 19 
 Bacteria, 10, 17, 20, 21 
 
 classification of, 18 
 
 movements of, 18 
 
 and the putrefactive pro- 
 cess, 20 
 
 of Cohn, 18 
 Bacteriacece, 16, 17, 18 
 
 affinity of, to the Oscillatorians, 
 6,19 
 
 alliance of Palmellacece with, 
 6,19 
 
 (Bacteria of Cohn), 18 
 
 in relation to Lyngbya, 22 
 Bacteriform bodies in gelatinous 
 
 fronds, 5, 6 
 
 Bacterium, 17 
 
 species of, 19 
 
 termo, 19 
 
 Zooglcea, form of, 19 
 
 minuteness of reproductive 
 particles of, as compared 
 with those of Lyngbya, 22r 
 23 
 Batracliospermacece, 16, 29 
 
 characters of, 16, 29 
 "habitat of, 16, 29 
 Batracliospermum, 20 
 Bdellia, 62 
 Beggiatoa, 24, 25 
 Bivalves (Lamellibrancliiata), 63 
 Bog moss (Sphagnum), 11 
 Bosmina, 64 
 Boston water supply (Dr. Farlow) r 
 
 24 
 
 Bracliioncea, 61 
 BracJiionus, 61 
 
 amphiceros, 61 
 Brancliiopoda, 63, 64 
 
 classification of, 64 
 Branchipus, 45, 64 
 Bulbochcete, branched filaments of r 
 28 
 
 setigera, 28 
 Bursaria, 51 
 Bursarina, 51, 56 
 
 classification, 51, 56 
 
 habit of some, 51, 56 
 
 C. 
 
 CALCIUM, carbonate, 8 
 
 Camptocercus, 64 
 
 Campylodiscus, 42 
 
 Candona, 63 
 
 Canthocamptus, 64 
 
 Carbon, source of, in aquatic plants, 
 
 20 
 
 Careliesium, 57 
 Cellssform Alga3, 16, 32 
 Cell-sap, 10 
 Ceratium, 35 
 Geratophylluin, 48 
 
INDEX. 
 
 75 
 
 Cercomonas, 32 
 Chcetogaster, 62 
 Chcetoglena, 34, 35 
 Chcetonotus, 58 
 
 larus, 61 
 Chcetophora, 29 
 Chcetophoracece, 16, 28 
 
 characters of, 28, 29 
 
 zoospores of, 28 
 
 habitat of, 29 
 ChoBtotypUa, 34, 35 
 Chalk water, 10 
 Cham, 11 
 
 antherozoids of, 31 
 
 stem of, 31 
 Characece, 31 
 
 characters of, 31 
 CMlodon, 54 
 Chilomonas, 32 
 Clilorogonium, 33 
 Chromogenous Bacteria, 18, 19 
 Chydorus, 64 
 Chytridium, 43 
 
 parasitic and colourless, 31 
 C'iZiata, 44, 49, 50 
 
 classification of, 51 
 
 their import in water, 50 
 Cladocera, 45 
 
 definition and arrangement, 64 
 Cladopliora, 27 
 
 glomerata, habitat of, 27 
 
 crispata, habitat of, 27 
 Clatlirulina, 48 
 
 habitat, 48 
 Clay, 9 
 Closteriece, 40 
 Closterium, 40 
 
 Cobwebs, examination of, 70, 71 
 Coccochloris., 38, 39 
 
 probably mistaken for the 
 
 Gonidia of lichens, 39 
 Cocconeidece, 42 
 Cocconeis, 42 
 Cocconema, 42 
 Clathrocystis ceruginosa, 18 
 
 roseo-persicina, 18 
 C 'odium amphibiorum, 31 
 
 Cvlastrum, 40, 41 
 Coelenterata, 44, 58 
 
 definition of, 46 
 
 of fresh waters, 58 
 Coenosarc, 59 
 
 Cohn's, Dr., classification of J5ac- 
 ferm, 18, 19 
 
 researches, 20 
 Colacium, 33 
 Coleoptera, 45, 67 
 OoleochcBte, 29 
 Coleps, 58 
 Colletonema, 42 
 Colpoda, 54, 55 
 Conferva, 27 
 
