'On a rock by LindisfarnSt. Cuthbert sits, and toils to frameThe sea-born beads that bear his name.'
'On a rock by LindisfarnSt. Cuthbert sits, and toils to frameThe sea-born beads that bear his name.'
One solitary species of the Crinoid Star-fishes has of late years been found to flourish in our own seas; it is, however, affixed to a stalk (pedunculated) only in the early periods of its existence.
When first discovered by Mr. Thompson in its infant state, thePentacrinus Europæuswas believed to be a distinct animal. It was taken attached to the stems of zoophytes of different orders, and measured about three-fourths of an inch in height. In form it resembled a minute comatula mounted on the stalk of a Pentacrinus. Subsequent research has proved that the little stranger was merely the young state of the feather starComatula rosacea, and that although for a certain period attached to a slender waving stem, the Pentacrinus, when arrived at a certain stage of development, feels fully able to start life on its own accord, and hence takes opportunity to break off its early ties, and become a freeanimal, dependent upon its own exertions for subsistence.
It is no uncommon thing, as a late writer forcibly remarks, in the inferior classes of the animal kingdom, to find animals permanently attached from the period of their birth, and during all their existence. Familiar examples of this occur in the oyster, and various other bivalve shell-fish, as well as in numerous compound zoophytes. We likewise meet with races which are free and locomotive in their first stages, and afterwards become permanently fixed; but an animal growing for a period in the similitude of a flower on a stem, and then dropping from its pedicle, and becoming during the remainder of its life free and peripatetic, is not only new, but without any parellel in the whole range of the organized creation.
The Comatula, or as it is commonly called, the Rosy Feather-star, is allowed to be without exception the most lively of all the star-fishes. Its movements in swimming are said to resemble exactly the alternating strokes given by the medusa to the liquid element, and have the same effect, causing the animal to raise itself from the bottom, and to advance back foremost even more rapidly than the medusa. It has ten very slender rays with numbers of long beards on the sides. The body, which is of a deep rose colour, is small and surrounded with ten little filiform rays. The extremities of these organs are shaped like claws, by means of which the animalattaches itself to various kinds of sea-weed, and other submarine objects.
The adult Comatula generally measures about five inches across its fully expanded rays.
Before treating of what are termed thetrueStar-fishes, we require to dwell briefly upon an intermediate family named by Professor Forbes theOphiuridæ, 'from the long serpent or worm-like arms, which are appended to their round, depressed, urchin like bodies.... They hold the same relation to the Crinoidea that the true Star-fishes hold to the Sea-Urchins. They are spinigrade animals, and have no true suckers by which to walk, their progression being effected (and with great facility) by means of five long flexible-jointed processes placed at regular distances around their body, and furnished with spines on the sides and membraneous tentacula. These processes are very different from the arms of the true Star-fishes, which are lobes of the animal's body, whereas the arms of the Ophiuridæ are super-added to the body, and there is no excavation in them for any longation of the digestive organs.'[16]
The British Ophiuridæ are now classed under two genera; of the Ophiuræ, or Sand-stars only two species (O. texturataandO. albida) are found on our shores; and the Ophicomæ, or Brittle-stars, of which there are ten.
An extraordinary feature, characteristic of all the above-mentioned animals, is the great tendency which they have to mutilate themselves, and throw their limbs about in fragments on the slightest provocation. If a specimen be handled, a certain number of fragments will assuredly be cast off. If the rays become entangled in sea-weed, or even if the water in which the animal resides happens to become impure, the same disastrous result follows, until nothing but the little circular disc remains. As a set off against this weakness, both the Ophiuræ and the Brittle-stars possess reproductive powers of a high order. Hence it not unfrequently happens that if each and all the rays of a specimen be rejected, the animal will live on, and eventually, perhaps, become a complete and perfect star-fish.
The best means of preserving an Ophiura is to let the devoted animal remain for a time expanded in sea-water, then with a small pair of forceps lift it carefully up, and plump it into a bath of cold 'fresh' water, letting it lie there for about an hour. The animal speedily dies, as if poisoned, in the fresh liquid, in a state of rigid expansion. Some writers recommend that, at this stage, the specimen should be dipped for a moment into boiling water, and then dried in a current of air; but I have never been able to detect any great benefit arising from the adoption of the process.
