seh) # 2) rin, ft ; leet ay wee CATT Res iY at * iit Freak! B VOLT Cy Ww ‘7 rs ity nee. yee ~ 3 rit Vex yee48 i) <7A 2 sk oe Ay i}! +3 fa jet ¢ } i li Pineo lo ei cal Sei naan PRINCETON, N. J. eg ern ee Cpe I el tttmae “COX, ‘ oa 1a% et ys ' ~ ¥ ivy, .s Law.» ; t wi nae a bn oe a Oe wet ’ a 4 et Ay aoe hd =n TTT a a weet Y\\\ \\\ \ (Myrmecophaga jnbata. ) The Great Ant-Eater. LIFE IN ITS LOWER, INTERMEDIATE, AND HIGHER FORMS: OR, MANIFESTATIONS OF THE DIVINE WISDOM IN THE NATURAL HISTORY OF ANIMALS. BY PHILIP HENRY GOSSE, F-.R.S. Second Edition, LONDON: JAMES NISBET AND CO., 21 BERNERS STREET. M.DCCC,LVIL. EDINBURGH: PRINTED BY BALLANTYNE AND COMPARY, PAUL’S WORK. PREFACE. THE greatest part of the following Work was originally published in the form of successive papers in “ Excelsior.” Several entire chapters have, how- ever, been added, to make the survey of the animate creation more complete, and the whole has been care- fully revised. The design of the author has been to present to general readers, who have not the time or inclination for the study of works more elaborately technical, a glance at the more interesting phenomena of animal life; and, in particular, the diversities of structure that the physiologist recognises as he travels up the complex scale, and the wondrous adaptation which exists between these and the various functions, habits, and instincts of living beings. And, finally, he has endeavoured, unobtrusively, to lead the mind of the reader to God, and to link the perfections of creation with His glorious and immutable attributes. Lonpon, December 1856. ~ Disc ss ORR CA man CONTENTS PAGE eer PION ane cure St ra a Oe er oe ee ne RAR Eh Hrfe, wv its Rotwer Forms. CHAPTER I. INFUSORIA, ; " - : : é 9 CHAPTER II. INFUSORIA— Continued, CHAPTER Ill. PORIFERA (Sponges), : : : : ; ; : 25 CHAPTER IV. PORIFERA (Sponges)—Continued, : : ' 39 CHAPTER V. POLYPIFERA (Polypes), _. : : . ’ nt 49 CHAPTER VI. POLYPIFERA (Polypes)—Continued, , : Mama bag CONTENTS. CHAPTER VII. POLYPIFERA (Polypes)—Continued, CHAPTER VIII. ACALEPHE (Sea-blubbers), CHAPTER IX. ACALEPHE (Sea-blubbers)— Continued, CHAPTER X. ECHINODERMATA (Star-fishes), ECHINODERMATA (Star-fishes)—Continued, CHAPTER XI. CHAPTER XII. ECHINODERMATA (Star-/fishes)— Continued, CHAPTER XIII. HELMINTHIA (Intestinal Worms), PA elt Hite, in its Intermediate Forms, CHAPTER XIV. ANNELIDA ( Worms), MYRIAPODA (Centipedes), CHAPTER. XV. ¥ PAGE 65 76 85 91 99 108 116 133 145 CONTENTS. Vil . PAGE CHAPTER XVI. INSECTA (Insects), : - : ; : ‘ P 149 CHAPTER XVII. Insecta (Jnsects)— Continued, . ; : ‘ 158 CHAPTER XVIII. INSECTA (Insects)—Continued, : ‘ ‘ yom yes 170 CHAPTER XIX. INSECTA (Jnsects)—Continued, ; : ‘ ; - 178 CHAPTER XX. ARACHNIDA (S~2ders, Scorpions, and Mites), ‘ ; 184 CHAPTER XXI. ROTIFERA (Wheel-bearers), . : : : : - 195 CHAPTER XXII. CRUSTACEA (Crabs and Shrimps), . : : : ‘ 204 CHAPTER XXIII. CRUSTACEA (Crabs and Shrimps)— Continued, ; . 213 CHAPTER XXIV. CIRRIPEDIA (Barnacles), : ‘ : . ° ‘ 223 m CHAPTER XXV. POLYZOA AND TUNICATA, z : : ; > 227 CHAPTER XXVI. CONCHIFERA AND GASTROPODA, (Shell-fish), . A : 239 Vili CONTENTS. PARE Tit: Hite, i its Higher Forms. 7 ’ PAGE CHAPTER XXVII. Pisces (Fishes), - : ; ; : ; ‘ ; 251 CHAPTER XXVIII. Pisces (Fishes)—Continued, . : * ; ; : 263 CHAPTER XXIX. AMPHIBIA (Frogs and Toads), : of em ; 3 274 CHAPTER XXX. REPTILIA (Jeptiles), : ; ; : : . : 285 CHAPTER XXXI. REPTILIA (Reptiles) —Continued, . é ; : 0 ae CHAPTER XXXII. AVES (Birds), : : : ; , ; : > 304 CHAPTER XXXII. AvES (Birds)—Continued, . : 4 5 : 2 BIS CHAPTER XXXIV. TAMMALIA (Quadrupeds), z _ ; : ; : 326 CHAPTER XXXV. MAMMALIA (Quadrupeds)—Continued, . ; 7 , 336 . CHAPTER XXXVI. MAMMALIA (Quadrupeds)—Continued, . . . : 346 INDEX, 6000030640 Pi eis Sei tae ale pe caaae LIFE. INTRODUCTION. “THe works of the Lord are great ;’ but we must not estimate this greatness by their actual dimensions; else a man would be of less importance than a hippopotamus, and the Bass Rock would be immensely more valuable than either. Itis a greatness not measurable by rule and line; not to be determined by bulk and weight; it is to be estimated by far other qualities,—by the relative import- ance which the objects bear to each other, by the variety and complexity of their parts, by the elaborateness with which they are constructed, by their fitness for the pur- poses which they are destined to subserve, and especially by the degree in which they shew forth the power, wisdom, skill, and goodness of Him who made them for His own glory. Many of theanimals of which we are about to speak are so minute that the unassisted eye takes no cognisance of their presence ; yet most of these,—perhaps all, if we were able to investigate them,—are so curiously fashioned, A s ”) LIFE, so elaborately constructed, as to deserve to be included in the category of those works which the adoring Psalmist says are GREAT. We propose in this volume to describe the various phases of animal life, commencing at the foot of the scale, where we catch the first glimmering of the vital spark, and tracing it step by step upwards through its various de- velopments and changes, its forms and functions. But what is LIFE? There isa mystery couched under that little word which all the research of philosophers has not been able to solve. Science, with the experience of ages, with all the appliances of art, and with all the persevering inge- nuity and skill that could be brought to bear upon it, has ardently laboured to lift the veil; but philosophy, and science, and art, stand abashed before the problem, and confess it a mystery still. The phenomena, the properties of life, are readily observable. We take a bird in our hands; a few moments ago it was full of energy and animation ; it shook its little wings as it hopped from perch to perch ; its eyes glanced brightly, and its throat quivered as it. poured out the thrilling song which de- lighted us. Now the voice has ceased, the eye is dim, the limbs are stiffening, and we knowthat it will move no more. Chemical changes have already begun to operate upon its organs ; decomposition is doing its work, and goon the beautiful little bird will be a heap of dust. We say that its life has gone ; but what is it that has gone? If we put the body in the most delicate balance, it weighs not a grain less than when it was alive; if we measure it, its dimensions are precisely the same; the scalpel of the anatomist finds all the constituent parts that made the CELLS. 3 living being ; and what that mighty principle is, the loss of which has wrought such a change, alike eludes research and baffles conjecture. We are compelled here to recog- nise the Great First Cause, and to say, ‘ In Him we live, and move, and have our being.” The researches of modern science, however, aided by the inventions which it has brought into requisition, though they have been unable to throw a single ray of light on the nature of Life itself, have yet done much to make us familiar with its phenomena. The microscope, in par- ticular, has opened to our inquiry what we may call a world of life, under phases and forms as strange and sur- prising as they were before unknown. It has enabled us also to separate and analyse the various substances or tissues of which the highest forms of animate being are composed, and to resolve them into their first elements. Numerous and diverse as are these substances— bone, cartilage, sinew, nerve, muscle, hair, the teeth, the nails of the hand, the transparent lens of the eye,—all are reducible to one kind of structure. This structure is a cell. All organic substances are made up ofcells. The pri- mary organic cell is a minute, pellucid, globule, invisible to the naked eye, and containing within it a smaller cell, called the nucleus, which again contains a still more mi- nutegranule, called the nucleolus, orlittle nucleus. Eventhe highest animals, in the early development of the embryo, are composed entirely of nucleated cells, which afterwards assume the forms peculiar to the various tissues. In the lowest classes of animals, their more simple bodies consist almost entirely of cells of this kind. If we take a minute portion of the gelatinous flesh of a medusa or a zoophyte, 4. LIFE, and crush it between two plates of glass beneath the microscope, the substance is presently resolved into a multitude of oval pellucid granules, each of which for a short time maintains a spontaneous motion, sometimes rotating upon itself, but more commonly jerking or quivering irregularly. These are the primary cells, and their motion is, doubtless, to be attributed to the presence of certain hairs, called cilia; for we cannot believe that it is at all connected with currents in the fluid that surrounds them, to which it has sometimes been referred. Cilia play an important part in the economy of all animals. Even in the highest forms, many of the inter- nal surfaces are furnished with them, and nearly all the motions which do not depend upon muscular contraction are produced by them. In the lower tribes, especially those which are aquatic, the office of these organs becomes more important and more apparent, until in the very lowest we find all movement originating with them. The form of these essential organs is that of slender, tapering hairs, commonly arranged in rows, resembling the eyelashes, whence their name. The base of each hair is attached to the surface of the body to which it belongs, its whole length besides being free.* During life each cilium maintains an uniform motion of a waving or lashing kind, bending down in one direction and then straightening itself again. ‘This movement is not performed by all the cilia together or in unison, but in rapid succession : for example, the instant after one has begun to bend, the next begins, then the next, and so on; so that before the first has re- * Perhaps it would be most correct to consider a cilium as formed by the wall of a cell drawn out to a fine point. CILIA. 5 sumed its erect condition, perhaps half a dozen of its suc- cessors are in different degrees of flexure. This sort of motion will probably be better understood by referring to that beautiful and familiar spectacle, the waves produced by the breeze upon a field of standing corn. The motion is exactly the same in both cases. The wind, as it sweeps along, bends each stalk in turn, and each in turn reas- sumes its erect posture ; thus the wave runs steadily on, though the stalks of corn never remove from their place. The appearance of the ciliary wave, when viewed under favourable circumstances with a good microscope, is so exquisitely charming, that even those who have been long familiar with it can scarcely ever behold it without admiration. ee > Oe APiclews a 4 : A ns ; aan r eS Sn ea anes eee hee atte » ee Si 7 ey a4 <@ a PART L LIFE, IN ITS LOWER FORMS. taepdl ter =" os x 2s 9. hve ea Ce ee at ent ate eas ie SG Ties ie Meee ay pore mi ie 4% < nt * ' ¥ a be* - ad s | * i * Lat . ie C4 » i } a fol ae j b ‘ ‘ F Ve, bar tyes eet roses ison ee Yeon ; Placa Sg RBA Mie. £ (ie as F 7 . : : i i Ast. pty he A ei aa : a oe " a } *s 1 ia 4 ant 1a”, hry s We Wee bee: "SC _ aor ee Infusoria. CHART E Be 1. INFUSORIA. THE most minute and the most simple of all living beings, so far as the powers of the best microscopes have yet reached, closely resembles such a ciliated cell as we have been describing. It has been called the Twilight Monad (Monas crepusculum) ; so named because it is considered to be, as it were, the unit of existence—the point where the glimmering spark of life first emerges out of the darkness of nonentity. It consists of a tiny speck of pellucid mat- ter, rounded in form, and supposed, from its movements and from analogy, to be furnished with a single cilium, by the lashing action of which it rows itself through the water. No words can convey an adequate idea of the \ size of an animal so minute as this; but the imagination | may be assisted by supposing a number of them to be | arranged side by side in contact with each other, like the beads of a necklace, when twelve thousand of them would | ~ go comfortably within the length of a single inch.* Hight | * An esteemed lecturer is reported to have lately said that the cheese-mite is an animal of middling size in existence; in other words, that there are creatures as much smaller than it as there are larger. This is not strictly correct, The largest animal known is the Rorqual (Balenoptera bodps), which ¢ 10 LIFE, IN ITS LOWER FORMS, hundred thousand millions would be contained in a cubic inch ; and as they are found swarming in water to such a degree as that each is separated from its neighbours by a space not greater than its own diameter, a single drop of such water has been estimated to contain a thou- ., sand millions of living active beings. If we take a bunch of leaves, of the common sage, for example, or a few twigs of hay, and, tying them into a bundle, suspend them in a jar of water, allowing the contents to remain untouched, but exposed to the air, some interesting results will follow. If we examine it on the second day, we shall find a sort of scum covering the surface, and the whole fluid becoming turbid, and slightly tinged with green. If now we take, with the point of a quill or a pin, a minute drop of the liquid, and examine it with a good microscope under a magnifying power of about two hundred diameters, we discover the water to be swarming with animal life. Immense multitudes of minute round or oval atoms are present, which move rapidly with a gliding action. These are animals of the genus Jonas just described. Among them we shall probably see other bodies still more minute, resembling short lines, most of which are seen to be com- posed of more or fewer bead-like bodies, united into a chain. These occasionally bend themselves, wriggle nimbly, and effect a rather rapid progression in this manner. The scum, or transparent pellicle, is found to be composed of countless millions of these latter, congregated about as is about 100 feet in length. The smallest is the Twilight Monad above men- tioned, whose dimensions are saa39th of an inch. It is evident that the middle term between these extremes is 3d of an inch, which is about the length of the common house-fly, which may be therefore considered as an animal of medium size in creation, INFUSORIA. 13 thickly as they can lie, into patches. They constitute the genus Vibrio. Several may be seen among them briskly wriggling along, which resemble a little coil of spiral wire. Such forms bear the generic appellation of Spirillum.* As all infusions of vegetable or animal substances are found to be speedily filled with animals resembling these, in great variety, though not always of the same species, the circumstance has been seized by naturalists to afford a name by which this class of beings should be distin- guished. ‘They have been therefore called Infusoria, or infusory animalcules; a very extensive group, and one which, in a more advanced state of our knowledge, it may be found desirable to divide, since it includes animals of very different grades of organisation. Those of which we have spoken are among the simplest of these forms: we shall now describe others of a higher place in the scale, and more attractive in their appearance and in their habits. Every day during which the infusion is allowed to stand, it will display fresh forms, and generally those which appeared most abundantly in the earlier stages will be found successively to die out, and be replaced by other species. The more highly organised kinds will usually be discovered at the later periods. But there is a very beautiful form, and one which can- not fail to possess great interest for the young microscopi- cal student, which commonly occurs pretty early. Perhaps we shall see some of the stalks of the macerated hay, or floating portions of the semi-decomposed leaves, clothed with what appears to the naked eye to be a very delicate * Recent researches, however, render it probable that these are the earliest stages of Intestinal Worms. 12 LIFE, IN ITS LOWER FORMS. white mucor, or mouldiness. Such a fragment placed in the “live-box” of the microscope will not fail to present many groups of one of the most attractive of all the Infusoria, the lovely genus Vorticella. (See Plate I. Fig. 1.) A little bell of glassy transparency is affixed by a sort of nipple to a slender filament or stem, eight or ten times its own length. The bell has a broad and thick rim or lip, within which, on the two opposite sides, are apparently two pairs of cilia,* which are sometimes withdrawn, sometimes protruded, and are vibrated with a rapid snatching motion (a).. The result of this is very curious, for when any atom in the water is drawn near the bell-mouth, it is not driven away or drawn in, but is whirled round in a con- tinuous circle above either pair. This gyration may be frequently seen, even when the cilia are so far withdrawn as to be invisible. Within the glassy bell are seen many pellucid bodies, which have been supposed to be numerous stomachs ; these are continually changing their sizes, forms, and relative positions ; since they are not defined vesicles, but simply excavations of the common mass of gelatinous flesh, produced by the escape of the food from the open extremity of the gullet. Besides these globules, there aro scattered granules, a contractile bladder, and a band-like dark organ, which is called the nucleus, and which appears to possess the reproductive function. Tn general, the animal floats loosely through the water, the thread fully extended, but rarely so straight as not * The cilia are really placed ina complete circle around the bell-mouth; and the appearance above mentioned is merely an optical illusion, dependent on the relation of these parts of the circle to the eye, as viewed in perspective. INFUSORIA. Be to shew slight undulations ; the basal extremity of the stem is affixed to the support ; and the bell slowly roams about, with the length of its tether for a radius, now turning its open mouth, now its sides, and now its foot to the eye. On any shock, such as a tap with the nail on the stage or “live-box,’—instantly, with the quickness of thought, so that the eye can scarcely trace the motion, the long stem is contracted into a beautiful spiral (0), suddenly bringing the bell close to the point of adhesion, when it immediately, but gradually (c), uncoils to its full length. It does not seem alarmed by tapping, except when fully extended ; for if we tap the box all the time it is unfold- ing, it does not shrink again, until it has reached its full extension, but then it does instantly. It frequently, how- ever, springs back again, when partially uncoiled, of its own accord, several times in succession. Hence we may presume that the spiral contraction is the result of alarm ; but that though alarm may be felt from the bell’s contact with substances in the water, or from currents, &c., at any time, a shock or tap produces this effect only when the stem is tense, and capable of vibration. The whole of the actions of this little animal are very sprightly and elegant. The ordinary increase of the animals of this class is by self-division. In the Vorticelle it takes place in the fol- lowing manner :—One of the full-grown bells begins to alter its form, becoming first globular (0), then a flattened sphere (c), presently a slight notch or depression is observed in the upper part of the outline, and it soon becomes apparent that this depression is a constriction extending all round, which gradually becomes deeper and more 14 LIFE, IN ITS LOWER FORMS. marked (d). As the two divisions become more separate, each assumes an oval form, united at length to its fellow only at the base (¢). At this time the motion of the cilia is plainly visible, forming a circle in each within the body, near the summit. As the process goes on, the con- nexion between the two is reduced to a mere point, and they become capable of separate motion, so far as to diverge and look in opposite directions; the point of union being the common stem (/). At this stage we may observe that the bell which is destined to remain is open at the top, within which the ciliary waves are chas- ing each other in continuous wheels, the other bell being closed at the summit. But on the latter, which is ultimately to be thrown off, a new and highly interesting phenomenon appears. The cilia, which before the division had played around the mouth, have become obliterated, probably by absorption ; the orifice at that extremity has closed up permanently, for this is to be the base of the new animal; and a new bell-mouth and a new wheel of cilia, are to be formed at the opposite end, which at present remains attached to the common stem. The first indication we can detect of this new formation is a very slight motion in the water, a little quivering around what we must as yet call the basal part. Presently there appear waved hairs, which seem very flexible, and the motion of which resembles that of a fringe of loose silk moved through water, an action very different from the regular waves of perfect cilia. These waving hairs increase rapidly in length, and in the vigour and rapidity of their undulations, which gradually become decidedly rotatory, producing at length strong currents in INFUSORIA. 15 the surrounding water, and imparting a tremulous motion to the whole bell. It is evident now that the separation is imminent, for the minute point of connexion cannot long withstand the rushing current of these rotatory paddles. At length the bell suddenly shoots away (g), gliding with great swiftness through the water, borne by its numerous paddles, and whirls about for a while in a headlong, giddy manner. At length it chooses a place of rest, becomes stationary, fixes itself by that end which had formerly been the mouth, but is now closed up, and presently begins to rise by the development of a slender stalk, which, though minute at first, quickly increases in length, until it attains the original dimensions. But another mode of increase, yet more singular, has been fouud to prevail in these creatures, At certain periods the Vorticella closes its ciliated mouth, and passes into a sort of chrysalis state, taking a globular or bladder- like form, with a distinct double wall. After remaining a while in this encysted condition, pencils of slender fibres shoot out from two or more points, each fibre terminated by a minute globule. This form has been often detected by the older observers, without a suspicion that it was but - a, stage in the metamorphoses of Vorticella. By Ehrenberg it was constituted a distinct genus, underthe nameof Acineta. According to Dr Stein, who first made known the true nature and relations of these forms, the Acinete “have no roouth ; it is, indeed, difficult, from the toughness of their tunic, to effect a rupture; no food or stomach sacs, like- wise, can be found in them, their substance being homo- geneous, granular, soft, and containing, besides its very 16 LIFE, IN ITS LOWER FORMS. fine granules, some larger globules, probably of oil (fat), a contractile sac anteriorly, and an elliptic discoid granular nucleus, often accompanied by another smaller, finely granular, discoid globule, well defined. | “The larger nucleus is the one destined to undergo the first change; this it does by the development of fine cilia around its periphery, which actively vibrate, and so cause its rotation, Whilst this goes on, it increases in size, ad- vances towards the anterior of the Acineta, which takes on active contractions, and thereby ultimately ruptures its integument, allowing the embyro (ciliated nucleus) to escape. On its emergence, the embyro swims away rapidly by means of its cilia ; what further changes it undergoes are yet to be discovered. * However, the part the Acineta body has to perform is not completed by the production of the one embryo ; but the same process has to be repeated again and again, until its formative granular mass is used up, when the Acineta becomes a contracted, shrivelled, empty sac, seated upon the persistent stalk. . “ After an emission of an embryo, the Acineta body contracts strongly ; some of its diverging fibres shorten, whilst others are entirely withdrawn. This contracted condition, after lasting for a time, relaxes; the Acineta resumes its usual movements; the fibres spread out anew, moving about as usual in various directions ; and it finally regains its original characters, save that it is smaller, and, instead of a smooth, even surface, it has its tunic thrown into folds or undulations, The spot from whence the embyro escaped soon becomes imperceptible.”* * Condensed from Stein, in Pritchard’s Hist. of Infus. Animale., p. 587. (Ed. 1852.) INFUSORIA. is CHAPTER II. INFUSORIA, Continued. Tuts brief sketch of the history of the Vorticella will serve to illustrate that of the whole class of Infusoria ; as the facts, at least the earlier ones, with slight modifica- tions, are common to all. The round bodies resem- bling beads, which we mentioned as scattered in the interior of the bell, are characteristic of the whole of these animals, Professor Ehrenberg considers them to be so many stomachs, connected either with the com- mon mouth, or with an intestinal canal which runs through the body. To this conclusion he came by pro- secuting a series of curious and ingenious experiments. By mixing coloured substances, such as carmine or indigo, with the water in which the animalcules were living, he found that they readily imbibed them, and that the colouring matter was presently accumulated in these in- ternal vesicles, which then appeared crimson or blue, according to the pigment employed. Hence he applied the name Polygastrica to the class, a term which would be @8 appropriate as it is significant were it quite certain that his conclusions legitimately follow from his premises. But later naturalists have doubted that these vesicles are B 18 LIFE, IN ITS LOWER FORMS. stomachs at all, nor have they been able to discover any such common tube as the learned professor describes. The true explanation of the phenomena appears to be, that the gullet terminates by an open extremity in the midst of the gelatinous flesh that occupies the general cavity of the body; and that the food, as swallowed, passes in pellets, enveloped in mucus, into this flesh, having assumed globular forms from the rotation pro- duced by the lining cilia of the gullet. These pellets are partly absorbed, and partly expelled by a proper orifice. There is another curious organ found in a large number of these animals, the office of which is even more puzzling. It is commonly known as the contractile bladder. If we are watching one of these animalcules, a Paramecium, for example, we see in a particular part of the body a circular space perfectly clear and colourless, which gradually en- larges until it takes the appearance of a distended globose bladder. When arrived at its utmost dimensions it sud- denly contracts to a point, and presently begins to enlarge, until it reaches its former size and appearance, when it again contracts as before. This alternation of distensions — and contractions goes on continuously ; the latter taking place at regularly measured intervals, perhaps of about a minute. We feel assured, from numerous observations, that the bladder is filled by some fluid which gradually percolates into it, and that this is discharged by the periodic contraction ; but what is the nature of this fluid, and what relation the process sustains to the general economy, we are ignorant. Our own opinion is, that the organ, with its accessories, is the first rudimentary form of the urinary system of higher animals, INFUSORIA. . 19 The external organs of these animals are few and simple. In all, except the lowest forms, the mouth is surrounded by rows of strong cilia, by the vigorous vibrations of which currents are perpetually formed in the water, which bring to the entrance of the stomach whatever particles of matter suitable for food there may be float- ing about. Besides these, the whole surface of the body is, in many species, clothed with delicate cilia, which act as paddles to row the animal rapidly along. A few of the more highly organised genera are furnished with bristles, styles, or hooks, which appear to be merely cilia more than usually developed and deprived of vibratile power. They serve as instruments of locomotion, for crawling, or climbing about aquatic plants. In many species we see a red speck, which is probably an organ of sight in a very rudimental condition ; perhaps possessing a sensibility to the presence of light without distinct vision. Some of the members of the class are protected by a shell formed of silex, or the substance of flint. These shells may be considered as indestructible, and they are found in a fossil state, the memorials of Infusoria which existed in former ages in multitudes that defy calculation, and almost exceed belief. There is in Bohemia a moun-\ . tain composed of a substance which, from its use in the arts, has long been known by the name of polishing slate. | Professor Ehrenberg has found this substance to be en- tirely composed of the shells of fossil Infusoria, the genera and species of which can even yet be distinguished. Of these, he computes that 41,000,000,000 are contained in every cubic inch of a stratum fourteen feet thick. On the shores of certain lakes in Sweden a fine powder is 20 LIFE, IN ITS LOWER FORMS. found in large quantities resembling flour in appearance. The natives of these districts have long been in the habit of collecting this, and of using it, under the name of bergmehl, or mountain-meal, as an article of food. This, also, the microscope reveals to be composed of the remains of incalculable millions of shelled Infusoria. Some interesting examples of a protecting case of dif ferent structure are found in the family Tintinnide. They are animals allied to the Vorticella, but inhabiting a transparent tube, open at the top, of a gelatinous or mem- branous texture. This case is affixed to the stems of water-plants, sometimes by its base, when it is erect, at others prostrate, adhering by its side, and occasionally _ placed at the tip of a footstalk, like a tiny handbell turned upside down. The animalcule protrudes to a consider- able distance from the margin of its glassy cell, unfolding a ciliated mouth like that described in the preceding chapter ; but on the least disturbance it shrinks, a little shapeless ball, down to the very bottom of its tube. Sometimes two animals dwell in the same tube, and their amicable movements are viewed with ease through the transparent walls of their miniature crystal palace. Those who have never looked through a microscope can scarcely form an idea of the beauty of these little animals, Engravings of many of them, and technical descriptions, are, indeed, to be found in published works ; but of their brilliant transparency, their high refractive power, resembling that of flint-glass, their sudden and sprightly motions, their general elegance and delicacy, and the appearance of intelligence which they display, neither books nor engravings will give any adequate conception. INFUSORIA. 21 On the surface of stagnant ponds may often be seen, especially in spring, a stratum of what looks like a bright green powder. If a small quantity of this be taken up and examined, many curious and beautiful forms will be discovered. A large portion of the substance will pro- bably consist of different species of the genus Huglena—little active creatures, somewhat resembling fishes in shape, of a rich green hue, with a large red eye. Among them we may find what is sometimes called the High-priest’s Breastplate (Gonium pectorale), consisting of sixteen oval green masses, disposed regularly in a transparent shell of square form, like emeralds set ina plate of the purest glass. Another brilliant casket of gems is the Pandorina morum (Plate I. fig. 2), a species which we have taken in the neighbourhood of London. It is a crystal globe en- closing about thirty globose animals of a rich green hue, from each of which proceeds a long, whip-like proboscis, about as long as the radius of the globe. By means of these filaments it proceeds rather quickly, rolling over in an irregular manner as it goes. Its appearance is very rich and beautiful, particularly when the light is transmitted, as it sometimes is, through the interstices of the animal- cules, and gleams through their dark-green bodies. The newly-invented paper-weights, consisting of balls of solid glass, in which are imbedded some beautiful coloured objects, will give an idea of this creature. Many kinds are interesting from the close resemblance in form which they display to other well-known objects, animate or inanimate. The Volvow (fig. 3) rolls majesti- cally through the water, revolving regularly on its axis like an artificial globe ; and as it is of greatly superior 22 LIFE, IN ITS LOWER FORMS. dimensions to most others of the class, we may compare it to the planet Jupiter surrounded by a host of moons.* The Stentors, also, are of comparatively large size, being distinctly visible to the naked eye ; these resemble trum- pets in form. One beautiful species, hence named Trachelocerca olor, charms the eye by its close resemblance to a swan. It has a plump, rounded body, a slender- pointed tail, and a very long and graceful neck, the motions of which, thrown into arching curves, and pro- truded in every direction, give the most lively represen- tation of the elegant waterfowl after which it is named. Indeed, in one species of this genus, 7. biceps, we may see the living representative of the celebrated bird usually considered to be as scarce as tho lost Dodo itself—the swan with two necks. The genus Ameba has long been celebrated among microscopists, from its power of constantly changing its form, whence it is sometimes called the ‘‘ Proteus.” It consists of a mass of clear, jelly-like matter, with a few eranules, two or three of the supposed stomachs, and a contractile bladder. But its peculiarity is that which we have just mentioned. It is ever altering its outline; and to so great a degree, that not only are no two ever found alike, but the same specimen does not retain the same shape for two successive minutes. Here a point projects and gradually pushes out more and more, while a sinuosity * Many of the organisms which, principally on account of their spontaneous movements, were considered as animals, when Professor Ehrenberg published his elaborate work, ‘‘ Die Infusions-thierchen,” are now generally admitted to be plants. And there are not a few who contend that the beautiful Gonium and Volvox must be removed from the domain of the zoologist also. As this position is not, however, quite established, their elegance pleads for them to remain for the present where we have put them. INFUSORIA. 23 is forming in some other part; one portion is contracting, another enlarging ; so that the only idea that can be given of its shape, is by comparing it to the figure of a country upon a map, which is perpetually transformed into that of some other country. These are but a few examples of the variety of form which this curious class of animals presents to us: it re- mains now only to give, to those who may be desirous of examining them for themselves, a few instructions to aid their researches. A good microscope is, of course, indis- pensable ; if the study is intended to be pursued scienti- fically, a compound achromatic, with magnifying powers ranging from fifty to five hundred diameters, must be employed ; but very much entertainment, and a good idea of many of the forms, may be obtained with an ordinary simple microscope of three powers. The pene- trating and defining properties of a microscope are of more importance than mere enlargement. If we were asked where specimens are to be obtained, we might reply, almost everywhere, provided water be present : but even in the air they have been lately detected by the eminent Prussian professor. In ditches and ponds, in the trenches of meadows, in the ruts of highroads, in marshes, in lakes and rivers, in estuaries, and . even in the sea, various species may at almost all times be found. Stagnant waters, especially such as are covered with a thick scum, contain some species in immense abundance, but these are generally of the simplest struc- ture: little hollows in boggy ground, especially where a red sediment betokens the presence of oxide of iron, fre- quently contain species of great rarity and beauty ; but 24 LIFE, IN ITS LOWER FORMS. clear standing water, in which the more delicate aquatic plants grow, and particularly when covered with duck- weed, will be found the most productive resource both for number and variety. The mode of collecting them is very aaa The water must be dipped up in a phial, which may be tied to the’ end of a walking-stick ; a moment’s examination of its contents with a pocket-lens will determine whether the water is worth carrying home. If no moving particles are seen, another dip may be taken elsewhere; should this likewise prove valueless, another locality should be sought. When brought home, a small drop may be taken at random, and placed in what microscopical observers call an aquatic box or live-box; a small fragment of duckweed-root, or the stem of some slender water-plant, put in also, will aid the search : this should then be examined with a low power at first, the observer proceeding to the use of higher powers for the closer examination of particular specimens. Should any of our readers who may possess a micro- scope, or access to one, be disposed to investigate these minims of existence, we shall be disappointed if they do not find objects which will not only please their fancy and inform their understanding, but also give them fresh and unexpected ideas of the ways of Him whose glory is no less displayed in the construction of an animalcule than in the creation of a solar system. 7 i Aan a “! ‘ ae te f - iz , »- nl a) i pt \ ‘3 ' ; ; “4 ‘ eer Af ) . a7 et eel we Bal en i, 4 ve, ' i A * =; Tap © ae « PM i a vee } iad Nite oa ee pieiiey & ec pe ah nt r) i - har sal or Lae ane , eA tae Fes Pak epee oS hee rs vag ae a OF he aI Ys ye? 0 ua . : i ie | ‘ ee 4. ee ieee same c= SP LtA 2 x } Wa v oe | ead oA) 5 Sy wy al | % y Pa ae bd J ¢ ee a ae { “ 7 m bgt Ay’ 7 ; Sug a nid & } ae S yetn 1 ene ae ; Bose RV Aes 7a 0 #y mM Sih tS iat eee ({ | i liq Uta Po rift or ra. (S po ne ges.) SPONGES. 2a CHAPTER ITI. PoRIFERA (Sponges). WHAT is an animal? Nothing seems easier than to answer this question. Our thoughts in a moment recall the image of the stately horse shaking his neck of thunder, and projecting columns of vapour through his translucent nostrils ; or the painted tiger crouching in the jungle, awaiting in lithe readiness the approach of some unconscious antelope to make his mortal spring; or the trembling antelope itself, as it pants, and struggles, and groans beneath the fangs of its merciless foe. Nothing appears simpler than to define an animal. ). They swim energetically, with a vibratory rotation on _ the long axis ; increase by self-division (c) ; and at length, by transverse constriction and elongation (d), grow into jointed vegetable threads (e), the lowest joint still retain- ing the eye-speck. This interesting phenomenon, the reality of which has been ascertained by Kiitzing beyondall possibility of doubt, dissipates the idea of any supposed line of demarcation between the organic kingdoms of nature ; and proves that the disputes which have been so pertinaciously maintained between zoologists and botanists on their boundary ques- tion, have been concerning words rather than things. Among the organisms the position of which has been most debated, are some very familiar to us, from our habitual employment of some of the species for domestic purposes. ‘They constitute the extensive and widely- distributed class PorirEera, or the Sponges, the history of which forms the subject of this chapter. We shall not enumerate the names or record the opinions of the contro- SPONGES. a | versialists who have contended for scientific dominion over these bodies ; naturalists of the highest eminence have been arrayed on each side. We shall content ourselves with giving the judgment of Dr Johnston, the learned historian of British Sponges, and one well worthy of being listened to with respect; and we quote him the rather because his decisions, while they tersely exhibit the real merits of the case, have so yielded to accumulated evidence as to shift from the side first advocated to the opposite. When the “ History of the British Zoophytes” was published, the author omitted the Sponges, and gave the following summary of his reasons for so doing :—“ If they are not the productions of Polypes, the zoologist who retains them in his province must contend that they are, indivi- dually, animals ; an opinion to which I cannot assent, seeing that they have no animal structure or individual organs, and exhibit no one function usually supposed to be characteristic of the animal kingdom. Like vegetables, they are permanently fixed ; like vegetables, they are non- irritable ; their movements, like those of vegetables, are, extrinsical and involuntary ; their nutriment is elaborated in no appropriated digestive sac ; and, like cryptogamous vegetables, or alge, they usually grow and ramify in forms determined by local circumstances ; and if they present some peculiarities in the mode of the imbibition of their food and in their secretions, yet even in these they evince a nearer affinity to plants than any animal whatever.” * A few years later, however, the learned writer published his “ History of British Sponges,” in the introduction to * Brit. Zooph., p. 29. 