 simple filaments of, 26 
 
 Ijonibycina, habitat of, 27 
 
 floccosa, habitat of, 27 
 Confervacece, characters of, 16, 26, 
 27 
 
 segmentation of, 16, 26, 27 
 
 genera of, 16, 26, 27 
 
 habitat of, 16, 26, 27 
 Conferva, confounded with, 21 
 
 Lyngbya murdlia, 22 
 Coniferce, discoidal tissue of, 11 
 Conomycetes, 72 
 Copepoda, 45 
 
 definition, arrangement, and 
 
 habitat of, 64 
 CordylopJiora, 58, 59 
 
 characters of, 58, 59 
 
 lacustris, 58, 59 
 
 rivularis, 58. 59 
 Cosmariece, 40 
 Cosmarium, 40 
 Cotton, 11 
 Cristatella, 45 
 Cristatellidce, 67, 68 
 Crumenula, 34, 35 
 Crustacece, 45, 63 
 Cryptomonas, 34 
 Crystalline forms, 9 
 Culex, 45, 67 
 Cyathomonas, 32 
 Cyclas, 45, 68 
 Cyclidium, 32, 51 
 
76 
 
 INDEX. 
 
 Cyclopidce, 64 
 Cyclops, 45, 64 
 Cyclotella, 42 
 Cymbella, 42 
 Cymbellece, 42 
 Cyphidium, 48 
 
 aureolum, habitat of, 49 
 Cypridce, 63 
 Cypris, 45, 63 
 Cyrena, 68 
 Cythere, 63 
 Cytheridcc, 63 
 
 D. 
 
 DAPHXELLA, 64 
 
 Daphnia, 45, 64 
 
 Daphnidce, 45, 64 
 
 Dead or decaying organic matter, 10 
 
 vegetable matter, 10 
 
 animal matter, 11 
 Denticula, 42 
 Derostomum, 60 
 DesmidiacecB, 17, 20, 38, 39 
 
 characters of, 39 
 
 classification of, 40 
 
 aquatic, 39 
 Desmidiece, 40 
 Desmidium, 40 
 Desmids, 6 
 Desmobacteria, 19 
 Dialytic currents, 20 
 Diaptomidce, 64 
 Diaptomus, 64 
 Diatoma, 42 
 Diatoniacece, 17, 39 
 
 movements of, 20 
 
 characters of, 41 
 
 genera of, 41 
 
 classification of, 42 
 Diatoms, 6 
 Didymocladon, 40 
 Didymohelix, 6 
 Difflugia, 14, 48 
 
 oblonga and habitat, 49 
 
 proteiformis and habitat, 49 
 Dileptus, 43 
 
 Dinobryonacece, 16 
 
 classification of, 36 
 Dinolryon, 36 
 Diplodorina, 37 
 Diptera, 45, 67 
 Discoidal tissue of pine, 11 
 Discoloration of water, causes of, 6 
 Distigma, 33 
 Docidium, 40 
 
 Dotted and pitted tissue, 11 
 Draparnaldia, 29 
 Duck-weed (Lemna), 11 
 Dujardin's symmetrical Ciliata, 58 
 
 arrangement of Infusoria, 49 
 
 Rotifera, 61 
 Dytiscus, 45, 65 
 
 E. 
 
 EDBIOPHTHALMATA, 45, 65 
 Eggs of Entozoa, 12 
 Elopliorus, 67 
 Emydium, 66 
 Enclielia, 51 
 
 habitat of, 51, 52 
 
 classification of, 51 
 Enchelys, 51 
 Encyonema, 42 
 Endochrome, 10 
 
 cleavage, in Oscillatoriacece, 22 
 
 in Confervacece, 22 
 Enoplidce, parasitic nematodes, 60 
 Enter omorplia intestinalis, 32 
 Entomostraca, 11, 33 
 
 with parasitic Vorticellina, 57 
 
 description of, 63 
 Ephemera, 67 
 Epipyxis, 36 
 Epithelia cast off in the ordinary 
 
 exanthems, 71 
 Epithelial scales, 12 
 Epithelium from the cutaneous 
 surface, 12 
 
 from the mouth, 12 
 Epithemia, 42 
 Euastrum, 40 
 Euchlanidota, 61 
 
INDEX. 
 