When examining any of the Brittle-stars, I havealways found it an excellent plan to raise them up by aid of the forceps applied to the disc. By this means a specimen may be moved about without any fear of mutilation; whereas if the fingers be used as forceps, an unhappy result will assuredly follow.
TheOphiocoma rosula, figured on Plate 9, will serve to convey to the reader a general idea of this class of animals. Its popular title is the Common Brittle-star, indicative of the inherent fragility of the species, as also of their prevalent appearance at the sea-shore; but, though so exceedingly 'common,' we must at the same time in justice add, that theO. rosulaexceeds in beauty many other species which are rare, and consequently more highly prized by the collector.
It is very abundant on all parts of the British coast, and is often found in clusters upon the stems ofL. digitata, and as frequently upon the under side of boulders. In dredging, the Brittle-star is an unfailing prize. It is a marvellous sight when the scrapings of the ocean bed are spread out upon the dredging-board for examination, to see hundreds of these singularly delicate creatures twisting and twining about in all directions,—over each other's bodies, through the weed, sand, shells, and mud, and strewing fragments of their snake-like arms upon every surrounding object.
At the mere mention of 'Star-fishes,' the most uninitiated reader will at once realize in his mind'seye a tolerably correct notion of the form of these curious productions of the marine animal kingdom, even although he had never seen a living or dead specimen.
The body of the animal is divided into rays, like the pictured form of one of the heavenly stars, and the fancied resemblance is most apparent in the Asteridæ, or true Star-fishes, of which we are now about to speak.
This wonderful race of animals, for their beauty of colour, elegance of shape, and peculiarity of structure, possess a great degree of interest, not only to the naturalist, but also to the casual observer by the sea-side.
There are fourteen British species of Asteriadæ, which are arranged under four families, namely—the Urasteriæ, the Solasteriæ, the Gonasteriæ, and the Asteriæ. This group contains no less than eight generic types, clearly distinguished from each other by certain characters, 'derived from the outline of the body, the number of rows of suckers in the avenues, and the structure and arrangement of the spines covering the surface and bordering the avenues.'
There are four species of Star-fishes belonging to the genus Uraster, the most common of which is theUraster rubens, or Common Cross-fish.
No person in the habit of visiting the sea-shore can be unfamiliar with the likeness of this creature,which is generally seen lying wedged in some rocky crevice, or among the Fuci, there patiently waiting the return of the tide.
At such a time, the Devil's-hand (as the Irish people term it), does not appear by any means attractive. If placed in water, however, its appearance becomes wonderfully improved.
Here is a small specimen, just brought from the sea-shore at Cockburnspath (a most romantic and delightful locality, situated on the coast of Berwickshire). It is neatly wrapped up in a mantle of sea-weed. Freed of its verdant envelope, I deposit the youthful Rubens upon his back—'willy-nilly'—in a tumbler partly filled with clear sea-water, and then proceed to watch its movements through a magnifier.
At a glance we perceive that each of its five rays is grooved on its lower surface, and filled with minute perforations, through which is gradually protruded a multitude of fleshy suckers, knobbed at the end. It is by aid of these organs that the animal grasps its food, and changes its position, as we shall presently see. One of the rays is now slowly lifted up and moved about in various directions, while from its extreme point the suckers are extended to the utmost limit. No sooner do they touch the side of the vessel than they are firmly fixed and contracted. Apoint d'appuibeing thus gained, the animal is enabled by degrees to draw itsbody round, so as to get another regiment of suckers into play, and, by such plan of operations being repeated, the animal is eventually enabled to 'right itself,' and crawl up the polished surface of the glass.
Generally, when the Star-fish is disturbed, or placed on a dry piece of stone, the suckers are withdrawn into the body, leaving no signs of their previous existence except a series of minute tubercles. In fact, the Asterias, although enabled to adhere with great tenacity to any foreign object when immersed in water, possesses but little power to retain its hold if the fluid be removed. Hence the young zoologist, keeping this peculiarity in mind, should not too hurriedly return a verdict of 'Found dead,' when he meets with a helpless specimen upon the beach, for in all likelihood, were the creature to be laid for a few minutes in a rock-pool, it would soon exhibit signs of returning animation.