32 LIFE, IN ITS LOWER FORMS. which he elaborately examines the whole question, con- cluding with the following verdict :—“ Few, on examining the green Spongilla, would hesitate to pronounce it a vege- table, a conclusion which the exacter examination of the naturalist seems to have proved to be correct ; and when we pass on from it to an examination of the calcareous and siliceous marine genera, the impression is not so much weakened but that we can still say with Professor Owen, ‘that if a line could be drawn between the animal and vegetable kingdoms, the Sponges should be placed upon the vegetable side of that line.’ We shall possibly, how- ever, arrive at an opposite conclusion if, proceeding in our inquiry, we follow the siliceous species, insensibly gliding, on the one hand, into the fibro-corneous Sponge, filled with its mucilaginous fishy slime, and, on the other, into the fleshy Tethya, in whose oscula the first signs of an obscure irritability shew themselves. Sponges, therefore, appear to be true zoophytes; and it imparts additional interest to their study to consider them, as they probably are, the first matrix and cradle of organic life, and exhibit- ing before us the lowest organisations compatible with its existence.” * Many of our readers are probably cognisant of only one kind of Sponge,—the soft, plump, woolly, pale-brown article, so indispensable in our dressing-rooms ; or, at the most, two, if they chance to have noticed the large-pored, coarser sort with which grooms wash carriages. It may surprise such persons to be informed that the streams and shores of the British Isles produce sixty or seventy distinct species of Sponge ; and that every coast, especially in the * Brit. Sponges, p. 68, SPONGES. oo tropical seas, where they are very numerous and varied, has species peculiar to itself. A Sponge, as it is used in domestic economy, is merely a skeleton : it is the solid frame-work which in life sup- ported the softer flesh. This skeleton is composed of one or two of the following substances,—flint, lime, and a peculiar horny matter. The first two are crystallised, and take the appearance of spicular needles either simple or compound, varying greatly as to their length, thickness, shape, and curvature, but constant in form in the same species. The horny matter, of which the common domestic Sponge affords an example, is arranged in slender, elastic, translucent, tough, solid fibres, united to each other irregularly at various points, and in every direction, and thus forming an open netted mass commensurate with the size of the whole sponge. The horny Sponges are almost confined to the warmer seas, but the siliceous and calcareous kinds are common with us, especially the former. The solid parts are, during life, invested with a glairy transparent slime, so fluid in most species as to run off when the Sponge is taken out of its native element; yet this clear slime is the flesh of the animal. The spicula, whether of flint or lime, or the horny fibres, are so arranged as to form numberless pores, with which the whole animal is perforated; it is to these that our common Sponge owes its most valuable property of imbibing and retaining water, as we shall presently see when we investigate the history of this species in detail. In life the surrounding water is made to flow through these pores by a continual current (interrupted, however, at the will of the animal) from without into the interior of the c o4 LIFE, IN ITS LOWER FORMS. body. But whither goes this current? The pores lead into large channels, which also run through the body, like the drains from individual houses, which run into the main sewers ; and these open on the exterior of the body by more or less conspicuous orifices called oscuda, or mouths. From these latter the effete water is poured in forcible streams, and thus a circulating current is maintained. It was Dr Grant who first established the fact of this current from personal observation. His account of the discovery is full of interest. ‘I put a small branch,” he observes, “of the Spongia coalita, with some sea-water, into a watch-glass, under the microscope, and, on moving the watch-glass so as to bring one of the apertures on the side of the Sponge fully into view, I beheld, for the first time, the splendid spectacle of this living fountain vomiting forth from a circular cavity an impetuous torrent of liquid matter, and hurling along, in rapid succession, opaque masses, which it strewed everywhere around. The beauty and novelty of such a scene in the animal kingdom long arrested my attention ; but after twenty-_ five minutes of constant observation, I was obliged to withdraw my eye from fatigue, without having seen the torrent for one instant change its direction, or diminish in the slightest degree the rapidity ofits course. I continued to watch the same orifice, at short intervals, for five hours —sometimes observing it for a quarter of an hour ata time,—but still the stream rolled on with a constant and equal velocity.” ‘The vehemence of the current then began to diminish, and in about an hour ceased.* No one can have looked with any attention at the rocks * Edin, Phil. Journ, xiii. 102. SPONGES, 35 on any part of our shores that are left exposed by the sea at low spring-tide, without noticing irregular masses of yellow fleshy substance incrusting them, which rise into little conical hillocks perforated at the extremity, like the crater-cones of tiny volcanoes. This is the Crumb-of-bread Sponge (Halichondria panicea), one of our most common species ; and it is peculiarly suitable for displaying the currents of which we have been speaking (Plate II. fig. 2). Dr Grant remarks, that it presents the strongest current which he had seen. ‘Two entire round portions of this Sponge,” he says, ‘‘ were placed together in a glass of sea- water, with their orifices opposite to each other at the distance of two inches; they appeared to the naked eye like two living batteries, and soon covered each other with feculent matter. I placed one of them in a shallow vessel, and just covered its surface and highest orifice with water. On strewing some powdered chalk on the surface of the water, the currents were visible at a great distance ; and on placing some small pieces of cork or of dry paper over the apertures, I could perceive them moving by the force of the current, at the distance of ten feet from the table on which the specimen rested.* The publication of these facts convinced naturalists that the gelatinous flesh of the Sponge exerted some vigerous action by which the currents were maintained, and cilia were suspected to be the organs. But the closest scrutiny failed to detect them, until first Dr Dobie, and then Mr Bowerbank, succeeded in seeing them in action in a living native Sponge. Insimilar situations to those where the Crumb-of-bread Sponge occurs, may be found, but much * Edin, Phil. Journ., xiii. 104. 36 LIFE, IN ITS LOWER FORMS. more rarely, the elegant Sack Sponge (Grantia compressa). It takes the form of a little flattened bag of angular out- line, and of a whitish hue, with an orifice at each angle. The bags, which are frequently clustered, hang by a slender base from the stalks of sea-weeds, or from the naked rocks (Pl. II. fig. 3). When examined they are found to be hollow, with thin walls ; and if asmall portion be torn off and placed beneath a microscope, it will exhibit well the structure of a spicular Sponge. The substance will appear crowded with, and almost composed of, calcareous crystals, most of which are stars of three radiating points, but some are linear needles, and on the exterior are many which are pointed at one end, and terminate in a bent, club-like knob at the other. It was this species which, under Mr Bowerbank’s expe- rienced eye and delicate manipulation, revealed the moving cilia. By tearing specimens in pieces (for the use of the keenest cutting instruments so crushed the texture as to destroy the parts), and examining the separated edges with high powers, he found that the sides are composed of a number of hexagonal cells, defined by the peculiar arrange- ment of the triradiate spicula, and having their walls formed by a multitude of nucleated granules (fig. 4). These angular cells are laid at right angles to the long axis of the Sponge, extending from the outer surface to the inner; and they are crossed, near the middle, by a thin partition, perforated in the centre. In this perfora- tion, several long, whip-like cilia were seen lashing with energy, and the same organs were afterwards found to be connected with the granules of which the cell-walls were composed. By means of the wavings of these cilia, then, SPONGES. we the water is made to flow through the cells from without, being discharged into the interior of the sack, and poured out in streams from the orifices (oscula) which terminate the angles of the Sponge.* This beautiful and interesting discovery leaves no doubt of the animal nature of the Sponges, which is still further confirmed by some interesting observations we had lately an opportunity of making on the irritability of Halichon- dria sanguinea. “When carefully watched under a power of 70 diame- ters, this brilliant species exhibits the following appear- ances :—At first we discern an uneven surface with little eminences here and there, like hills in an undulating coun- try. A great number of very slender glassy rods project at various angles from the surface, perfectly straight, equal in thickness in every part, with blunt tips. Webs of the investing membrane cling around the bases of these rods (spicula), and are a little elevated with them. “ Presently from one and another of the hillocks, a round bladder is seen pushing out, which gradually length- ens, until it becomes elliptical. It is composed of a clear gelatinous membrane, excessively subtile, with a yellowish granular film spread irregularly over its surface. Orifices are now perceived in the rounded tip of the bladder, the formation and increase of which are so very gradual, as to defy detection, except by the result... .. These orifices slowly alter, increasing or diminishing; sometimes a minute one appears at the margin of a large one, aug- menting at the expense of the latter, until the dividing film stretches across,—a narrow straight isthmus between * Trans. Micr. Soc. iii, 137. 38 LIFE, IN ITS LOWER FORMS. two lakes of equal dimensions. Sometimes the whole bladder wrinkles and partially collapses into a rugose column, and then slowly distends again, when the open- ings are seen as they were before. ... . “The efferent stream pours out at each of these orifices, carrying with it foecal matters from the interior, and any light-floating atoms that may be in the vicinity, as I saw with beautiful distinctness, by making the surrounding water slightly turbid. “On my touching the bladder with the point of a needle, it at once shrank up into a wrinkled column, but did not retract, and presently distended again. Thus the specimen exhibited very distinctly those characteristics of animal life —sensibility to touch, and spontaneous movements.” * * Tenby, 320. SPONGES. 39 CHAPTER IV. Porirera (Sponges). Continued. TxoucH the horny or keratose Sponges are distinguished from those which have calcareous or siliceous spicula in them, this distinction must not be understood to imply that the former are totally destitute of these bodies, but only that they possess them in an excessively minute proportion. Mr Bowerbank, in his elaborate and valu- able investigations ‘‘ On the Keratose Sponges of Com- merce,’ has found spicula of very minute dimensions imbedded in the substance of the horny fibres of various species.* Still the immense preponderance of the cor- neous structure fully warrants their isolation as a natural group. The horny fibres, as we have already said, form an irregularly netted mass, uniting to and separating from each other at various angles and distances, without the least order. They are not tubular, as has been sup- posed, but solid and of unequal thickness in different parts. Sometimes they are rigid and coarse, as we have seen ina large tubular Sponge on the shores of Jamaica, almost * Trans. Micr. Soc. i, p. 32. 40 LIFE, IN ITS LOWER FORMS. emulating the entangled twigs of a thorny bush in their inelastic stiffness. But more commonly the slenderness and arrangement of the fibres impart to the Sponge that elasticity which is one of its most valuable qualities. In order to apprehend truly the character of any Sponge, it should be examined alive if possible ; but if this be im- practicable, at least specimens should be selected which have been dried as they came from the sea, without hav- ing been subjected to any processes of washing, pressing, or cleansing. In specimens of Turkey Sponge in this condition, Mr Bowerbank finds the horny fibres surrounded by a beautiful tissue of branching vessels in great abun- dance, enclosed in an external membrane or sheath. This tissue Mr Busk has succeeded in injecting with coloured fluid. The fibres are also covered with a web of darker colour than their substance, composed of minute granules, which are conjectured to be incipient gemmules ; for nucleated gemmules were found on the fibres of other specimens, in which the granulose texture was wanting. The macera- tion in fresh water, however, and the immersions in diluted acid to which the commercial Sponges are subjected, remove the whole of the gelatinous flesh, and render this structure inapparent in specimens sold in the shops. In commerce two kinds of Sponge are known—the Tur- key and the West Indian. But of the former Mr Bower- bank makes two species, undistinguishable indeed by any marks that the naked eye can appreciate, but recognised in an instant on microscopical examination, by the presence or absence of the investing vascular tissue above men- SPONGES. 41 tioned. Both of these species grow abundantly in the eastern parts of the Mediterranean, especially around the numberless islets of the Grecian Archipelago. Smyrna is the great market fur the Sponge trade, and the expor- tation of this article forms no inconsiderable source of its prosperity. Great Britain imports annually about 60,000 Ibs. of Sponge, paying duty of 6d. per lb., with five per cent. addition. The greater portion comes from the Levant, but Barbadoes and the Bahamas supply a coarser sort, chiefly used for washing carriages. Its pores are large, and it has projecting lobes; the fibres possess little cohesion, and hence it is commonly called “rotten.” The Grecian Sponges grow in moderately deep water, usually assuming a more or less manifest cup-form. Those which reside in the deeper recesses of the sea are said to be of larger dimensions, as well as of finer texture, than such as are more exposed to the action of the waves. Aristotle, who enjoyed peculiar facilities for the study of these organisms, and who has speculated on their nature, says that in a living state they are black, except as covered with the light earthy sediment of the sea :—a circumstance which, notwithstanding his high authority, we venture to doubt. He may possibly have supposed specimens to be alive which were dead, and blackened with sulphuretted hydrogen, In many of the Greek islands, the diving for Sponge forms a considerable part of the occupation of the inhabi- tants, as it has done from the most remote antiquity. Hasselquist says :—“ Himia is a little, and almost unknown island directly opposite Rhodes. It is worth notice, on 42 LIFE, IN ITS LOWER FORMS. account of the singular method the Greeks, inhabitants of the island, have to get their living. In the bottom of the sea the common Sponge is found in abundance, and more than in any other place in the Mediterranean. The inhabitants make it a trade tofish up this Sponge, by which they get a living far from contemptible, as their goods are always wanted by the Turks, who use an incredible number of Sponges at their bathings and washings. A girl in this island is not permitted by her relations to marry before she has brought up a certain quantity of Sponges, and before she can give a proof of her agility by taking them from a certain depth.” * In other islands the same custom prevails, but with reversed application, as in Nicarus, where the father of a marriageable daughter be- stows her on the best diver among her suitors,—“ He that can stay longest in the water, and gather the most Sponges, marries the maid.” t In fact, the employment seems to be common to both sexes and all ages. Savary, describing a little insular de- pendence of Rhodes, named Syme, observes as follows :— ‘The Sponges which grow around this isle are the only resource of the inhabitants. Men, women, and children, all learn to dive. All must seek beneath the waters the only patrimony which nature has left them. The men excel all in this dangerous art. They precipitate them- selves into the sea, and descend to an enormous depth. Often they do violence to themselves in retaining their breath too long, and on emerging vomit a mouthful of blood. At other times they run the risk of being devoured * Voyages in the Levant (1766), 175. + Pomet’s Hist. of Drugs, v. 102. SPONGES. 43 by sea-monsters, against which the knife which they carry is but a poor defence. They distinguish with clearness distant objects through the crystal element, and as soon as they perceive voracious fishes, they shake rapidly the foot of the rope, and in an instant are drawn up to their boat. I learned these particulars from a diver of the country, who complained sadly of his hard lot and of his small profits.” * The uses of Sponge have been appreciated from very ancient times. We learn from Aristotle that it was used to line the brazen armour which his countrymen wore in battle. ‘ The kind called Achilleum, fine in texture, and very thick and strong, they put under helmets and greaves, viz., between-the armour and the skin, whereby blows are rendered less stunning.” The same kind was employed, as with us, for cleansing purposes. Thus Homer says :— “Then with a sponge he drest His face all over, necke and hands, and all his hairie breast.” + And in the Odyssey, the seats and tables after the slaughter of the suitors are cleansed by ‘“ well-soaked sponges.” { Martial also informs us, § that the tables after meals were carefully scoured with wet sponges ; for the Greeks and Romans knew not the comfort of table-cloths, which the Nineveh marbles shew to have been familiar to the Asiatics. Another use was that of conveying liquids to the mouths of persons incapable, from exhaustion or other causes, of drinking ; and the Christian remembers with interest that the last office rendered to the Lord Jesus in his humilia- tion, was the moistening of his lips by means of a sponge. || * Lettres sur la Gréce, 96. + Iliad, lib. xviii. t Odyssey, lib. xxii. § Apophor. n. cxliv. || Matt. xxvii. 48. 44 LIFE, IN ITS LOWER FORMS. Pliny alludes to the Sponge as one of the articles used by painters of his day: it has been conjectured from this that water-colours were employed in ancient art, and the Sponge probably performed a similar office to that which it holds in the hands of a modern artist—washing out lights, &e. In modern surgery, the use of the Sponge is great. The flowing blood in operations is absorbed by it; acrid dis- charges from wounds and ulcers are thus imbibed; and dangerous hemorrhages are checked and sometimes arrested by its application. The sponge-tent, formerly much used for dilating sinuses and small openings, was made by dipping the sponge into melted wax, and then compressing it until it became cool, between iron plates.* The quality of bibacity in which the value of Sponge chiefly consists, is owing to the multitude of minute channels with which its whole substance is perforated, and is dependent on the law of capillary attraction. By this law fluids ascend, in tubes of small diameter, to a height which increases in proportion to their tenuity, as any one may observe who will plunge the end of a fine glass tube into water. It is not requisite that the tubular form should be perfect or uninterrupted; the interspace between two closely approximated fibres will serve as a capillary tube; and thus the sponge-fibres present a series of canals, through which any fluid, with which a portion of the surface is in contact, will continue to flow until the whole are filled. A very different process is this spontaneous imbibition of water by capillary attraction from that already de- * Pereira, Mat. Med. § 1814. SPONGES. 45 scribed, by which a constant stream enters at the pores, and passes out at the oscula. The one is a mechanical, the other a vital operation. The latter is performed only during life and health, and contributes to the nourishment of the animal ; the former goes on after death, and is of no benefit to the Sponge, though very useful to its possessor. The one may be compared to that indiscriminate devouring of books, which we sometimes see in great readers—a voracity insatiable indeed, but which leaves the mind as empty as it was before ; the other to that guarded selec- tive reading which ever watches to extract mental food, separating and rejecting by a secret, but potent alchemy, the useless and the bad. Or we may compare the one to a soul dead in trespasses and sins, incapable (because destitute of spiritual perceptions) of distinguishing truth from error, and therefore carried about by every wind of doctrine of those who lie in wait to deceive,—the tools of Satan and his agents, whose purposes they are unconsci- ously serving. ‘The other may be likened to a living soul, who brings everything to the touchstone of the Word, proving all things, and holding fast only that which is good, by which he is nourished and edified, his spiritual life is developed, and he grows in knowledge, in service, and in grace. Perhaps we may carry this parallel further. The eclectic process in the Sponges is not so simple a thing as might be supposed. Irom the common water, which bathes all alike, various and dissimilar substances are separated, selected, and appropriated by different species. ‘“ For example, it is very common to find growing on the same rock, or seaweed, a siliceous, a calcareous, and a horny 46 LIFE, IN ITS LOWER FORMS. sponge; they have all the same exposure, and: are all recipients of the same nutriment, yet does each act upon this differently. One extracts from the fluid silica, which it causes to assume a solid crystalline form; another selects in the same manner the calcareous particles, which, obedient to the laws of life, assume figures novel to them in their mineral state ; and again, another rejects both the lime and the flint as injurious to its constitu- tion.” * So, when the minister of the Word, “a Scribe instructed unto the kingdom of heaven, bringeth forth out of his treasury things new and old,” souls of varying powers, cir- cumstances, and necessities, receive the same truths ; and the Spirit of life in their heart, ministering to every one severally as He will, admonishes one, stimulates another, guides a third, comforts a fourth ; and thus the Word is found “ profitable for doctrine, for reproof, for correction, and for instruction in righteousness.” The manner in which the Sponges increase their race is highly curious, and affords a beautiful example of the care which the All-wise God has exercised over His lowest creatures. According to Professor Grant,t there are found at certain seasons of the year, within the channels of a living Sponge, innumerable yellow granules, imbedded in the gelatinous flesh. These gradually increase in size, and project more and more into the channels, until at length one by one becomes freed, and is immediately hurried along to the nearest outlet by the constant ex-current. On examination, it is now seen to be a little oval gemmule, * Johnston: Brit. Sponges, 16. + Edin. Phil. Journal, xiii. SPONGES. 47 which one might call an egg, but that it possesses the faculty of spontaneous motion. The larger extremity is covered with excessively minute cilia, by the waving motion of which, as by innumerable oars, it is rowed along through the water, exactly like one of those In- fusoria which we described in a former chapter, and for which it might readily be mistaken. It does not, therefore, fall to the bottom of the sea as soon as the ejective impulse of the parental current is exhausted, but continues to shoot along, until, exerting apparently a power of choice, it meets with a suitable locality for its settlement. Here it lodges, spreads out an adhesive film of gelatinous matter, absorbs its now useless cilia, becomes stationary, grows by increase of its circumference, and soon develops all the structure, and exercises the func- tions, that characterised its parent. “Tt is curious,” observes Professor Jones, ‘to observe the remarkable exception which Sponges exhibit to the usual phenomena witnessed in the reproduction of animals, the object of which is evident, as the result is admirable. The parent Sponge, deprived of all power of movement, would obviously be incapable of dispersing to a distance the numerous progeny which it furnishes, They must inevitably have accumulated in the immediate vicinity of their place of birth, without the possibility of their distri- bution to other localities. The seeds of vegetables, some- times winged and plumed for the purpose, are blown about by the winds, or transported by various agencies to distant places; but in the present instance, the still waters in which Sponges grow would not have served to transport their progeny elsewhere ; and germs, so soft and 48 LIFE, IN ITS LOWER FORMS. delicate, could hardly be removed by other creatures. Instead, therefore, of being helpless at their birth, the young Sponges can, by means of their cilia, row them- selves about at pleasure, and enjoy for a period powers of locomotion denied to their adult state.” * * Outline of Anim. Kingd. 17. ee j Ah mn ele - pe ae ee a, vd : . . , F 7 : ra — . rie " ' - %, € Cars” er 5 ee ae oe I Se hea egRT Cee tween Capit Selene uel % we Cele Ps ee | s : a x J BI ce, ai, ae | ~ - Pat see hae sa rk. Sr wc m Polypifera. POLYPES, 49 CHAPTER YV, Ponypirera (Polypes). Continued. Ir any of our wonder-loving readers Will put a small phial into his pocket, and stroll through some hedge-rowed lane or quiet field at the sweetest season of the year, he may find food for meditation in the results of his walk. Let him direct his steps to the side of the first ditch or pool in which the water is not fetid, where the surface is already mantled over with the verdant duck-weed, and where many aquatic plants, springing from the bottom, wave their leaves in the limpid element. Stooping down on the brink, let him lift with his fingers a little of the coating of duck-weed, disturbing the water as slightly as possible, and then, peeping through the opening ho has made, examine slowly and carefully the bottom thus revealed. On the mud he will probably see a good many round knobs of jelly, from the size of a turnip-seed to that of a pea, of a transparent green hue, and others of the same kind adhering to the stalks and under surfaces of the leaves of the aquatic plants :—let him select a few of D 50 LIFE, IN ITS LOWER FORMS. these, place them, with some clear water and a fragment of some plant, in his phial, and hasten home. He will have obtained a creature which, about a century ago, electrified the scientific world, and opened up a new and most marvellous chapter in the history of Life. It is the Fresh-water Polype (Hydra viridis). The invention of the microscope had given an immense RK impetus to natural \ science ; and a gal- axy of illustrious men had by its means been an- nouncing wondrous { 7 facts, the records of ff which fill the pages of the Philosophical Transactions of our own Royal Society, i as well as many Hydra viridis—{nat. size magniied.) works of ereat merit - specially devoted to microscopy. ‘But yet, when, in 1744, Abraham Trembley of Geneva declared what he had seen of this little fresh-watet animal, this living ball of green jelly, it was regarded as a thing incredible, and even im- possible. The facts “were so contrary to all former ex- perience, and so repugnant to every established notion of animal life, that the scientific world were amazed; and while the more cautious among naturalists set themselves to verify what it was difficult to believe, there were many who looked upon the alleged facts as impossible fancies. The discoveries of Trembley were, however, speedily con- POLYRHES, 51 ‘firmed ; and we are now so familiar with the outlines of the history of the fresh-water polype, and its marvellous reproductive powers, that we can scarcely appreciate the vividness of the sensation felt when it was all novel and strange: when the leading men of our learned societies were daily experimenting on these poor worms, and trans- mitting them to one another from distant countries, by careful posts, and as most precious gifts; and when even ambassadors interested themselves in sending early in- telligence of the engrossing theme to their respective courts.” * Let us try to see what Trembley saw. Put the phial in a window, and allow it to remain untouched a while. The balls of jelly have all attached themselves, some to the glass sides, some to the plant, but they are balls no longer. Each is a thread of some half-inch in length, and about as thick as small twine, adhering by one extremity ; while from the other radiate, like a star, six slender threads, which are waved irregularly through the water, thrown into spiral coils or various contortions, elongated, contract- ed, elongated again, slowly or suddenly, and in different degrees, Two or three minute water-insects are swimming giddily about ; one of them, as he shoots unconsciously by, just touches one of these slender threads. In an instant the playful course is arrested; the little thing strives to pursue his way, drags the flexible cord that holds him hither and thither ; redoubles his efforts, pulls away and stretches it till we think it must break and free him. No! like a skilful angler, the Jelly is but wearying his victim : suddenly the thread is thrown into corkscrew coils, * Johnston, Brit. Zooph. 126. 52 LIFE, IN ITS LOWER FORMS. and the helpless insect is dragged in; another thread is brought to bear upon it, and another. Poor thing! “actum de eo est,” it is all up with him! He is dragged helplessly to the base of the radiating threads, and there, in the midst of their circle, an aperture is gaping, which stretches wider and wider, while the prey is slowly sucked in, until it is quite engulphed within the gelatinous body. But, for some time before this, the prey had become quite motionless ; its struggles, though violent at first, had soon entirely ceased, and it was evident that a fatal effect had been produced by the mere contact of those slender threads. What is the nature of this subtle venom that resides in a creature apparently so low in the scale of being, so simple in structure, and almost homogeneous in substance ? Worms, and the larvee of insects, that may be wounded, and even chopped into pieces, and yet survive for hours, die suddenly from a touch of these gelatinous threads! “J have sometimes,” says Baker, “forced a worm from a polype the instant it has been seized, at the expense of. breaking off the polype’s arms, and have always observed it to die very soon afterwards, without one single instance of recovery.”* On the other hand, the tiny water-fleas, and other minute Crustacea, frequently escape with im- punity even from the very mouth of the polype ; for they are enclosed in a horny shell, which evidently protects their vital parts from the morbific touch. The microscope throws light on the question, and re- veals a most elaborate system of offensive weapons with which these soft and sluggish creatures are provided. * History of the Polype, 33. POLYPES, 53 According to Corda, each tentacle forms a slender mem- branaceous tube, filled with an albuminous substance nearly fluid, mingled with sonte oily particles. This substance, at certain definite points, swells out into tubercles or dense warts, which run round the tentacle in a spiral line. Hach wart is furnished with several spine- bearing vesicles, which are organs of touch, and with an organ of highly curious structure, which is the weapon of offence. The organ of touch consists of a fine sac, enclosing another with thicker walls, within which there is a small cavity. rom the upper extremity, where the inner and the outer sacs are in contact, there projects a long cilium, or fine pointed bristle, which is not retractile, and appears to be immoveable. The weapon of offence is placed in the midst of these spines, in the centre of each wart. It consists of an oval- transparent sac, imbedded in the substance of the wart, with its perforated extremity exactly at the surface. At the bottom of the interior of the sac there is a body, in shape resembling a saucer, in the centre of which stands a small oval, solid body, bearing on its summit a cal- careous dart, pointed at its extremity, and bifid, or sagit- tate, at its base. This dart can be projected at the will of the animal, and again withdrawn into the sac. When the prehensile instinct is exerted, the darts are thrust out with force, and, entering the tissues of the prey, retain it : while at the same time, in all probability, a subtle but potent poison is injected, the effects of which we have already alluded to. | But this is a modern discovery. The circumstance in 54 LIFE, IN ITS LOWER FORMS, the economy of these animals which appeared so anoma- lous, was the mode in which they were both naturally and artificially multiplied. They were manifestly animals, yet it was found that they could be propagated by slips or cuttings, like plants! In the warm weather of sum- mer each polype is observed to shoot forth, from various parts of its body, little warts, or knobs, which increase rapidly, until in a few days they assume the form of the parent animal, each one being furnished with a circle of tentacles, though still attached at its lower end. The young one, which up to this period had received its nutri- ment from the parent’s stomach, from which a channel had communicated with its own, now catches prey with its own tentacles, the duct closes, the connexion of the base with the mother becomes more slender, and at length the little animal falls off, and commences independent life. Such is the ordinary mode of increase—generation by gemmation. In autumn, the Hydra propagates by means of eggs, which are deposited around the parent ; the basal portion of her body being spread over them,.and becoming a horny protecting skin. She immediately dies, and the eggs are hatched in the ensuing spring.* ’ But these strange animals may be artificially increased at pleasure, and that by means which, to higher animals, would inevitably destroy, instead of multiplying life. If the head of a polype, with all its tentacles, be cut off from the trunk with scissors, it will presently develop a new trunk and base, while the headless trunk begins to shoot out new tentacles ; and thus, in a little time, two perfect * Laurent, L’Institut, No. 465. POLYPES, 55 animals are formed. If one of these be cut into three, four, or half-a-dozen pieces, each pigce supplies the want- ing parts, and so many animals are made, all as perfect and active, and endowed with the same functions, as the first. Nor does it signify in what direction the mutila- tion is made ; a longitudinal, a diagonal, or a transverse division is equally successful ; nay, even a small portion of the skin soon grows into a polype. It was from this power of perpetual reproduction, that this singular animal received the name of Hydra, by which it is known among naturalists ; as if it realised the ancient monster of fabulous story, whose heads sprouted anew as fast as they were cut off by Hercules. Most curious monstrosities were produced by the expe- riments of philosophers on these animals, especially by partial separations. Ifa polype be slit from the summit to the middle, one will be formed having two heads, each of which will capture and swallow food. If these again be slit half-a-dozen times, as many heads will be formed surmounting the same body. If now all these be cut off, as many new ones will spring up in their place, while each of the severed heads becomes a new polype, capable of being, in its turn, varied and multiplied ad infinitum ;— so that in every respect our little reality exceeds its fabu- lous namesake. The polypes may be grafted together. If cut-off pieces be placed in contact, and pushed together with a gentle force, they will unite and form a single one. The head of one may be thus planted on the trunk of another. Another method of uniting them, perhaps still more wonderful, is by introducing one within the other; the 56 LIFE, IN ITS LOWER FORMS. operator forced the body of the one into the mouth of the other, pushing it down so that the heads were brought together. After forcibly keeping it for some time in this state, the two individuals at length united, and a polype was formed, distinguishable only by having twice the usual number of tentacles. There is one species which can actually be turned inside out like a glove, and yet perform all the functions of life as before, though that which was the coat of the stomach is now the skin of the body, and vice versd. If it should chance that a polype so turned had young in the act of budding, these are, of course, now within the stomach. If they have arrived at a certain degree of maturity, they extend themselves towards the mouth of the parent, that they may thus escape when separated. But those which are less advanced turn themselves spontaneously inside out, and thus place themselves again on the exterior of the parent. A multitude of other variations, combinations, and monstrosities, have been, as it were, created by the ingenuity of philosophers ; but these are sufficient to give a notion of the extraordinary nature of these animals, and to account for the wonder with which they were re- garded. The Hydra was, until lately, considered as an animal of very simple structure, being composed of mere gra- nules of jeily, set in a glairy, enveloping fluid. But the further we push our researches, the more are we disposed to hesitate in pronouncing on the comparative simplicity or complexity of any organism. We have already seen the elaborate array of weapons in the tentacles. M. POLYPES. 