 77 
 
 Euglena, 14 
 
 vvridis, habitat of, 41 
 Euglenacece, 16, 33 
 
 classification of, 16, 33 
 Euglypha, 14 
 
 tuberculaia, habitat of, 49 
 Eunotia, 42 
 Eunotiece, 42 
 Euplota (Ehr.), 54 
 
 classification of, 54 
 Euplotes, 54 
 
 F. 
 
 FARLOW on Clathrocystis, 18 
 
 on certain Algcs yielding 
 odours to water, 24, 25 
 Feather, 12 
 Fibres of fabrics, 12 
 
 of silk and wool, 12 
 Filamentous Algcv, 16, 17 
 Fission in Coccocliloris compared 
 with that of Desmidiacece 
 and DiatomacecB, 39 
 in Palmellacece generally, 39 
 Flagellata, 13, 14, 15, 32 
 
 classification of, 16, 32 
 Floscularia, 61 
 ornata, 61 
 Fragilaria, 42 
 Fragilariece, 42 
 Fresh-water Alga?, 15 
 
 distribution of, 16, 17 
 Polypes, 58, 59 
 Polyzoa, habitat of, 55 
 Frustule of Desmidiacece and 
 
 Diatomacece compared, 41 
 Frustulia, 42 
 Fungi (microscopic), 72 
 Fungous life and simple decay, 20 
 Furcularia, 61 
 
 G. 
 
 GAMMAKUS, 45, 65 
 
 characters of, 45, 65 
 fluviatilis, 45, 65 
 pulex, 45, 65 
 
 Gasteropoda (univalves), 45, 68 
 
 Gastrochceta, 51 
 
 Gelatinous frond of Volvocacece, 37 
 
 Germ-cells of Chara, 31 
 
 Gerris, 67 
 
 lacustris, 67 
 
 Globules of Chara, 31 
 
 GlossipJionia, 44, 62 
 
 Gomplionema, 42 
 
 Gomphonemece, 42 
 
 Goniometry, 9 
 
 Gonium, 37 
 
 union of the cells of, 38 
 and Volvox, union of the cells,, 
 sequential to cleavage, 38 
 
 Gonoltlastidia, 59 
 
 Gonophores, 59 
 
 Gordius and Mermis, 60 
 
 Gregarina, 14 
 
 Gromia, 39, 44, 48 
 
 fluviatilis, habitat, 39, 44, 48 
 hyalina, habitat, 39, 44, 48 
 
 Gymnolcemata, 67 
 
 Gyrinus, 67 
 
 Gyrosigma, 42 
 
 H. 
 
 HABITS of aquatic insects, 67 
 
 Hair of rabbit, 12 
 
 Halteria, 53 
 
 Haziness, detection of, 6 
 
 Hemiptera, 45, 67 
 
 Hemp, 11 
 
 Heteromita, 32 
 
 Heterocercus, 67 
 
 Hexamita, 32 
 
 Hicks, on the " diamorphosis" of 
 
 Lyngbya muralis, 22 
 Himantidium, 42 
 Himantoplwrus, 51 
 Hippocrepia, 45 
 Hirudinea, 44 
 
 classification of, 62 
 
 characters of, 61 
 
 habitat of, 61 
 Hirudo, 62 
 
78 
 
 INDEX. 
 