A simpler, though not so sure a test for ascertaining whether a Star-fish be living or not, is to handle the specimen. If it feels soft and flabby, it is dead; but if tolerably firm to the touch, it may be 'recalled to life,' by the means pointed out.
It may not be out of place to chronicle here a singular circumstance which the writer has often verified in connection with the true Star-fishes. It is this. When any captured specimens have been placed in confinement, no matter how large or small such might be, they never moved through the liquidelement with a tithe of the rapidity that I well knew they were capable of. At the sea-side, I have seen a specimen of the Cross-fish glide through the water so nimbly, yet withal so gracefully, that I have felt inclined to rank natation among the few other acomplishments of which the species can boast.
TheUraster rubensis also popularly known as 'Five Fingers.' For ages past it has been subject to the bitter denunciation of fishermen and others, for the injury which it is said to inflict upon oysters. At one time, according to Bishop Spratt, the Admiralty Court laid penalties upon those engaged in the oyster-fishing who did not tread under their feet, or throw upon the shore, a fish they call a Five-Finger, resembling a spur-rowel, because that fish gets into the oysters when they gape, and sucks them out. Poets have also endeavoured to perpetuate the vulgar opinion:—
'The prickly Star-fish creeps with fell deceit,To force the Oyster from his close retreat,Whose gaping lids their widened void display;The watchful Star thrusts in a pointed ray—Of all its treasures robs the rifled case,And empty shells the sandy hillock grace.'
'The prickly Star-fish creeps with fell deceit,To force the Oyster from his close retreat,Whose gaping lids their widened void display;The watchful Star thrusts in a pointed ray—Of all its treasures robs the rifled case,And empty shells the sandy hillock grace.'
Even yet the oyster fishermen at certain localities wreak all possible vengeance upon the 'submarine Dando's,' for their supposed gourmandizing propensities. I saysupposed, for although so many naturalists have studied the question, it is not, up to the present time, satisfactorily settled. Some deny the alleged tendency altogether, while lesssceptical observers are unable to understand the mode in which the Star-fish could injure an animal apparently so capable of self-defence as the oyster. According to certain authors, the Star-fish encircles the oyster with its five fingers, and by some clever process of suction destroys the unfortunate mollusc. Others, again, maintain that the first step of the attack is the injection of some marine chloroform between the shells of the oyster, and that during the insensibility that follows, the Star-fish effects an entrance.
As this is an interesting subject, perhaps the reader would like to have the exact words which are used by two celebrated naturalists, one of whom attempts to vindicate the character of the Asteridæ, the other to blacken it.
Sir John Dalyell—a high authority upon all matters of marine zoology—shrewdly remarks: 'I have not heard it suggested that the Star-fish possesses any kind of solvent compelling the bivalves to sunder. Neither can its hostility be very deadly to the larger univalves, from the distance to which they are enabled to retreat within their portable dwellings. Their general habits are, to force the shells of smaller bivalves asunder, and to devour the contents; they likewise consume the substance of ordinary fishes entire; nevertheless, as far as I am yet aware, their destruction of oysters is destitute of evidence. The Star-fish sometimes shows an eversionof stomach, or of some membrane of it. Whether this may be the means of affecting their prey, merits investigation.'
Professor Jones, who affirms that in the latter suggestion Sir J. Dalyell has nearly hit upon the true solution of the problem, thus gives whatheconsiders to be the correct mode of procedure on the part of the Star-fish: 'Grasping its shell-clad prey between its rays, and firmly fixing it by means of its prehensile suckers, it proceeds deliberately to turn its stomach inside out, embracing in its ample folds the helpless bivalve, and perhaps at the same time instilling some torpifying fluid, for the shells of the poor victim seized soon open, and it then becomes an easy prey.'
Now, many fishermen with whom I have conversed hold the same opinion as Bishop Spratt, and believe that when the oyster is gaping the Star-fish insinuates a finger, and hastily scrapes out the delicious mouthful; nay, further maintain that the Star-fish is far from being successful at all times, very often, especially when there has only been one ray inserted, the frightened oyster grasps it with all his might, and obliges his discomfited opponent to retire minus a limb.