57 Gervais has shewn that the component granules of the body are of diverse forms, and, in all probability, sustain different relations to the general economy. The whole body consists of a sac, with thin dilatable walls, enclosing a capacious cavity, which forms the stomach: the granules which border this cavity are conical papille projecting into the stomach, and are supposed to have a digestive function ; the exterior series are lengthened, and consti- tute an integument, while some of the intermediate ones are arranged in bands, which are, with little doubt, pre- sumed to be muscular. The muscular bands in the ten- tacles are still more distinct, running in four series, which pass diagonally to and fro from side to side, forming lozenge-shaped spaces by mutual intersection. 58 LIFE, IN ITS LOWER FORMS. CHAPTER VI. Poutypirera (Polypes). Continued. Lxt us suppose that the buds continually put forth from the sides of the Hydra, instead of falling off to commence a new and isolated existence, remained permanently at- tached to the parent stock, giving forth in their turn buds, becoming permanent branches. We should then have the essential form of a Compound Polype; such, for example, as that of the great marine family, Sertulariade. Here we find the germ first developing a single Hydra-like polype, consisting of a slender stem or body of granular flesh, enclosing a stomachal cavity, the orifice of which is surrounded by a circle of sensitive tentacles. Soon, how- ever, a lateral bud projects, which shoots upward and develops a similar head of tentacles, while, from the side of this, another shoot still carries up the rising stem, which assumes a plant-like condition of branching stalks, with many lateral tentacled buds. It is true that mm these marine species we commonly find an additional structure, of which no trace appears in the fresh-water Hydra. The whole compound animal is enclosed in a tube of trans- parent substance, somewhat flexible though firm, resem- POLYPES, 59 bling horn, an exudation from the gelatinous integument ; and this tube, at every bud, takes the form of an open cell or cup (varying much in shape according to the species), into the cavity of which each individual polype- head can withdraw itself on alarm, and from the orifice of which it protrudes and expands when seeking prey. In the accompanying Plate, the figure a represents one of the most regular of these species ; and, therefore, one whose construction is peculiarly intelligible. It is a group of the Polype named Laomedea geniculata, very com- monly found springing from the broad leathery leaves of the fingered tangle, Laminaria digitata, that great olive- brown sea-weed that waves its huge fronds to and fro just below the level of the lowest spring-tides. The first ap- pearance of the Polype is a slender horny thread that creeps along the surface of the leaf, adhering firmly to its surface. Presently such a tiny budding stem as we have just described springs up from the root-thread, which con- tinues to creep on its way over the leaf, now and then bending its course at an abrupt angle, and sending up fresh stalks at regular intervals, which at length become a miniature forest. A few such stalks are represented at a, of the natural size ; and, at fig. b, one of these, or at least a portion of one, is shewn as it appears considerably mag- nified. The horny tube is seen, with its cup-like cells: the body of the Polype, a thread of gelatinous flesh, per- meates the stem and the branches, maintaining a common life: at intervals, the polype-heads project in the manner of buds, each occupying its transparent cell, and displaying its crown of tentacles which radiate on every side. The lower cells are commonly empty, the polype-heads having 69 LIFE, IN ITS LOWER FORMS. died out, successively, as young ones continually shoot forth at the extremities of the branches. At certain seasons of the year peculiar vesicles appear, which are special organs of reproduction. The analogy to a plant is maintained here also; we have already seen the development of a stem with buds, growing into twigs and branches ; here we have the fruit-capsules bearing the germs of another generation. Sometimes we find these organs few in number, seated here and there in the angle formed by the branches, or by the buds with the stalk. At other times they are very numerous, crowded together on the stalk, projecting in regular succession in the same plane, which forms a right angle to the arrangement of the cells. Hach of the cap- sules or vesicles is a tall, vase-like, transparent body, considerably larger than a cell, but closely resembling it, except that its summit is abruptly narrowed to a short rim like a pitcher. One of these organs is represented in fig, 0. The common nutrient flesh permeates the capsule as — it does a cell, and develops therein a very peculiar em- bryo. When somewhat matured, the permeating tube is seen swollen out into separate ovate sacs, ten or more in number, each of which contains several embryos. Those nearest the mouth of the vesicle are first developed, and escape successively by slowly emerging from the pitcher- like rim. Fig. ¢ represents a vesicle much magnified, with its included embryos in various degrees of maturity, and one in the act of escaping. ‘The appearance of the tiny creature when it finds itself at liberty is most surprising and interesting, especially when, from a crowded forest of POLYPES. 61 Polypes, the embryos are escaping “by thousands. Mr Peach, who first observed them, thus describes the scene he saw. Having, on the 19th of February, placed a specimen of Laomedea dichotoma in a large glass of sea-water, he found, a day or two after, that the water appeared muddy, an appearance caused by myriadsof moving objects, that resembled umbrellas without handles, or very wide and short hand-bells. ‘I took,” says this agreeable ob- server, “asmall quantity of the water, and placed it under the microscope, when thousands of the objects were sport- ing about in all directions, moving at a rapid rate by the ciliary appendages on their rim, All at once they would withdraw their cilia, and the handle-like appendage on the back, and become a mere speck ; and after resting a short time they would again throw out their cilia and appendage, and round they went waltzing with each other. It was perfectly astonishing in this crowded assembly to find that they very seldom came into collision ; and if so, how soon matters were again accommodated. They continued active up to the 2d of March, when I lost them as if by magic. I fancied they might have been the young of worms; therefore, I took the Laomedea, washed it, took fresh sea- water and filtered it through three or four folds of fine linen, and placed the specimen in this: the next morning I had a still more innumerable host of these delightful things. They assume various positions, and when in the water they remind me of thousands of parachutes thrown from a balloon, descending in various states of expansion.” The author of these pages has had an opportunity of confirming and extending the observations of Mr Peach. Tt is easy to find the minute, sylph-like creatures, for all 62 LIFE, IN ITS LOWER FORMS. that is needful is to place in a vessel of sea-water a frond of sea-weed studded with the zoophyte, and in a few hours scores or hundreds will be seen, even with the naked eye, playing and dancing about in the most amusing manner. Fig. d represents the embryo, very highly magnified. In structure the tiny animal, which, though just born of a stationary zoophyte, is now swimming at will in a sprightly manner through the free water, is evidently a Medusa ; in all essential particulars being the very coun- terpart of one of those exquisitely delicate animals which Professor Forbes has so beautifully describedand portrayed in his “Monograph of the British Naked-eyed Meduse.” It consists of an umbrella-shaped disk of translucent jelly, the diameter of which is about doth of an inch. Four vessels cross the disk at right angles, and from the centre of union there springs a fleshy peduncle, with a sort of neck, capable of many varied motions and many alterations of form. The margin of the disk carries twenty-four slender _ tentacles, exactly corresponding to those of the parent Polype, and essentially to those of the Hydra, being studded | with warts, which analogy pronounces to be ageregations of barb-bearing capsules, instruments for arresting and killing prey. At the bases of the tentacles, arranged at certain definite points on the margin of the disk, are placed eight beautiful organs, which are doubtless the seats of a special sense. Each of these organs consists of a trans- parent globe, not enveloped in the substance of the disk, but so free as to appear barely in contact with it. In its interior is borne a smaller globule or lens, of high refrac- tive power, placed a little towards the outer side. Almost every one, on first beholding these organs, would unhesi- POLYPES. 63 e tatingly pronounce them eyes, and 4 they are considered by some eminent physiologists. Others, however, con- sider them to bear a closer analogy to our organs of hear- ing, the crystalline globule (or ofolithe) being, as it is stated, capable of vibration within its vesicle. Whatever they be, the same organs are found, in the same form, in that class of animals just alluded to, the Jelly-fishes or Medusze. . The disk is endowed with an energetic power of con- traction, by which the margin is diminished, exactly like that of a Medusa in swimming; and the tentacles have also the power of individual motion, though in general this is languid, their rapid flapping being the effect of the contraction and expansion of the disk just mentioned, pro- ducing a quick involution and evolution of the margin, — and carrying the tentacles with it. Occasionally, how- ever, all the tentacles are strongly brought together at their tips, with a twitching, grasping action, like that of fingers, which is certainly independent of the disk. The phenomena, of which an example has been given in this paper, have almost as greatly startled the philo- sophers of our age, as those connected with the reproduc- - tion of the Hydra astonished our ancestors a century ago. As in the former case, they were disbelieved, denied, ridi- culed, confirmed, believed, wondered at, and at length have found a place among the recognised laws of organic life, as the Law of the Alternation of Generations. When we come to speak of the Medusz as a class, we shall have occasion to revert to the topic again ; for the present we may state, that the order described is found to prevail among many species and genera of the marine Polypes. 64 LIFE, IN ITS LOWER FORMS. That order is briefly as follows :—The Polype, a fixed and rooted animal, increases its own individual life for a while by putting forth a succession of budding heads, but at a certain period gives birth to a number of beings that bear no resemblance to itself in form or habit, but are, to all intents and purposes, free swimming Meduse. Lach of these, after pursuing its giddy course for a time, produces a number of eggs, which change into active animals having the closest resemblance to Infusoria. Each of these latter presently becomes stationary, and affixed to some foreign body, along which it creeps, as a root-thread, shooting up tubular and celled Polypes, as described in the early part of this chapter. It is evident that this is a very different thing from the metamorphosis which takes place in Insects and Crustacea, where it is but one individual passing through a succession of forms, by casting off a succession of garments that con- cealed, and, as it were, masked the ultimate form. The butterfly is actually contained within the caterpillar, and can be demonstrated there by a skilful anatomist. In this’ case, however, there are distinct births, producing in a definite order beings of two forms, the one never producing its image directly, but only with the interposition of a generation widely diverse from it. Hence, to use the striking though homely illustration of one of the first propounders of this law, any one individual is not at all like its mother or its daughter, but exactly resembles its grandmother or its granddaughter, POLYPES. 65 CHAPTER VII. PoLyPiFrERA (Polypes). Continued. Wao is there, among the thousands that throng from our cities and towns to breathe the air of the coast and to gaze out on the boundless sea, that is not familiar with the Sea-Anemones? And who is not eloquent in their praise ? Who has not admired the starry flowers, all instinct with life and sensation, that spread their beauteous petals beneath the crystal water ?—the Anthea, with its snaky locks of satiny green, tipped with pink ; the Thick-horned . Bunodes in the dark tide-pool, sheltered beneath over- arching tufts of crimson and purple weeds, as if, like the modest violet, it would hide its charms, those pellucid eenes of crimson and white, set in gorgeous array, of which it needs not to be ashamed; the Daisy Sagartia, expanding its broad and flat circular disk, soberly hued and margined with an elegant fringe, over the edges of some narrow fissure in the leprous rock? Who has not felt somewhat of a naturalist’s enthusiasm at seeing the sea-worn stones studded with the plump, glossy, fruit-like, Smooth Anemones (Actinia), their array of tentacles care- fully packed away within the body, waiting the return of E 66 LIFE, IN ITS LOWER FORMS, the tide which has left them dry, and each one contracted into a hemispherical button of tremulous flesh, varying exceedingly in colour,—brown, chocolate, dark red, purple, crimson, pink, flesh-colour, green, olive, and not unfre- quently, especially in the overgrown specimens, specked all over with light green on a dark red ground? Yes; our readers are doubtless familiar with these attractive crea- tures, and are prepared to hear with interest some of the details of their curious structure and economy. In order to understand the subject more perfectly, it would be desirable to study the Sea-Anemones at home and at leisure. Nothing is more easily accomplished. Carry down to the rocky margin of the sea, at low tide, a wide-mouthed phial, and select your specimen. It adheres firmly to the stone by a broad fleshy base, but the attach- ment is one of adhesion merely; there is no organic con- nexion between the animal and its support. You will find no difficulty in detaching it, if you proceed gently and with care, working the back of your finger-nail, or (if you like it better) a thin slip of wood, under the circumference of the fleshy base, and gradually proceeding onward. When you have succeeded in getting it off, drop it into your phial, which you may partly fill with sea-water, and carry home. A nice little aquarium may now be improvised for its accommodation. A washing-basin, or a soup-tureen, will answer admirably ; or a delft foot-bath, or a milk-dish, or a brown earthen pan. Whatever vessel you choose, puta few pieces of rock on the bottom, half-fill it with clear sea-water, and place in it a few (only a few) living sea- weeds. If you mean to establish an aquarium of consider- ¢ POLYPES. 67 able duration, your sea-weeds must be procured with their root-bases uninjured, the fragments of rock on which they grow being knocked off by the help of a hammer and chisel; but for a shorter period—a week or two, for example—it will suffice to pluck up the living sea-weed with the fingers, securing as much of the base as possible. The bright-green weeds are the best. In a wash-basin of moderate size, a dozen Sea-Anemones may be accommodated comfortably, and will flourish and display their beauties and their instincts for an indefinite period, without any further care, if the vessel be so placed that the sun’s light may every day fall on it, yet not so exposed as to become tepid. The water, maintaining its purity and its clearness, will not need to be changed ; and a scene of charming interest will be constantly presented. The animals will soon begin to re-attach themselves by their broad basal disks to the pieces of rock, or to the sides of the vessel, and after a few hours will have made themselves at home in their new habitation. Some of them will be contented to abide week after week where they first chanced to settle; others, more restless, will manifest a travelling propensity, shifting their position from one part of the stone to another, or from rock to rock, or crawling slowly along the sides of their prison. It is true the motion is not appreciable to the eye, being about as tardy as that of the hour-hand of a watch; still it is not uncommon for an Actinia to accomplish a march of three or four inches in the course of a night. It is effected by a gliding of the muscular base along the surface, much like the crawling of a snail. A Sea-Anemone, or Actinia, is essentially a Hydra, 68 LIFE, IN ITS LOWER FORMS. being a cylindrical column of flesh, with the free or upper extremity truncate, and surrounded by one’br more circular series of tentacles. The interior is hollowed to form a stomach, which is closed inferiorly, and opens superiorly by a slit in the disk. This orifice is margined by two muscular lips, excessively extensile, dilatable, and variable in form. The space between the stomach and the outer walls of the body is occupied by a number of perpendicu- lar septa, or partitions of membrane, which are set in a radiating manner, dividing the whole into chambers. In these chambers are situated the ovaries, in the form of frilled bands, much ccnvoluted and covered with cilia, the germs of which are developed in the interseptal cham- bers, and find their way out through a duct which opens at one of the angles of the mouth. It is a pleasing sight, and one by no means uncommon, to sce five, ten, or twenty young, of various sizes, but perfect in form, expelled from the duct, and dispersed around, where they soon attach themselves and constitute a colony around their parent. | While in the body of their mother, they occasionally find their way into the tentacles, as these organs are hollow, and communicate with the interseptal chambers. Sir John Dalyell, who had paid great attention to these animals, thought that this was their normal position. “The embryos,” he says, “appear first in the tentacula, © from whence they can be withdrawn and transmitted to others by the parent, and are at last produced by the mouth. In the course of six years a specimen preserved by the author produced above two hundred and seventy- six young; some pale and like mere specks, with only POLYPES. b 69 eight tentacula; others florid, and with twenty. They are frequently disgorged along with the half-digested food, thirty-eight appearing thus at a single litter. An em- bryo extracted artificially from the amputated tip of a tentaculum began to breed in fourteen months, and sur- vived nearly five years. Monstrosities by excess are not uncommon among the young, one produced naturally consisting of two perfect bodies; and their parts, sustained by a single base, exhibited embryos in the tentacula at ten months, bred in twelve, and lived above five years. While one body was gorged with food, the other con- tinued ravenous.” * It is interesting to see the Actinie fed ; and as they are very voracious, they are rarely unwilling to gratify their benefactors with a display of their swallowing powers. Their natural prey consists of the smaller Mollusca, Anne- lida, Star-fishes, Crustacea, and, in short, of any animals which they are able to seize and to retain, The tentacles have the same prehensile power as those of the Hydra,—a power which depends on the presence of projectile barbed weapons, ordinarly coiled in elastic cells. These organs are found in inconceivable multitudes imbedded in the tissues of the tentacles, of the lips, of the stomach, of the frilled ovarian bands, and especially, in some species, in long threads which are protruded from pores in the integu- ment of the body. The structure of these weapons is as follows :—Each con- sists of an oval or elliptical sac of transparent membrane, within which is seen a thread coiled up, and in some instances an oblong or lozenge-shaped chamber. At the * Rep. Br. Assoc, 1834; and Edin. New Phil. Journ. xvii. 70 LIFE, IN ITS LOWER FORMS. pleasure of the animal, or under the stimulus of pressure, the thread is shot forth from one end of the cell with great force, until it extends to a length from twice to fifty times that of the cell. When fully extended, it is seen that the thread is but a continuation of the cell itself; that when it was dormant, it was turned in ; and that in the process of expulsion, every part of its length has actually been turned inside out, like the finger of a glove. Sometimes the thread appears simple, but in those cases in which a cham- ber appeared within the cell, it is furnished with an armature of barbed threads, which after expulsion pro- ject from the sides of the thread in various directions. The propulsion of the thread is sufficiently forcible to enable it to enter the tissues of other animals, and the barbed structure enables the weapon to retain its hold in the flesh, which facts warrant the presumption that a highly poisonous fluid is at the same time injected, capable of arresting and destroying animal life. Some of the forms of these organs are represented in the accompanying figures, | ey - = as oT ~—— = a iw ay ie kn eR os ere es 15 be orem eri ne ee a A PART I. LIFE, IN ITS INTERMEDIATE FORMS, A - ol ia fy “sible 7 7 Sh) i eee a Y 2050 be aieag ot wing ig a ey Bis4 tes lalate MM AE enn ae pre. oe i \ a. eo fo ‘. Lé P| al UT) Os 9 4) ‘ent whys 5\ ry sh a if? eal NS « has 2S tty “opuesere See ey nena 2 a ‘ ls Bia “ee yu | — dye ¢ Pear a oe ete ie WORMS, lea CHAPTER XIV. ANNELIDA (Worms). Taz forms of animate existence which we have briefly examined in the previous chapters, may be likened to the humbler ranks of society; the Vertebrata are certainly the aristocracy ; but between these there ranges a great middle class, the most populous, the most ingenious, and in some respects the most interesting, of the whole, They constitute the important divisions which naturalists term Articutata and Moxuusca. We have alluded to the populousness of these sections : a single subdivision of one of them (Insects) is believed to be at least twenty times as numerous in species as all other animals put together.* We do not expect our readers to study technical zoology at the breakfast-table, nor to make a dish of prawns the * Some years ago, an eminent zoologist gave the following table as his esti- mate of the probable number of existing species of animals, deduced from facts and principles then known Later discoveries tend to increase rather than to diminish the estimate. Quadrupeds .. ... 1,200 “Worna’? sh. phe Te, 2,600 Bird six son mle. ae O. 200 Racdiatey .cog icc i tees seni saree {000 Raptiles) oi. se. assnes 1500 Polypes, 6; 2. ses. aes ade 71,690 RIShES.— stse rss. ete 6,000 Testacea str ay vas! as 4 E00 Insects... ... ...1550,000 Naked Testacea ... ... 600 making an aggregate of 577,600 species. (Swainson's “ Geog. and Classif. of Quadrupeds,” p. 28.) 134 LIFE, IN FITS INTERMEDIATE FORMS. text of a lecture ; but still, if the function of the palate have not utterly extinguished that of the eye, they can scarcely have picked one of those dainty animals to pieces without having observed that it is encased in a sort of armour composed of many rings, the edges of which over- lap, and which thus work one within the other. This circumstance forms the most prominent characteristic of a grand division of living beings, which are thence called ANNULOSA (ringed), or ARTICULATA (jointed). Another mark of distinction is that their skeleton is external ; the outer skin, hardened in most cases into a horny crust, affording attachment to the muscles, and giving by its solidity and resistance precision and force to their con- tractions. In some cases, indeed, this structure is less obvious, the skin being rather membranous than crusta- ceous, but even there it is more tough and leathery than the internal parts. But the most important distinction of all, though it is one which is appreciated only by the anatomist, is the condition of the nervous system. That remarkable sub- stance, neurizne—which is the material seat of all sensation, and the proximate source of all motion, the ultimate link of matter, whereby the spirit lays hold of it—is either not discernible at all in the inferior creatures we have been considering, or else exists only in the form of slen- der threads, without any centres of accumulation. We now no longer find it in this rudimentary condition. In the Articulate animals there is a distinct arrangement of the nerves, which, in general, run down the middle of the body in two parallel cords, united at certain intervals by knobs or aggregations of the nervous substance, called WORMS. 135 ganglions, which send forth ramifying threads on each side, thus distributing sensibility to all parts of the body. There is in all these creatures a distinct head,* fur- nished with various organs of sense ; and for the supply of these the nervous matter is more abundant there than in other parts, forming a thick ring round the gullet and uniting into an enlarged ganglion above it. In confor- mity with this concentrated condition of the nervous sys- tem, the animals with which we have now to do display a perfection of sense, an energy of motion, and a versatility of instinct, which are unknown to those ranks that are below them in the vital scale. In all these qualities, as well as in the physical peculiarities which we have enu- merated, there exists considerable diversity ; so that the great division before us is naturally divided into several subordinate, but still important groups. We cannot in these pages review every link in the vast chain of Nature, though we may safely predicate that there is not one which would not well repay the investi- gation by some fresh evidence of the perfections of the Godhead ; not one which would not testify with fulness and clearness— “The hand that made us is divine!” The humblest class of Articulated animals is that of the Worms (ANNELIDA), which are not very remotely sepa- rated from those lengthened forms of EcHINODERMATA, which we lately considered. An Earth-worm or a Leech is not, indeed, an articulate animal, strictly so called ; but it * In some of the Worms, indeed, as well asin the Rotrrera, the head does not exist in its ordinary distinct form, but the organs of sense are present, and the exception is more apparent than real, 136 LIFE, IN ITS INTERMEDIATE FORMS. is an annulose one, for its body is composed of an immense number of rings, which, partially slipping one within the other, impart the power of alternate contraction and elon- gation, which is so remarkable in these creatures. Scarcely a single oyster can be dredged from deep water —especially if the ground be rocky——which is not more or less covered with shelly tubes, that sprawl and twist over its surface in various contortions, so firmly adhering to it as not to be removed without fracture. Stones, pieces of crockery, broken glass, and all sorts of shells, are liable to be overspread with these white pipes, after they have been immersed a short time in the sea; and similar structures occur, of a smaller kind, about the pebbles that lie on the shore near low-water mark. These are the dwellings of marine worms called Serpule. If we select a shell on which is seated a cluster of these pipes, and put it into a basin of sea-water, we shall soon be delighted with a brilliant spectacle. Let us sup- pose the tubes to be of that kind which is about as thick as a tobacco-pipe, which is adherent for the most part of its length, but rears upwards at its extremity, and displays a smooth circular mouth (Serpula contortuplicata). Down in the depth of the interior we presently discern what resembles a cork of a bottle, gradually pushed up till it reaches the orifice, which it accurately fits. It is a conical stopper, of a brilliant scarlet hue, marked with a number of ridged lines all diverging from the centre. The stopper still emerges, and we see that it forms the end of a long slender stem, which is slowly pushed out to make room for other emerging organs in the form of a double fan of scarlet threads radiating from a sort of WORMS. 137 collar, and arranged somewhat like two petals of a flower, with a deep bend or sinuosity where they unite. The extreme beauty of the display cannot but elicit our admiration ; we raise a finger to point out some par- ticular item to a companion, when, lo! the whole apparatus disappears like a vision; with the speed of thought the whole has been retracted into the pipe, the stopper enter- ing last of all, and tightly closing the aperture. Our friend Serpula is an exceedingly prudent personage, and will not soon emerge from his strong castle again, after receiving such a fright as the lifted finger gave to his sensitive ganglia ; and when he does, it will not be without great caution. Meanwhile, as we are waiting his reappearance, we will briefly discuss some points of his organisation. Those beautiful fan-shaped petals are gills, the breathing organs of the animal, whereby he derives from the sea- water the oxygen necessary for the renewal of the blood, which is constantly exhausted in the building-up of the various tissues. Their situation at the anterior extremity of the body is a wise provision, since they can by this arrangement be periodically bathed in the surrounding water, with the least possible exposure of the animal. In other species, however, which do not inhabit tubes, the gills are situated on other parts of the body. Thus in the common Lug (Arenicola), or Mud-worm, so well known to every fisherman for its value as bait, the gills form little tufts of a crimson hue on the rings of the middle part only. While on the exquisite Leaf-worms (Phyllodoce) they resemble heart-shaped leaves, arranged in a row on each side throughout the entire length. 138 LIFE, IN ITS INTERMEDIATE FORMS. That singular stopper, of which the function is so mani- fest, is one of a pair of tentacles ; organs which in general are exactly alike. Here, however, one is destined to close the orifice, and as one only could perform that office, the other is quite plain, a simple thread, while this is enlarged into a conical plug. What wise contrivance is manifested here ! We wondered at the extraordinary rapidity with which the timid animal disappeared on alarm, and are curious to know the mechanism by which it is effected. Each of the rings of which the body is composed carries on each side a little wart-like foot, within which is a bundle of horny bristles, like the filaments of a hair-pencil, capable of being protruded and withdrawn. The microscopic structure of these is most elaborate, but we cannot detail it here ; it may be sufficient to say that it is by the pro- trusion of these pencils in turn, which press backwards against the sides of the tube, that the animal pushes its: foreparts out. | But the retreat requires a more powerful machinery for its extraordinary fleetness ; and this deserves a more close investigation. On carefully examining a Serpula recently dead, we observe, by means of a lens, a pale yellow line running along the upper surface of each foot, transversely to the length of the body. This is the border of an ex- cessively delicate membrane, and on placing it under a high power (say 300 diameters) we are astonished at the elaborate provision here made for prehension. This yellow line, which cannot be appreciated by the unassisted eye, is a smal] muscular ribbon, on which stand up edgewise a multitude of what we may call combs, or rather sub- | WORMS. 139 triangular plates. The edge of each plate is cut very regularly into six sharp teeth, which curve in one direc- tion, and one other, curved so as to face these. The combs stand side by side, parallel to each other, along the whole length of the ribbon ; and there are muscular bands or fibres seen affixed to the smaller end of every plate, which doubtless give it independent motion. We have counted one hundred and thirty-six plates on one ribbon ; there are two ribbons on each thoracic segment, and there are seven such segments; hence we may compute the total number of prehensile comb-like plates to be about one thousand nine hundred, each of which is wielded by muscles at the will of the animal ; while, as each plate carries seven teeth, there are between thirteen and four- teen thousand teeth hooked into the minute cavities and roughnesses of the interior surface of the cell, when the animal chooses to descend. No wonder, with so many muscles wielding so many grappling hooks, that the re- treat is so rapidly effected ! The bundles of bristles which line the wart-like feet, are very extensively found in this class of animals; and in some species they exhibit strange and singular forms, resembling the fantastic but formidable weapons of some semi-savage people. ‘Thus in a flat scaly worm (Polynoe), common enough under stones at the water’s edge, the armoury consists of several sorts of weapons. First, there are long lances made like scythe-blades set on a staff, with a hook at the tip to capture the fleeing foe, and bring him within reach of the blade. Among them are others of similar shape, but with the edge cut into deli- cate slanting notches, which run along the sides of the 140 LIFE, IN ITS INTERMEDIATE FORMS. blade, like those on the edge of our reaping-hooks. These are chiefly the weapons of the lower bundle ; those of the Polynoe—(with its lances magnisied.) upper are still more imposing. The outmost are short, curved clubs, armed with a row of shark’s teeth to make them more fatal; these surround a cluster of spears, the long heads of which are furnished with a double row of the same appendages; and lengthened scimitars, the curved edges of which are cut into teeth like a saw. To | add to the effect, imagine that all these weapons are forged out of the clearest glass instead of steel; that the larger bundles may contain about fifty, and the smaller half as many, each ; that there are four bundles on every segment, and that the body is composed of twenty-five such segments ; and you will have a tolerable idea of the garniture and armature of this little worm, that grubs about in the mud at low-water mark. Some of the Worms, both of the sea, and of fresh- waters, manifest a singular power of self-multiplication. In one or two species of Syllis, and in some of the genus WORMS. 141 Nais, the last segment of the body increases in size, and becomes marked with segments, which grow more and more distinct ; in time, a head begins to form at the ante- rior end, which is furnished with antenne. At length this strangely-made animal breaks off from the parent, and enters upon an independent existence. The facts have been denied ; but we can give the testimony of per- sonal observation to their truth, having witnessed the process in both the genera above mentioned. Many of the marine Worms are remarkable for gor- geousness of colouring; and not a few display opaline reflections and metallic changes of hue of great splendour. There is a species, by no means rare on our coasts, called the Sea-Mouse (Aphrodite), which rivals the humming- birds in the magnificence of its array. It is a curious animal in many respects. The form is unusual, at least in this class, being somewhat oval; it is a flattened, un- shapely creature, about an inch and a half in breadth, and some three or four inches long, of a dusky brown hue, except at the sides, which are clothed with a dense coat of long, slender bristles. It is in these that the creature’s glory resides. This clothing reflects the most glowing prismatic colours, crimson, scarlet, orange, yellow, green, blue, and purple, ever varying according to the angle at which the rays are reflected to the observer's eye. Thus are verified the lines so familiar to our infancy : ** Let me be dress’d fine as I will, Flies, worms, and flowers, exceed me still.” In another allied species the side bristles exhibit a structure, which admirably adapts them for weapons of defence. The tip of each bristle is a barbed spear, being 142 LIFE, IN ITS INTERMEDIATE FORMS. beset on two sides with numerous points directed back- wards. As these bundles of spears are retractile, however, the tender flesh of the animal would be liable to laceration when they are withdrawn into the interior of the foot ; but a beautiful provision is made to meet this emergency. Kach of the barbed javelins is furnished with two mem- braneous blades, between which it is enclosed, in repose ; these prevent the points from coming into contact with its own flesh, while they readily open, and offer no impe- diment to the extrusion of the weapon. In the common Earth-worm (Lumbricus), the rings are very numerous, and each ring is furnished with eight retractile bristles, by means of which it traverses its long burrows. Mr Charles Darwin has satisfactorily proved that earth-worms are most valuable agents in fertilising lands, especially in undisturbed pastures, gradually cover- ing the surface with their casts, and thus forming a layer of finely pulverised earth of the richest character. A field which had been limed was examined after about eighty years, when the lime was found to be evenly covered, to the depth of thirteen inches, with this animal mould.* The Leeches (Hirudo, &c.) are not provided with bristles for locomotion ; but a compensation is given them in the form of a sucking disk at each extremity. They move, as is well known, by the alternate adhesion and detach- ment of each sucker. The Medicinal Leech (H. medici- nalis) performs its useful office, under the concealment of one of these suckers ; and hence its mode of action is not generally known. Its mouth is furnished with three * Proceed. Geol. Soc., vol. ii. WORMS. 143 small semi-oval tubercles arranged in a triangle, the upper edge of each tubercle being cut into minute but sharply serrate teeth. When a vacuum is made beneath the an- terior sucker, these tubercles are brought into close con- tact with the skin of the patient: proper muscles then move them to and fro in a saw-like fashion, when the minute teeth presently cut through the skin and superfi- cial vessels, and the blood flows profusely, under the at- mospheric pressure, into the stomach of the Leech. It is very remarkable that blood is not the natural food of the Leech ; and that the fluid which it so greedily swallows does not pass into the intestine, but remains in the stomach for many months; and, what is still more curious, it does not coagulate during the whole of that time, as it would do in an hour if exposed to the air, but continues to retain its fluidity. Hence it has been not unreasonably concluded that this habit is rather a special provision ordained by the Divine mercy to render these creatures subservient to the alleviation of human suffering than necessary to supply the wants of the animals them- selves. We must not, however, suppose that the “‘ convenience, health, or safety” of man is the only object of the crea- tive wisdom of God. There are numberless provisions expressly made for the comfort and wellbeing of the in- ferior creatures themselves ; and no creature is so mean, worthless, or humble, but it has been the object of His paternal care in multitudinous instances, a few of which only, doubtless, we are cognisant of. Two or three ex- amples of benevolent foresight and curious contrivance have been mentioned in this paper, and the enumeration 144 LIFE, IN ITS INTERMEDIATE FORMS. might be extended almost ad libitum: but these are sufli- cient to shew that God cares not only for sparrows, but even for worms also. What, then, shall we infer from hence? Shall we take up the infidel sentiment of the poet, so unjustly be- lauded— ** He sees with equal eye, as God of all, A hero perish or a sparrow fall ; Atoms and systems into ruin hurl’d, And now a bubble burst, and now a world ?” Nay, rather, let our comfortable conclusion be, that which the Lord Jesus teaches us to draw from analogous ex- amples: “ If God therefore so clothe the grass of the field, which to-day is, and to-morrow is cast into the oven, shall he not much more clothe you?” ‘Ye are of more value than many sparrows.” CENTIPEDES. 