 Holoplirya, 54, 55 
 Holotrocha, 61 
 Hormospora, 38 
 Human hair, 12 
 Hyalotheca, 40 
 Hydatina senta, 61 
 Hydatincea, 61 
 Hydrcena, 67 
 
 Hydrachna (a genus of water- 
 mites), 45, 66 
 
 geograpliica, 66 
 
 globula, 66 
 
 Hydrachnea (water-mites), 66 
 Hydra, 44 
 
 classification of, 58 
 
 attenuate, 58 
 
 /Msca, 58, 59 
 
 viridis, 58, 59 
 
 vulgaris, 58, 59 
 Hydrida, 44 
 
 characters of, 58 
 Hydrobia, 68 
 Hydrocytium, 43 
 Hydrodictyon, 40 
 
 related to Pediastruni, 41 
 Hydroida, 58 
 Hydrometra, 67 
 
 stagnorum, 67 
 Hydrophilus, 67 
 Hydrozoa, 41 
 Hypliomycetes, 72 
 
 I. 
 
 ICHTHYDINA, 61 
 
 Ichtliydium, 58 
 
 podura, 61 
 Infundibulata, 45 
 
 Infusoria, 6, 3 3, 44 
 
 orders of, reduced to the 
 
 CiKata, 46 
 I^secto, 45, 47, 66, 67 
 
 K. 
 
 KERONA, 53 
 
 polyporum parasitic on 
 Hydra, 59 
 
 Keronia, 51 
 
 classification of, 53 
 
 habitat of, 53 
 Kirby and Spence, their notice of 
 
 the aquatic larvas of insects, 67 
 
 L, 
 
 LACHRYMA.RIA, 54, 55 
 Lamarck's genus, Stylaria, 62 
 LameUibranchiata (Bivalves), 45, 
 
 68 
 
 Larvae of aquatic insects, 11 
 Lemania, 29 
 LemaniacecB, 29 
 Lemna, 11 
 Lepidoptera, 67 
 
 scales of, 12 
 Leptothrix oclirea, 7 
 Leucoplirys, 56 
 
 Ley dig, Cilio-crustaceans of, 61 
 Libellula, 45, 67 
 Limncea, 68 
 Limniades, or fresh-water Potyzoa, 
 
 67,68 
 
 Limnius, 67 
 
 Limnocliares liolosericus, 66 
 Linen, 10 
 Living animals, 43 
 
 forms, 13 
 
 plants, 15 
 Lolosa, 44, 48 
 
 definition and classification of, 
 
 44,48 
 Lopliyropoda, 63 
 
 classification of, 63 
 Lumbricini, 62 
 Lynceidce, 64 
 Lyngbya, 21 
 
 in relation of Bacteriacce, 22 
 
 referred to the Oscillatorians, 
 22 
 
 in relation to TJlvacece, 22, 23 
 
 confounded with Confervacece, 
 22 
 
 muralis, dimorphism of, 22 
 Lyngbyece, 21 
 
INDEX. 
 
 79 
 
 M. 
 
 MACKOBIOTUS, 45, 66 
 Malacostraca, 45, 65 
 Marl, 9 
 Mastogloia, 42 
 Megalotrocha flavicans, 61 
 Megalotrochcea, 61 
 Melania, 68 
 Jlelic&rta, 61 
 Melosira, 42 
 MelosirecB, 42 
 Meridian, 42 
 MeridionecB, 42 
 Mermis and Gordius, 60 
 Mesocarpus, 26 
 Mesostomum, 60 
 Micrasterias, 40 
 ,Microbacteria, 19 
 Micro co ecus, 17, 20, 22 
 
 species of, 18 
 
 resembled by segments of 
 
 minute filamentary species 
 Microcoleus, 21 
 Microhaloa, 38 
 
 frond of, 19 . 
 Microscopic Fungi, 72 
 Microscopical mineralogy, 9 
 Mildews, 72 
 Milne sium, 66 
 Mineral matters, 8 
 MOLLUSCA, 45, 67 
 
 definition of, 47 
 
 proper, 47, 68 
 Molluscoida, 45, 47, 67 
 McwowZacecB, 16, 32 
 
 habitat of, 16, 32 
 
 classification of, 16, 32 
 Monas, 16, 32, 
 Monormia, 24 
 
 Monostyla quadridentata'Jol 
 Monotroclia, 61 
 JfowZds, 72 
 Movement, spontaneous, 14, 
 
 kinds of, exhibited by Pro- 
 
 toplnjta and Protozoa, 14 
 Mycelium, 72 
 
 N. 
 