If the writer might venture to suggest an opinion, he would express his belief that the following is the correct account of the state of matters. He believes with the fishermen that frequently the star-fishbegins his attack by inserting an arm, but he does not believe that the oyster under such circumstances escapes with life. Let us suppose the star-fish to have succeeded in insidiously introducing a ray within the shell of the apathetic oyster, and that the oyster immediately resented such intrusion by closing his shell with all the force he can exert. The opposite argument at this stage is, that the intruder is obliged frompainto abandon his hold, and even pay for his audacity by the forfeit of a limb. But against this we advance the notorious fact, that the star-fish, like so many marine creatures of a similar organization, is remarkably indifferent to pain. I therefore believe the true explanation to be, that the oyster being unable to sustain such continued muscular exertion for nearly so long a time as the star-fish can tolerate the pressure upon its ray, the latter is consequently, in the long run, successful.
The number of rays in the several genera of the true Star-fishes is extremely various. In the genusUraster, as we have seen, five is the predominant number. If we turn to the two species which comprise the genusCribella, we still find the quintuple arrangement adhered to. InSolaster endeca, on the contrary, the rays vary from nine to eleven, and even reach as high as twelve or fifteen inSolaster papposa.
In the genusPalmipeswe have the pentagonal form, it is true, but the space between each ray isfilled up, so as to resemble the webbed foot of a bird, hence the popular title of this solitary species, 'The Bird's-foot Sea-star.' 'It is the flattest of all its class, and when alive it is flexible like a piece of leather.' Passing by the 'Cushion-stars' (which have fiveangles—it seems a misnomer to call them rays), which connect the true Star-fishes with the Sea-Urchins, we come lastly to the 'Lingthorn,'Luidia fragillisima, with its seven rays. This is the animal of which Professor Forbes discourses so pleasantly about its winking derisively at his despairing endeavours to preserve even a small portion of what at that time was his maiden specimen. The Luidia is even more brittle—more regardless of its wholeness, than theOphiuræ, which renders the capture of a perfect specimen a most difficult task.
'Truly the skill of the Great Architect of Nature is not less displayed in theconstruction of the Sea-Urchin than in the building up of a world.'—P. Forbes.
Sea-Urchins
1 THE APLYSIA or SEA-HARE2 PURPLE-TIPPED SEA-URCHIN3 Spine of PURPLE-TIPPED SEA-URCHIN4, 5 Suckers of PURPLE-TIPPED SEA-URCHIN6 COMMON SUN-STAR
Sea-Urchinsare frequently taken in dredging. Several common species, usually of a small size, are often found among the rocks situated between tide marks.
Into the aquarium no specimens larger than from one to two inches in diameter should be introduced, and even these require to be closely watched, for if afflicted with a fatal illness, I know of no animal whose remains sooner taint the water. Almost before life is extinct, the Urchin throws out a light-coloured nauseous fluid, that speedily poisons the surrounding water, and, of course, causes the destruction of any inhabitants of the tank who may neither have the sense nor opportunity to inhale copious draughts of fresh air. As a rule, if the suckers are motionless, or if on touching the animal it is found not to be adherent to any object, transfer it at once to your 'infirmary' for further observation.
I have always found small specimens to be muchmore lively and walkative, (if I may be allowed the expression) than their more corpulent brethren.
The inflexible, mail-like crust, or shell, as it is commonly called, of the Echinus is perhaps one of the most marvellous objects on which the eye can rest. Although at first sight it appears to be a solid calcareous box, it is in reality composed of several hundred pentagonal plates,[17]of various sizes, so closely dove-tailed together that their marks of junction are scarcely perceptible. Upon a superficial examination we are apt (most erroneously) to consider this wonderful piece of work to be more elaborate than the wants of the animal demand. The fact of the Lobster or Crab throwing off its entire shell at certain seasons, to admit of the increased growth of the animal is a truly marvellous phenomenon, still, it would more excite our wonder were we to find that, instead of being cast away at all, the hard, inelastic envelope which surrounds the bodies of crustaceans was made to swell or expand proportionately with the soft parts of the animal! Now, the mosaic-like shell of the Sea-Urchin, though built up, as before stated, of several hundred pieces, is by a beautiful process slowly and imperceptibly enlarged correspondingly with the growth of the animal.