145 CHAPTER XV. Myriapopa (Centipedes). THERE is a small class of animals, familiar enough to all, because several species are common in every garden, which seem but slightly removed above the ANNELIDA we lately considered. If we take one of the many-ringed sea-worms, a Nereis or a Phyllodoce, for example, and compare it with a Scolopendra from beneath a stone, or a Julus from a decaying tree, we shall be at once struck with the resemblance in structure between the two forms ; the leading character in each case being that the greatly lengthened body is composed of numerous segments, each the counterpart of the others, and each bearing a lateral pair of short limbs. The limbs in the Myriapod are made of distinct joints, which is not the case with the Annelid ; the integument of the body is of a firmer and more horny character ; and the stiff segments are separated by a thin flexible mem- brane, so that considerable freedom of motion is allowed ; but these modifications have respect mainly to the sphere of action of the animal, which is terrestrial ; a greater degree of firmness and compactness being necessary for vigorous movements on the solid earth, than for those performed in water. K 146 LIFE, IN ITS INTERMEDIATE FORMS. Air now becomes the medium of respiration, and, ac- cordingly, this function is carried on by a new set of organs, called trachew, These are pipes which ramify throughout the whole body, communicating with the at- mosphere by certain minute orifices (spiracles), situated one on each side of every segment. There is considerable diversity between the animals of this class in organic development. The feeble inert Julus is but little elevated above the Worm ; its body being divided into forty or fifty segments, each of which carries two pairs of minute and powerless feet. Its mouth is furnished with a pair of horny plates, with toothed edges, which are brought into contact by a movement from right to left. The head bears a pair of thread-like horns, evi- dently organs of sense ; these are shadowed out in the appendages of the heads of many ANNELIDA; but being now, for the first time, distinctly jointed, a new name is given them,—that of antenne. These organs henceforth occupy an important place in the economy of the Arricvu- LATA. In the Centipede (Scolopendra), we have a much more vigorous and formidable creature. The most obvious change from the Julus is the concentration of its parts ; the segments are greatly reduced in number, but propor- tionally developed in size ; they are furnished with more powerful muscles, and each bears but a single pair of limbs, which are longer, more distinctly jointed, and en- dowed with greater powers of motion. Besides the cutting blades, with which the mouth is armed in common with the Julus, the Scolopendra is endowed with peculiar weapons of offence in the form of a pair of stout curved _ CENTIPEDES. _. 147 pointed fangs, working transversely in front of the head. Each of these fangs is perforated, and bears a bag of viru- lent poison, which is infused into the wound made by the point, exactly like the venom of the viper. The fangs are moved by very powerful muscles, so that, wielded by an animal of acute perceptions, and of considerable strength and swiftness, it may be reasonably expected that they become the ministers of speedy death to multi- tudes of insects on which the Centipede habitually feeds. Even man has learned to dread their power ; the species are numerous in all tropical countries, where many of them attain a large size ; not infrequently being seen a foot in length, and an inch in breadth ; the bite of these species is much more formidable than the sting of the Scorpion, always producing fever, and sometimes death. As if this were not enough to make the Centipedes for- midable, some kinds appear to be endowed with that mysterious power, possessed by certain fishes also, of communicating electric shocks to other creatures. A smart discharge, quite sensible to the human nerves, is said to be given by Geophilus electricus, a lengthened slen- der species, not uncommon in our gardens. This same species is also luminous in the dark, giving out a pale blue gleam from every part ofits body. We once had an opportunity of making some observations on this interest- ing luminous creature, which are recorded elsewhere,* and to which we therefore refer our readers. The animals of this class undergo certain changes of form in their progress from infancy to the adult condi- tion ; these, however, can scarcely be called metamor- * Zoologist, for 1843, p. 160. 148 LIFE, IN ITS INTERMEDIATE FORMS. phosis. They rather consist of a progressive increase of the number of limbs, and of segments. At birth, the Julus is destitute of limbs, which do not appear till after the first moult. Three pairs are now developed, and with these the little creature must be content until the second moult, after which it possesses seven pairs. These are placed on the foremost segments, the posterior rings being, as yet, destitute of limbs. The third moult occurs when the animal is a month old; it has now twenty-two segments, and twenty-six pairs of feet. Thirty-six pairs of feet signalise the fourth moult ; and after the fifth, there are forty-three pairs, and thirty segments. Finally, in the adult condition, thirty-nine segments are distinguished in the male, and sixty-four in the female.* * Savi. INSECTS. | 149 CHAPTER XVI. Inszcta (Insects). WE have now to do with a host of creatures, which, though of minute dimensions, are sufficiently conspicuous in many aspects to have been objects of popular interest in all ages. We find no longer the soft gelatinous bodies, sluggish habits, and indeterminate forms, which have so generally characterised the races through which we have passed ; but active and agile animals, of firm and solid parts, furnished with well-appointed limbs, liberally en- dowed with organs of sense, in full variety and perfection, and displaying a versatility of instinct, and a measure of intelligence that would scarcely be surpassed by the noblest of the brute creation. The mailed and powerful Beetle, the soaring Butterfly, the predaceous Dragon-fly, the industrious Bee, the sagacious Ant—are representa- tives of the Class of INnsrctTs. The unparalleled number of species included in this division, and the consequent abundance and variety which exist in the details of structure and habits, render it difficult to give anything like a popular view of the whole Class within reasonable limits. Probably above 150,000 species of Insects exist in the cabinets of European collec- 150 LIFE, IN ITS INTERMEDIATE FORMS, tions ; by which word “species” we mean animals as distinct from each other as the Rat from the Mouse, or the Blackbird from the Thrush ; races of animals, each of which has descended from an original first parent, created distinct and separate at the beginning of the world. Insects are composed of rings, or annular segments, like the ANNELIDA ; and a caterpillar, which is an imma- ture butterfly or moth, is much like a Worm ; but in the full-grown Insect we see a manifest condensation of form, the segments being generally compacted together, except at two points, where division is very manifest. Thus, if we look at a Wasp, we see that it is distinctly divided into three portions, the head, the trunk (thorax), and the body (abdomen); separated by constrictions so deep as nearly to cut off the mutual connexion of these parts. All perfect or full-grown Insects shew the same divisions, though not commonly so strongly marked. The appella- tions “ Insecta” and “ Entoma” (whence entomology) have. been hence given to the Class, these Latin and Greek terms signifying “ cut into.” , The perfection which is bestowed on the organs of sense. in these animals, especially when we consider their minute- ness, is calculated to fill us with adoring admiration of the skill of ‘the Great Workmaster.”. Take an example from the eyes, which are of several kinds, evidently designed for distinct’ modes of vision, of which we, who have but one sort of eyes, can form no adequate notion. The Bee and many other insects have on the crown of the head a number, usually three, of simple glassy eyes, set like “ bull’s-eyes ” in a ship’s deck ; and besides these a great compound eye on each side, consisting of a multitude of INSECTS. ; 151 lenses aggregated together upon the same optic nerve. The microscope reveals to us that the compound eye of an Ant contains fifty lenses ; that of a Fly, four thousand ; that of a Dragon-fly, twelve thousand ; that of a Butterfly, seventeen thousand ; and that of a species of Mordella (a kind of beetle), the amazing number of twenty-five thou- sand. Every one of these regular, polished, and many- sided lenses, is the external surface of a distinct eye, fur- nished with its own iris, and pupil, and a perfect ner- vous apparatus. It will thus be seen that each hexagonal facet forms a transparent horny lens, immediately behind which is a layer of pigment diminishing to a point in the centre, where it forms a pupil; that behind this a long six-sided prism, answering to the crystalline and vitreous humours in the human eye, extends, diminishing to its lower extremity, where it rests upon the retina, or net- work expansion of the optic nerve. Some of the minuter details of this exquisite organisation are still matters of conflicting opinion ; but these we omit, as our purpose is rather to convey to our readers a general idea of the structure of this complex organ of vision. ‘ This also cometh forth from the Lord of Hosts, which is wonderful in counsel and excellent in working.” (Isa. xxviii. 29.) With very few exceptions, the animals of the previous Classes are confined to the waters ; the density of such a medium being requisite for the support of their soft and feeble bodies. But the solid external investiture of Insects, and their well-jointed limbs, impart to them suffi- cient firmness and precision of motion to range the earth and air ; many species being endowed with organs which enable them to swim, run, or fly at their pleasure. Pro- 152 LIFE, IN ITS INTERMEDIATE FORMS. fessor Owen thus eloquently speaks of the various powers of these indefatigable little creatures :— “Some traverse the surface of the earth with a suc- cession of steps too swift for definition ; some by leaps so extraordinary as to have excited the powers of the dyna- mical calculator from the earliest periods. The waters also have their insect population, some swiftly cleaving the clear element, some gyrating on the surface, while others creep along the bottom. Nor are the activities of the aquatic insect confined to that lower sphere. The Nepa, or the Dytiscus, at the same time, may possess its organs of creeping, of burrowing, and of flight ; thus, like Milton’s fiend, it is qualified for different elements, and ‘Thongh straight, rough, dense, or rare, With head, hands, wings, or feet, pursues its way, And swims; or sinks, or wades, or creeps, or flies.’ * The muscular strength of insects is immense. We once were surprised by a feat performed by a Beetle (Oryctes maimon) common in the United States. Wehad put the insect, for want of any box at hand, beneath a quart bottle full of milk upon a table, the hollow at the bottom allowing him room to stand upright. Presently, to our surprise, the bottle began slowly to move and glide along the smooth table, propelled by the muscular power of the imprisoned insect, and continued for some time to peram- bulate the surface, to the astonishment of all who wit- nessed it. The weight of the bottle and its contents could not have been less than three pounds and a half; while that of the beetle was about half an ounce, so that it readily moved a weight 112 times exceeding its own, A * Comp. Anat. i. 213. INSECTS. 153 better notion than figures can convey will be obtained of this feat by supposing a lad of fifteen to be imprisoned Oryctes maimon. under the great bell of St Paul’s, which weighs 12,000 Ibs., and to move it to and fro upon a smooth pavement by pushing within. Mr Newport has given other instances of insect-power equally remarkable. Having once fastened a small kind of Carabus, an elegantly formed Ground Beetle, weighing three and a half grains, by a silk thread, to a piece of paper, he laid a weight on the latter. At a distance of ten inches from its load, the insect was able to drag after it, up an inclined plane of twenty-five degrees, very nearly eighty-five grains; but when placed on a plain of five degrees’ inclination, it drew after it one hundred and twenty-five grains, exclusive of the friction to be overcome in moving its load, as though a man were to drag up a hill of similar inclination a waggon weighing two tons and a half, having first taken the wheels off. 154 LIFE, IN ITS INTERMEDIATE FORMS. According to the same excellent authority, the Stag Beetle (Zucanus cervus) has been known to gnaw a hole an inch in diameter through the side of an iron canister in which it was confined, and on which the marks of its jaws were distinctly visible, as proved by Mr Stephens, who exhibited the canister at one of the meetings of the Entomological Society. Let us look at the powers of Insects exercised in the act of flying. The House-flies (Afusca domestica), that wheel and play beneath the ceiling for hours together, ordinarily move at the rate of about five feet per second ; but if excited to speed, they can dart along through thirty- five feet. in the same brief space of time Now in this period, as Kirby and Spence observe, ‘a race-horse could clear only ninety feet, which is at the rate of more than a mile ina minute. Our little fly, in her swiftest flight, will in the same space of time, go more than one-third of a mile. Now compare the immense difference of the size of the two animals (ten millions of the fly would hardly counterpoise one racer), and how wonderful will the velo- city of this minute creature appear! Did the fly equal the race-horse in size, and retain its present powers in the ratio of its magnitude, it would traverse the globe with the rapidity of lightning.”* Some of the flies that haunt our gardens shoot along so rapidly that the eye cannot follow them in flight. | Nor are these tiny creatures less masters of the arts of running and leaping. De Lisle mentions a fly so minute as almost to be invisible, which ran nearly six inches in a second, and in that space was calculated to have made * Introd. to Entomology. INSECTS. 155 one thousand and eighty steps! This, according to the calculation of Kirby and Spence, is as if a man whose steps measured only two feet, should run at the incredible rate of twenty miles in a minute. Every one has had occasion to observe, not always without an emotion of anger, the leaping powers of the Flea (Pulex irritans). A bound of two hundred times its own length is a common feat ; as if a man should jump twelve hundred feet, or a quarter of a mile! What a pity that Insects were not allowed to be competitors in the athletic games of old ! With regard to their organisation, all Insects in the mature state are armed with three pairs of legs ; which are divided into several parts, as, the hip, the thigh, the shank, and the foot, by distinct hinge-joints: the foot itself (tarsus) consists of several jointed pieces, and is usually terminated by two hooks, and often furnished with adhesive pads, or other organs accessory to locomotion. In most of the tribes there are also wings, two pairs in general (but in one extensive Order the hinder pair is obliterated) ; each of these organs consists of two films of highly elastic membrane, stretched over a frame-work of strong tubes, as the silk of an umbrella is expanded over its ribs. In the Order Coleoptera (Beetles), the fore pair are thick, leathery, and opaque, chiefly serving as shields to protect the hind pair in repose ; and in some other Orders they are somewhat coriaceous ; while in the beau- tiful Lepidoptera (Butterflies), the transparency of both pairs is concealed by a covering of minute feather-like scales, overlapping each other, reflecting various colours, and arranged in a mosaic of inimitable beauty. 156 LIFE, IN ITS INTERMEDIATE FORMS. The power of these organs, so delicate and filmy in appearance, we have before alluded to, but it may be illus- trated by another anecdote. Leeuwenhoek has recorded a remarkable instance, in which he was an eyewitness of the comparative capabilities of the Dragon-fly and the Swallow, as relates to the perfection of their flight. The bird and the insect were both confined in a menagerie about a hundred feet long; and apparently their powers were fairly tested. The swallow was in full pursuit, but the insect flew with such astonishing velocity, that this bird of rapid flight and ready evolution was unable to overtake and entrap it ; the insect eluding every attempt, and being generally six feet before it. The organs of the mouth vary much in form and func- tion in different insects. Ina Beetle they consist of two pairs of jaws, generally hooked and toothed, working hori- zontally, and an upper and an under lip, closing the mouth above and below. ach lower jaw bears one or two fila- ments, consisting of several joints ; and a similar pair is affixed to the lower lip. These filaments are called palpi, and are supposed to be highly endowed organs of touch. They greatly resemble the antenne, or horns of many joints, which project from the front of the head; but these latter are considered to be organs of hearing. If we look at a Gnat piercing our hand with its blood- sucking tube, or a Butterfly pumping up the nectar of a flower through its spiral tongue, or a Fly dissolving grains of sugar with the fleshy lips of its proboscis, we shall not very readily allow them any analogy with the apparatus of jaws and lips which we have just described. Yet great as is the dissimilarity, it is now established, that all these INSECTS. 157 forms of mouth are but modifications of the same model, adapting it to different functions. The sheath, horny and tubular in the Gnat, soft and muscular in the Fly, is the lower lip ; the piercing lancets in the former are the jaws, which are inconspicuous in the latter. The elegant coiled spire of the Butterfly consists of two tubes, which are the lower jaws, greatly lengthened; and the labial palpi, stout and hairy, stand up on each side of them : the other essential parts can be detected only by the skill of the anatomist. Some of the most interesting of the phenomena which occur in the economy of Insects, are the transformations which they exhibit in their progress of growth ; the changes of their form being frequently so great, that it would be impossible, but for the testimony of experience, to avoid the conclusion that the same insect, in infancy, youth, and adult age, belonged to widely distinct and re- mote orders of existence. We shall enter into some details of this interesting subject in our next chapter. 158 LIFE, IN ITS INTERMEDIATE FORMS. CHAPTER XVII. Insecta (Insects). Continued. How delightful is the season, when the Butterflies begin to spangle the fields and woodlands! Welcome visitants they always are, in their airy grace and beauty ; not less welcome than the flowers on which they alight, and whose brilliant hues and delicate petals are rivalled by their painted and filmy wings. “The Butterflies are come!’ Yes, it sends a thrill of pleasure through the heart, after the long dreary winter, to see the first Butterfly of the season sailing on its broad sylphic pinions in the warm beams of a calm April morn- ing. Perhaps it is the pretty little Orange-tip (Manev- plum cardamines), that attendant on early spring, coursing along some rural lane; or the Brimstone (Gonepteryx rhamni), hovering over a perfumed cluster of primroses, itself scarcely to be distinguished from one of them. Perhaps it is the Admiral (Vanessa Atalanta), whose fine scarlet bands afford so rich a contrast to its black velvet wings ; or the Peacock ( V. Jo), with its gorgeous violet eyes; or the Tortoise-shell (V. urticw), clouded with yel- INSECTS. 159 low and orange and black,—busy among the lowly nettles, attentive to the grand occupation that forms ‘The Whole Duty of Butterflies,’—the providing for the continuance of the race, by depositing here an egg and there an egg, on the stems or beneath the leaves of those grim and for- midable weeds. But even if it is one of much humbler pretensions, the White (Pontia brassice) of our kitchen- garden, still it is a Butterfly, and we look upon it with a hearty welcome, forgiving, and for the moment forgetting, all the robbery it committed upon our cabbage before it was born. And these frail creatures are worthy of our kindly re- gard, not only for their association (true children of the sun, as they are) with all that is most lovely in scenery, and most delightful in season, but because of their own personal claims to our admiration. If we capture that Red Admiral or Peacock that is so intent upon the nettles, what a glorious creature should we think we had obtained if we had never seen anything like it before! How light and papery, yet how strong and effective, are these broad wings! with what an elegant pencil has this pattern of beautiful colours been traced! But stay! let us look closer at this painting, aiding our sight with a pocket- lens. It is a most exquisite mosaic, fashioned out of innumerable coloured pieces, of regular shape and ar- rangement. If we look at our fingers’ ends with which we have touched, though ever so lightly, these pencilled surfaces, we see that some of the colouring is transferred to them ; and if we have pressed the wing, as in seizing it for the purpose of capture, we find that the finger presents the 160 LIFE, IN ITS INTERMEDIATE FORMS. pattern of the touched part in all its beauty. Now by touching with the charged finger-end a strip of glass, and placing this latter beneath a microscope, we discover an extraordinary specimen of the Divine handiwork. Hun- dreds of objects are left adhering to the glass plate, which we know not whether to call scales or feathers. They dis- play considerable variety of form, but the most common is oval, or semi-oval, with a little projecting stem or quill at oneend. ‘They are thin and flat, transparent and mem- branous in texture, with several ribs running lengthwise, the points of which project beyond the end of the scale. These scales, then, produce the beautiful party-coloured patterns of a Butterfly’s wing; but of positive colour they possess individually no trace under the microscope, save a dull smoky appearance. It is by the separation and reflection of the prismatic hues that they appear beau- tiful, but by what law some reflect none but red, some none but yellow, some none but blue rays, we know not. On examining the wing that has been denuded of its coloured scales, we see a transparent, dry, brittle mem- brane, pitted with innumerable punctures arranged in lines ; these are the depressions in which the stems of the scales were originally planted. They were so ordered that the extremity of one scale reposed on the base of its suc- cessor, overlapping and concealing its stem, so that the arrangement resembled that of tiles or slates on a roof. We have said they are innumerable; the expression is not literally exact, but you will think it excusable when you hear that Leeuwenhoek computed the number of scales on a Silkworm Moth (Bomiyx mori), to exceed 400,000 ; and those which bespangle the wings of the INSECTS. 161 great tropical Moths and Butterflies, some of which expand eight or nine inches, must be vastly more numerous, since the size of the scales does not at all depend on the dimensions of the wing. The whole Class of Insects is subject to metamorphosis ; that is, the same individual animal in the course of its progress from infancy to adult age assumes an appearance and form, with organs both external and internal, different at different stages of its life. In none of the Orders are these transformations more remarkable than in that which we are now considering, the elegant Order Lepipoprura, the Butterflies and Moths. The parent Butterfly, seeking on restless wing for the plant which shall form a suitable food for her unborn young, at length lays on its leaf an egg, cementing the tiny atom to its surface by a natural glue, which imme- diately hardens. In a few weeks a minute Caterpillar breaks from the prison, and frequently commences exist- ence by devouring with its powerful jaws the horny egg~ shell which it has just vacated. But vegetable matter is its proper diet, and, by the providence of its mother, it finds its habitation cast on a plant which is suitable for its nourishment ; it is like an ox placed in the midst of an unbounded pasture. The little worm feeds, and feeds, and feeds, with won- derful voracity: it does nothing else in short, and conse- quently grows with rapidity. It soon finds its skin too strait for it, for this can stretch only to a certain extent, and has no power of actual growth as ours has, and the horny parts, as the head and feet, cannot even expand, being quite rigid. What must be done? It splits its L 162 LIFE, IN ITS INTERMEDIATE FORMS. skin and throws it off; a new one, soft and expansile, having been prepared beneath it. This presently hardens, and when by the rapid growth of the Caterpillar this is stretched to its utmost capacity, it also is split and cast off ; and a similar process is repeated four or five times in succession. By this time the insect has attained its full size ; it has not yet, indeed, finished life, but it will need to eat no more ; all its nourishment is taken in the Caterpillar state, which it now prepares to quit for that of the Chrysalis. No one would have recognised the worm-like Caterpillar as the offspring of the aerial Butterfly; perhaps one might say, without a figure, “ He is so changed that his own mother would not have known him,” but the character in which the masquerader next appears is as little like either. Look at the stiff Chrysalis, all points and angles, im- moveable except for a slight wriggle in his armour, tied up to the stalk of a plant, like a knave to a whipping-post, and say what heis like! Certes, you will not guess (sup- posing you are not of the illuminati) either Caterpillar or Butterfly. The process of transformation is well worthy of being witnessed, and we will describe it as we once had the pleasure of observing it, in the case of one of those beau- tiful large species known as Swallow-tails. It was an American Butterfly, but so very closely allied to our fine native species the Papilio Machaon, and the scarce P. Podalirius, that should you ever be so fortunate as to witness the transformations of either of these magnifi- cent insects, you will see that the one process is the exact counterpart of the other. INSECTS. 163 When the Caterpillar has attained its full size, it crawls to the under-part of a branch, and spins a little knob of silk, of which it takes hold with its hindmost false legs: it then spins a girdle, composed of many contiguous threads of silk, fast- ened at each end; making a bow large enough to admit the body, and in- tended to support the Chrysalis; this, when finished, the Caterpillar puts over its head, It conti- nues in this state about two days and a half, during which time it has gradu- _ Transformations of Butterfly. ally lost its power of holding on by the feet, and rests with its whole weight upon the knob and cincture of silk. It now casts off its Caterpillar skin, and enters the Chrysalis state. By good fortune we were happy enough to see this change take place in one of our captives. The Caterpillar appearing very uneasy and restless, we watched it at inter- vals for about half an hour; when, by strong and appa- rently painful inflations, a slit was made in the back of the third ring or segment, and the Chrysalis forced itself 164 LIFE, IN ITS INTERMEDIATE FORMS. through ; gradually extending the slit forwards, till the head was split and separated, and backwards for several rings. The skin was then gradually pushed down: we had won- dered how it would get through this part of the business, for the weight of the Caterpillar pressed the silken girth very tightly round the body ; but there seemed no real difficulty ; the loose skin being worked backwards by the motion of the segments. When it was pushed down to the extremity, the tail of the Chrysalis was thrust out underneath, and pressed upwards to take hold of the little knob of silk ; this being done, the old skin was jerked off by the writhing of the body. The silken cord was now round the body, between the sixth and seventh rings, and the Chrysalis twisted and turned, till it got the girth three rings nearer the head, about the middle of the wing- cases; the skin was so soft and the silk so slender, that it cut into the wing-cases, so far as to be invisible, but no ill resulted from this circumstance to the perfect Butterfly. The newly transformed Chrysalis is soft, with the skin resembling in consistence wetted parchment ; its shape is not very remote from that of the Caterpillar; in the course of an hour or two, however, it materially alters its form. Some of its segments contract and condense, pro- minent angles appear, the skin roughens and becomes very rigid, and the creature has assumed the condition in which it will pass a sort of torpid vegetative existence, through some nine or ten months in the year, or even more. In the case of which we are speaking, the transition to the Chrysalis state occurred near the end of August, and INSECTS.. 165 it was not until the middle of July of the following year that the Butterfly was matured. When this period of second birth approaches,—so apt an emblem of the resurrection, that the ancient Greeks, who used the same term (¥vy7, psyche) to signify a but- terfly and a soul, called the resurrection ‘the hope of worms,”—it is manifested by a change in the appearance of the Chrysalis. The skin becomes very thin and fragile, and, for some days before the exclusion, the colours, spots, and marks of the perfect Butterfly are distinctly per- ceptible, through the transparent integument, but all in miniature. At length the hour arrives; the Chrysalis, which for some hours has appeared uneasy, wriggling, and apparently inflating its body, succeeds in splitting the thin and brittle skin of the back. The imprisoned Butterfly pushes out ; the head with its palpi and antenne and its spiral tongue, and the legs, are all drawn out of their several sheaths, the latter limbs are thrown forward, and the insect stands on them, weak and staggering. It rests a moment or two, then proceeds ; the painted wings now appear, minute and. hanging against the sides like wet paper, but perfect in their colours and markings. The Butterfly is free ! It essays to lift its wings, but these organs, all soft and flabby as they are, are utterly unfit for flight. But see, a change is coming over them! ‘They are swelling irregu- larly, crumpling up, puckering into folds here and there, as their vessels are distending with fluids from the body. They look hopelessly spoiled. Though small at first, they were at least symmetrical ; but now they look like pieces of wet paper crushed up in the hand and partially opened, 166 LIFE, IN ITS INTERMEDIATE FORMS. and the further the work proceeds the worse it appears to grow. But by and by, they begin to become smooth and even again ; the distension and expansion have reached to every part in an uniform ratio, and wings of full size and perfect form are developed, still, however, soft, flaccid, and pendent. A quarter of an hour more removes this defect ; the elegant organs momentarily acquire rigidity ; at length the insect can raise them to an erect position. As soon as this is attained, the beautiful creature marches to and fro, as if rejoicing in its new powers, and proud to display them ; but in reality testing the capabilities of its organs, and perhaps accustoming itself, by repeatedly opening and shutting its wings, to the practice of those muscular movements on the force and precision of which its flight will depend. At length it launches into the air, and sails away to the inviting flowers, a happy denizen of a new element. | Processes essentially parallel with those above described take place in the history of all Insects, though the varieties of habit produce a certain amount of variety in the de- tails. Nota few, as the Insects of the orders ORTHOPTERA and NEUROPTERA, are active in the pupa state; but, in general, as in Beetles, Bees, and Flies, the creature in this stage is motionless, swathed and helpless, ike the chrysalis of a Butterfly or Moth. Of the former condition the Dragon-fly (Zibellula) may afford.us anexample. The early stages of this vigorous flier are passed beneath the waters. The female, poising her body over the surface of some pool, deposits her eggs, which sink to INSECTS. 167 the bottom, where they are speedily hatched. The larva is a somewhat uncouth, broad, and flat, olive-coloured animal, rather spider-like, having six sprawling legs, which crawls about the mud at the bottom of ponds, or glides by a singular mechanism through their waters. The hinder extremity of the body is furnished with several leaf-like processes, capable of being brought closer toge- ther, or opened at pleasure. These close the orifice of a cavity, whose sides are very muscular. When the Insect wishes to move rapidly, it opens this cavity, which thus becomes filled with water ; then, by a contraction of the walls of the cavity, the water is forcibly ejected ina stream as from a syringe ; and, by the re-action produced by the impact of the jet d’eau upon the surrounding fluid, the creature shoots ahead, with its legs closely packed along its sides. But the most singular part of its structure is its face. “ Conceive,’ says the graphic and eloquent Kirby, “ your under lip to be bony instead of fleshy, and to be elongated downwards, so as to wrap over your chin, and extend to its bottom ; that this elongation is then expanded into a triangular convex plate, attached to it by a joint, so as to bend upwards again, and fold over the face as high as the nose, concealing, not only the chin and the first-mentioned elongation, but also the mouth and part of the cheeks: conceive, moreover, that to the end of the last-mentioned plate are fixed two other convex ones, so broad asto cover the whole nose and temples ; that these can open at pleasure transversely like a pair of jaws, so as to expose the nose and mouth, and that their inner edges, where they meet, are 168 LIFE, IN ITS INTERMEDIATE FORMS. cut into numerous sharp teeth, and spines, or armed with one or more long and sharp claws, you will then have as accurate an idea as my powers of description can give of the strange conformation of the under-lip of the larva of the tribes of Libellulina (Dragon-flies), which conceal the mouth and face precisely as I have supposed a similar con- struction of your lips would do yours. You will probably admit that your own visage would present an appearance not very engaging while concealed by such a mask ; but it would strike still more awe into the spectators were they to see you first open the two upper jaw-like plates, which would project from your temples like the blinders of a horse; and next, having, by means of the joint at your chin, let down the whole apparatus, aud uncovered your face, employ them in seizing any food that presented itself, and conveying it to your mouth.” Such is the larva, from which the pupa does not differ in any respect, except that the rudiments of the future wings are seen budding out from the thorax. It is no less active, no less fierce, no less voracious than the larva. When the time of its transformation approaches, it crawls out of the water up some aquatic plant, or on a twig upon the bank, where it remains a while for the skin to dry. Presently, a crack appears down the back, and the fly begins to emerge, as represented in the lower left-hand figure of the accompanying engraving. As soon as the feet are free, it invariably bends backward, and hangs with its head downward, as if exhausted, for some minutes. Then it rears itself up, catches hold of the twig with its hooked feet, and draws the extremity of its body out of the pupa-case, leaving the latter firmly fixed by its own INSECTS. 169 feet to the support. The wings are minute, soft, and dense, but they soon expand (as described in the case of the iQ Ay UY i} il Me iM Vet Hi \ se) A Hy | Transformations of Dragon-fly. Butterfly), and acquire the firmness, transparency, and gloss which are so admirable in the perfect Insect. 170 LIFE, IN ITS INTERMEDIATE FORMS, CHAPTER XVIII. Inseota (Insects). Continued. In Insects we perhaps reach the highest point of compa- rative perfection among invertebrate animals, whether we regard the condensation of their organs, the solidity of their skeleton, the consequent vigour and precision of their movements, the concentration of their nervous sys- tem, or the manifold intelligence which they display. That wonderful adaptation of means to ends, which, so often recurring as we study the instructive actions of animals, calls forth more than anything else our recogni- tion and praise of an all-wise Creator, is nowhere more conspicuous than in Insects; and is pre-eminently seen in what have been felicitously termed the architectural. habits of such species as prepare habitations for them- selves, or protections for their offspring. Most of our readers are familiar with that exquisite solution of a geometrical problem*—the honeycomb. * Réaumur, the eminent French entomologist, proposed to M. Konig, one of the ablest mathematicians of his day, the following problem :—‘‘ Amongst all possible forms of hexagonal cells, having a pyramidal base composed of three similar and equal rhombs, to determine that which could be constructed with the least expenditure of material.” The mathematician undertook the solu- INSECTS. 17% They have learned that the industrious Bees, impelled by nature to live in society, combine to form a common structure of cells, for the reception of the eggs and young, which are to form the future commonwealth, and the store of food which is necessary for their nutrition. This work is to be formed out of wax—a substance that does not exist as yet, but which is to be elaborated by a natu- ral chemistry from the bodies of the Bees themselves. The cells are perfect hexagons, divided from each other by the thinnest possible walls that the material will sus- tain, and built in double series, the bottom-point of one being the point between the bases of three others, which open in the opposite direction. Now, it is found by ob- servation, that the walls are not built up in those thin plates, which we see them to be when perfected ; but, on the contrary, that the wax is laid down in rounded knobs, out of which the cells are then excavated by the jaws of the workers, each one knowing exactly, by her wondrous instinct, how much may be pared away, without breaking into the domains of her fellow-artificers, who are similarly excavating on every side of her. But the labours of the Hive-Bee, though truly admir- tion of this very beautiful theorem, and at last demonstrated that, among all kinds of cells with pyramidal bases, that would require the least quantity of material which should have its base composed of three rhombs, the angles of which should measure respectively 109° 26’ and 70° 34’, M. Maraldi, another eminent naturalist, had in the meanwhile calculated, with as much accuracy as he was able, the real angles met with in the cell of the Bee, which he had estimated, the former at 109° 28’, the latter at 70° 32’, leaving only two minutes of difference between the calculation and the result of measurement ; and more recent researches, conducted with the delicate instruments of modern science, have shewn even that slight discrepancy to be erroneous, and proved that the figures pointed out by mathematical research, and those adopted by the insect- labourer, are precisely identical.—(Jones’s ‘‘ Nat. Hist. of Anim.,” ii. 235.) 