 NaididcB or Naiadidce, 62 
 
 speck-like eyes, 62 
 
 how known from insect larvae, 
 
 62 
 
 JVais, 44, 62 
 Nassula, 54, 55 
 Naucoris, 67 
 Navicella, 68 
 Navicula, 20, 42 
 Naviculece, 42 
 Nematoda, 44, 46 
 
 characters of, 60 
 Nematodes, minute parasitic, 60 
 Nemertians, 60 (Note). 
 Nemertida, 59 
 Nepa, 67 
 Nephelis, 62 
 Neritina, 68 
 Neuroptera, 45, 67 
 Nimphula, 67 
 JVifeZZa, 11 
 
 stem of, 31 
 Nitzschia, 42 
 Noctiluca, 14 
 Nostoc, 24 
 
 verrucosum, Thuret on, 24 
 Nostocliacece, 16, 21 
 
 characters of, 23 
 
 classification of, 24 
 
 reproduction of, 24 
 Nostochinece, 25 
 Notonecta, 45, 67 
 Nucules of Cliara, 31 
 
 0. 
 
 ODONTIDIUM, 42 
 Odour versus taste, 24 
 CEcistes crystallinus, 61 
 (Edogoniacece, 16, 27 
 
 characters of, 16, 27 
 (Edogonium, simple filament of, 28 
 
 habitat of, 28 
 Oken's genus Proto, 62 
 
80 
 
 INDEX. 
 
 OligocJueta, 44, 62 
 
 or Setigera, characters of, 62 
 
 habitat of, 62 
 Oniscidce, 65 
 Opercularia, 57 
 Ophiocytium, 43 
 Oplirydium, 56 
 OpJiryoglena, 56 
 Oscillatoria, 21 
 OscillatoricB, 22 
 Oscillatoriacece, 16, 20, 21, 24 
 
 characters of, 16 
 
 classification of, 16, 21 
 
 allied to Nostocliacece, 21 
 
 ubiquitous, 23 
 OscillatoriecB, 21, 22 
 
 size of, 21 
 
 minute segments of .resembling 
 
 Micrococcus, 21, 22 
 Oscillatorians, 6, 19, 21, 22, 23 
 
 altitudinal range of, 23 
 Ostracoda, 45, 63 
 
 classification of, 45, 63 
 
 and habitat, 45, 63 
 Ova of Entozoa, 12 
 Oxytriclia, 53 
 
 P. 
 
 PALMELLA, 38 
 
 frond of, 38 
 Palmellacece, 17 
 
 characters of, 17, 38 
 
 classification of, 17, 38 
 
 limits of, 38 
 
 fission in, 38, 39 
 
 some referable to Volvocacece, 
 
 38,39 
 
 Paludicella, 45, 68 
 Paludina, 45, 68 
 Pandorina, 37 
 Panoplirys, 54, 55 
 Paramecia, 54 
 
 classification of, 54 
 
 habitat of, 54, 55 
 Paramecium, 14, 44, 54 
 
 aurelia, description of, 55 
 
 Parnus, 67 
 
 Particles of chalk, clay and marl, 9' 
 Pathogenous Bacteria, 18 
 Pediastrece, 40 
 
 classification of, 40 
 
 relationship of, to Desmidiace<x r 
 
 38 
 Pediastrum, 40 
 
 and Hydrodictyon provision- 
 ally associated, 40, 41 
 Pelecida, 52 
 Penium, 40 
 Peranema, 33 
 Peridiniacece, 16, 35 
 
 classification of, 16, 35 
 
 habitat of, 16, 35 
 Peridinium, 35 
 Peroxide of iron, 6 
 Phacus, 34 
 Pliilodincea, 61 
 Phryganea, 45, 67 
 Phylactolcemata, 67 
 Phyllopoda, 45, 64 
 
 definition and arrangement of,. 
 64 
 
 habitat of, 64 
 Pliysa, 68 
 Physomycetes, 72 
 Pinmdaria, 42 
 Pisidium, 68 
 Planaria, 44, 60 
 Planarida, 59, 60 
 
 classification of, 60 
 
 habitat of, 60 
 Planariola, 58 
 Planaii'ljis, 68 
 Pledonema, 25, 26 
 Pleurocarpus, 26 
 Pleuroplirys, 48 
 
 habitat of, 48 
 Pleurocarpus, 26 
 Pleuromonas, 32 
 Pleuroxus, 64 
 Plumatella, 68 
 PlumatellidoB, 68 
 Polypary, 59 
 Polyselmis, 33 
 
INDEX. 
 