The gradual enlargement of the Echinus shell takes place in the following manner:—
Over the entire surface of the globular shell, spines, and joints of the living Urchin, there exists a delicate membrane that insinuates itself between the pentagonal plates above mentioned, and continually deposits around the edges a certain portion of calcareous matter (carbonate of lime). The same process being also carried on by the fleshy covering that surrounds the spines, &c., it must be evident that so long as the vital power of the animal exists, each plate and spine, still keeping to its original form, must be daily and hourly augmented in size until the Sea-Egg has attained its full and mature dimensions.
As to how the spines retain their relative position in each plate, as the latter gradually becomes enlarged, I cannot positively state; but may be permitted to mention, that, judging from carefully prepared sections of the plates when submitted to the microscope, each spine appeared to my eye to be by some singular process urged along in a kind of groove to its proper place.
The hedgehog-like spines that surround the globose body of the Sea-Urchin are all moveable at the will of the animal,—each prickle being connected by a ball-and-socket joint to a pearly tubercle, which acts as the 'socket' on which the 'ball' of the spine revolves. If the spine be removed, a comparatively smooth surface will be left, on which are various sized tubercles systematically arranged.Situated at regular intervals between the tubercles are ten broad bands, disposed in pairs, and containing many hundreds of very minute perforations, or ambulacral orifices, as they are generally termed by naturalists.
Through these apertures issue numerous sucker-like feet, closely resembling those of the Star-fish, but endowed with far greater powers of contraction and extension.
The number of suckers is very great. In an Urchin measuring exactly three inches in diameter, by aid of a hand lens, I counted no less than 3300 pores in the ten avenues. Now, these pores are always situated in pairs, and as each sucker occupies a pair of pores, it will give 1650 as the total amount of suckers.
There is no doubt that it is almost entirely by means of these curious organs that the Sea-Urchin is enabled to move about from place to place, although no less an authority than Professor Agassiz asserts to the contrary. 'How, in fact,' says this author, 'could these small tentacula, situated as they generally are in that part of the body which is never brought into contact with the ground when the animal moves, and overhung by calcareous solid spines—how, I ask, could these flexible tubes be used as organs of motion? It is an undeniable fact, and I have often observed it myself, thatit is with their spines the Echini move themselves, seize theirprey, and bring it to their mouthsby turning the rays of their lower edge in different directions. But the correction of an error respecting the functions of the ambulacral tubes does not solve the problem relating to their nature and use. This problem we are yet unable to solve, as we know nothing more respecting them than that they are connected with the aquiferous system.'
Many other writers, among whom is Professor Forbes (from whose work on Star-fishes I have transferred the foregoing extract), assert, in opposition to the great Swiss naturalist, that the Echinidæ move by the joint action of their suckers and spines. 'The argument,' says the great British naturalist, 'against the suckers being organs of motion, founded on their position above as well as below, would equally apply to the spines, to which organs Professor Agassiz has attributed all progressive powers in these animals.'
The fact is now so well established, that it is scarcely necessary for the writer to state, that from personal observation he can fully confirm the evidence of Professor Forbes relative to the functions of the suckers of the Sea-Urchins. But although that talented author entertained no doubt as to the organs in question being powerful locomotive agents, he evidently seems to have felt himself unable to suggest any purpose they could possibly serve when situated on the back or upper part of the animal.
My own experience incontestibly proves that the suckers in question are used for precisely the same purpose as those situated in any other part of the body. I am enabled to state, from having repeatedly witnessed the phenomenon, thatthe Echinus can walk about with equal facility while lying on its back as in its more natural position. The advantage of this power to the animal under certain circumstances will be apparent upon a little reflection.
With regard to the spines, I fancy their purpose is almost solely to assist the Urchin to burrow in the sand, and to protect it from the attacks of its enemies. It may be, however, that at particular times they serve as aids to locomotion, but that their assistance can be, and is, often dispensed with entirely by the animal, I can most positively assert.
