Изображения страниц
PDF
EPUB

or

seen.

Although the snail and the slug belong | furrows are purplish flesh-colour, to the gasteropoda, we shall have little or the ridges are porcellainous white; the nothing to say of them in this paper, since larger specimens commonly display three they and their friends are provided with spots of dark brown, arranged lengthwise. pulmonary sacs or air-cavities, which en. When tenanted by its living inhabitant, and able them to breathe on land, and are not crawling at ease in clear water,--its foot dwellers in the deep at all.

spreading out to twice the extent of the The sea-snails (or gasteropods) are to be base of the shell, its mantle turned up and found on almost every variety of shore, covering the shell, its head (armed with inhabiting different zones of depth, from two straight long tentacles) protrading high-water mark to the deep-sea bottom. from the front of the shell,--it is a very The pretty, many-coloured, ridged winkle elegant creature. The furrowed cowry is congregates in hollows of the rock, scarcely the only species that lives in the British within reach of the spray, except at spring- seas, but about 150 species are known to tides. The limpet adheres by thousands exist, and most of them are valued as ornabut a little lower. On the boulders, about ments. The beauty arises in part from the half-tide level, the purple and one or two small amount of animal matter which the species of trochus (or top-shells) may be shells contain, but depends still more on

Lower still, to the verge of extreme the deposit of a layer of shelly matter over low tide, we find the purple-spotted trochus, the whole exterior, when the mantle is the ridged and furrowed rock-shell, the clasped around it. In the young cowry, dog-winkle, the chitons (looking like the before this final deposit of nacre or pearl millepedes of our gardens) and the lovely has taken place, the edge of the shell is little cowry enveloped in its variegated sharper, the mouth wider, and the spiral mantle. If we turn over stones at the structure more apparent. water's edge, especially in spring, we may There is a small species known by the find the sea-lemon, the lovely Eolis coro- name of the money cowry, which is dredgeil nata, and other naked-gilled creatures, in the Pacific and Eastern seas, and is the which resort thither to lay their coils of current coin of the natives of Siam, Bengal, spawn, the pleuro-branchus, and the great and many parts of Africa. In Benga} purple sea-hare, which stains the stones 3,200 of these shells are reckoned to be with its rich crimson dye.

equivalent to a rupee, or about two shillings The sea-snails possess a mouth sur- of English money. Several hundred tons rounded with contractile lips, and some- of cowries are annually imported into times armed with horny teeth in the palate. Liverpool, for the purpose of carrying on They seem also to have very acute organs trade with West Africa. In the Friendly of smell, since animal substances let down Islands permission to wear the orange in a net to the bottom often draw thousands cowry as an ornament is only granted to together in one night. With these facilities persons of the highest rank. they rasp their way through the shells The shape of the shell in the cones is of mussels, or feast upon dead animals indicated by their name. They are genewhich chance may throw in their way; rally very beautifully coloured, and some while in their turn they serve as food to species are so highly valued that so high a the sea-stars, which swallow the young fry price as 300 guineas has been given for : and seize the full-grown individuals with single specimen.

The animals are very their long arms.

predatory in their habits, and some of You are probably familiar with a little them are said to bite the hands of their shell, elegantly marked all over with trans. captors. The volutes are also remarkable verse ridges, and varying in size from that for their beauty of form and colouring, and of a split-pea to that of a large horse-bean. are much sought after by collectors. It is to be picked up on every sandy beach, Come we now to the whelks, concernina and is called the furrowed cowry. The which you will, perhaps, be able to testify

[ocr errors]