 81 
 
 PolysipJionia, 24 
 Polytrocha, 61 
 Polyzoa, 45 
 
 fresh-water, habitat, 68 
 Polyzoarium, of the Limniades, 67, 
 
 68 
 
 Pond- weed (Pntamogetori), 11 
 Primordial utricle, 10, 22 
 
 in Confervacece, 10, 22 
 
 in Oscillatorice, 10, 22 
 Prorodon, 54, 55 
 Prosobrancliiata, 45, 68 
 Prostomum, 60 
 Protococcus, 37 
 
 compared with Volvox, 37 
 
 the Pediastrece, 
 38 
 
 incomplete cleavage of, 37 
 Protopliyta, 14, 15 
 Protozoa, 15, 44 
 
 definition of, 46 
 Protozoan, 14 
 Pseudopodia, 14, 48 
 Pulmonifera, 45, 68 
 Pythium, 43 
 
 parasitic and colourless, 31, 43 
 
 B, 
 
 BADIOLARIA, 44 
 
 defined and classified, 48 
 Ranatra, 67 
 Reticularia, 44, 47, 48 
 
 defined and classified, 48 
 Rhizopoda, 44, 46 
 
 distinct from the Infusoria, 46 
 Rhizopods, 6 
 Rhizoclonium, 27 
 
 species of, 27 
 
 rivulare, habitat of, 27 
 Rhynclionema, 26 
 Rivularia, 21 
 Rivularice, 21, 23 
 Kod-like Algee, 17 
 , 44, 61 
 
 vulyaris, 44, 61 
 
 Rotifera, 6, 44, 60, 61 
 
 resemble Entomostraca, 60, 61 
 characters of, 60 
 Ehrenberg's and Dujardin's 
 grouping of, 61 
 
 S. 
 
 SAND, 8 
 
 Scales of Lepidoptera, 12 
 
 Scenedesmus, 40 
 
 Schizotrocha, 61 
 
 Sciadium, 43 
 
 Scolecida, 44, 59 
 
 Scytonema, 21 
 
 Scytonemece, 21 
 
 Sediments, mode of collecting, 4 
 
 microscopical examination of ,5 
 
 high powers, and immersion- 
 lenses desirable, 6 
 Segmentation in Confervacece, 22 
 $ece and ventral uncini of JVav 
 
 adidce, 62 
 Setigera, or Oligochceta, characters 
 
 of, 62, 63 
 /S^a, 64 
 Sigara, 67 
 Silicious particles, 8 
 Silk, 12 
 
 SipJionida, 45, 68 
 Siphonacece, 16, 29, 30, 31 
 
 characters of, 30 
 
 habitat of, 31 
 Smuts, 72 
 Soil-air, 71 
 Sorotroclia, 61 
 Spectrum analysis, 9 
 Sphcerobacteria, 18 
 Spfioerozosma, 40 
 Sphagnum (bog-moss), 11 
 Sphinctocystis, 42 
 Spiral vessels and fibres, 11 
 Spirillum, 17 
 
 species of, 19 
 Spirobacteria, 19 
 
 species of, 19 
 Spirogyra, 26 
 
 G 
 
82 
 
 INDEX. 
 