172 LIFE, IN ITS INTERMEDIATE FORMS. able, are equalled, if not indeed surpassed, by those of the social Wasps ; though these latter, because they do not minister to our wants, and perhaps, also, because of their irascibility, are viewed with a dislike, which has tended to avert from their architecture that measure of popular attention which it well deserves. The common Wasp (Vespa vulgaris) conceals her work beneath the surface of the earth ; there she builds a sub- terranean city. We say “she,” for it is observable that the populous commonwealth which teems forth on the uncovering of a ‘ Wopse’s nest,” is exclusively the pro- geny of one mother Wasp, which has survived the winter ; and the city was built, or at least founded, by her alone. She first finds or makes an excavation in some hedge- bank—a winding gallery a foot or more in length, and an inch in diameter, opening at length into a capacious chamber, as large as a butter-firkin, or larger. This being prepared, she seeks her materials for building. These are not wax, but paper. From winudow-sills, weather-beaten palings, old posts, and similar sources, the industrious in- sect collects the minute surface-fibres with her mandibles, bruising them, and moistening them with a liquid from her mouth, until they form a pappy substance, which is nothing else than a true paper. “‘ With this material the mother Wasp begins to line the roof of her burrow, always building from above down- wards. The round ball of fibres which she has previously kneaded up with glue, she now forms into a leaf, walking backwards, and spreading it out with her mandibles, her tongue, and her feet, till it is almost as thin as tissue- paper. INSECTS. 173 “One sheet, however, of such paper as this would form but a fragile ceiling, quite insufficient to prevent the earth falling down into the nest. The Wasp, accordingly, is not satisfied with her work till she has spread fifteen or sixteen layers, one above the other, rendering the wall altogether nearly two inches thick. The several layers are not placed in contact like the layers of a piece of pasteboard, but with small intervals or open spaces be- tween, appearing somewhat like a grotto built with bivalve shells, particularly when looked at on the outside. This is probably caused by the insect working in a curvilineal manner. ““ Having finished the ceiling, she next begins to build the first terrace of her city, which, under its protection, she suspends horizontally, and not like the combs in a bee-hive, in a perpendicular position, The suspension of which we speak is also light and elegant, compared with the more heavy union of the hive-bees’ combs. It is, in “fact, a hanging floor, immoveably secured by rods of simi- lar materials with the roof, but rather stronger. From twelve to thirty of these rods, about an inch or less in length, and a quarter of an inch in diameter, are con- structed for the suspension of the terrace. They are ele- gant in form, being made gradually narrower towards the middle, and widening at each end, in order, no doubt, to render their hold the stronger. “The terrace itself is circular, and composed of an immense number of cells, formed of the paper already de- scribed, and of almost the same size and form as those of a honeycomb, each being a perfect hexagon, mathemati- cally exact, and every hair’s-breadth of the space com- 174 LIFE, IN ITS INTERMEDIATE FORMS. pletely filled. These cells, however, are never used as honey-pots by Wasps, as they are by Bees ; for Wasps make no honey, and the cells are wholly appropriated to the rearing of their young. Like other Hymenopterous Insects, the grubs are placed with their heads downwards ; and the openings of the cells are also downwards ; while their united bottoms form a nearly uniform level, upon which the inhabitants of the nest may walk. “When the foundress Wasp has completed a certain number of cells, and deposited eggs in them, she soon in- termits her building operations, in order to procure food for the young grubs, which now require all her care, In a few weeks these become perfect Wasps, and lend their assistance in the extension of the edifice; enlarging the original coping of the foundress by side walls, and forming another platform of cells, suspended to the first by columns, as that had been suspended to the ceiling. “In this manner several platforms of combs are con- structed, the outer walls being extended at the same time ; and, by the end of the summer, there are generally from twelve to fifteen platforms of cells. Hach contains about 1060 cells—forty-nine being contained in an inch and a half square, and, of course, making the enormous number of about 16,000 cells in one colony. Réaumur, upoa these data, calculates that one vespiary may produce every year more than 30,000 Wasps, reckoning only 10,000 cells, and each serving successively for the cradle of three generations. But, although the whole structure is built at the expense of so much labour and ingenuity, it has scarcely been finished before the winter sets in, when it becomes nearly useless, and serves only for the abode of a INSECTS. | 175 few benumbed females, who abandon it on the approach of spring, and never return ; for Wasps never make use of the same nest for more than one season.” * Some Hymenopterous Insects excavate cells, for the habitation of their young, out of solid timber. The large and beautiful Violet Bee (Xylocopa violacea) of Spain, for example, bores a cylindrical hole into a post to the depth of fifteen inches, the first inch being horizontal, and the rest perpendicularly upwards. The sawdust which accu- mulates from the action of her jaws, she stores up in a little heap, for future use. Having completed her tunnel, she lays an egg at the furthest extremity, gluing it to the wood. She then collects the farina of flowers, and, making it into a paste with honey, covers with it the new-laid egg, and fills a space of the tunnel of about an inch in length. Now the store of sawdust comes into request. Grain by grain she carries it in, and, with her glutinous saliva, cements it in the form of a ring to the tunnel wall, imme- diately under the food she has treasured up. When this has hardened, she carries in more grains, and cements them in a narrower ring to the former, proceeding thus till the whole space is occupied, and a transverse partition is formed of cemented sawdust, which completely seals up the egg and food in a closed chamber, and forms a floor for the attachment of a second egg. This she provides for and seals up also, and so proceeds till she has divided the tunnel into ten or twelve cells, each occupied by an egg, and sufficient food to meet the wants of the grub until its arrival at the winged state. * “Tnsect Architecture,” 75 176 LIFE, IN ITS INTERMEDIATE FORMS. It is evident that, since the earliest-laid egg will be hatched first, and will soonest come to maturity, it will want its liberty before its younger brethren are ready for theirs. But it is imprisoned at the very end of the tun- nel ; how, then, can it be freed, without destroying all the other cells in its course? This emergency is provided for. A back-door is prepared, in the shape of a gallery, leading sideways from the furthest cell to the surface of the post; this the young Bee has the instinct to avail itself of ; the rest following in succession, each breaking through its own floor, and then finding a clear passage. There is a Bee somewhat resembling the Hive-bee, but rather stouter (Megachile centuncularis), common in sum- mer in our gardens, which lines the tunnels that she bores in firm earth with portions of the leaves of rose-beeches. These she cuts into the required patterns with inimitable rapidity and accuracy, and forms them into thimble-like cells within the tunnel, fitting the end of one into the mouth of another, and storing each cell with an egg, and the needful store of food. But the workmanship of this species is exvelled by that of another, the Poppy Bee (Osmia papaveris). Her hole resembles in form a Florence flask, but is no more than one-third so large. The walls are made very smooth, and thus prepared for her most exquisite tapestry. The material used for this purpose, “is supplied by the petals of the scarlet field-poppy, from which she succes- sively cuts off small pieces of an oval shape, seizes them between her legs, and conveys them to the nest, She begins her work at the bottom, which she overlays with three or four leaves in thickness, and the sides have never INSECTS. 177 less than two. When she finds that the piece she has brought is too large to fit the place intended, she cuts off what is superfluous, and carries away the shreds. By cutting the fresh petal of a poppy with a pair of scissors, we may perceive the difficulty of keeping the piece free from wrinkles and shrivelling ; but the Bee knows how to spread the pieces which she uses as smooth as glass. “When she has in this manner hung the little chamber all round with this splendid scarlet tapestry, of which she is not sparing, but extends it even beyond the entrance, she then fills it with the pollen of flowers mixed with honey, to the height of about half an inch. In this maga- zine of provisions for her future progeny she lays an egg, and over it folds down the tapestry of poppy-petals from above. The upper part is then filled with earth.”* Many other examples might be given of the wonderful instinct of Insects manifested in the construction of dwellings, as those of the Mud-wasps (Pelopeus) of America, the Termites of tropical Africa, and the Ants of all countries. Jor these, however, we must refer our readers to works specially devoted to the economy of Insects. * “Ins. Arch.” 56. 178 LIFE, IN ITS INTERMEDIATE FORMS. CHAPTER XIX. Tnsrota (Insects). Continued. Tus Class of minute animals is so immense, that it would be impossible within our limits to give a hundredth part of what is on record concerning them, even if we omitted all technical details, and confined ourselves to that which is popularly interesting. The study of the whole Class is felt to be far too large for one human life to embrace with any degree of completeness, and hence we hear of men eminent as coleopterists, lepidopterists, hymenopte- rists, &c., from their having devoted themselves to some one or other of the subordinate groups of this vast assem- blage. We shall just give a bird’s-eye view of these subdivisions, indicating here and there some of the more prominent points of interest for which each is distinguished. — — Chief among them stands, by universal consent, the order of Beetles, principally because they are the most “perfect” of Insects. By this term “perfect” as applied to struc- ture, which has sometimes stumbled uninitiated students, we do not, however, mean to imply that a House-fly or a Bug is not as perfectly adapted for its mode of life as a Beetle, nor that it is in the least degree less worthy of an INSECTS. 179 Omnipotent Creator. The word is used by naturalists in a technical sense, to express the degree in which we find those peculiarities developed that constitute any particular group. Those peculiarities of structure, for example, that make an ‘Insect what tt ts, and not a Worm or a Crustacean, are found to be present in the greatest intensity, and in the fullest combination, in the group of Beetles, and hence we say that these are the most perfect of their class. A Beetle is not more perfect as an animal than any other, but it is a more perfect msect, or rather, more perfectly an insect. You may very readily identify a Beetle by its mouth being armed by two pairs of forceps-like jaws, and by its - fore-wings being hardened into leathery sheaths for the hinder wings, and- meeting in a straight line down the centre. The technical name CoLEoprTEra, or Sheath-wings, expresses the latter character in Greek. Many species of this group are pre-eminent for beauty of colour, especially the many-coloured refulgence of bur- nished metal, as in the Buprestidae, and the Cetoniadie, and _ the Eumolpide, and others ; and the lustre of the richest precious stones, as in many of the Diamond-beetles and others of the Curculionidae, whose wing-sheaths under a lens look as if they were dusted with pounded gems. The Glow-worm, that lights our hedge-banks with its feeble spark in the soft summer nights of July, is a Beetle, and so is the Firefly of the West Indies, that carries a pair of flaming lamps upon his back. The pretty scarlet Lady-bird, that appears to have had a “ favourable erup- tion” of black buttons, is a little Beetle that every child knows and loves; and the dreadful Death-watch, that scratched the doom of our great-grandmothers on their 180 LIFE, IN ITS INTERMEDIATE FORMS. bedposts, is one still smaller. Very few of this great group render the slightest direct service to mankind ; we do not at this moment recollect any but the Cantharis, or Blister-fly, which is useful in surgery. Those insects which have the fore-wings somewhat leathery, but less rigid than those of Beetles, and sheath- ing the lower pair in such a way that their edges overlap each other, are called OrTHOPTERA, or Straight-wings. The Locust, Grasshopper, and Cricket, all of which make a crinking sort of music by rubbing their stiff wings in various ways over each other, are of this sort: and so is the Earwig, that spoils our dahlias by eating holes in their tender petals, and the ferocious Mantis of the tropics, that holds up its sawlike arms as if in the attitude of prayer (hence called Prie-Dieu), but really watching to smite down any unwary fly that may be passing, and to seize it between the locking-spines of its fore-arms. Who that has sauntered by a river’s side in the burning noon of summer is not familiar with the arrowy Dragonfly? He swoops down in wide curves, and just touches the water in his rushing flight, and turns, and darts to and fro, with a speed and a power that seem to mock the ring- net of the eager insect-hunter. The sun’s ray gleams from the ample pinions as they speed past our eyes, as from surfaces of polished steel, and the long and slender body that is poised behind is clad in mail of green, and azure, — and gold. Ha! we have struck down the bold warrior with our cane, and there it lies, spinning round in the erass, and rustling its beautiful wings, with tremulous vibrations, in its fruitless attempt to fly. Poor creature, thou wilt flyno more! no more will the vigorous impulses INSECTS. 181 of those filmy pinions bear thee aloft on the thin air, and carry thee in impetuous evolutions after thy tiny prey! But what elegant organs these wings, now still in death, are! they are like plates of talc of extremest thinness, through which expands a network of nerve-ribs, a lace that no collar on fair lady’s neck ever equalled; every component thread of which is a tube communicating with the air-pipes or lungs of the body! How appropriate is the term Nreuroprera, or Nerve-wings, for such Insects as these ! And now we come to the “industrial” classes, to use an expressive term of modern coinage. The Butterflies are fine ladies that go a-shopping among the flowers, the Beetles are the starred and jewelled nobility, the Dragon- flies are warriors, true knights-errant furnished with the pomp and circumstance of war; but the humble, useful, ever busy Bee is an artisan—a representative of that class who are “fruges producere nati;” and not less industrious and skilful (though far from so serviceable to us) are its cousins, the Wasp and the Ant. The architectural instincts of these Insects we have briefly treated in the preceding chapter. This order is termed HyMmnoprTeEra, or Membrane-wings ; but the technical distinction between these and those which we have just dismissed is that these possess, at least in one sex, a horny tube at the extremity of the body, which is sometimes connected with a poison-bag, and is called a sting, and at others is simply an instrument for the piercing of animal or vegetable substances, in order to deposit eggs in them. Buta much more obvious differ- ence is found in the character of the wings, which are so 182 LIFE, IN ITS INTERMEDIATE FORMS. shaped that the hind pair seem as if cut out of the fore pair, with which they interlock by means of small hooks during flight, so that both might readily be mistaken for a single pair. The nervures are commonly stouter, and form a wider network, and the membrane is generally less delicate than in the preceding Order. All the forms of Insects which we have been enume- rating agree in one point, viz., that their mouth is fur- nished with biting jaws; those that follow, on the other hand, have the same organs, but so modified in develop- ment and altered in function as to constitute a sucking, pumping, or piercing apparatus. The elegant Leprpop- TERA, or Scale-wings, including the Butterflies, which are active by day, the sonorous-winged Hawkmoths, that probe tubular flowers in the twilight, and the Moths, which swarm in the early hours of night, constitute the next order. Their chief peculiarities have been already mentioned, and we shall therefore merely mention the Silkworm, the caterpillar of an Oriental moth, now natu- _ ralised throughout the civilised world, as another example of an Insect to which man is largely indebted. An extensive group is called Hemiptera, or Half-wings, because the majority of them have the fore-wings curiously varied in texture, the basal portions being of a stiff leathery consistence, while the terminal part, separated from the former by an abrupt line, is thin and membranous. The vast tribe of Bugs comes here, all of them repulsive and disgusting from their rank pungent odour, but in many cases adorned with rich colours, and often bearing the most bizarre forms. Here, too, are usually placed, though distinguished by some entomologists, the insects which INSECTS. 183 produce the lac of India, and the splendid dye called “eochineal” of tropical America. The sole possession of the latter insect was an object of jealous care with the government of the Spanish colonies, and go highly was it valued by other nations, that our own East India Com- pany offered a reward of L.6000 sterling to any one who should be so fortunate as to introduce it into their domi- nions. That object has been effected, and cochineal is now cultivated in many countries. Finally (for we need not stop to describe the few para- site, darkness-loving, uncomely insects that belong to the wingless orders), we have the order of Diprera, or Zwo- wings, including the Gnats, the House and Flesh Flies, whose chief distinction is indicated in their name. This is a populous group, and many of its members display habits and instincts which are highly entertaining ; per- haps none more so than those of the common Guat, from the construction of its tiny boat of eggs, to its emergence from the water, empowered to suck our blood in its mer- ciless practice of phlebotomy. 184 LIFE, IN ITS INTERMEDIATE FORMS. CHAPTER XxX. ARACHNIDA. (Spiders, Scorpions, and Mites.) TaE common consent of mankind regards most of those creatures of which we are about to speak with revulsion and abhorrence ; and it must be confessed that the closer examination which the scientific naturalist bestows on them, has only resulted in more firmly fixing upon them the stigma of a bad character,—decidedly, undeniably bad. The poet’s verdict is true, when he calls the Spider— “Cunning and fierce—mixture abhorr’d.” Bloodthirsty and vindictive, treacherous and cruel even to their own kind, bold and prompt in warfare, ever vigilant, full of stratagem and artifice, highly venomous, lurking in darkness, endowed with curious instincts, and furnished with many accessory means for the capture and destruc- tion of other animals—the Spiders and Scorpions do not move our esteem, it must be confessed ; and an entomo- logist of the highest eminence,* carrying out the notion that the seen things of nature are symbols and pictures of the unseen and spiritual, views in these creatures the * Kirby, Bridgewater Treatise. SPIDERS, SCORPIONS, AND MITES. 185 types of the evil spirits ; a supposition not unwarranted by the expression of our Blessed Lord, “ Behold, I give unto you power to tread on serpents and scorpions, and over all the power of the enemy!” * Yet even these re- pulsive animals are the handiwork of Infinite Wisdom; and half-an-hour may be worse spent than in briefly run- ning over some of the peculiarities of their structure and habits. And, first, a few words on their structure. They may at once be distinguished from true Insects by having four pairs of legs instead of three. They exhibit a greater condensation of outward form, there being generally but one division, that which separates the abdomen from the fore part, which latter, because it includes in one the parts answering to the head and chest of insects, is commonly called the cephalothorax. The head is destitute of antennae, but those organs are replaced by a pair of claws terminat- ing either in a single hook, or in pincers. The eyes are always simple lenses, sometimes moderately numerous, and then usually arranged in groups, and occasionally placed at the summit of a sort of pillar on the back, a provision which must greatly assist circumspection. Internally, also, the organisation is more condensed, and of a higher type than in Insects. The nervous knots or ganglia are few and central, sending out radiating threads to the circumference and extremities. The breath- ing organs are either lungs, enclosed in bags, or radiating air-tubes (trachew), which communicate with the atmo- sphere by minute slits in the skin. The Spiders and Scorpions belong to the former category, and are named * Luke x. 19, 186 LIFE, IN ITS INTERMEDIATE FORMS. Pulmonaria; the Harvest-men and Mites to the latter, and are called Zrachearia. We naturally associate Spiders with cobwebs, and the faculty of spinning threads from the hind part of the body ig one of their most marked characteristics ; but all do not make webs, properly so called. Inthe south of Europe and in the West Indies, certain large Spiders belonging to the genus Céeniza are called Trap-door Spiders, from their singular architectural instincts. The female excavates a burrow in soft earth, an inch in diameter, and six to ten inches in depth; this is lined with a dense tapestry re- sembling paper, formed of her silk; and the mouth is closed with a circular door, formed of many layers of silk, with pellets of earth interwoven into the exterior, but which is so smooth on the interior, and so accurately formed, as to fit the orifice with the utmost accuracy ; while a hinge of silk at one part of the circumference allows the lid to be raised for the exit of the owner, when it closes by its own elasticity. Judging from specimens which we have examined in Jamaica, the lid is always punctured with a number of holes, such as might be made by a very fine needle, which penetrate through the whole substance, the light being clearly seen through each hole. We have conjectured that the object of these orifices may be the admission of air and light into the cell, when the lid is tightly closed, for the comfort of the inmate. The Spider habitually resides in her well-built house, coming abroad to hunt, and retreating with her prey to the bottom of her domain. In the hot parts of the world, Spiders (Mygale) closely allied to these are found, which are often of immense size, SPIDERS, SCORPIONS, AND MITES. 187 very hairy, and usually black, gray, or reddish-brown in colour. These monsters prey even upon small birds ; a statement which has been denied upon insufficient grounds, but which rests on the concurrent testimony of such men as Perty, Stedman, Moreau de Jonnés, and Palisot de Beauvois. They do not, however, spin nets, but steal upon their prey, and overcome it by violence. The Spider which is so common in our houses, filling the angles of rooms, the crevices of old walls, and the in- terstices of the foliage in shrubs and hedges, with a dense web, belongs to the sedentary division. It is the Tegena- ria domestica of zoologists. The web is nearly horizontal, with a tube at the inner part, within which the Spider is ordinarily lodged, motionless, with its head projecting and its fore feet stretched out upon the expanse of the web,— “* And hush’d in grim repose, expects its insect prey.” No sooner does a thoughtless fly alight on the web, than out rushes the Spider with lightning rapidity, seizes it with her fangs, and carries it into the den to be sucked and exhausted of its juices. Walckenaer thus describes her domestic economy: “She constructs a bag of silk shaped like a purse, ballasted with bits of plaster, for the suspension of her cocoon. ‘The orifice of the bag she covers with a little web, on which she sits, watching without ceasing for the appearance of her offspring. Her cocoon, formed of fine web, contains about 150 eggs, which are laid in May and June.” * : There is a little Spider (Argyroneta aquatica), found occasionally in ponds and rivers, which turns its spinning * Aptéres, ii. 4. 188 LIFE, IN ITS INTERMEDIATE FORMS. powers to a curious purpose. It forms a residence beneath the surface of water, which, like our diving-bells, is filled with air. It is commonly said that she first spins loose threads, connecting the stems of water-plants, among ' which she weaves a little cell, which she then manages to fill with air successively carried down in bubbles from the surface, in some unknown manner, But Baron Walcke- naer, who writes from personal observation, describes the process differently. The abdomen is covered with a close down, which does not permit the water to wet the skin; when beneath the surface the whole body is enveloped in a coat of air, so that it resembles a ball of quicksilver. “When the Argyroneta would construct its nest, it swims to the surface, Este and, head downward, pro- = trudes the extremity of the abdomen, dilating its spinnerets, and then dives with rapidity. By this process she produces , — a little bubble of air, AY 77 which, independent of ~/// the silvery coating which envelopes the body, ap- pears as a little globule attached to the tail. She a isd y A HAN ; \\ Swims to the stalk of / the plant to which she \| IA UK would fix her nest, and, TheiWatar faders touching it with the bubble, the air detaches itself and adheres to the plant. The Spider then remounts to the SPIDERS, SCORPIONS, AND MITES. 189 surface, collects another air-bubble, which she adds to the former. When she has, in this manner, sufficiently en- larged her balloon of air, she encloses it with silk of extreme whiteness. Within this balloon, which is open below, she then sits in a reversed position. She then stretches through the water irregular threads, which converge to her habi- tation, and which arrest minute water-mites and other insects. These are seized, and carried within doors to be eaten, but sometimes the prey is borne to the surface, and devoured on the bank.” * The accuracy of these observations has been recently confirmed by Professor Bell. Among the largest and best known of our native species is the handsome Garden Spider (Kpeira diadema). Its form is familiar to every one in the latter part of summer and autumn, its plump abdomen gray or fawn colour, elegantly spotted with white, and its legs widely extended, as it hangs head downward on its perpendicular web, which is formed of concentric circles of fine thread, on a frame-work of radiating lines. This geometric web is a beautiful example of an insect-manufacture. Having formed the foundation of her net and drawn the skeleton of it, by spinning a number of rays converging to the centre, she next proceeds, setting out from that point, to spin a spiral line of unadhesive thread, like that of the rays which it intersects, and to which she attaches it, and, after numerous circumyolutions, finishes it at the circum- ference. This line, together with the rays, serves as a scaffolding to walk over, and it also keeps the rays pro- perly stretched. Her next labour is to spin a spiral line * Aptere, ii. 383. 190 LIFE, IN ITS INTERMEDIATE FORMS, from the circumference towards the centre, but which stops somewhat short of it ; this line is the most impor- tant part of the snare. It consists of a fine thread studded with minute viscid globules, like dew, which, by their adhesive quality, retain the insects that fly into the net.* The skilful constructor then stations herself in the very centre, where she patiently hangs head downward ; and, her feet extended upon the rays, “lives along the line,” until the arrest of some unwary fly rouses her to vigorous action. Approaching the struggling victim, she pours out her glutinous web in extraordinary profusion, direct- ing it by means of her great hind feet in a broad and dense ribbon around the fly, whose every limb is rapidly enveloped by it. The pointed poisonous claws are now plunged into its body, and the juices sucked at leisure. The threads of a Spider’s web, fine as they are, must not be considered as simple filaments, but as ropes com- posed of many strands. ‘The spinning apparatus consists of four little teats or warts at the hinder extremity of the body. The upper pair of these are perforated at their tips with innumerable holes of inconceivable minuteness, so as to resemble a colander, and through each of these holes proceeds a thread. The lower pair are similarly perforated, but are set in addition with a number of pro- - minent tubes, which furnish threads also. Within the body at this part there are several bags filled with gummy matter, which at the will of the animal is forced through the orifices, and hardens into elastic silk on exposure to the air. The Spider applying the ends of the teats to any fixed object, the gum adheres, and by her progress a cord * Blackwall, in Zool. Journal, y. 181. SPIDERS, SCORPIONS, AND MITES. ") al is drawn out which consists of as many constituent threads as there are minute orifices in her spinnerets. Want of space forbids us to do much more than allude to the renowned Tarantula (Lycosa tarentula) of Italy. The bite of this Spider is reputed to produce lethargy, melan- choly, and delirium, which are only to be cured by the influence of music exciting the patient to dance. It is now pretty, well established that these pretended cures were | “oot up” for the sake of imposing on the credulous. The Spider itself belongs to a very extensive genus, represented — in almost all countries, and everywhere displaying the same habits. They live on the ground, running swiftly ; the females carrying their large egg-case about with them during the breeding season, and refusing to part with it ; or, if forcibly deprived of it, becoming stupid, and, as it were, stunned, utterly regardless of personal safety, till the dear object is restored, when, in an instant, animation and vigour return. As there is a Spider which descends by means of its web into the depths of the water, so there are others which, by the same medium, ascend to the regions of the clouds. These are the Gossamer Spiders (Linyphia, Theri- dion, &c.), minute species, scarcely exceeding in size a pin’s head. They have the power of shooting out filmy threads into the free air, which, on some undetermined principle, usually thought to be connected with electricity, rise with considerable buoyancy, and at length carry up the little aeronaut with them. After a while, becoming saturated with moisture, they descend, and large tracts of ground are frequently seen, in autumn, covered with the delicate films of flocculent web. 192° LIFE, IN ITS INTERMEDIATE FORMS. The last Spider which we can here notice is the little Hunter (Salticus scenicus), which, in its zebra-like marking of black and white bands, is frequently seen leaping on window-sills and garden-fences, in the burning sun of summer. Its manners cannot be better described than in the words of old Evelyn :—“Such I did frequently ob- serve at Rome, which, espying a fly at three or four yards’ distance upon the balcony where I stood, would not make directly to her, but crawl under the rail, till, being arrived to the antipodes, it would steal up, seldom missing its aim ; but if it chanced to want anything of being perfectly opposite, would at first peep, immediately slide down again, till, taking better notice, it would come the next time exactly upon the fly’s back. But if this happened not to be within a competent leap, then would this insect move so softly, as the very shadow of the gnomon seemed not to be more imperceptible, unless the fly moved ; and then would the spider move also in the same proportion, keeping that just time with her motion, as if the same soul had animated both these little bodies ; and whether it were forwards, backwards, or to either side, without at all turning her body, like a well-managed horse. If, however, the capricious fly took wing and pitched upon another place behind our huntress, then would the spider whirl its body:so nimbly about as nothing could be ima- gined more swift ; by which means she always kept the head towards her prey, though, to appearance, as im- moveable as if it had been a nail driven into the wood, till, by that indiscernible progress (being arrived within the sphere of her reach,) she made a fatal leap, swift as lightning, upon the fly, catching him in the poll, where SPIDERS, SCORPIONS, AND MITES. 193 she never quitted hold till her belly was full, and then dragged the remainder home.” * There are several hideous forms of the group in tropical climates, of which the best known is that of the Scorpions. It is impossible to look on one of these, and not be re- minded of a lobster—the great palps, with stout dilated pincers, resembling closely the claws of that much more respectable crustacean. The Scorpions are widely scat- tered ; several are found in the south of Europe, but it is in the tropics that they most abound. The Scorpio afer of the East Indies grows to six inches in length, and its sting is rather a formidable affair. We once experienced the effects of a West Indian Scorpion’s venom, which were, however, not more severe than those of a wasp’s or bee’s sting. The weapon is a hooked, very acute joint at the extremity of a six-knobbed tail, within which is a bag of subtile poison, infused into the wound through two minute slits near the point. These animals lurk under stones and in dark crevices, living on beetles and other insects, which they catch with their claws. Tiny species closely resembling them, except that the tail and the sting are wanting, are common in old books and papers, and sometimes parasitically infesting insects. These con- stitute the genus Chelifer, and form the connecting link between the Scorpions and the Harvest-men or Shepherd- spiders (Phalangium), which are so common in autumn, - remarkable for the great slenderness and length of their many-jointed legs, which continue to move a long time after being separated from the body. The tribe of Mites comprises small and generally very * “Travels in Italy.” N 194 LIFE, IN ITS INTERMEDIATE FORMS, minute animals. Scarlet is their favourite livery, and it often has the appearance of satin or velvet. The Water- mites (Hydrachna) are merry little creatures that scuttle along through the water of our pools, looking like tiny globules of red sealing-wax. The Cheese-mite (Siro do- mesticus) is So common, that possibly, gentle reader, you may have emulated the feats of Samson, slaying thousands at a time, and that with a jaw-bone. If you are fond of dogs or of cattle, you have also, doubtless, made the ac- quaintance of a vile creature called a Tick (Ixodes), which attaches itself to the poor brutes in some spot inaccessible to their efforts—such as behind the ears, or at the root of the tail—and then, plunging a beak of sharp horny lancets into the flesh, sucks the blood, till its own body is gorged and swollen from the size of a hemp-seed to that of a horse-bean, when it drops off to make room for another bloodthirsty sucker. And, finally, some of these crea- tures (Sarcoptes) of minute dimensions, burrowing beneath the skin, become the cause of certain highly infectious cutaneous diseases, which are unhappily too common where cleanliness is neglected. WIUEEL-BEARERS. 195 CHAPTER XXI, Rotirera ( Wheel-bearers). NEARLY two centuries ago, a great impetus was given to physical science by the application of the newly-invented Microscope to substances so minute, that their forms, or at least their structure, could scarcely be appreciated by the unassisted sense. The waters were found to be teem- ing with living creatures of multitudinous kinds, consti- tuting what might be called a new world of life. The excessive minuteness of these creatures being their most obvious character, and the imperfection of the instruments as yet in use permitting no more than a vague perception of their exterior figure, it was natural that they should be associated in one group, under the term Animalcules. More precise observation has, however, determined that, among these minute forms, are comprised animals of very various grades of organisation. Some are the simplest creatures known, as the Monads, of which we treated in the first chapter of this volume; some are not animals at all, but plants of a very low grade, endowed with animal-like powers of locomotion ; some are the larvee of INSECTS ; some are minute ANNELIDA and CRUSTACEA ; and a considerable number, of high interest from their beauty, their sprightly motions, their perfect transparency, 196 LIFE, IN ITS INTERMEDIATE FORMS. and their comparatively complex structure, constitute a peculiar class of themselves, under the title of Rotirera. The relation which this group bears to other recognised classes of animals, has been a matter of some debate. It seems generally admitted that they come into the Annu- lose Division ; and we are inclined to place them above the ANNELIDA, having relations both with Insrcta and Crustacea, and forming a link by which the lowest forms of these highly-organised creatures are linked with the highest [NFrusORIA. | The earliest known species is one of the most abundant ; and though it is not so typical of the class as many others, being one of the lowest forms in organisation, yet as it exhibits, with peculiar clearness, the characteristic movement which has given a name both to itself and its class, it is popularly considered as the representative of the whole. We allude to the common Wheel-animalcule (Rotifer vulgaris), which is found in most collections of fresh water, and in vegetable infusions that have stood exposed for a few days. The form of this tiny creature, which does not exceed goth of an inch in length, is spindle-shaped or barrel- shaped, the lower part tapering to a slender foot, of many joints, capable of being sheathed, telescope-fashion, one within another, and the upper part expanding into two circular disks set with vibrating cilia. It is the motions of these cilia which are so peculiar and characteristic of the whole class; they immediately arrest the attention of the observer, who is struck with wonder to behold what appear to be the dark teeth of two cogged-wheels, set side by side horizontally, and running rapidly round with the WHEEL-BEARERS. 197 ceaseless regularity of a complex piece of machinery. The early observers supposed that the wheels really did rotate, though they found it impossible to imagine how any part of a living animal could do so. And no beholder can wonder at their supposition, for with all our knowledge of how the phenomena is produced, it is almost impossible, while looking at it, to persuade ourselves that there is not an actual rotation of the parts. The explanation of the appearance has been already given:* it is a rotatory pro- gression of waves caused by the rhythmical bending and straightening of cilia, in themselves stationary. The effect of this movement is to produce circular vortices in the surrounding water, which are made conspicuously mani- fest when any minute particles of solid matter are held in suspension; as when a little carmine or indigo is mixed with the water. In this case, the coloured atoms are caught, and involved in the rapid rotation, passing off after many gyrations, in a continuous thick stream from a point between the two wheels, like the dense black cloud of smoke that streams away behind a steamer’s funnel. The objects of the ciliary rotation are principally two. When the animal is stationary, adhering to foreign sub- stances by the extremity of its foot, the vortices bring ever fresh particles of water to be respired, and whatever atoms fit for food may be floating in the vicinity; the whirls leading to a central point, at which is placed the entrance to the stomach. On the other hand, when the animal relinquishes its foot-hold and commits itself to the open water, the cilia act like a steamer’s paddle-wheels, * See page 4, supra. 