from experience, both as to the taste of the sometimes been supposed that the Roman animal and the absence of brilliant colours purple dye was obtained. Certainly a in the shell. The shells, however, present beautiful purple colour is frequently obmany interesting varieties of form and served on the nacre, in the throat of the marking, and the animals are worth atten- various species of purpura ; and the purpuro, tion for their structure and habits. They lapillus, a small shell found very abundantly have a trunk, which they can not only bend on our own shores, has the power of secretin all directions but withdraw entirely into ing this dye. Such was the estimation in the body, just as when the finger of a glove which this dye was held at one time that, is pushed back into the part that covers amongst more than one of the nations of the palm. As this proboscis incloses a antiquity, it was death for any one but the tongue furnished with a hundred rows of sovereign or supreme judges to wear garsharp teeth, the animal is able to file his ments dyed with Tyrian purple. With the way into the hardest shell. Burrowing in Romans the purple was indicative of sovethe sand in chase of hapless bivalves, he reign power, and their emperors alone were bores a hole (cunning fellow !) close to the permitted to wear it. The dye, which was hinge where the fish is, and then sucks out extracted by breaking the shells of the purtheir life. Look at this old valve of a mac- pura, was often mixed with other substances, tra. Like hundreds more that you may which brought out more brilliantly the pick ap at high-water mark, it is perforated natural colour. The curious eggs of these in the place described, the hole so smooth creatures may sometimes be found in clusand so perfectly circular that you would ters, affixed to little stones, and indeed, suppose a clever artizan had been at work when first deposited, some of them seem drilling the massive stony shell with his always to be thus anchored, affording supsteel wimble. These carnivorous molluscs port to others, which stand, acrobat fashion, are not restricted in their destructive opera- on the shoulders of the first. tions by any ties of kindred, by any fine It is proper to say that, in the opinion of notions of morality, for the shell of the some, the Tyrian purple was obtained from whelk itself is not unfrequently found per- a species of murex, or rock-shells, the ani. forated, just as if by one of its own species. mals of which closely resemble the ordinary

Mr. Lewis one day threw a good-sized whelks. Mr. Gosse says there is little whelk into a vase, in which was a hermit- doubt that the purpura is one of the animals crab, destitute of a shell. Pagurus clutched enumerated by Pliny as used by the an. the shell at once and poked in his inter- cients for obtaining this dye ; though the rogatory claw, which, touching the opercu- principal and that which yielded the richest lum of the whelk, made that animal with. hue was probably the murex trunculus, a draw and leave an empty space, into which common Mediterranean shell, which does Pagurus popped his tail. In a few minutes not extend to our shores. The old myth the whelk, tired of this confinement in his relating to the discovery of the purple dye own house, and all alarm being over, began tells us that the Tyrian Hercules was one to protrude himself, and in doing so gently day walking with his sweetheart along the pushed the crab before him. In vain did shore, followed by her lap-dog, when the the intruder, feeling himself slipping, cling playful animal seized a shell that had just fiercely to the shell ; with slow but irresist- been washed up on the beach. Its lips ible pressure the mollusc ejected him. This were presently dyed with a gorgeous purple was repeated several times, till at length tint, which was traceable to a juice that was Pagurus gave up in despair.

pressed out of the shell-fish. The lady was To this family also belongs the helmet- charmed with the colour, and longed to have shellone of the largest of the gasteropods, a dress of it, and, as wishes under such cirthe shell of which is beautifully sculptured cumstances are laws, the enamoured hero by Italian artists in imitation of antique set himself to gratify her, and soon succameos—and the purpura, from which it has 'ceeded in extracting and applying the dye which afterwards became so famous. The trochus. It is not often that the top-shaped shell of one species of murex is employed as shells are found perfect, for they are genea lamp in the Shetland cottages ; being sus- rally worn away at the apex, so that the pended horizontally and filled with oil, when colouring substance is removed, and the the canal projecting straight from the front point of the shell is white. But the shells of the shell serves for the reception of the are to be found plentifully on every coast, wick.

either empty and cast ashore by the waves, One of the largest of the mollusca is the or living and adhering to the seaweeds that strombus gigas of the West Indies, whose are laid bare at low water. Here, for inshell often measures a foot in length, and stance, is a purple-spotted top. Before we weighs several pounds. The shelly matter take him up, let us notice for a moment of the interior, which exhibits beautiful pink with what an easy, even movement he tints, is much used in the manufacture of glides along over the leaves of the seaweed, cameos, and immense numbers of the shells now over the stony projections of the pool, are imported into this country for that now on the broad weeds again. On lifting purpose.

the shell we find that the fine, fleshy, apricotComing again to our periwinkles, which coloured animal clings with considerable belong to the great family of the turritellido, force to the weed ; and, on transferring it we shall never vote them to be “not worth to a glass bottle, we get a better sight of a pin” when we find them doing service as the organ by which it maintains both its barometers. The Swedish peasants have stability and its movements.