My experiments were always conducted in glass vases, up the smooth, polished sides of which my specimens frequently advanced. Upon reaching the surface of the water, I have seen an Urchin roll completely round and move along on its back, then after a time change its position, and travel round the circumference of the vesselwhile attached by its side, the body of the animal being sometimes inverted.
At such times as these it must be quite evident that the spines would be totally useless, and that by the suckers alone did the animal perform its interesting movements.
According to a certain writer, there are some foreign species of the Echini remarkable for possessing spines, which act both as offensive and defensive weapons. 'On one occasion' (this writer says) 'when searching for a fish in the crevice of a coral rock, I felt a severe pain in my hand, and upon withdrawing it, found my fingers covered with slender spines, evidently those of the Echinus, of a grey colour, elegantly banded with black.
'They projected from my fingers like well-planted arrows from a target, and their points being barbed could not be removed, but remained for some weeks imbedded as black specks in the skin. Its concealed situation did not permit me to examine this particular Echinus. In some experiments I approached the spines with so much caution, that had they been the most finely pointed needles in a fixed state no injury could have been received from them, yet their points were always stuck into my hand rapidly and severely.'
In addition to those above described, the Sea-Urchin is provided with other organs, in shape somewhat resembling minute pincers, supported on fleshy stems, which always keep up an incessant motion when the animal is in a healthy condition. They are scattered in great numbers over the surface of the body, among the spines, and around the mouth of the Urchin.
The use of these singular objects—by naturaliststermed Pedicellariæ—is totally unknown. Some writers think they are an integral part of the Echinus, others describe them as distinct and parasitic animals. There is good reason to believe that the former will eventually be proved to be the correct explanation of the matter.
Its masticatory apparatus is not the least wonderful portion of the Sea-Urchin. The teeth, five in number, which may frequently be seen protruding from the mouth, are of extreme hardness, and of seemingly disproportionate length. They are not fixed in sockets as ours are, or they would be speedily worn away by their action on the shelled mollusca upon which the animal feeds, but fresh substance is added to each tooth as fast as it is worn away by use, as in the case of many gnawing animals. 'In order to allow of such an arrangement, as well as to provide for the movements of the teeth, jaws are provided, which are situated in the interior of the shell, and these jaws, from their great complexity and unique structure, form perhaps the most admirable masticating instrument met with in the animal kingdom. The entire apparatus removed from the shell consists of the following parts. There are five long teeth, each of which is enclosed in a triangular bony piece, that for the sake of brevity we will call jaws. The five jaws are united together by various muscles, so as to form a pentagonal pyramid, having its apex in contact with the ovalorifice of the shell, while its base is connected with several bony levers by means of numerous muscles provided for the movements of the whole. When the five jaws are fixed together in their natural position, they form a five-sided conical mass, aptly enough compared by Aristotle to a lantern, and not unfrequently described by modern writers under the name of "the lantern of Aristotle." The whole of this complicated machinery is suspended by muscles from a frame-work fixed in the interior of the shell, and may often be picked up upon the beach, or still better exposedin situin a dead Echinus, by those who would examine closely this wonderful piece of mechanism.'[18]
I have made two careful drawings of the jaws and teeth of the Echinus. No. 1 represents, as it were, the 'elevation' of the pentagonal pyramid above described, while No. 2 constitutes the 'plan' of the same object.
TheEchinus sphæra, or common Egg-Urchin, may often be seen forming a curious ornament in the drawing-rooms of the "West End," and also in the dwellings of the poorer classes, who, according to some authors, boil it like eggs, and so eat it. Hence its popular title. Among the ancients the Echinidæ were accounted a favourite dish. 'They were dressed with vinegar, honiedwine or mead, parsley and mint. They were the first dish in the famous supper of Lentulus when he was made Flamen Martialis. By some of the concomitant dishes they seemed designed as a whet for the second course to the holy personages, priests and vestals, invited on the occasion.'
The illustration on Plate 10was drawn from a living specimen, and gives a somewhat unusual representation of a Sea-Urchin. In general the spines alone are shown, but I have endeavoured to give the uninitiated reader some faint notion of the appearance which thesuckerspresent when extended from the surface of the shell.