198 LIFE, IN ITS INTERMEDIATE FORMS. and row it swiftly along in any given direction at the creature’s will. The skin in this species is membranous, but somewhat firm, folded upon itself at certain points of the circum- ference, so that one portion can, to a certain extent, be sheathed within another, as in the ANNELIDA and in the larvee of Insects. In many genera, however, the integu- ment hardens into a firm horny shell (dorica), which takes different forms, the most common being that of a tortoise- like box, as in Brachionus, &c., with a wide orifice in front (often armed with projecting spines) for the protrusion and expansion of the ciliary wheels, and a smaller one in the rear to give issue to the flexible-jointed foot, which commonly terminates in two pointed toes, The structure and composition of this integument are similar to those of Inszots and CRUSTACEA. Owing to the crystal transparency of these tiny crea- tures, we are enabled, with the aid of microscopic powers, to discern their internal structure and economy with a clearness which no dissection would avail to shew ; even were not dissection precluded by their minuteness. They are thus perceived to possess a comparatively high condi- tion of organisation, The muscular, the nervous, the digestive, and the reproductive systems are, in particular, well developed. Long and broad ribbons of muscular texture pass from organ to organ, playing freely in the general cavity of the body, their contractions and extensions plainly visible. These are very numerous, some passing down longitudinally, others transversely, their extremities being inserted into the lining tunic of the integument. Sometimes the muscles WHEEL-BEARERS. 199 take the form of slender but lengthened threads, and others are seen, crossing, in various directions, like a net, the ampler viscera. From this rich muscular development, the movements of the Rotirera are very varied and vigorous. The nervous system is very peculiar and remarkable in this class. It exists in a form wholly without parallel in the Invertebrate Classes, namely, that ofa single mass, well defined, and often of immense comparative size, which, in spite of all our reluctance, we can compare only to the brain of the VERTEBRATA. This great nerve-mass is placed in the head of the animal, and commonly carries, seated on its hinder part, a red eye (sometimes two) of simple structure, apparently composed of a lens and a pigment mass. The great ganglion sends off a pair of threads to the nape, where they unite into a small ganglion below an organ of sense, which, in its most ordinary form, is a tubular projection, furnished with a terminal tuft of hairs, and which appears to be the representative of the antennee in Insects. In a few cases we have detected threads of extreme tenacity floating in the cavity of the body, which we believe to have a nervous character; but besides these, we know of no offshoots from the great central brain. It is certain that nothing answerable to the double chain of ganglia, united by threads, and running down the length of the body, that are so characteristic of the ANNULOSA generally, exists in this class. Scarcely less anomalous is the condition of the mouth. Far down in the body is seen an oval pellucid mass, con- taining a curious array of symmetrical pieces that work vigorously on a central table, like a pair of hammers on an anvil, Strange as is its position, this organ is nothing 200 LIFE, IN ITS INTERMEDIATE FORMS. else than the mouth, its place being caused by the inver- sion of the fore parts of the body, permanently in some species, as Rotifer, but in others, as Scaridium, Furcel- laria, &c., transiently, the mouth being brought to the exterior when in action. The hammer-like pieces are the representatives of the upper jaws (mandibula), and the two halves of the table-like piece, against which they work, are the representatives of the lower jaws (mamille) of INSECTS. The food, after having been subjected to the pounding and crushing action of these hammer-like jaws, passes off behind through a slender gullet into a capacious sto- mach, into which bile is poured from glands (either a single pair or very numerous) which are appended to it, This is succeeded by an intestine, and this by a rectum, which terminates in an orifice behind the foot. It is a curious circumstance that there exists one genus in this Class—hence named Asplanchna—which has no intestine nor any posterior outlet to the stomach, the foecal portions of the food being regurgitated and expelled from the mouth. Still more remarkable is the fact, that all the males in the Class are entirely destitute of the diges- tive apparatus ; neither mouth, jaws, gullet, stomach, nor intestine being found, nor any vestiges of these organs, in any male Rotiferon. - So far as has been observed, the sexes are separate throughout the class. The peculiarity just noticed is not the only one that distinguishes the sexes. The male RovIFERA are invariably smaller, less fully organised, and more short-lived than the females; they commonly have scarcely any resemblance to their partners, though the WHEEL-BEARERS. 201 males of all the species have a very close similarity to each other. The females produce and deposit, one at a time, very large oval eggs, enclosed in a brittle shell. The young appear in the perfect form, being subject to no metamor- phosis, and for the most part with all their organs com- plete. In some of the lower forms, as Stephanoceros, Me- licerta, &c., the young are hatched in a grub-like condi- tion, from which the tentacles, disk, &c., develop them- selves by gemmation. The genera just alluded to, and some others, are inca- pable of locomotion, except in earliest infancy; the young soon attaching themselves by the foot to some solid object. They now secrete and throw off from the surface of their body successive coats of gelatinous matter, which form an erect cylindrical case around them, into which they can wholly retire for protection, by contracting their fore parts on alarm. In general, this tube is simply gelatinous and transparent, except that it sometimes becomes par- tially opaque when old, by the adhesion to its exterior of Diatomacee, floccose particles, &c.; but in one species (Melicerta ringens), which hence becomes invested with a high interest, the tubular case is strengthened by a layer of solid pellets, manufactured by the animal for the occa- sion, and deposited, pellet by pellet, and layer upon layer, just like the bricks in a piece of masonry. This species is one of peculiar beauty, and any of our young readers who possess a microscope, or have access to one, will do well to obtain an hour’s examination of it. Fortunately, it is by no mecns a rare animal in still waters where aquatic plants grow: the slender, much divided 202 LIFE, IN ITS INTERMEDIATE FORMS. leaves of Myriophyllum are pretty sure to be more or less studded with the erect tubes, which are quite visible to the naked eye. On being brought under the microscope with a power of 100 or 150 diameters, you can see a tall chimney of a yellowish-brown hue, standing on a leaf, slightly widen- ing from the bottom upwards, and terminating in an irre- gular edge. Presently, a pellucid body peeps from the summit, like a sweep out of the chimney-top (pardon the similitude), and, rising higher and higher, suddenly unfurls a disk of four expansive petals, not altogether unlike those of a Heart’s-ease, but made of crystalline material, and set round the margins with a row of those beauteous cilia, whose dark waves chase each other in ceaseless play, up and down, round and round, in the most charming manner. Behind the disk, which by a bend of the upper part of the body is brought to assume a vertical position, there is a little hemispherical cavity on the surface, which is lined with cilia, and this is connected by a series of cilia with the sinus of the two great upper petals of the disk. The ciliary wave, after making the circuit of the disk, passes off behind in a great current through the sinus just alluded to, carrying with it all the floating particles that are not fit for food, or that have not been carried into the mouth. These particles are hurled along until they reach the little hemispherical cavity, in which they are | caught and whirled round and round with great rapidity. Here, too, they are probably mixed with some glutinous secretion, and the effect of the gyration is the consolida- tion of the particles into a little globular pellet. No sooner is this ready, than the animal quickly bends forward its WHEEL-BEARERS. 203 body till the cavity touches the edge of its case, where the globule is deposited. The erect position is now assumed again, materials for a new globule begin to accumulate, and in a minute or two this is ready, and is deposited beside its predecessor ; and thus the case is swiftly built up, brick by brick. 204 LIFE, IN ITS INTERMEDIATE FORMS. CHAPTER XXII. Crustacea (Crabs and Shrimps). THE dark, mysterious world of waters hides many a “moving creature that hath life ;” and the solitary pacer along the black line of sea-weed that bounds the domains of earth and sea, or the curious Paul Pry that is ever and anon peering into nooks and holes and crannies in the surge-worn rocks, is continually surprised by some strange being, some minim of existence it may be, uncouth and slow, or lithe and elegant, and rapid as lightning; dull and sombre as suits its obscure retreat, or bright and gaily- tinted from the solar ray ; some new combination or modi- fication of organs ; some novel exhibition of instinct, habit, or function; that awakens his admiration, and, if he be accustomed to turn from the creature to the Creator, elicits the tribute of praise to Him who made all things for His own glory. The CRUSTACEA pre-eminently make the waters their home; they are the aquatic division of that mighty host of living things, that range under the title of ARTICULATA. The Insects, Spiders, and Mites, counting their armies, as they do, by hundreds of thousands, leave, with scarcely an exception, the sea untouched; and though a goodly num- ber of these are found in the fresh waters of river, lake, CRABS AND SHRIMPS. 205 and pool, they are few compared with the vast body. The solid earth and free air constitute ther sphere of exist- ence. The Crustacea, on the other hand, though repre- sented by a few species that crawl on the land, and more efficiently in fresh waters, mostly range the sea, dwelling, according to the diversity of their structure and instinct, from the sunny surface to the unilluminated depths; from the shallows of the shore to the boundless solitudes of the ocean; from the genial waves of the Equator to the ice- fields of the Pole, to “Arctos and eternal frost.” Nor let this last assertion be considered as a sounding platitude with which to sweep the sentence round grace- fully ; for it is literally true: as far into the dreary regions of the Pole as our bold explorers, or still hardier whale- fishers have penetrated, they report the Arctic Sea to swarm with small Crustacea. One little species, in par- ticular, found in immense numbers beneath the ice, was turned to account in the temporary sojourn of the dis- covery expeditions in winter quarters, The men had often noticed the shrinking of their salt meat which had been put to soak, and a goose that had been frozen, on being immersed to thaw, was, in the lapse of forty-eight hours, reduced to a perfect skeleton. The officers aftetwards availed themselves of the services of these industrious little anatomists, to obtain clean skeletons of such small animals as they procured, merely taking the precaution of tying the specimen in a loose bag of gauze or netting, for the preservation of any of the smaller bones that might be separated by the consumption of the ligaments. In most respects, Crustacea are so much like Insects, that the older naturalists, and the illustrious Linneus 206 LIFE, IN ITS INTERMEDIATE FORMS. among the number, arranged them under the great class Insecta. They have, however, a greater number of limbs ; the full provision being five pairs of true feet, and three pairs of organs, which (because of a certain ambiguity in their function, like that useful piece of furniture of which we read— —— ‘‘Contrived a double debt to pay, A bed by night, a chest of drawers by day,”)— are called foot-jaws. Besides these, a great number of the species have five or six pairs of jointed limbs attached to the under-side of the abdomen, which are generally used for progression, and are called false-feet Their mouth is furnished with three pairs of jaws and two pairs of an- tennee. It must be borne in mind, however, that the total complement of these members is not found present in every species, some of them being wanting in certain extensive groups. The researches of a naturalist who has paid much atten- Prawn. tion to this class, Mr Spence Bate, have shed a flood of CRABS AND SHRIMPS, 207 interesting light on the office of the organs last-named.* Any one may easily identify them in the Lobster or Prawn, Take the latter. On each side of the long sword-like and spiny beak that projects above the head, there is an organ consisting of three stout joints, at the tip of which are - three threads, of which two are of great length, and formed of numberless rings, and the third is short. These organs, then, constitute the inner pair of antenne. Below these there is a pair somewhat similar, but they consist each of five joints, and one long thread, with a large flat plate on each side. ‘These are the outer antenne. The former are the organs of hearing, the latter those of smeiling. In the living animal, the inner antenne are always car- ried in an elevated posture, and are continually flirted to and fro with a rapid jerking motion that is very peculiar, striking the water every instant. It is very conspicuous in the Crabs, from the shortness of the organs in question. When next our readers, gazing on the tenants of those wonderful marine tanks at the Zoological Gardens in the Regent’s Park, see a Crab tapping the surrounding water, and, as it were, feeling it—they may understand that he is trying it for the vibrations of sound: it is the action of vigilant listening, which never relaxes its guard. To help the perceptions of the animal, the many-jointed filament which strikes the water is fringed with hairs of great delicacy, standing out at right angles to the stalk, so that the slightest vibrations cannot fail to be conveyed to the sensorium. This may be called the outer ear; but in the interior of the basal joint, which is large and swoilen, there is a cochlea, or inner ear, having calcareous walls of * Ann. and Mag. of N. H., July 1855, p. 40. 208 LIFE, IN ITS INTERMEDIATE FORMS. delicate texture, to the centre of which passes the auditory nerve. The outer antenne differ greatly from the inner in their internal structure, though they resemble them so much in form. In the Crabs, the basal joints form a sort of box or compact mass, with an orifice on the side next the mouth, closed or opened at pleasure by means of a little door with a hinge, on the interior side of which a long bony lever is fastened, with the necessary muscles attached to it. In the Lobster and Prawn the door is wanting, but the orifice is protected by a thin membrane; and in some of the lower forms it is placed at the end of a strong spine or projection. In all cases, however, the orifice “is so situated that it is impossible for any food to be con- veyed into the mouth without passing under this organ ; and of this the animal has the power to judge its suit- ability for food by raising the operculum [or door] at will, and exposing to it the hidden organ—the olfactory.”* Who can refrain from exclaiming, at the sight of such beautiful, such exquisite contrivances for the safety and wellbeing of creatures so mean, “ Great and marvellous are thy works, Lord God Almighty !” The “ crust,” or skin which envelopes the body, in these animals, differs from that of Insects, inasmuch as it gene- rally contains a considerable portion of carbonate of lime. In many of the smaller forms, as in the Shrimps and Prawns, it takes the consistence of thin transparent horn; but in the larger, as the Lobsters and Crabs, it acquires a great density, is perfectly opaque, and of the hardness of true shell, or even of stone. In the tips of the stout * Bate, loc. cit. p. 44 CRABS AND SHRIMPS. 209 claws of the Crab (Cancer pagurus) we see it at its maxi- mum of induration. The breathing organs furnish another point of diversity between the Crabs and Insects. In the latter they are air-pipes, in the former gills ; always contrived, though under many modifications of form and position, to extract the vivifying oxygen from water, and not from the atmo- sphere. Even the terrestrial species, as the common Woodlouse or Button (Oniscus), that rolls itself up into a ball in our gardens, need a certain degree of moisture to surround them, and hence they crawl out of their damp retreats only in wet weather. In the common Crab the gills are those long, finger-like, pointed pyramids of whitish substance often called “ dead men’s fingers,” that are seen in two groups, when the carapace or ‘ shell” is removed. If we examine them, we shall find each pyramid to consist of a vast multitude of thin membranous plates closely packed together, but yet admitting the water to flow freely between them, which is kept in constant circulation by means of innumerable cilia with which the surfaces are clothed. ' The increase of the race is effected only by means of eges, no Crustacean that we remember bringing forth its young alive. Every one is familiar with the eggs, ‘‘ spawn,” as they are termed—of the Prawn, the mass of intensely red globules that is carried beneath the belly, and that is so difficult to remove. The difficulty arises from the manner in which the false feet, all fringed as they are with fine hairs, penetrate the mass ; and thus we perceive another use of these organs, besides that of locomotion, already alluded to. The eggs, as they are laid, are de- 0 210 LIFE, IN ITS INTERMEDIATE FORMS. posited on the false feet, and are carried about by the female parent until near the period of hatching. In some of the Opossum-shrimps (Myside) the eggs are carried in one or two oval pouches beneath the thorax ; while in the curious little Water-fleas (Cyclopide), and the still more remarkable Epizoa, the eggs are carried on each side of the tail in two oval or cylindrical bags, generally of large size, and sometimes of such length as to exceed that of the whole animal besides. Like Insects, the Crustacea undergo a metamorphosis— perhaps with one or two exceptions. No one, uninstructed, could possibly recognise the earliest stage of the common Shore Crab (Carcinus menas). A hemispherical carapace or shell, not so big as a small pin’s head, sends up from its centre a long, pointed, curved spine, while another spine curves downwards from the front beneath the body like a beak ; the eyes are without stalks ; there are two pairs of jointed feet, ending in tufts of stiff bristles; and a long jointed body carried straight behind, which ends in two bundles of diverging spines. Such is the grotesque character under which our little masquerader makes his “first appearance on any stage.” After a time he drops his outer garments, and assumes a second form—widely different from the former, and still sufficiently remote from the ultimate one; and it is not till the third moult that the little creature, now grown to the size of a hemp- seed, begins to be recognisable as a Crab ; though even now he has several stages to pass through, several doffings of coats and trousers, before he is quite a proper Shore Crab, comme il faut. This periodic casting of the skin is a needful provision CRABS AND SHRIMPS. 211 for growth in these animals, as in Insects ; in them it is confined to the caterpillar state, in which alone growth takes place ; but here it prevails, because growth is con- tinued, long after the perfect form is attained. The rigi- dity of the encasing armour forbids the possibility of in- crease in its capacity. The growth, therefore, is periodic. At certain intervals the hard crust is thrown off in several pieces, a new crust having been prepared beneath, which is at first soft, flexible, and expansile. The body, now freed, instantly enlarges in all directions, and, in a few minutes, has attained the full extent of growth needed. The crust at once hardens, and in a brief space becomes as inflexible as was its predecessor, admitting no further enlargement either of its own surface or of the contained organs. The animal usually undergoes this process in the most retired situation it can find, instinctively con- scious of its unprotected condition when soft, and appa- rently feeling sick and feeble. Another interesting circumstance in the economy of this Class, and the last we shall at present notice, is the power of renewing injured or lost limbs. If one of the joints of a Crab’s leg be wounded, it would bleed to death but for this provision. The animal, however, wisely adopting the saw of “ Young Jem” in our nursery-rhyme— ‘Better lose part than all”— stiffens the hurt limb, and suddenly throws it off, the separation invariably taking place at the point where the second joint is united with the first. A small gland is placed here, according to Mr H. Goodsir,* which supplies * Ann. of N. H., vol. xiii., p. 67. 212 LIFE, IN ITS INTERMEDIATE FORMS. material for future legs as required. “ When the limb is thrown off, the blood-vessels and nerve retract, thus leav- ing a small cavity in the new-made surface. It is from this cavity that the germ of the future leg springs. A scar forms over the raw surface caused by the separation, which afterwards forms a sheath for the young leg.” “ As the growth advances, the shape of the new member be- comes apparent, and constrictions appear, indicating the position of the articulation ; but the whole remains unpro- tected by any hard covering until the next change of shell, after which it appears in a proper case, being, how- ever, still considerably smaller than the corresponding claw on the opposite side of the body, although equally perfect in all its parts.” * * Jones’s “‘ General Outline,” p. 343, CRABS AND SHRIMPS. 213 CHAPTER XXIII. Crustacea (Crabs.and Shrimps). Continued. PERHAPS the most singular of all animal existences, and certainly the most remarkable of the Class to which they belong, are those Crustaceans which constitute the Order Epizoa, so called from their parasitical habits. The grand principle of economy is so perfectly carried out in Crea- tion, that not only is every spot of inorganic nature turned to account in providing for some existences proper to it, but even the bodies of living animals are made to afford a dwelling-place and a feeding-ground for multitudes of other creatures. The intestines, the layers of muscle, the coats of the eye, the sinuses of the skull, afford, as we have already seen,* in different animals, a home for cer- tain creatures of strange conformation, which are found under no other conditions, and are thence called. Intes- tinal Worms, or more correctly Enrozoa, t. ¢., animals which live within other animals. The gills of fishes, the breathing pouches, the interior of the mouth, and various parts of the surface of the body, become, on the other * See Chapter XIII., supra. 214 LIFE, IN ITS INTERMEDIATE FORMS. hand, the residence of another group, the Epizoa, of which we are speaking. Though these two groups of parasitic animals are very diverse in zoological rank, or, in other words, in the de- eree of complexity which their structure exhibits, they merge into each other by imperceptible gradations, so that there are some intermediate forms (as there almost always are on the confines of great groups), which it is very difficult to arrange in either Class, because this would involve their violent separation from near kindred. It must be borne in mind that our lines of demarcation are artificial, though, for perspicuity’s sake, we must draw them somewhere. One of the most interesting points in the economy of these creatures is the variety which is displayed in their armature. Deprived, for the most part, of limbs, or having these members when present strangely disguised, it was necessary to their existence that they should be furnished with some means of affixing themselves firmly to their prey, and various are the mechanical contrivances which serve this purpose. There is a minute Worm (Gyrodactylus) which lives upon the gills of certain species of the Carp tribe, whose adhering disk, when viewed be- neath the microscope, is most formidable to behold. It is armed all around its circumference with sharp curved hooks, while its centre is provided with a pair of much larger hooks, all intended to be plunged deeply into the flesh of the unfortunate fish, while the blood is sucked at leisure. In Caligus, a creature a hundred times as large as that just named, found on various marine fishes, the object is effected by an array of hooked fangs and pincer- CRABS AND SHRIMPS. 215 iike claws, combined with sucking-disks, while a slender tube pierces the flesh and pumps up the vital juices. Chondracanthus,—which looks like a tiny doll dressed up in a long petticoat, fantastically studded all over with curved prickles,—clings to the gills of the John Dory by means of its stout hooked foot-jaws, of which there are three pairs. More strange still is the furniture of the ZLerneopoda. Here two long arms proceed from the thorax, which, curving forward, meet at their tips in front of the head, and uniting, carry a knob or button, which, being thrust into the flesh of some miserable Shark or Salmon, main- tains the needful hold for the robber’s operations. A similar creature (A chtheres), that infests our common Perch, has a contrivance more elaborate still : the two arms unite as before, but the knob at the point of junction now be- comes a bell-shaped cupping-glass, beset within its rim with -an array of recurved hooks. Hanging by means of this grappling-iron to the gums of the fish, it allows its body to swing without fear or danger of dislodgment, in spite of the currents that are perpetually flowing through the mouth and gills. In some very long and slender forms constituting the family Penellade, parasitic upon the bodies of fishes, as the Sprat and Anchovy, the entire head is plunged into the tissues of the prey, sometimes into the eye, and is retained there by a curved prong which pro- ceeds backward from each side of the head, exactly on the principle of an anchor. An additional firmness is secured to the Lernea, which infests the gills of the Cod; by the prongs or flukes of the anchor being furnished with pro- cesses shooting off irregularly on all sides, which, being 216 LIFE, IN ITS INTERMEDIATE FORMS. imbedded in the flesh, like the roots cf a tree in the soil, resist all opposing influences to drag it away. This form is one of the most bizarre of the whole ; for, besides this strange rooting head which is concealed, the exposed body resembles a twisted sausage, without limbs, to which the external ovaries hang, like rolls of thread twined loosely together. Every ditch and pool is tenarited by tiny nimble crea- tures, which move through the water by a succession of little leaps, whence they are called Water-fleas. Some- times the ponds swarm with them to such a degree that the fluid contents seem not water but blood, or other strange liquid, according to the colour of the little animals. These belong to the Order Enromostraca, and, though small, many of them being undistinguishable without microscopic aid, they are highly curious. Many of them are enclosed, either wholly or in great measure, in a shell, which takes the form of two convex plates, either soldered together down the back, or united there by a hinge, leay- ing the opposite edge free for the protrusion of the head and feet. The close resemblance of the latter (Cypridide) to the bivalve shells of Motuusca is remarkable. In general these little animals have but a single eye in the middle of the forehead, which is of large size in pro- portion, round, and generally of a brilliant red hue, glis- tening like a ruby, so that it furnishes a beautiful study — under the microscope. Inthecommon Water-flea (Daph- nia pulex), the eye is bluish black, evidently composed of about twenty crystalline lenses, and though quite in- cluded within the shell, its motions, which are quick and partly rotatory, can be distinctly perceived. CRABS AND SHRIMPS. 917 For the protection of the eggs in this genus there is a peculiar provision. They are proportionally large and few in number, and, when laid by the mother, are not committed to the free element, but are deposited in a sort of chamber between the valves of the shell, above the animal’s back. Here they are carried until the young are hatched ; and even for some days more the little ones avail themselves of the same safe retreat, until they are strong enough to get their own living. For the most part in this Order, however, the eggs are excluded in two large oval bags, which hang behind the parent, one on each side, these bags (external ovaries) being frequently each as large as the whole animal. When matured the young escape, and the sacs slough away, to be soon replaced by a new pair. Some of this race are not enclosed in shells: the genus just alluded to (Cyclops) and its fellows have the upper parts pro- tected by a large buckler and hollow horny rings, much like the armour of the Shrimp and Lobster, Cyclops—in its young and mature states. and some are deprived of everything answering to a shield. Of the latter sort, which is, however, the exception to the general rule, is the Brine-Shrimp (Artemia salina), which delights in the intensely salt pits of salt-works, as at Lymington, and elsewhere.” * See an interesting account of this Shrimp in ‘‘ Excelsior,” vol. i, p. 229. 218 LIFE, IN ITS INTERMEDIATE FORMS. The hiatus between these “ Insects in Shells,” as the appellation Enromostraca signifies, and the true Crabs, is occupied by an immense host of creatures still small, but generally of a size above that of the Water-fleas. They are commonly jointed throughout, without any carapace or buckler on the fore parts of the body. The terrestrial species are arranged here, of which the garden Armadillo, or Woodlouse, already alluded to, is a familiar example. They approach the nearest of the Crustacea to the true Insects. Many of them have the faculty of rolling them- selves more or less completely into a ball, like the hedge- hog, and apparently for the same purpose, of opposing a passive resistance to annoyance. The Orders Isopopa and AMPHIPODA, distinguished inter se principally by the struc- ture of the limbs, are composed of these forms, which, though they are of various interest, we are compelled sum- marily to dismiss. And thus we come to the most highly endowed repre- sentatives of the Class, one of the most remarkable charac- teristics of which is that their eyes, instead of being imbedded in the head, or at most immoveably seated on the surface, are placed at the tip of horny, jointed stalks, which can be swayed about in various directions, greatly increasing the animal’s range of vision. Hence this Order is called PopoPHTHALMA, or Stalk-eyed Crustacea. The strangest of these are the Glass-crabs (Ph yjllosoma), | animals of extraordinary beauty, found abundantly in the tropical oceans, swimming at the surface far from land. One species has been recently taken on the British shores. They look like an oval plate of the purest glass, with a broad tail and- slender divergent limbs, so transparent and CRABS AND SHRIMPS. 219 colourless that they can scarcely be detected but for the eyes, which are of a lovely blue hue, and are carried at the end of long stalks. Our common Prawns (Palemon) are beautiful examples of pellucid structure ; and when alive, they form, from this circumstance, from the dark-brown lines with which they are adorned, from their elegant shape, and sprightly, graceful motions, very interesting objects in a marine Aquarium ; the moreso as they are among the most easily kept, being readily reconciled to captivity, and keeping themselves in health and condition, without trouble to their possessor, on the animalcules and garbage that else would accumulate on the bottom. Their manner of feeding, by the hand-like use of their long slender claws, which seize the food and present it to the mouth; the brushes of hair with which some of the feet are fringed, serving as cleansing organs, and the effective way in which these are made to reach all parts of the body, and to keep it scrupulously clean; the flapping of the false feet beneath the abdomen in the process of ordinary swimming; the occasional sud- den stroke upon the water of the broad tail-plates when the creature is alarmed, causing it to shoot backward with the rapidity of thought to the distance of several inches; the structure of the eyes, and the singular reflection of a candle from their interior, like the flash of a policeman’s bulls-eye; and even the internal organs, the pulsation of the heart, and the passing of the food, as masticated, into the stomach, can all be seen and studied to advan- tage in these parlour pets. An hour’s observation on their organisation and their manners, if our readers have the opportunity of watching any marine Aquarium, 220 LIFE, IN ITS INTERMEDIATE FORMS. would furnish a most interesting and instructive lesson in physiology. The broad plates which expand like a fan at the tail of the Prawns and Lobsters, form their great resource for swift and sudden locomotion. The common Lobster is said to be able to dart back by this means thirty feet, with the fleetness of a bird on the wing; and when we think of this feat, we must not forget the great density and resistance of such a medium as water, in which it is accomplished. The existence of these plates, and the great development of the abdomen which carries them, distinguish these from the proper Crabs, which have no terminal plates, and in which the abdomen is re- duced to a thin flap bent under the body and pressed close to it, except when it is forced out of place by the spawn, which the females deposit between it and the thorax. Some of the Crabs have the power of swimming, but it is by a very different mechanism from that of the Lob- sters; and it affords us one of the many examples which the naturalist is constantly meeting with, of the infinite resources of the wisdom of God in creation. In the com- mon eatable Crab (Cancer pagurus), with the exception of the foremost pair of limbs, which are expanded into power- ful grasping claws, all the feet are terminated by a short sharp-pointed toe. But we have some species common on our shores (Portunus, §c.), in which the hindmost legs have the last joint dilated into a broad, thin, oval plate, which being fringed, as are also the other joints, with stiff hairs, constitute oars, and being worked in a peculiar manner, row the animals swiftly to and fro, at the surface or through CRABS AND SHRIMPS 221 the deeps. Others, which are more strictly oceanic, dis- play the same structure in a yet higher degree. It is impossible to walk along a beach by the edge of the tide without observing many univalve shells running to and fro, with an agility far greater than that of the sluggish mollusks, whose houses they originally were. On looking closely at them, we see the antennee, eyes, and claws of what seems a minute Lobster projecting from each. If we take it up, the jealous little rogue withdraws into the house, pulling his legs after him, and claps one stout claw upon the other, in such a way as effectually to bar the intruder’s entrance. We may smash the shell upon a stone, and thus execute a forcible ejection (it is no more than he deserves, for the house is not his own, and he pays no rent), and then we see that the hinder parts are curiously distorted and twisted, to fit it for tenanting a spiral shell. It is not a Lobster at all, but a Hermit-crab (Pagurus), and this is the mode of life for which it is cre- ated. ‘The abdomen is covered with a soft skin instead of a shelly crust, and therefore needs protection; and this is provided by the instinct which teaches the Crab to search for some empty univalve shell of suitable size, and to appropriate it for himself. Some laughable scenes occur when the old house becomes too strait for him to live any longer in it, and his growing bulk compels him to look out for a new lodging. Like a sound philosopher, he never loses grasp of the old shell till he has found a better. Tropical countries have many species of Crustacea, which, from their terrestrial habits, are denominated Land- crabs. Those of the West Indies (Gecarcinus) make bur- rows in the soft earth, whence they wander by night for 222 LIFE, IN ITS INTERMEDIATE FORMS. forage. Once in the year they are said to come down from the mountains in troops, surmounting every obstacle in their way to the sea; after depositing their eggs in the water they return much enfeebled. Of the habits of an East Indian species (Thelphusa cunicularis), Bishop Heber thus speaks in his interesting Journal: “ All the grass through the Deccan generally swarms with a small Land- crab, which burrows in the ground, and runs with con- siderable swiftness, even when encumbered with a bundle of food as big as itself; this food is grass, or the green stalks of rice, and it is amusing to see the Crabs sitting, as it were, upright to cut their hay with their sharp pin- cers, and then waddling off with their sheaf to their holes as quickly as their sidelong pace will carry them.” And since they are so anxious to get out of our sight, we will take the opportunity to make our bow to them and the whole tribe of Crabs and Shrimps together. BARNACLES, 223 CHAPTER XXIV. CIRRIPEDIA (Barnacles). WHoEVER is familiar with the rocky coasts of our sea-girt isle, is aware that that belt of rock which is included be- tween the levels of high and low tide, is ordinarily studded with millions of little shelly cones, often packed so closely together, that there is not proper standing room for them, so that the individual cones are forced out of their proper shape, and compelled to rise into a lengthened distorted form. He may chance, moreover, to have seen a log of timber drifted in from the wide ocean, or the bottom of a ship just returned from a twelvemonth’s tropical voyage, either of which has probably displayednumbers of singular beings, which he may be disposed to associate with the Bivalve Mollusca that he finds on the sandy beach. For they con- sist of a flattened shell, composed of many pieces, usually of a blueish-white hue, marked with orange, but set at the end of a more or less lengthened stem of a wrinkled eristly substance, by which it is firmly attached to the sub- merged timber. Now the stony cone seated on the rock, and the delicate multivalve swinging at the end of the long footstalk, are members of the same class—they are both Barnacles. In 224 LIFE, IN ITS INTERMEDIATE FORMS. order to see their affinity, nothing more would be needful than to detach a piece of the rock, and a fragment of the timber, each with one or more of its tenants adhering, and plunge both into a glass of sea-water. Presently you would see, within the open mouth of the cone, two little shelly pieces separate, and out comes a most exquisite apparatus. It is something like a hand of many slender fingers, thrust forth, opened, closed again with a clutch, and drawn in. Look now at the delicately coloured valves of the stalked kind. These separate, and a similar hand is thrust out, makes its clutch, and disappears. The structure of both, and the action, are the same. ‘The principal differences are the absence of the footstalk in the former case, and the soldering together of the valves into a conical shape. The one represents the Acorn or Sessile Barnacles (Bala- ~ nide), the other the Stalked Barnacles (Lepadide). The “hand” thrown cut is a_ beautifully adapted implement for the capture of prey. The Lepas, indeed, possesses in its footstalks a little more freedom of motion than the firmly-soldered Balanus ; but both are fixed, and are therefore incapable of pursuing their prey. They are hence dependent for subsistence on such minute animal- cules as the currents of the waters may bring within reach ; and the constantly recurring clutches help to increase these currents. But they domore. If we examine each of the long “fingers” (cirri) which compose the hand, and which are set in expansible pairs, we shall see that it is composed of a great number of joints, whereby it is en- dowed with great flexibility, and that it is also studded with fine but stiff bristles, which stand out at right a BARNACLES. 