ally be seen diverting themselves by sailing about in this manner; but as soon as a storm arises, or any thing gives them disturbance, they retract their arms, take in as much water as, with the weight of their body, renders them heavier than the medium in which they swim, and sink to the bottom. Several of these animals were observed by M. Le Vaillant, on the sea near the Cape of Good Hope; and, as he was desirous of obtaining perfect specimens of the shells, he sent some of his people into the water to catch them: but, when the men had nearly approached them with their hands, the animals always sank; and, notwithstanding every art they could employ, they were not able to obtain a single one. The instinct of the animal showed itself superior to all their subtlety; and, when their disappointed master called the men away from their attempts, they expressed themselves not a little chagrined at being outwitted by a shell-fish.

These animals are found in the Mediterranean, the Indian Ocean, and in the neighbourhood of the Cape of Good Hope.

'OF THE CYPRÆAS, OR COWRIES*.

There is no tribe of shells which, on the whole, are more beautiful than these. From their high polish and brilliant colours, they have derived the name by which they are most commonly known in France, of Porcelaines. The species are very numerous. In uncivilized countries, several of them are worn as ornaments, both by men and women; and some of them are worn as amulets or charms against disease.

They reside in the sand at the bottom of the sea, and are furnished with a membrane, which is so extensive,

These shells are univalve, involuted, of a somewhat ovate shape, obtuse, and smooth. The aperture is linear, extended through the whole length of the shell, and dentated on both sides. The animal is a Limax, or Slug.

that they are able to throw it over their whole shells, and thus to preserve them always pure and polished. These animals have two horns; and the canal by which they respire, is situated on the top of their head.

*
THE TIGER AND MONEY COWRY.

There are few shells of the present tribe more common in collections, and at the same time more beautiful, than the former of these species. It is found both in the Indian and Adriatic Seas. The latter are well known on almost all the coasts of Africa and India, where they are employed by the natives in commerce, instead of money, about two thousand of them being esteemed equal in value to a rupee. The negro women, it is stated, fish for them usually three days before or after the full moon; and, at the Maldivian Islands, thirty or forty vessels are annually laden with them, for exportation into Africa, Bengal, Siam, and other countries, for the purposes of commerce.

Of the Cowries, a very remarkable fact has been stated by M. Bruguière, that when the animals find their shells too small for the increased dimension of their body, they quit them, and proceed to the formation of new ones of larger size, and consequently better adapted to their wants.

* DESCRIPTION. The Tiger Cowry is usually about four inches and a half long; of an ovate shape, obtuse behind, and rounded before. It is highly polished, of a ferruginous colour, with dark brown spots, and a yellowish longitudinal line along the back. It has sometimes a yellowish or bluish gloss. The under part is white.

SYNONYMS. Cypræa Tigris. Bosc.-Le Tigre. Cuvier.

Linnæus.-Porcelaine Tigre.

+ DESCRIPTION. This species is about three quarters of an inch in lengh, is of a whitish colour, and has a knotted margin.

SYNONYMS. Cypræa Moneta. Linn.-Porcelaine Monnoie. Bosc.-Le Cauris. Cuvier.

As soon as the Cowry has abandoned its covering, the hinder parts of its body begin to furnish anew the testaceous matter, which is afterwards condensed upon its surface. This secretion is continued, until at length the shell appears of the consistence of paper: and the mouth or opening of the shell, which at this period is very wide, soon afterwards contracts to its proper form and dimension. The edges are thickened, and formed into those beautiful folds or teeth, which are so remarkable on each side of the opening of these shells; and by means of the membranaceous wings of the animals, the highly polished surface of the whole exterior of the shells is by degrees completed.

OF THE BUCCINUM OR WHELK TRIBE▪.

The situations in which the animals of the present tribe are chiefly found, are submarine rocks, stones, and weeds. To these they adhere so firmly, as not easily to be loosened, either by the waves or the currents of the A few of them are of large size. Their shells are peculiarly thick and strong; and some of the larger kinds were anciently employed as trumpets, by the sound of which armies were summoned to battle.

ocean.

THE PURPLE-STAINING WHELKT.

In ancient times, these animals, or some others of the present tribe, were very celebrated on the coasts of the

The shell is univalve, spiral, and gibbous. The aperture is ovate, and ends in a short canal or gutter, which bends to the right. The animal is a Limax, or Slug.

+ DESCRIPTION. The length of this shell is generally from an inch to an inch and a half. It is of an ovate shape, acute, and spirally striated, without protuberances: the pillar is flattish. It varies in colour, being white, cinereous, or yellowish, and sometimes being transversely barred.

SYNONYMS. Buccinum lapillus. Linn.-Buccin teinturier.

Bosc.

Mediterranean, on account of a valuable purple dye which was extracted from them. They have, however, of late been entirely neglected, in consequence of the discovery of cochineal, from which a dye equally excellent, and at much less cost, is procured. The number of these shells necessary to have been collected together. for the purpose of dying even a small quantity of cloth, must have been very great. The dying matter, like the ink in the Cuttle-fish, is found in a peculiar reservoir, situated in the upper part of the body, and on one side of the stomach. The reservoir is very small, being seldom so large as a small pea.

The natives of South America, who employ the juice of these animals in dying, extract it in two ways. They sometimes break the shell, and, taking out the animal, lay it on the back of one of their hands: with a knife they press the juice from the head towards the tail, then, separating the part of the body into which it is collected, throw the rest away. The usual mode, however, is not to break the shell, but only to squeeze the animal until it throws up the juice; they then return the animal to the rocks, where it soon recovers from its bruises.

When the juice is first extracted, it is of a greenish colour, and viscous consistency, and in smell is not unlike garlic or assafoetida. This juice does not assume

a purple tint, until it has been some time exposed to the action of the sun and air. It is then so indelible, as to bid defiance to any known chemical process to extract it. In a handkerchief, the corner of which I stained with it, the colour was retained with undiminished brilliancy for several years.

These animals adhere to rocks and stones, and feed on the smaller kinds of marine worms, which they suck by means of a tubular proboscis, situated beneath the head. They are able to close the aperture of their shells, and thus to secure themselves from the attack of all the smaller animals of the deep: this is done by means of a thin horny cover or operculum, which is attached to their body, and is exactly the size of the opening.

OF THE HELICES OR SNAILS IN GENERAL.

The All-wise Author of Nature has denied to these animals the use of feet and claws, to enable them to move from place to place; but he has made them ample amends, in a way more commodious to their habits and mode of life, by a broad skin along each side of the belly, and the power of motion which this skin possesses. By this motion they are enabled to creep, and by the skin, assisted by the glutinous slime emitted from their body, they adhere securely even to the smoothest

surfaces.

When the snail is in motion, four horns are distinctly seen on its head; but the two uppermost and longest of these deserve peculiar consideration, both on account of the various motions with which they are endued, and also from their having eyes at their summits. These eyes appear like two blackish points, and when taken from the body are of a bulbous figure. They have but one coat; and the vitreous, the aqueous, and the crystalline humours, may be discovered in them. Snails are able to direct these eyes towards different objects at pleasure, by a regular motion out of the body; and sometimes they hide them, by a very swift contraction into the belly. Under the smaller horns, is the animal's mouth; and, though the substance of this may appear too soft to be furnished with teeth, yet it has no fewer than eight. With these it chews leaves and other substances, seemingly harder than any part of its own body; and with them it sometimes bites off even pieces of its own shell.

From various experiments that have been made on snails, it appears that they are possessed of considerable powers of reproduction. Spallanzani found that their heads might be cut off, and that, in a certain time, other heads would be formed.