When in moobserved that whenever the periwinkles tion it strongly reminds one of the human ascend the rocks it is a sure sign of a storm tongue. being at hand, their instinct having taught The shell, the solid house of stone, which them to place themselves out of the reach our friend trochus has built up to cover his of the dashing of the waves. When, on the head in the hour of danger, combines the contrary, they make a descent upon the comfortable with the ornamental. Its sand, it is an indication of a calm. The general form is that of a cone of much periwinkle is even worth notice for its pretti- regularity, but with an oblique base; this ness, as it exhibits itself when crawling upon conical form being the result of the winding the glass of an aquarium, or on the sea- of a very long cone upon itself in a spire. weeds where it finds its food. The body is If you examine a dead shell with care, you prettily banded with multitudes of narrow will see that this is really so. The trochus dark markings, and the mode in which the is one of our showy shells. This specimen creature slides itself over the glass is very before us has for its ground-colour a chaste, curious.

cool grey, occasionally. varied with tints of The true turritellce have an elongated reddish buff, but most conspicuously adorned spiral shell, with a small opening. The with a series of large and regular spots of wentle-trap is a very pretty shell, found in purplish crimson, running along the lower tolerable profusion on our sands. A specimen angle of the spire from the base to the sumof the royal staircase wentle-trap would for- mit. Each of these spots passes off into an merly fetch eighty or ninety pounds. Besides oblique line above, the repetition of which these shells, the construction of which pre- augments the beauty of the pattern. The serves the usual spiral order, some of the mol-interior of the shell has a glory of quite luscs of this family form an irregularly tabu- another character. It is covered with a coat lar habitation. Of these the vermetus is re- of nacre, or pearl, of exceedingly brilliant markable for the close resemblance of its shell and rich lustre; and the presence of this to that of the serpula ; but when perfect, it inward pearliness is quite characteristic of may begenerally distinguished by the regular- genus, and of most others belonging to ly spiral twisting of its first-formed portion. the same family—the turbinidæ. Many of

Among the turbinidæ, or top-shells, we the fine large tropical species are specially may give a few minutes' attention to the conspicuous for this adornment. De Montfort mentions a necklace, which he had seen, their foot turned upwards ; but as soon as that was made out of the nacral part of the the winds ruffle the ocean they empty their shell of a turbo, and which was much more air-cells and sink to the bottom. brilliant and beautiful than any of the finest Another beautiful gasteropod is the earOrient pearls. A trochus in an aquarium will shell, in which the colours present great perform the part of a mower, using its tongue variety and richness. Its shell, when the as a scythe, and cutting down the green surface is polished, possesses a pearly lustre, film of vegetation that forms on the glass. with resplendent metallic hues. It is con.

There is a small shell extensively em sequently in high esteem as an ornament. ployed for ornamental purposes, and known The animal attaches itself to the rock, after under the name of “ Venetian shells.” They the manner of the limpet, holding on by its are used for making studs, necklaces, brace. large muscular foot with such force that lets, and pins, and really form a very beau- considerable strength is required to detach tiful ornament. This shell is a small uni- | it. When it is undisturbed, the shell is valve, not unlike the trochus, and is referred usually a little separated from the rock; and by Dr. Lankester to the genus Phasianella. the best mode of securing the animal is to The nacre is very brilliant, assuming various place some instrument ander its edge, and tints of blue and purple. Species of the crea- endeavour to remove it before the creature ture are found in the Mediterranean Sea, is alarmed. Sometimes, when the hand has and it is from this fact that they may have been thus used under water, and not with found their way to Venice, and thus to Eng. sufficient caution, the shell has been drawn land, with their ordinary name. Shells of down firmly upon it, and fatal results have this kind are also brought from Australia ; followed. and in the South Kensington Museum are Another gasteropod, noted for the firmseveral strings of them, which are said to be ness of its hold, is the limpet, whose shell used by the natives of Tasmania as orna- is one of the commonest found on the sea. monts.

shore. The adhesion is caused by atmoTanthina is a pretty name, belonging to spheric pressure, just as with a boy's sucker; a creature possessing a beautiful snail-like for the limpet is enabled to raise the centre shell, and from this circumstance, and the of that part of the body that rests on the fine violet at the base of its shell, receiving rock, while the edge is closely pressed upon the name of violet snail. When irritated or it. The firmness of hold is also increased alarmed, the ianthina pours out a violet fluid, by the fact that, after the animal has rewhich darkens the water around it, and thus mained for some time in one spot, it forms a serves for its concealment, in the manner of hollow, into which the shell sinks, so that the ink of the cuttle-fish. But the most there is no possibility of reaching its edge. remarkable circumstance in the history of It would almost seem indeed too tight a fit this delicate and beautiful creature consists to allow limpet himself to stir, but as he is in its production of a peculiar float or raft, exclusively a vegetarian in his diet, he must composed of numerous gristly little vessels manage in some way to get his daily dinner filled with air, which springs from the small of greens. A peering naturalist, out one foot, in place of an operculum. To the night upon his sea-side prowlings, with a lower şurface of this curious float the egg- bull's-eye lantern at his girdle—much to the capsules are attached, and thus the ianthina mystification, no doubt, of the coast-guard carries its offspring about with it until the watching on the cliffs above-observed the young animals are fully formed. The ion- strange phenomenon of old aldermanic lim. thing inhabit the Mediterranean and the pets crawling hither and thither, with tilted warmer parts of the Atlantic Ocean. The shells, about the tender mossy green that shores of the islands of St. Heler and As.