295 angles from the surface. Now the “fingers,” expanded like a fan, and curved like a half-open hand, make the framework of a net, while the transverse bristles, those of each “ finger” meeting and interlocking with those of the next, constitute a series of meshes occupying the inter- stices, and the whole, cast out and withdrawn, form a most efficient strainer of the water, arresting every minute atom, living or dead, which, being then passed down to the mouth at the bottom of the net, is either swallowed or rejected, according as it is fit for food or worthless. The Barnacle, whether sessile or stalked, passes through a series of metamorphoses, which shew that, although its appearance and instincts when adult have a great resem- blance to those of the Moxuusoa, its affinities are truly with the Crustacea. It begins life in a form exactly like that of a young Entomostracous Crustacean, with a broad carapace, a single eye, two pairs of antenne, three pairs of jointed, branched, and well-bristled legs, and a forked tail. It casts off its skin twice, undergoing, especially at the second moult, a considerable change of figure. At the third moult it has assumed almost the form of a Cypris or Cythere, being enclosed in a bivalve shell, in which the front of the head, with the antenne, is greatly de- veloped, equalling in bulk all the rest of the body. The single eye has become two, which are very large, and attached to the outer arms of two bent processes like the letters U U, which are seen within the thorax. In this stage the little animal searches about for some suitable spot for permanent residence ; a ship’s bottom, a piece of floating timber, the back of a whale or turtle, or the solid rock. Whenits selection is made, thetwo antenne, P 226 LIFE, IN ITS INTERMEDIATE FORMS. which project from the shell, pour out a glutinous gum or cement, which hardens in water, and firmly attaches them. Henceforth the animal is a fixture, glued by the front of its head to its support. Another moult now takes place ; the bivalve shell is thrown off, with the great eyes, and their U-like processes, and the little Cirriped is seen in its true form. It is now in effect a Stomapod Crustacean, attached by its antenne, the head greatly lengthened (in Lepas, &c.), the carapace composed of several pieces (valves), the legs modified into cirri, and made to execute their grasping movements backwards instead of forwards, and the whole abdomen obliterated or reduced to an incon- spicuous rudiment, POLYZOA AND TUNIOCATA. 227 CHAPTER XXV. PoLyZOA AND TUNICATA. Ws speak of the “ scale of animal life,” as if species rose above species in a perfectly regular linear series, as to their development in organisation, like the steps of a ladder, beginning from the lowest, simplest forms of life, and proceeding step by step, without any interruption, till we arrive at the highest, Man, “who was made after the image of God.” This is, perhaps, the common notion among those who have ever attempted to consider the matter philosophically,—to contemplate Creation as a whole, a system, a plan. And the notion is aided by our systematic books. We are compelled, by the very nature of a book, to treat of creatures in this linear manner ; we cannot do otherwise: we must begin with something, then go on to something else, and so proceed till we leave off. Nobody has yet invented a book in which the pages shall run on in parallel or complex series, instead of suc- cessive ; nor would it be possible to read it otherwise than successively, if it could be so written. _ However, there is much in nature to confirm the com- mon notion. Linear series we find everywhere. Proofs may be found in these very pages; we have treated of 228 LIFE, IN ITS INTERMEDIATE FORMS. animals whose structure manifestly ascends in uninter- rupted gradation, such as that beautiful chain we noticed in the EcHINODERMATA, for instance. It is not that the principle is not correct, but that it is not true throughout: it is not the only principle. In fact, we find, in tracing up linear gradations, points occurring ever and anon, where, though the series does not break, other series link themselves on laterally, which may themselves be pursued linearly, and which in like manner send off side-chains, which link with other linear series. Let us illustrate this by a homely simile. Let us sup- pose that a person with eyes capable of only microscopic vision had before him a purse made of netted beads, and was endeavouring to discover the plan on which it was constructed. He is able to see but a single bead at a time. He takes one and numbers it ; perhaps names it: and is conscious that another is in contact with it ; this also he numbers ; and finds a third, and a fourth, and so on, running on in straight succession. He presently con- cludes that he understands the structure ; it is plainly a linear series. But soon he comes to a bead—perhaps it is number 10—which has in contact with it not only the number 11, but also a bead at each side. If he leave the original line, which he finds he can follow on if he so choose, he will discover that either of these lateral beads is the first of a series, which leads on linearly, till by and by, after sundry offshoots and beuds, he comes into the original line at bead number 20, or 35, or 150, as the case may be. And from the offshoots of these secondary chains, he can pursue similar chains ever branching off POLYZOA AND TUNICATA, 229 and ever merging into one another. Now this would be very puzzling ; and it would not be till after a great deal of examination in detail, and a great deal of “ putting two and two together,” and many happy guesses, that he would at length master the idea of a quincuncial plan—the order of a net. But suppose that the net, instead of being woven on a single plane, as all our nets are formed, were made to in- crease in every possible direction—a net to be estimated by solid instead of superficial measure, like the cells which go to make up the pulp of an apple—how would the plan be complicated ! And how much more of protracted observation and study would be necessary before the in- quirer could master this model by the slow study of a bead at a time! Now, we do not mean to say that the great plan of Creation can be correctly represented by a series of meshes in a plane, nor by a mass of cells in a solid, nor by circles set circularly till a larger circle is formed, and many of these set to constitute a still larger circle, and then again others still larger; we will not set our seal to any of those models, which have been from time to time proposed with great confidence as “the natural system.” But the comparison may help some of our readers better to appreciate the fact, that while there is a beautiful order in creation, the existence of which is readily dis- covered, it is an order, not simple, but highly complex in its relations. A notable example of the breaking down of the linear arrangement occurs in a series of creatures which we have now to introduce to our readers: a series which, com- 230 LIFE, IN ITS INTERMEDIATE FORMS. mencing at a point far lower than that to which we have ascended in our previous observations, rises in uninter- rupted gradation, though not without many lateral rela- tions, to the very highest type of animal existence. If we have been in the habit of picking up sea-weeds from the shore where they have been washed by the waves, or from the little sheltered rock-pools where they delight to grow, we have often seen spread over their smooth fronds what looks like a little piece of muslin, only that it is more delicate, more filmy. It adheres quite firmly to the surface, so that it cannot be rubbed off ; and if we apply our thumb-nail to it, we discover that, thin as it is, the substance of which its_ subtile meshes are composed is stony or shelly in its nature, and so hard as to scratch the nail. What isit? It is one of the sea-mats (Membranipora pilosa). We bring the magnifying power of a pocket-lens, or a microscope, to bear on it, and our sense of beauty is at once gratified. We see a net-work of glassy cells, each closely resembling a slipper inshape, arranged in the most orderly manner side by side, yet so that the opening of one shall be in contact with the middle of its nearest neighbour, sidewise, while the toe of the slipper touches the heel of the next, lengthwise. The margin of the orifice is a little thickened, like the binding of a slipper, and there are springing up from this rim six short spines which arch over the opening, and a very long one from the front which runs up in the line of the instep. The slipper-like cell is transparent as glass, but in the sub- stance are seen many oval bladders or cavities. These cells are so many houses inhabited by active POLYZOA AND TUNIOCATA. ae animals. In the specimens which you pick up on the beach nothing more than this would be seen, however closely you might examine them, but in our sample just taken out of the water, we shall be able to shew much more. ‘The broad orifice surrounded by spines is covered during life with a very delicate elastic membrane, stretched across it like the head of a drum, and towards the front of this there is a slit with two lips in the form of a cres- cent. From the lips of the slit a case or tube of the thinnest possible skin passes through the middle of the cell, within which plays a polype to and fro, capable of protruding itself to a great extent, as well as of retreating far into the depths of its cell, according to its pleasure. In the latter state the animal is bent upon itself with a double fold, somewhat like a person lying in bed with his knees tucked up; but when it wishes to expand itself, two pairs of muscles, which are seen in the form of threads on each side, draw the body forward, and the skin that envelopes it turns inside out, just as we draw off a stock- ing. It gradually protrudes from the slit as it unfolds, and then displays a number of long tentacles which are regularly packed side by side in a bundle ; but when these are quite protruded, they suddenly expand into the shape of an elegant bell or cup. The appearance of the animal is now very beautiful; it is as clear as spun glass; the sprightly motions which it exhibits increasing its beauty. Each of the thread-like tentacles seems to have a double row of black teeth, like the cogs of a watch-wheel which run rapidly along in ceaseless course ; those of one side of the tentacle running towards the tip, and those of the other side towards the base. Striking and beautiful, 232 LIFE, IN ITS INTERMEDIATE FORMS, however, as this motion is, so that it is impossible to look at it without admiration, it is not really a progression of any of the parts. This appearance of moving teeth is caused by very fine cilia, the nature and action of which have already been explained. It will be sufficient here to say, that the combined action of the whole of the cilia forms a whirlpool, the centre of which is the mouth at the bottom of the bell of tentacles, and that every atom that comes within range is sucked in and engulphed. This is a representative of a class of animals called PoLyzoa ; it contains numerous genera and species differ- ing much in the form and arrangement of the cells, but displaying a remarkable uniformity in the structure of the animals themselves. In many species the series of cells is attached to a foreign body only by its base, standing erect, often spread out and divided like a much-cut leaf, or set in single order, one cell springing out of the ’ tip of another, and bearing a third on its extremity, with occasional branchings, so that the total structure resembles a tiny shrub. Many of these creatures bear highly curious appendages, than which we know scarcely anything Bugul aviacularia (nat. size), and more interesting as a microsco- a cell magnified, shewing the , expanded polypide, and a Pical study. Take, for example, “birds-head.” Bicellaria ciliata, or Bugula avicu- laria. On the outside of some of the cells in these species there is a little tubercle, to which is articulated, by a POLYZOA AND TUNICATA. 233 slender joint, an organ which has been aptly compared to the naked head of a vulture. This organ has a beak with two mandibles, the lower of which alone is moveable, opening and shutting like that of a bird, but with far greater width of gape, as the lower mandible can be opened till it extends behind in the same line with the upper. Each edge of the mandible (in the first-named species) is furnished with five strongly projecting teeth; the lower has a single tooth at its point, which fits into the notch between the terminal pair of the upper. The whole back of the head is transversely wrinkled. The movements of this strange appendage are in keep- ing with its curious structure. The whole head ordinarily sways to and fro upon the slender joint of the poll at inter- vals of a few seconds ; but besides this motion, which is even, though rather quick, the lower mandible which com- monly gapes to its utmost extent, now and then, at irregu- lar intervals, closes with a strong sudden snap, much like the snapping of a turtle’s jaws, and presently again opens and leisurely resumes its former expansion. We may dis- tinetly see the muscles which move the lower mandible; they occupy the position of the palate and extend back to the inner surface of the skull, if we may borrow such terms from the organ which this organ mimics. It is very interesting to witness these singular motions, and it is scarcely possible to observe them without believing that _the animal exercises an active volition in performing them. But the observation of these “ bird’s heads” suggests curious questions. Do they form a part of the polype’s organisation? Why, then, are they found attached to some cells of a specimen while others are destitute of 234 LIFE, IN ITS INTERMEDIATE FORMS. them? Why do some specimens possess them and not others? Why are some species of a genus furnished with them while some are destitute of any such appendages, though essentially the same in every other respect? No light is thrown on these questions by anatomical exami- nation. It would appear that the animal within is quite independent, organically, of the “ bird’s head,” for, as Dr Reid has remarked, and as we have personally observed in several species, the “ bird’s head” continues to move for a considerable time after the death and decomposition of the polype. It has been suggested that the use of the organ is to grasp and kill passing animalcules, which then may be drawn into the cell by means of the ciliary cur- rents of the tentacles ; and this appears not improbable, and receives confirmation from the toothed structure of the beak. The organ in question, with its singular function, may minister to the support of the common life in another way less direct but not less effective. The seizure of a passing animal, and the holding of it in the tenacious grasp until it dies, may be a means of attracting the proper prey to the vicinity of the mouth. The presence of decom- posing animal substance in water invariably attracts crowds of infusory animalcules, which then breed with amazing rapidity, so as to form a cloud of living atoms around the decaying body, quite visible in the aggregate to the unassisted eye, and these remain in the vicinity, playing round and round until the organic matter is quite con- sumed. Now, a tiny Annelid or other animal, caught by the bird’s head of a Polyzoan and tightly held, would presently die ; and though in its own substance it might POLYZOA AND TUNICATA. 235 not yield any nutriment to the capturer, yet by becoming the centre of a crowd of busy Infusoria, multitudes of which would constantly be drawn into the tentacular vor- tex and swallowed, it would be ancillary to its support, and the organ in question would thus play no unimportant part in the economy of the animal. Many members of this Class possess organs analogous to these, but differing considerably in the details of their construction ; and some are also furnished with long stiff bristles, which, moving freely on a joint at the base, can be made, at the will of the animal, to sweep across the face of the cell with considerable force, perhaps with the view to clear it of any extraneous matters that might otherwise annoy or hurt it. Some genera, which have no organs answering to these, inhabit membranous cells instead of shelly ones, as Bowerbankia and its allies; in others, the cells are immersed in a firm fleshy mass, as is the case with the Alcyonidiadee. From the Ponyzoa the transition is easy and short to the Tunitcata. The essential structure is the same in both. The body consists of a sac, with two orifices, usually placed near together, or the discharging one on one side, and a little below the receiving orifice. The circle of ten- tacles around the mouth of the Polyzoan is reduced in the Tunicate (Ascidia) to short processes, which guard the orifice, and a similar circle is conferred upon the dis- charging one. On the other hand, there now appears a distinct breathing organ in the form of a hanging bag of membrane, the inner surface of which is covered with oblong cells, set in rows, and these cells are lined with cilia, whose movements resemble those of a toothed wheel. 236 LIFE, IN ITS INTERMEDIATE FORMS. _ The breathing cilia are, in short, transferred from the pro- jecting tentacles to the interior of the body. There is, moreover, in the Tunicata a pulsating heart, and also a circulation of blood. In many families of this Class the individual animals are aggregated together like those we have just described, having a common corporate, as well as an individual life. Such are the brilliantly-coloured masses, like stars set in coloured jelly, that are common on sea-weeds and sub- merged stones. These are Botryllide. We know of no example of an isolated Polyzoan ; they are all compound animals, though in a few cases the cells stand up singly and remotely, from the common uniting root-thread ; but in the TunicaTa we find many examples of single life. Of this sort are the strange uncouth creatures that are so abundantly brought up by the dredger from the sea- bottom, attached to stones and old shells, and resembling a bag of tough leathery skin, with two orifices, and hence called Ascidia, from the Greek word doxés, aleather bottle. Some of these are large, rough with irregular lumps and > depressions, and opaque; others are smaller, smooth, pellucid, and brilliantly coloured. If they are plunged into a vessel of sea-water we see the orifices periodically opened wide, and suddenly contracted to a point ; and by careful observation we may detect the entering and out- going currents of water that pass through these apertures. There are some species which, though not strictly com- pound, are aggregated together in a highly curious manner. Such are the Salpe, which are found swimming in the free ocean; sometimes solitary, sometimes united into long flexible chains of transparent animals, which swim with POLYZOA AND TUNICATA. 237 serpentine movements. The genus Pyrosoma contains ani- mals ageregated inanother manner. These are lengthened Ascidians, united to each other so as to compose a long free tube, open at one extremity and closed at the other. This is also an oceanic genus, and is remarkable for being vividly luminous, the light displaying the most gorgeous and varied hues. We shall close this chapter with an extract from Mr Bennet’s ‘‘ Wanderings,” in which he records his own observations of these interesting animals. “On the 8th of June, being then in lat. 0° 30’ south, and long. 27° 5’ west . . . late at night, the mate of the watch came and called me to witness a very unusual appearance in the water, which he, on first seeing it, con- sidered to be breakers. On arriving upon the deck, this was found to be a very broad and extensive sheet of phos- phorescence, extending in a direction from east to west, as far as the eye could reach. The luminosity was con- fined to the range of animals in this shoal, for there was no similar light in any other direction. I immediately cast the towing-net over the stern of the ship, as we ap- proached near the luminous streak, to ascertain the cause of this extraordinary and so limited phenomenon. The ship soon cleaved through the brilliant mass, from which, by the disturbance, strong flashes of light were emitted, and the shoal, judging from the time the vessel took in passing through the mass, may have been a mile in breadth. The passage of the vessel through them in- creased the light around to a far stronger degree, illumi- nating the ship. On taking in the towing-net, it was found half filled with Pyrosoma (Atlanticum ?), which shone with a beautiful pale-greenish light, and there were also 238 LIFE, IN ITS INTERMEDIATE FORMS. a few shell-fish in the net at the same time. After the mass had been passed through, the light was still seen astern, until it became invisible in the distance, and the whole of the ocean then became hidden in darkness as be- fore this took place. The scene was as novel as beautiful and interesting.” SHELL-FISH. 239 CHAPTER XXVI. CoNCHIFERA AND GastTRopopa (Shell-jish). Sucu of our readers as are familiar with the fish-market at Southampton have, doubtless, often seen a large sort of shell-fish which are sold under the name of “Old Maids.” The fishwoman, perhaps herself an ‘ old maid,” will tell you that these humble sisters of hers, these rivals in celibacy, are dug up from the muddy margin of the harbour, into which their burrow descends a foot or more deep ; that the hunter for them is aware of their presence by a jet of water spirted from the mouth of the hole as soon as they become aware of his, a fact of which his ap- proaching footsteps inform them ; and that he instantly plunges his narrow spade or fork in an oblique direction, and raises the unlucky bivalve, with a cloud of mud and water, into the air. Now, if we examine one of these “Old Maids,” which naturalists designate as the Sand Gaper (ya arenaria), we find that we have an animal closely resembling those Ascidie that we lately described. It is enclosed in a leathery wrinkled coat, with the two orifices placed near the end of a rather long tube; the internal anatomy differs little from that of the creatures just named, ex- = 240 LIFE, IN ITS INTERMEDIATE FORMS. cept that there is an opening in the side for the protru- sion of a moveable fleshy organ called the foot ; but ex- ternally there is this peculiarity, that, in the substance of the coat, there are formed two valves or convex plates of stony substance (shell), which are united-along one side by a hinge, and enclose the soft parts, as the leaves of a book are contained within the covers. This, then, is a bivalve shell-jish, as it is commonly (though incorrectly) named, and it is the representative of an extensive Class of animals, found all over the world, in fresh and salt waters, and designated CoNCHIFERA, or “Shell-bearers.” There is, itis true, very great diversity in the details of form and structure that we find in this immense assemblage of animals; but all these variations can be easily traced by insensible gradation to this primal form, and thence to those lower types which we have already described. Sometimes the orifices for receiving and discharging water are prolonged into two distinct tubes with fringed extremities, as in that lovely and deli- cate shell that inhabits our sandy beaches, called, from its diverging rays of pink and yellow, the Setting Sun (Psammobia vespertina), where the two tubes, when fully extended, are twice the length of the shell. At other times we find the tubes again reduced to simple openings, and one of these forming a mere slit, scarcely to be dis- tinguished from the common opening of the coat or mantle, as in the Mussels (Mytilide). This separation of the mantle, again, occurs in various degrees, from its condi- tion as a mere orifice for the protrusion of the foot, to that of the Oysters (Ostreade), where it is open all round, a fleshy counterpart of the shelly valves, bordered by a SHELL-FISH. 241 short but close fringe. In the beautiful Pectens, “the butterflies of the Moxnuusca,” the mantle is still further modified, for it is furnished with | four rows of long moveable con- ‘sk tractile tentacles, and with two rows of eyes that sparkle and glow like the most brilliant gems. Another and a parallel modifica- tion takes place in the breathing organs, which, instead of being a Pecten. closed sac, as we saw it in the Ascidiw, become thin flat leaves, much like the folds of the mantle or the shell-valves, which are placed a pair on each side. Their structure is no less modified than their form, for instead of oval ciliated cells on the internal surface, each of the four leaves (in the Pecten, for instance) consists of a vast number of straight, slender, transparent filaments, evidently tubular, arranged side by side, so that 1500 of them would be contained within the length of an inch. Strictly, however, these are but one filament, excessively long, bent upon itself again and again, at both the free and the attached end of the gill-leaf, throughout its whole extent. This repeated fila- ment is armed on each of two opposite sides with a line of vibrating cilia, the two lines moving in contrary direc- tions, exactly as on the tentacles of the Potyzoa, which are the breathing organs there; by this action a current of water is made continually to flow up and down each of these delicate filaments; so that the blood which circulates in their intérior (for they are, doubtless, blood-vessels) is continually exposed, throughout this its long and tortuous course, to the action of oxygen. Q 242 LIFE, IN ITS INTERMEDIATE FORMS. Like all organic functions, the action of these cilia is not under the will of the animal. If, during life, a small portion of the gills be cut off, the motion of the cilia will convey the fragment swiftly away, with a smooth easy mo- tion, through the surrounding fluid, in a definite direction. It does not even cease with the life of the animal. A specimen which we examined had been dead at least fifteen hours, yet when we placed the torn fragments of the branchiv, one after another, beneath the microscope, the energy of the ciliary action, as the wave flowed with uniform regularity up one side and down the other of every filament, filled us with astonishment. Even the next morning, twenty-six hours after death, when the tissues of the filaments were partially dissolved, the ciliary motion was still going on, on portions that preserved their integrity. The leaves which form the mantle are useful, not only for protecting these gills and the other delicate organs which are situated within their embrace, but for manu- facturing the valves of the shell. This process has been ably described by Professor Rymer Jones, as it takes place in the Scallop (Pecten maximus), and we shall quote his words :— “Tt is the circumference or thickened margin of the mantle alone which provides for the increase of the shell in superficial extent. On examining this part, itis found to be of a glandular character, and, moreover, not unfrequently provided with a delicate and highly sen- sitive fringe of minute tentacula. Considered more attentively, it is seen to contain in its substance patches of different colours, corresponding both in tint and rela- SHELL-FISH. 243 tive position with those that decorate the exterior of the shell. “When the animal is engaged in increasing the dimen- sions of its abode, the margin of the mantle is protruded, and firmly adherent all round to the circumference of the valve with which it corresponds. Thus circumstanced, it secretes calcareous matter, and deposits it upon the ex- treme edge of the shell, where the secretion hardens and becomes converted into a layer of solid testaceous sub- stance. At intervals this process is repeated, and every newly-formed layer enlarges the diameter of the valve. The concentric strata thus deposited remain distinguish- able externally, and thus the lines of growth marking the progressive increase of size may easily be traced. “Tt appears that at certain times the deposition of cal- careous substance from the fringed circumference of the mantle is much more abundant than at others ; in this case ridges are formed at distinct intervals ; or if the border of the mantle at such period shoots out beyond its usual position, broad plates of shell, or spines of different lengths, are secreted, which, remaining permanent, indi- cate, by the interspaces separating successively-deposited erowths of this description, the periodical stimulus to increased action that caused their formation. “Whatever thickness the shell may subsequently attain, the external surface is thus exclusively composed of layers deposited in succession by the margin of the mantle ; and seeing that this is the case, nothing is more easy than to understand how the colours seen upon the exterior of the shell are deposited, and assume that definite arrangement characteristic of the species. The border of the mantle 244 LIFE, IN ITS INTERMEDIATE FORMS. contains in its substance coloured spots ; these, when minutely examined, are found to be of a glandular cha- _racter, and to owe their peculiar colours to a pigment secreted by themselves ; the pigment, so furnished, being therefore mixed up with the calcareous matter at the time of its deposition, coloured lines are formed upon the exterior of the shell wherever these glandular organs exist. If the deposition of the colour from the glands be kept up without remission during the enlargement of the shell, the lines upon the surface are continuous and unbroken; but if the pigment be furnished only at intervals, spots or coloured patches of regular form, and gradually increasing in size with the growth of the mantle, recur in a longi- tudinal series wherever the paint-secreting glands are met with.” * The shell increases in thickness no less than in dia- meter ; and this also is effected by the mantle; the calca- reous matter being deposited, layer after layer, on the interior surface of the valve. There are no pigment-glands on the general surface of the mantle, and hence the interior of shells is always white or destitute of colour, except that brilliant iridescence which we are so familiar with in many shells, which constitutes mother of pearl. This prismatic reflection depends on série, or impressed lines, of micro- scopic minuteness, on the surface, and can be produced artificially on several substances, Pearls themselves are merely quantities of this calcareous matter poured out in abundance at one spot, often to surround some atom of sand, and thus prevent its edges from wounding the sen- sitive mantle. * General Outline, 385. SHELL-FISH._ 245 If we now come to the other great Class of shelled ani- mals, that named GasTROPODA, we find we have to make a considerable leap to pass the hiatus. For, in fact, there is no very close relation between the Bivalves and the Uni- valves. Possibly species may yet be discovered which will supply the links that are wanting ; but this is scarcely likely. Not that there is no transition. If we take that interesting shell called the Cap of Liberty, or the Torbay Bonnet (Pileopsis Hungaricus), we cannot but be struck with the resemblance which it bears to a single valve of such a shell as the Heart (/socardia cor) ; and in some of its near allies, as the little Cup and Saucer (Calyptrea Stnensis), there is a subordinate shelly plate in the interior, which has been considered as the vanishing representative of the second valve. The form of the shell in this Class is that of a cone, with the apex on one side of the centre. In the Limpets (Patella), the cone is short and low, and therefore unmis- takeable ; in the Torbay Bonnet the summit is a little rolled over, the commencement of that spiral form which we see in the Whelk and the Snail. Nay, if we take the extremes of this condition, as we see in the long many- whorled shells of the genera Turritella, Scalaria, and the like, it is not difficult to trace the same form, a cone drawn out to great length and twisted spirally on an axis. The animals of these shells are much higher in organic development than the ConcuiFERA. They have a distinct head, with organs of touch, of vision, of hearing, and of smell, and a mouth armed with a complex array of teeth for the purpose of rasping away the solid food on which they subsist. They have the faculty of locomotion, the 246 LIFE, IN ITS INTERMEDIATE FORMS. under surface of the body being dilated into a flat mus- cular foot, the action of which may be observed by any one who chooses to look at a snail gliding up a pane of _ glass. This great muscular crawling disk is so charac- teristic as to have given name to the Class, Gasrropopa, from two Greek words, signifying “ belly-footed.” A cabinet of shells is a beautiful and interesting sight ; the rich, varied, and delicate colours, the pearly irides- cence, the elaborate patterns, the porcellaneous texture, the perfect polish, the exquisite sculpture, and the grace- ful forms which we see profusely displayed there, must always delight the eye. No won- der that the conchologist regards his treasures, the spoils of every sea and every shore, as “an as- semblage of gems,” and that he delights to exhibit them as les de- lices des yeux et de Tesprit. The prices that have sometimes been given for rare or beautiful speci- mens would be considered fabu- lous, were they not capable of in- Wentletrap. dubitable proof. “In 1753, at the sale of Commodore Lisle’s shells, at Longford’s, four Wentletraps (Scalaria pretiosa) were sold for seventy-five pounds twelve shillings, viz..—one not quite perfect for sixteen guineas; a very fine and perfect one for eighteen guineas; another for sixteen guineas; and a fourth for twenty-three pounds two shillings.” , But higher prices than these have been given. That in Mr Bullock’s Museum, supposed to be the largest known, lod SHELL-FISH. 247 brought at his sale the sum of twenty-seven pounds, and was estimated, in 1815, at double that value ; and there is a tradition that a specimen was sold in France for 2400 livres, or 100 louis! Before we dismiss these examples of the great and populous “ middle-class” of animal life, we must give a momentary glance at the Cuttles and Squids (CeEPHALo- pops), which, while they possess much in common with the Univalve Mouuvusoa, rise still higher in the scale than they, are still more favoured in the development of fune- tion and structure, and lead us insensibly to the verge of the animal “aristocracy,” the VERTEBRATA. Strangely enough, the aspect and contour of these fierce and_ formidable creatures, the highest of all Invertebrate animals, bring us back to the lowest ; for a Cuttle-fish with its cylindrical body, its mouth at the extremity, and a circle of long flexible fleshy arms radiating around it, is (in form at least) just a Polype over again. There is, it is true, an immense difference in structure: the Cuttle is encased in a fleshy mantle, which is sometimes expanded into swimming fins, has a large head with staring eyes, a stout horny beak, like that of a parrot, of formidable power, and its arms are furnished with rows of sucking disks that act like cupping-glasses, and serve as so many instruments of prehension. Internally there is a shelly or horny plate which passes down through the substance of the mantle, and vestiges of a bony skeleton begin to appear in the form of a cartilaginous box which incloses the brain, and represents the skull of Vertebrate animals. Some species reside in an ample shell, as the Paper and Pearly Nautilus, both celebrated for their beauty. 248 LIFE, IN ITS INTERMEDIATE FORMS. A curious circumstance in the economy of these crea- tures is the secretion of a peculiar fluid of a most intense blackness, lodged in a vessel, variously situated in different species, and spouted out at the will of the animal. This substance, frequently called znk, from the use to which it was anciently applied, mixes freely with the water, dif fusing an impenetrable obscurity for some distance around, by which the animal often escapes from danger ; thus, as our illustrious Ray wittily remarked, hiding itself, like an obscure or prolix author, under its own ink. And lest any of our readers should slily add “ ecce signum!” we will say no more about the Moxuusca at this present, PARDEE, LIFE, IN ITS HIGHER FORMS. 7 ae é ty Boy ; ‘ : Boa > FISHES. : 251 CHAPTER XXVII. Pisces (Fishes). In passing from one country to another, we do not find any boundary lines in nature corresponding to those which we see upon our maps. There may be a gradual change of features, indeed ; as the vegetation that characterises Spain differs from that of France, and this latter from that of Prussia ; but the traveller is not conscious of any abrupt change, the last mile of his journey on one side of either frontier being pretty much the same as the first mile beyond it. We speak, too, of the various ranks and classes of society : the labourer, the artisan, the trades- man, the manufacturer, the merchant, the professional man, the scientific man, the statesman, the peer, the prince, the sovereign ; but the homes, the raiment, the manners of these, though characterised by well-marked diversities and peculiarities, are not separated by broad lines of demarcation, but pass imperceptibly into each other. The diversities exist in nature, but the boundary lines are arbitrary. So it isin Natural History. The student will do well to bear in mind continually that those subdivisions of organic beings which we call Classes, Orders, Families, aud Genera, are but convenient aids for recording and re- 5 se ae ee ee 252 LIFE, IN ITS HIGHER FORMS. membering facts. There is but one division which exists in nature,—that of Species. Each Species is separated from every other Species by an impassable boundary (whether we can in all cases determine it practically or not). It was originally created distinct, and distinct it remains. But the group of Species which we call a Genus is amerely arbitrary collocation ; convenient, indeed, as we before said, and to a certain extent natural, inasmuch as it is a formula for expressing the community of certain cha- racters ; but still arbitrary, inasmuch as it might be made more or less extensive, according to the pleasure of the naturalist who chooses the characters on which it is made to rest. And so of all the higher groups. The great Division of animal existences which we pro- pose now to consider presents peculiarities of structure and function, which we can seize and identify with great precision when we look at it as a whole. But if we exa- mine the points of contact between it and the great groups we have dismissed, we find these broadly-marked distine- tions becoming evanescent, and melting into those of the conterminous phalanx. One grand distinction of the higher animals is com- memorated in the title by which they are generally known,—VERTEBRATA. ‘They possess an internal skeleton composed of many pieces, and formed of a substance which is not deposited, layer by layer, like the shells of Mot- Lusca, but is capable of growth in the manner of fleshy tissues, being permeated both by blood-vessels and nerves, and undergoing a perpetual change in its component atoms. In its simplest form this substance is flexible and elastic, and is called cartilage; but by the addition, in various FISHES. 