The young Urchin sat very quietly while I was engaged in taking his portrait, but continually extended crowds of his slender tubular legs in all directions, as above indicated, much to my gratification and apparently to his own.
In preparing a Sea-Urchin for a chimney ornament, the most important point is to remove the spines so as to let the tubercles remain entire. In performing this operation some little experience is necessary. Several times I attempted the process by aid of a pen-knife and a pair of pliers, but not with a satisfactory result. Having mentioned my difficulty to a friend, he laughingly asked me if I had ever heard of a certain pilgrim who, for some peccadillo he had committed, was doomed to perform penance by walking to Loretto's shrine with peas in his shoes?Of course I was acquainted with the story, but could not see what it had to do with Sea-Urchins, and told my brother naturalist so. Still smiling, he said, 'Do you remember the relief that was said to be afforded to the humorous rascal, both mentally and bodily, byboiling his peas?' Yes. 'Well, then,' was the reply, 'do you boil your Sea-Eggs, and you will find your troubles speedily cease.' I did as I was directed, and found the advice of great service; for, after being an hour or two in the 'pot,' the spines of the Urchin may be totally rubbed off by aid of a nail brush, or some such instrument. Moreover, the colour of the shell is improved, and the dental apparatus may be drawn out entire, with the greatest ease.
I may here take opportunity to mention, that the student who may think proper to act upon the hint above given, should not boil the Urchin too long, or the fleshy parts will become dissolved, and the entire shell fall into a multitude of fragments.
This unfortunate result actually happened on one occasion to a genial, clever friend of mine, much to his chagrin and my malicious delight.
There are several other species of Sea-Urchins whose forms are tolerably well distinguished by their popular appellations. Thus we have the 'Silky Spined Urchin;' the 'Green Pea-Urchin,'—the latter is the commonest and prettiest of all its kindred, its back being covered with a kind of powdery green, asis seen on the elytra of many beetles; the 'Cake-Urchin,' which from its flattened form may be regarded as a link between the Sea-Urchins and the true Star-fishes; the 'Purple Heart-Urchin,' and the pretty 'Rosy Heart-Urchin,' appropriately named from the brilliant crimson hue that its body presents during life.
Thereis a very singular group of animals, theHolothuriadæ, that claims a passing notice, from their near relation in structural formation to the Sea-Urchins, although externally they also exhibit a certain resemblance to theAnnelides. They are commonly termed Sea-Cucumbers, from the fancied likeness which they bear, both in shape and colour, to their namesakes of the vegetable kingdom.
A Holothuria is very unattractive in appearance when lying listless upon the sea-beach, but if a small specimen be transferred to the aquarium, it exhibits features of a very singular and interesting character. When about to change its position, the head, hitherto concealed, is protruded and expanded, until it assumes the form of a beautiful flower.
The animal moves principally by aid of sucker-like feet, similar in form to those of the Asteriadæ, or Sea-Urchins. In most species, the body is divided longitudinally into five rows of suckers. In some, however, these organs are scattered over the entiresurface, while in the small Sea-Cucumber (Psolus phantapus), they are arranged in three rows upon a soft, oblong, flat disc, situated beneath the body of the animal, like the foot of a gasteropod mollusc.
Of one genus—the Trepang—many species are eaten by the omnivorous inhabitants of the Celestial Empire, by whom it is employed in the preparation of 'nutritious soups, in common with an esculent sea-weed, shark's fins, edible birds' nests, and other materials affording much jelly.' The intestines, which are generally found to be filled with coral, and solid masses of madreporic rock, are extracted, and the animal then boiled in sea-water and dried in smoke.
Nothing can possibly be less enticing than the black and shrivelled carcases of these defunct gasteropods, as they are seen spread out and exposed for sale in the China markets. There are many varieties of Trepang, some being held in higher esteem than others,—hence the great difference which exists in the price of the article. The lowest quality being ten dollars, and the highest fifty dollars, per pecul of 133 lbs.
The following are titles by which a few of the Holothuriæ are known in China:—
Great Black-Stone Trepang;Peach-blossom Trepang;Great White-Stone Trepang;The Bald Trepang;The Scarlet Trepang;Great Clear-Ball Trepang;The Middle Ash-Bald Trepang, &c., &c.