grew in patches on the rocks. He was cension are sometimes completely covered curious enough to mark their movements, with them. When the sea is quiet, they and found that, as morning approached, the appear in vast shoals on the surface, with limpets, in a comfortable state of repletion, glided away from the mossy patch, and be undergone preparatory digestion, it has to took themselves, with unerring precision, be further ground by these teeth. This each to his own hollow in the stone, into strange animal, as harmless as a butterfly, which he settled himself as snugly as if he used to be considered a mischievous creature had never moved at all.

---a prejudice perhaps resulting from man's The whelk is not alone in the possession propensity to associate evil habits with an of a wondrous rasp-like tongue. Many of unprepossessing appearance, –as though the sea-snails are furnished with ribbon- either beauty or ugliness were more than shaped tongues, studded with microscopic skin-deep! The Romans believed that the teeth, which exhibit such regular and con. mere sight of the sea-hare caused sickness stant shapes that a mere inspection of a sometimes death. Apuleius happened to fragment of a tongue will enable the natu- have a curiosity about this animal, for ralist to pronounce to a certainty upon the which he was accused of magic. The fool. affinities of the creature to which it belonged. hardy meddler who handled the animal From an ordinary individual of the common swelled, and possibly burst in consequence; limpet, a tongue two inches in length may at any rate his hair fell from his head and be extracted, armed with no fewer than 150 chin. Subtle poisons were concocted from or more bands of denticles, twelve in each its slimy corpse. But all modern naturalists row, so that in all it may possess nearly of reputation who have examined the sea2,000 teeth. The limpet uses this elaborate hare about its poisonous qualities, have organ as a rasp with which to reduce to agreed to pronounce it guiltless of the small particles the substance of the sea- crimes laid to its charge. weeds upon which it feeds. In some of our Around Weymouth, where the aplysia is common garden-slugs as many as 20,000 common, the fishermen and shore-boys call teeth may be counted. Wonderful, indeed, it the sea-cow. To this they are guided, is this complication of minute organisms ! as indeed are those who call it the sea-hare,

The sea-ears, or tooth-shells, are very by the pair of tentacles which stand erect, handsome mother-of-pearl shells, frequently but a little diverging from the back of the used for the inlaying of boxes. They are head, and look somewhat like a hare's ears. curved and tapering, resembling the tusk of When full-grown the animal is three inches an elephant, with an opening at each end, in length and upwards of an inch high. Its and a surface sometimes smooth, sometimes figure, when it crawls, scarcely exhibits the striated. If the spiral shells could be drawn same outline for two minutes together. out, they would all be found to consist of a See what has happened! “On dropping one tube, gradually widening from the apex to of the slimy beasts into this phial of clear the base ; so that the tooth-shell only differs sea-water,” says Mr. Gosse, “it immediately from its fellows in not being wound into resented the incarceration by beginning to whorls. The animals are carnivorous, and pour out from beneath the lobes of the are found in most seas, inhabiting a sandy mantle a thin stream of fluid of the most or muddy bottom.

royal purple hue, which freely diffused itself The aplysice, or sea-lares, are such queer- through the water. And see! It is still looking creatures that one would fancy them copiously exuding; and the whole contents to be great naked snails or slags ridiculously of the bottle are now fast becoming of so metamorphosed. If they had begun by fine and rich a tinge, as already to veil the being slugs, and then thought of changing form of the animal.” into hares, and next resolved to be camels, We come now to the nudibranchiate or and after all had contented themselves with naked-gilled gasteropods. The shell postheir original low estate, we could under- sessed by the embryo animals is shed early, stand the absurd shape they have got into. and never replaced. The animals are found The teeth of the sea-hare are in one of its on all rocky coasts, where they usually stomachs, and in that one which is farthest inhabit rather deep water, creeping about from the mouth, so that after the food has upon sea-weeds, and occasionally swimming.

« ПредыдущаяПродолжить »