253 degrees, of the calcareous element, it becomes hard, solid, and inflexible, and we call it done. Now, as in the highest forms among the MoLuusca we saw the external skeleton of shell gradually vanishing, and traces of an internal skeleton of cartilage appearing, (as the cranial ring, or skull, and the fin-plates, of the Cuttle-fishes)—so in the most rudimentary of the Fisuzs, as the Lamprey, and that curious creature the Sea-hag (Myzxine), and, more markedly still, in the dubious Lance- let (Amphioxus), the spinal column, instead of forming a series of distinct bones, is an undivided rod of cartilage ; in the latter two instances horny, flexible, and bearing the closest resemblance to the “ pen” of the common Squid. Perhaps it will be well to examine the nature of this distinctive skeleton as we find it in its normal development. Its most important element is the spinal column, which con- Ww, Vertebree of a fish, a, Lateral aspect. b. Front aspect. sists of a linear series of pieces attached to each other, and eee 254 LIFE, IN ITS HIGHER FORMS. running longitudinally through the animal. ‘These pieces are called vertebra. The best way to study a vertebra is to take that of a Fish,—one of the joints from the backbone of a Cod for example, since in this Class we find it most simply and yet most perfectly developed. We thus per ceive that it is composed of several parts :—-1. The centrai cylinder; 2. the superior arch, formed by two sloping side pieces, between which the spinal marrow passes; 3. the superior spinous process, projecting upward from the union of these pieces ; 4. the two lateral processes; 5. the infe- rior arch, formed as the superior is, protecting great blood- vessels; 6. the inferior spinous process, pointing downward. A number of the vertebre at the fore part of the column are so far modified in shape and proportion of parts as to be identified only by close study and comparison. They constitute the skull, a capacious chamber of bone formed to contain the brain, which is but the aggregation of seve- ral pairs of ganglia greatly developed. In front of these bones there is: placed another series, arranged in pairs, constituting the face; some of these are excavated into cavities to protect the organs of sense, and others form the jaws, &c. These may all be considered as integral parts of the vertebral column ; but besides these, there are important accessories yet to be noticed. First, there are a number of slender bones, which are articulated to the transverse processes of the vertebre, and arch outwards and down- wards. They form two series: 1. The hyoid arches, which spring from the skull: these are minute in the human skeleton; but in some animals, especially in Fishes, they are large and important, forming the great frame- FISHES. 255 work which carries the gills. 2. The ribs, which are in general developed in a ratio inverse to that of the hyoid arches. Secondly, we find two pairs of limbs, each con- sisting of several pieces articulated to each other, and free at one extremity, while the other is jointed to the spinal column, or suspended in the muscles of the body. Such is a brief enumeration of the essential parts of an internal skeleton, which, when examined in detail, with intelligence of the purpose which every part is intended to subserve, forms one of the noblest monuments of the wisdom of God that can be found in creation. It must be observed, however, that the various portions are seen in various degrees of development in different classes of animals, and that some of the constituents are occasionally either very rudimentary or entirely wanting. Not less important in the economy of a vertebrate animal is the condition of the nervous system. To this, indeed, the skeleton is ancillary. There is a great concen- tration of nervous matter in the fore part of the animal, constituting the brain, whence cords are given forth to the organs of sense, which are mostly situated in the vicinity. From its hinder part proceeds the spinal marrow, running along a tube formed by the superior arches of the vertebre, and giving off a number of threads on each side in sym- metrical pairs. The spinal marrow itself is not homoge- neous, but is composed of four cords fused together, of which the upper pair is destined to convey the commands of the will to the voluntary muscles, while the lower pair receives the sensations which are conveyed from without. Hence they are respectively termed the motor and the sensitive tracts of the spinal cord. 256 LIFE, IN ITS HIGHER FORMS. In like manner every lateral nerve is double, arising by two distinct roots, the one from the motor, the other from the sensitive tract. Besides these, there are series of nerves, extensively ramified, which do not originate from either brain or spinal column, but from scattered ganglia situated in various parts of the body, and destined to supply those important organs whose motions are independent of the will, and which are therefore distinguished as the organic or vegetative system. The blood is, in every case, composed of red “ globules” or (more properly) disks, suspended in a watery fluid. It circulates through two series of vessels, which ramify to every part of the body. The one series—that of the veins—receives the assimilated nutriment from the diges- tive system, and conveys the blood, so reinforced, but exhausted of its oxygen, to the heart, a great muscular chamber, which alternately contracts and expands without intermission. By these movements, the contained volume of blood is urged forward, in whole or in part, to the lungs, or (in such animals as are aquatic) to the gills, where it is brought into proximity with fresh oxygen, either from the inhaled air or water. This element readily combines with the blood through the excessively attenuated coats of the vessels, and revivifies it, restoring at once its brilliant red hue. Thus renewed, the vital fluid is returned to the heart, whence it is forced into the other series of vessels called arteries, which carry it forward to all parts of the body, and at length, uniting with the veins by excessively minute tubes called capilla- ries, situated at the circumference, and having built up FISHES. 257 the whole structure of the living temple in its course, it takes its return journey as we at first described it. The lowest Class of the great Vertebrate Division is that of Fisnes. They are distinguished by the simplicity of their outline, by their respiring by gills instead of lungs, by the enormous development of their hyoid appa- ratus, by their cold blood, by the modification of their limbs into fins, and by the possession of accessory organs of the same kind, especially the tail-fin, which is their grand instrument of locomotion. All these characteristics are, more or less obviously, dependent on the great fact of their aquatic life. We have already adverted to the existence among the Mouuusea of the rudiments of an internal skeleton, by which that great division overlaps, so to speak, the pre- sent. On the other hand, we find in most FisHes rem- nants of the external skeleton neither few nor unimpor- tant, by which they manifest their affinity with the crea- tures below them. ‘The scales of the majority of Fishes, the bony plates which we see in the Trunk-fish (Ostracion) and in the ‘* Tittlebat,” which every truant schoolboy knows, the recurved spinous tubercles with which the Thornback’s skin is studded, and the opercular bones or plates that cover the gills,—what are all these but portions of an external skeleton, in no way belonging to that series of bones which belongs to the fish as a vertebrate animal ? The rays of the fins which are not limbs (as the dorsal, the anal, and the caudal), and the blade-like bones pene- trating the flesh to which these are jointed, must also come into the same category. The scales which form the covering of most fishes are R 258 LIFE, IN ITS HIGHER FORMS. highly instructive objects. ‘‘ Examined separately,” says Professor Jones, ‘ each scale is found to be partially im- bedded in a minute fold of the living and vascular cutis, to which its under surface is adherent. Every scale is, in fact, made up of superimposed lamine of horny matter secreted by the cutis, precisely in the same way as the shelly covering of a mollusc; and by maceration the dif- ferent layers may readily be separated, the smallest and most superficial being, of course, the first formed, while the largest and most recent are those nearest to the surface of the living skin: as far as relates to the mode of growth, therefore, there is the strictest analogy between the scale of a fish and a shell. Various are the forms under which these scales present themselves to the ichthyologist ; sometimes, as in the Kel, they are thinly scattered over the surface of a thick and slimy cutis;* more generally © they form a close and compact imbricated mail; in the Pipe-fishes (Syngnathide) the whole body is covered with a strong armour composed of broad and thick calcareous plates; and in the Coffin-fishes (Ostracionide) the integu- ment is converted into a strong box made up of polygonal pieces anchylosed together, so that the tail and the fins alone remain moveable.” t The bones which compose the proper skeleton have little density or hardness in any fishes; and in one large sub- division—that containing the Sturgeons, Sharks, and Skates—they are wholly composed of cartilage. In the latter, which, in this as well as some other respects, are the lowest forms in the Class, we find, however, analogies and peculiarities which raise them above the highest. * Or, rather, imbedded in its substance. + ‘Gen. Outline,” p. 506. FISHES. 259 Teeth, which are so characteristic of VERTEBRATA, are nowhere found in such variety of form and function as among Fisues. They are not confined to the jaws, but are found by turns in almost every one of the bones that compose the mouth, though not in all species. They are generally simple spines, curved backwards; but innume- rable modifications of this form occur. Thus the jaws of the deadly Shark are flat and lancet-like, the cutting edges being notched like a saw; the front teeth of the Plaice and the Flounder are compressed plates; some, as the Wrasse, have flat grinding teeth; others, as the Sheep’s-head, have the grinding surface convex; and others, as the genus Chrysophrys, have convex teeth so numerous and so closely packed over a broad surface, as to resemble the paving-stones of a street. The beautiful- Cheetodons of warm climates, on the other hand, have teeth which resemble bristles, and these are set close to- gether like the hairs of a brush; while the Perch of our own rivers has them still more slender, minute, and nume- rous, so as to resemble the pile of velvet. Another of our well-known fishes, the bold and fierce Pike, is armed with teeth scarcely less formidable in size, form, and sharp- ness, than the canines of a carnivorous quadruped. In number, also, there is a great variety. The Pike, the Perch, the Cat-fish, and many others, have the mouth crowded with innumerable teeth, while the Carp and the Roach have only a few strong teeth in the throat, and a single flat one above; and the Sturgeon, the Pipe-fish, and the Sandlaunce, are entirely toothless. The eye in this Class presents a beautiful example of adaptation to the medium in which they live. From the 260 LIFE, IN ITS HIGHER FORMS. density of water being so nearly the same as that of the aqueous and vitreous humours, these have scarcely any power to refract the rays of light; and hence a high mag- nifying power is given to the crystalline lens. Its form is that to which the very highest possible power is assigned —a perfect sphere, and the density of its texture is very ereat. But as the power of a lens and the nearness of its focal point are in the same ratio, it was needful to bring the retina, or curtain on which the image is painted, very close to the lens; and this is done by diminishing the vitreous humour behind it, and thus flattening the sphere ; while a provision is made for maintaining this shape in certain plates of bone or cartilage, imbedded in the tough coat of the eye, called the sclerotica. The eye is never protected by an eyelid in fishes; the pupil is very large and incapable of contraction; and another peculiarity is, that (at least in many species) the one eye is moved independently of the other. The last organ we have space to notice at present is the air-bladder, which is found in most of the bony fishes. It is usually of a lengthened form, attached beneath the spine; but its shape is subject to some variety. Thus, in the Hedgehog fishes it is two-lobed, like a Dutchman’s breeches; sometimes it is a double sac; in the great Card family, and in the Electric Eels, it is divided into two compartments by a transverse partition, which, in the former case, is perforated to allow an intercommunication. In one of the Cat-fishes (Pangasius), it is divided into four compartments, and in others into many irregular cells. Thus, the air-bladder closely approaches in structure the lowest form of the dung in air-breathing VERTEBRATA, as FISHES, 261 in the Axolotes and the Newts, in which this organ is a simple bladder, and in the Frogs and Toads, in which it is subdivided into large cells; and it may, therefore, be considered as the first rudimentary appearance of an aerial respiratory apparatus. bs With regard to its function, in Fishes, it/appears prima- rily to be connected with swimming. Being condensed by muscular pressure, or allowed to expand, it renders the body either heavier or lighter; and thus enables the fish to swim at any height in the water according to its plea- sure. In general, the roving and surface-swimming species are furnished with the organ in question, while such as haunt the bottom are destitute of it; and this arrange- ment well agrees with the function we have ascribed to it. Yet it cannot be denied that there are some most unaccountable deviations from this rule. Thus, the Gur- nards, which are ground-fishes, are well furnished with bladders ; the two British species of Surmullet are deprived of the organ; while the Tropical species, which have the same habits, are provided with one. Again, of surface- fishes, our common Mackerel has no bladder, while the Spanish and Coly Mackerels, which have exactly the same manners, are each furnished with one. In many cases the bladder is hermetically sealed, but, in some instances, it communicates by a tube with the stomach, or the gullet. The air which it contains appears to be a secreted gas; it is found to be, in some cases, oxygen, and in others, strange to say, nearly pure nitrogen. The former gas occurs chiefly in species that live in very deep water. The blood, as already observed, is cold; that is, it com- 262 LIFE, IN ITS HIGHER FORMS. monly takes the temperature of the surrounding water; in some of the swift oceanic Fishes of the Mackerel family, however, such as the Tunny and the Bonito, the blood is found to be 10° higher than the temperature of the sur- face of the sea, even within the Tropics: the flesh of these Fishes is dark and dense. The blood-disks are sometimes circular, sometimes oval. They are larger than those of Mamaia and Birps; smaller than those of REPTILES, and especially than those of AMPHIBIA. The irritability of the muscular fibre is considerable, and is long retained. Fishmongers take advantage of this property, to produce rigid muscular contraction, after life has ceased, by transverse cuts and immersion of the muscles in cold water: by this operation, which is called “crimping,” the firmness and density of the muscular tissue are increased, In our next chapter, we shall enter into some details of the instincts and habits of Fishes, and some other matters connected with the Class, of more popular interest than these structural peculiarities, which, we fear, will prove but a dry morsel to many of our readers. | FISHES. 263 COEEA PTE Ra sXooVi LEER Pisces (Lishes). Continued. As the innate selfishness of our hearts always prompts the question, cuz bono ?—it may be as well to commence this chapter with a few particulars of the usefulness of FIsHES in ministering to our bodily wants. The value of fish as an article of human food has been appreciated in all nations and all ages. The earliest pictorial records of Egyptian every-day life are largely occupied with the cap- ture and preservation of these animals; various forms of nets, the fish-spear, the hook and line, are all in requisi- tion; and strings of fishes, split and salted, and hung out to dry, remind us of scenes familiar enough to the writer of these pages—the cod-fisheries of Newfoundland. Al- lusions to the hook and line occur in the most ancient of writings—the Book of Job; and, in the Mosaic law, “whatsoever hath fins and scales in the seas and in the rivers” was freely given to Israel for food. The most remote and savage tribes feed largely on a fish diet; and the ingenious devices and implements employed by the islanders of the Pacific Archipelago far exceed in variety, 264 LIFE, IN ITS HIGHER FORMS. and in their elaborate effectiveness, those produced by European art. Every sea, from the Pole to the Equator, is stocked with fishes; they abound in the rivers and lakes of all climates; even the “tarns” and little basins scooped out of the summits of mountain-ranges, hold species of interest and value peculiar to themselves. So that the beneficent Providence of God has thus stored up inexhaustible magazines of wholesome, palatable, and nu- tritious food, and placed them within reach of man for the supply of his necessity—the stimulus and the reward of industry. The fisheries of Britain are of national importance; the amount they contribute to the public wealth is immense; and they are regulated, even in many minute details, by repeated enactments of solemn legislation, An enumera- tion of the species which form the objects of our fisheries is itself startling :—the surmullet, gurnards of half-a-dozen kinds, sea-bream, mackerel, scad, dory, atherine, gray mullet of two kinds, gar-fish, salmon, herring, pilchard, shad, cod, haddock, pout, whiting of two kinds, pollack, » hake, ling, burbot, torsk, turbot, holibut, sole, flounder, plaice, dab, eels of three species, conger, thornback, skate of several kinds,—are all taken in quantities and brought regularly to market; not to speak of many other kinds, such as perch, trout, char, pike, carp, roach, tench, &., which are taken for the table, chiefly from our rivers, for individual amusement. The quantity of human food thus taken yearly from the water is enormous; an idea of it may be formed from the fact, that, of one species alone, and that a very local one, being confined to the western extremity of our island— FISHES. 265 the pilchard—the Cornwall fisheries yield 21,000 hogs- heads annually. What, then, must be the produce of all the species above enumerated, all round the indented coasts of Britain and Ireland? We have no suflicient data to determine the commercial value of British fishe- ries; but it has been loosely estimated by Mr M‘Culloch at £3,500,000, and by Sir John Barrow at £8,300,000, per annum. The possibility of capturing fishes of any particular species at any given time, with tolerable certainty, in such numbers as to constitute a fishery, is dependent on certain instincts and habits in such species, leading them to asso- ciate in multitudes in particular localities at particular seasons. The most prominent of these instincts is con- nected with reproduction. It is essential to the hatching of the spawn (or eggs) of most fishes, that it be deposited in comparatively shallow water, within reach of the vivi- fying influences of light and heat. Hence, as the season of spawning draws nigh, the various kinds leave the deep water, and approach, in countless hosts, the shores, where they are readily seen and captured. And it is a most beneficent ordination of God’s providence, that, at this season, they are in the very best condition for food: let the spawn be once deposited, and the fish is worthless. What is more vile than “ a shotten herring ?” Any one who will look with curiosity at the ‘“ hard roe” of a Yarmouth Bloater, may form a notion of the extent to which fishes obey that primal law, “ Be fruitful, and multiply, and fill the waters in the seas” (Gen. i. 22); for this hard roe is nothing else than the accumulation of eges in the ovary of a female fish: every seed-like grain 266 LIFE, IN ITS HIGHER FORMS. an egg, and all to be laid in the course of a few days— the contribution of one individual herring to the popula- tion of the seas! It would be no sinecure to count them ; but, partly by counting, partly by weighing, approxima- tions have been made to a knowledge of the extent of a fish’s family. Six millions of eggs have been estimated to lie in the roe of a single cod! Now, of course, an immense proportion of this number comes to nothing; perhaps three-fourths of these eggs are devoured by other fishes, or voracious creatures of one kind or other, almost before they well reach the bottom ; and of the proportion that is hatched, multitudes find a speedy termination of existence in the maw of their watch- ful and numerous enemies. For, as a general rule, fishes are universally carnivorous; every species preying with- out mercy upon all others that it can master and swallow. Some curious examples of this voracity are on record. Mr Jesse speaks of a Pike, to which he threw in succes- sion five Roach, each about four inches in length. ‘ He swallowed four of them, and kept the fifth in his mouth for about a quarter of an hour, when it also disappeared.” At a lecture delivered before the Zoological Society of Dublin, Dr Houston exhibited as “a fair sample of a fish’s breakfast,” a Frog-fish, two feet and a half long: in the stomach of which was a Cod-fish, two feet in length; the Cod’s stomach contained the bodies of two Whitings of ordinary size; and the Whitings in their turn held the half-digested remains of many smaller fishes, too much broken up to be identified. ‘* Harsh seems the ordinance, that life by life Should be sustained; and yet, when all must die, FISHES, 267 And be like water spilt upon the ground, Which none can gather up, the speediest fate, Theugh violent and terrible, is best. / . Oh, with what horrors would creation groan, What agonies would ever be before us— Famine and pestilence, disease, despair, Anguish and pain, in every hideous shape— Had all to wait the slow decay of nature! Life were a martyrdom of sympathy ; Death lingering, raging, writhing, shrieking torture: The grave would be abolished ; this gay world A valley of dry bones—a Golgotha— In which the living stumbled o’er the dead Till they could fall no more, and blind perdition Swept frail mortality away for ever. ‘Twas wisdom, mercy, goodness, that ordain’d Life in such infinite profusion—Death So sure, so prompt, so multiform, to those That never sinn’d, that know not guilt, that fear No wrath to come, and have no heaven to Jose.” MONTGOMERY, The statement has been common, in books of natural history, that fishes manifest no parental affection or care ; that the spawn, having been deposited in the proper situa- tion, the parents’ work is done, and all their solicitude ceases. It is possible that this may be the general rule; but it is not without numerous exceptions. As early as the time of Fabricius, it was known that the male Lump- sucker kept a strict watch over the spawn when laid, de- fending it with the most obstinate courage. And recent observations have added not a few other examples of pa- rental care among fishes, not exceeded by the devotion of the mother Jird. Within a few months of the writing of these pages, a most interesting detail has been published by Mr Warington, of the nest-building instincts and tender care of the commonest of British fishes—the tiny Stickleback, that swarms in every pool. 268 LIFE, IN ITS HIGHER FORMS. In the month of May the male Stickleback, which is then adorned with the most brilliant tints—his nuptial dress—begins to make a nest. For this purpose he selects small woody fibres, rootlets, &c., which he collects one by one; and, carrying them to the selected place, inserts them into the ground, and skilfully interweaves them, so as to form a ring. Now and then he collects minute bits of gravel, and brings mouthfuls of sand, all of which he lays upon the fibres to keep them steady. Thus a thick ring of interlaced materials is at length made, with a hole in each of the two opposite sides, through which the fish can squeeze himself. During the whole time the little creature resents the least intrusion on his operations, at- tacking his fellow fishes with the utmost fury, and driving them to a distance. The house being ready, the lady is invited to take possession; and the following curious scene ensues :— : “The female fish came out of her hiding-place, her attention being fixed apparently on the nest; when imme- diately the male became, as it were, mad with delight. He darted round her in every direction, then to his accu- mulated materials, slightly adjusted them, fanned them, and then back again in an instant. This was repeated several times. As she did not advance to the nest, he endeavoured to push her in that direction with his snout: . this not succeeding, he took her by the tail and by the side-spine, and tried to pull her to the spot, then back to the nest; and having: examined the two small openings alluded to, he thrust his nose in at the lower, and gradu- ally drew himself under the whole of the materials, making FISHES. 269 his exit at the opposite one, as though to prove to her that everything was prepared for spawning.” * The female now deposits her spawn in the nest; and is immediately repulsed by the male as earnestly as she had been invited. The nest is then opened by the male to the action of the water, which, by a peculiar motion of his body, called in the previous extract “ fanning,” constantly repeated, is driven in currents over the spawn. This pro- ceeds for about ten days; at the end of which period the male sets himself to destroy and scatter the materials of the nest, so as to leave a space of clean gravel about three inches in diameter. Let Mr Warington tell us what next :— “ Watching carefully, for a short time, to understand what all this busy alteration indicated, I at last had the pleasure of observing, by the aid of a long-focused pocket lens, some of the young fry—of course most minute crea- tures—fluttering upwards here and there, by a movement half swimming, half leaping, and then falling rapidly again upon or between the clean pebbles of the shingle-bottom. This arose from.their having the remainder of the yelk still attached to their body, which, acting as a weight, caused them to sink the moment the swimming effort had ceased. * Around all the space above mentioned, and across it in every direction, the male fish, as the guardian, conti- nually moved. And now his labours became still more arduous than they had been before, and his vigilance was taxed to the utmost extreme; for the other fishes, three of them twenty times larger than himself, as soon as they * “ Annals of Nat. Hist.” Oct. 1852. 270 LIFE, IN ITS HIGHER FORMS. perceived that the young fry were in motion, used their utmost endeavours continuously to pounce upon the nest and snap them up. The courage of this little creature was certainly now put to its severest test; but, nothing daunted, he drove them all off, seizing their fins, and striking with all his strength at their heads and at their eyes most furiously. All the assistance that could pos- sibly be afforded him was of course rendered, short of actual interference, by keeping them pretty well fed, in order to allay, if possible, their voracity. Another cir- cumstance, which appeared to add greatly to the excite- ment that he was constantly subjected to, arose from a second female fish, being in spawn, endeavouring most pertinaciously to deposit her ova in the same locality, and hence rushing frequently down towards the spot. But the male fish was ever on the alert; and although he did not strike at her in the furious way he attacked the larger ones, yet he kept continually under ber, with the formid- able back-spines all raised erect, so that it was impossible for her to effect her apparent object. “The care of the young brood, while encumbered with the yelk, was very extraordinary; and as this was gradu- ally absorbed, and they gained strength, their attempts to swim carried them to a greater distance from the parent fish; his vigilance, however, seemed everywhere; and if they rose by the action of their fins above a certain height from the shingle bottom, or flitted beyond a certain dis- tance from the nest, they were immediately seized in his mouth, brought back, and gently puffed or jetted into their place again. This was constantly occurring; the other fishes being continually on the watch to devour the FISHES. 271 stragglers, and make a savoury morsel of these Lilliputian truants. Indeed, the greater number of the whole brood must have fallen a prey to their voracity, as it was only some three or four that reached a size to place them be- yond the power of their destroyers.” * Some of our fishes perform long migrations in order to deposit their spawn. The Salmon, for instance, ascends rocky rivers from the sea, overcoming various barriers, and leaping up cascades, to accomplish its purpose, with indomitable perseverance and energy. The Eel, on the other hand, descends rivers to spawn in the brackish waters of estuaries, displaying equal determination. Of this a curious example is said to occur annually in the vicinity of Bristol. Near that city there is a large pond, immediately ad- joining which is a stream. On the bank between these two waters a large tree grows, the branches of which hang into the pond. By means of these branches the young Kels ascend into the tree, and from thence let themselves drop into the stream below, thus migrating to far distant watérs, where they increase in size, and become useful and beneficial to man. A casual witness of this circumstance remarked that the tree appeared to be quite alive with these little animals. The rapid and unsteady motion of the boughs did not appear to impede their progress. Did space permit, we could furnish many entertaining details of manners in this Class of animals, in their various modes of taking prey; but we must content ourselves with one. An interesting example of what we may be allowed to call skill, is afforded by the instincts of some * “ Annals of Nat. Hist.” Nev. 1855, 272 LIFE, IN ITS HIGHER FORMS. of those beautiful little tropical fishes called Cheetodons. In the East Indies these are kept in vases for the purpose of witnessing their unerring archery, as their feats in this way are highly amusing. The manners of these little fishes (abundantly confirmed by subsequent testimony) were first described by Dr Schlosser, in a communication to the Royal Society, on the authority of Mr Hommel, the Governor of the Hospital at Batavia. The little fish alluded to (Chelmon rostratus) “ frequents the shores and sides of the sea and rivers in search of food: when it spies a fly sitting on the plants that grow in shallow water, it swims on to [within] the distance of SERNA The Fly-shooter. four, five, or six feet; and then, with a surprising dexte- rity, it ejects out of its tubular mouth a single drop of FISHES. 273 water, which never fails striking the fly into the sea, when it soon becomes its prey. “The relation of this uncommon action of this cunning fish raised the Governor’s curiosity; though it came well attested, yet he was determined, if possible, to be con- vinced of the truth by ocular demonstration. For that purpose he ordered a large wide tub to bé filled with sea- water; then had some of these fish caught and put into it, which was changed every other day. In a while they seemed reconciled to their confinement; then he deter- mined to try the experiment. “ A slender stick, with a fly pinned on at its end, was placed in such a direction on the side of the vessel as the fish could strike it. It was with inexpressible delight that he daily saw these fish exercising their skill in shoot- ing at the fly with an amazing velocity, and never missed their mark.” * * «Phil, Trans.” for 1764, vol. liv., p. 89. 274 LIFE, IN ITS HIGHER FORMS. CHAPTER XXIX. Amputpia (Frogs and Toads). “To any person,” observes the eloquent historian of British Reptiles, “ capable of appreciating the interest at- tached to the study of physiological phenomena, the con- templation of an animal which at one period of its life is endowed exclusively with the organs of aquatic respira- tion, resembling the gills of fishes, with means of locomo- tion adapted only to a constant residence in the water, and with a digestive apparatus fitted exclusively for the assimilation of vegetable food, assuming by degrees the | function of atmospheric respiration, acquiring limbs which are formed for leaping on land with great strength and agility, and manifesting the most voracious carnivorous appetite, will not only excite feelings of the deepest admi- ration, but necessarily lead to the investigation of the laws by which such extraordinary changes are governed, and of the relations which they bear to the theory of continuous affinity, and to that of progressive develop- ment through the whole of the animal kingdom.” * Such phenomena are exhibited by the Toads, Frogs, and Newts, the familiar representatives of that limited * Bell's “‘ Brit. Rept.,” p. 72. FROGS AND TOADS. 975 Class of animals whose scientific appellation we have in- scribed at the head of this chapter. They thus afford a beautiful link in that tissue of “ chain-mail” which consti- tutes the Plan of Nature; for they evidently hold an in- termediate position between the FisHEs, whose respiration is exclusively aquatic, and the true Reprites, in which this vital function is exclusively aerial. Let us look a little more closely at this curious point,— the metamorphosis which the Ampurpra undergo, and the accompanying change in the character of their breathing organs. In the month of April, in almost every ditch and pool in the country, we see large masses of clear jelly, with black dots distributed at even distances throughout, or long strings of the same substance, in which the black dots are arranged in a double row. The former is the spawn of the Frog, the latter that of the Toad; and each dot is the maturing embryo of a single egg, which latter is a clear globe of about one-fifth of an inch in diameter. When the spawn is laid, the embryo is an opaque globule, darker at one side than at the other. In a few days, however, this begins to take the form of an animal—the head, the body, and the tail being distinct, as the little creature lies on its side within the egg, coiled up in a semicircle. Soon a kind of wart buds from each side of the neck—the future gills; and currents of water are seen to stream to and from these important, but as yet minute, organs. As time passes, the gills divide into branches, the nos- trils and the eyes appear, and traces of the mouth may be discerned. Meanwhile, the power of voluntary movement, at first confined to the head and tail, increases; and the ~ 276 LIFE, IN ITS HIGHER FORMS. little prisoner, as if impatient of confinement, tries to straighten itself by spasmodic efforts, and at length suc- ceeds in rupturing the skin of the egg and becomes free. It is now a Tadpole—a fish-like creature, without limbs, with an enormous head, and a body thinned off to Transformations of Frog. a long tail, which is furnished with a broad finny expan- sion above and below. The gills now attain their greatest size, and consist on each side of a pair of much-branched tufts, which, under the microscope, present a most inter- FROGS AND TOADS. 277 esting spectacle. The blood, forced from the heart in regular pulsations, is seen to diverge into each of the main gill-stems, sending off lateral streams to every tiny branch- let : the red globules are seen to chase each other along the tortuous vessels, to pass to the extremity of every ramification, and then, turning, followa backward course, until they reach the heart, the fountain from whence they issued. But now these organs begin to disappear: they gradu- ally diminish, until at length they can no longer be dis- cerned externally, though their function is carried on in a cavity of the body oneach side. The little animal increases rapidly in size, but does not change this its fish-like form for a considerable period, though minor modifications may be traced. Thus the mouth becomes developed, the eyes are perfectly formed, and the tail-fin grows greatly in perpendicular breadth, and is a powerful organ of locomo- tion. The little Tadpole begins greedily to devour vege- table matter, and manifests the effect of this diet in the change of its own hue from a dull black to a soft olive- green, with golden specks on the under parts. At length the period approaches when the Tadpole must leave its aquatic life, and become terrestrial ;—at least it must cease to respire water, and must derive its vitality from the air. The first step to such a change, is the de- velopment of limbs. First appear the hind-legs, in the ~ form of a pair of minute budding warts, which lengthen, become bent, and shoot forth tiny toes at the extremity. The fore-legs, always a little later than the hind, accom- pany the latter in their gradual progress. As the new organs of motion are acquired, the old one—the vibrating 278 LIFE, IN ITS HIGHER FORMS. tail with its fin—is lost. It is not thrown off, but its substance is gradually absorbed into the body. As this process takes place during the growth of the legs, when it is completed, the Tadpole has become a little Frog. The minute orifices which admitted the water into the gill-chamber have, at the same time, become closed, and breathing is henceforth performed exclusively by means of lungs, which are capacious sacs, subdivided internally into large cells. Such, then, is the metamorphosis which obtains in the most elevated forms of this Class, as our common Frog and Toad; and it may be witnessed with slight precau- tions by any one who will take the trouble to collect a mass of spawn from the nearest ditch, and transfer it toa fresh-water aquarium. In the Newts, which are no less common, the metamorphosis is less complete, and we per- ceive in their ultimate condition a closer alliance with FisHes ; since their limbs are small and feeble, their broad finny tail is retained through life, and is the principal organ of locomotion; for, in general, they continue more exclusively aquatic in their mode of life than the adult Frog or Toad. The eggs of the Newts are not deposited in a mass, but - singly, and that under interesting conditions. Professor Bell thus describes the process in the case of our largest and finest species, the Common Warty-newt (Triton cris- | tatus), the males of which are conspicuous enough in the vessels of the dealers in aquatic animals, in Covent Gar- den Market and elsewhere, by their roughened blackish upper parts, their high notched back-fin, and their rich orange under-parts, spotted with black. The female is of less brilliant hues, and is destitute of the tail fin. FROGS AND TOADS. 279 “The period when the deposit of the eggs commences, depends upon the season ; but the time when the greater number are produced, is during the months of May and June; and it is worthy of notice, that the different species of Newt are found depositing their eggs during a much longer period of the summer than the tailless Am- phibia, such as the Frog and Toad. At)the time I have mentioned, if the leaves of the various species of aquatic plants be observed, many of them will be found folded to- gether ; and within tke fold a single egg of the Newt will be discovered. It is, however, necessary for accurate observation from the commencement, that the female Newt be taken and placed in a vessel of water with the plants in question, that she may deposit the egg under the eye of the observer. The best plant for the purpose is the Polygonum persicaria, which is ordinarily chosen by the animal in its natural habitat.