 Spirostomum, 56 
 
 Spirotcenia, 40 
 
 Sponges, 44 
 
 Spongida, 44, 49 
 
 Spongilla, description of, 44, 49 
 
 spicules of, 44, 49 
 Staurastrum, 40 
 Stauro carpus, 26 
 Stauroneis, 42 
 Stentor, 56, 57 
 
 Stoneworts (Chara and Nitella), 31 
 Striatellece, 42 
 Striped muscle and fibrous tissue, 3 
 
 muscular fibre, 12 
 Stylonychia, 53 
 Surirella, 42 
 Surirellece, 42 
 
 Symmetrical forms of Infusoria, 58 
 Synedra, 42 
 
 T. 
 
 TABLE of Classification of Animal 
 
 Forms, 44, 45 
 Tdbdlaria, 42 
 Tardigrada (water-bears), 45 
 
 characters of, 65 
 
 classification of, 66 
 
 habitat of, 66 
 
 Tartrate of Ammonia, the T of, 20 
 Terpsinoe, 42 
 Thecamonadacece, 16 
 
 classification of, 34 
 Thorea, 29 
 
 Thuret on Nostoc verrucosum, 24 
 Trachearia, 45 
 Trachelius, 52 
 Trachelocera, 54, 55 
 Trachelomonas, 32 
 Trichoda, 52 
 Trichodina, 52 
 
 classification of, 52 
 TricJiomonas, 32 
 Trichoptera, 45, 67 
 Trichormus, 24 
 Trinema, 48 
 
 acinus, habitat, 49 
 
 TuUfex, 62 
 Turbellaria, 44, 59 
 
 characters of, 44, 59 
 Turbidity, 6 
 
 causes of, 6 
 
 Tylenchus,or so-called Vibrio tritici, 
 60 
 
 U. 
 
 ULVACEJE, 22, 23, 31 
 
 in relation to 1/ynglya, 22, 23 
 
 characters of, 31, 32 
 Unger, zoospores of Faucheria ob- 
 served by him, 30 
 Unicellular plants, 32 
 Unio, 45, 68 
 Urceolaria, 56 
 
 pediculus, parasitic on Plana- 
 
 ria, 57 
 
 also on Hydra, 59 
 Urceolarina, 56 
 
 classification of, 56 
 
 habitat of, 57 
 Urnatella, 68 
 Uro centrum, 56, 57 
 Urostyla, 53 
 IfaeZZa, 96 
 
 Y. 
 
 YALVATA, 68 
 Yascular plants, 11 
 Vauclieria, species of, 30 
 
 and Achlya, 30 
 
 zoospores of, 30 
 
 sexual reproduction of, 30 
 
 spores of, 30 
 Yegetable products, 11 
 Velia, 67 
 
 rivulorum, 67 
 Vibrio, 18 
 
 species of, 19 
 Yinegar-eel, 60 
 Volvocacece, 16 
 
 some confounded with Palmel- 
 lacece, 37, 38 
 
 classification of, 37 
 
INDEX. 
 
 83 
 
 Volvox, 37 
 
 amoeboids of, 14 
 
 sphere, nature of, 37 
 
 relation to Gonium and Proto- 
 
 coccus, 38 
 VorticelloB, 57 
 Vorticellina, 57 
 
 classification of, 57 
 
 habitat of, 57 
 
 W. 
 
 " Wasserbliithe," 18 
 WATER-BEARS (Tardigrada), 65 
 Water-mites (Hydracknea), 66 
 Water from the "blue-clay," 6 
 
 from bog lands, 6 
 Wool, 12 
 
 X. 
 
 Xanthidium, 40 
 
 Z. 
 
 Zooglcea form of Bacterium termo, 
 
 19 
 
 Zoology, the realm of, 14 
 Zoospores of Vaucheria, Unger's 
 
 observations, 30 
 Zoothamnium, 57 
 
 arbuscula, 58 
 Zygnema, 26 
 Zygnemacece, characters of, 26 
 
 classification of, 26 
 
 altitudinal ranges of, 26 
 Zygogonium, 26 
 Zygoselmis, 33 
 Zygotrocha, 61 
 Zymogenous Bacteria, 18 
 
 THE END. 
 
 PRINTED BY BALLANTYNE, HANSON AND CO. 
 LONDON AND EDINBURGH 
 

 1930 
 
 MOV* 
 
 
 DEC ' r