Great Black-Stone Trepang;Peach-blossom Trepang;Great White-Stone Trepang;The Bald Trepang;The Scarlet Trepang;Great Clear-Ball Trepang;The Middle Ash-Bald Trepang, &c., &c.
The illustration on Plate 11gives a good idea of the typical form of the Holothuriadæ. It represents a species of the genus Cucumaria,C. communis, or common Sea-Cucumber. Its length is from four to eight inches; but, like all its kindred, it possesses the power of considerably extending or contracting its body at will. The Tentacula are ten in number, pinnate and plumose, stalked and rather large. The body is five-sided, with numerous suckers on the angles, but more on the sides, which are papilose. The colour is yellow, or brownish-white, although specimens found on the Irish coast exhibit a purplish hue.
This, the most common species of its genus, is an inhabitant of deep water, and is therefore most frequently taken with the dredge. Occasionally, specimens may be found after violent storms stranded on various parts of the shores of the United Kingdom.
The Sea-Cucumbers possess the singular power of disembowelling themselves upon the slightest provocation, and also of throwing off their Tentacula entire. There is one species, indeed, that exhibits a still more wonderful phenomenon. At certain times members of this species will divide their body into a number of parts, each of which will in due coursebecome a new and completely-formed animal. After this the reader will be prepared to learn, that to build up a new inside, or create a new set of branchiæ, is to a Holothuria a very trifling and insignificant task.
'The origin and the source of the smallest portion of the universe overpowersour comprehension. How little can the acutest senses, the profoundest judgment,the widest view, embrace! It is as nothing; it is as less than nothing. We arecapable of doing no more than surveying the edifice and adoring the Architect.'Sir J. Dalyell.
Atseveral parts of the Scottish coast, and especially at North Berwick, may be found specimens of that curious gasteropod named the Aplysia, or Sea-Hare, theLepus marinusof the ancients.
On visiting North Berwick during summer, I have been astonished to discover, in almost every pool, from two to twenty of these creatures.
At rest, the Aplysia is not by any means inviting, but when in motion, elevating and depressing the fleshy mantle that covers over the fringed and lobed branchiæ, its appearance is exceedingly graceful.
Striding across a pool on the look-out for some Gobies, whose forms darting beneath a large stone had not escaped my glance, I perceived the water in the rocky basin gradually lose its crystal brightness, and become changed to crimson. The Gobies were therefore allowed to rest in peace, while I proceeded to investigate a phenomenon that, at the moment, seemed somewhat singular.
A kind friend and brother zoologist, who happenedto be near, called attention to the fact that the crimson stream flowed thickest near where my foot rested.
On closely examining the spot pointed out, and turning over some fronds of Dulse, we came upon a small fleshy ball of a dark brown colour, from which there still issued a fluid of vivid crimson hue. Having placed this strange object in a bottle, I soon pronounced it to be an Aplysia, with whose full-length portrait, as represented in books, I had previously been made acquainted.
The power which this animal possesses, under irritation, of spurting out a peculiar secretion, I also remembered to have seen mentioned by several writers on natural history.
Although generally believed to be gentle and perfectly harmless, yet, as Professor Forbes observes, few molluscs have had a worse character than the Aplysiæ. From very ancient times they have been regarded with horror and suspicion; and many writers on natural history, conversant with them only through the silly stories of ignorant fishermen, have combined to hold them up as objects of detestation. To touch them, according to European prejudices, was sufficient to generate disease in the foolhardy experimenter; while Asiatics, reversing the consequences, maintained, perhaps with greater truth, that they met with instantaneous death when handled by man. Physicians wrote treatises on theeffects of their poison, and discussed the remedies best adapted to neutralize it. Conspirators brewed nauseous beverages from their slimy bodies, and administered the potion confident of its deadly powers. Every nation in the world on whose shores the poor Sea-Hares crawled, accorded to them the attributes of ferocity and malignant virulence, although there never appears to have been the slightest foundation for a belief in their crimes.
A specimen of the Aplysia that I had in my tank deposited a stringy coil of spawn, which closely resembled that of the Eolis, with the exception that the eggs, instead of being white, were of a reddish tint.