water which conveys to their body the nutriment necessary for their support.

Cockles are in great request as food, and are caught for this purpose chiefly during the winter months. In places where they are not very numerous, they are picked up separately: but where they are sufficiently abundant, they are dug out of the sand, put into osierbaskets, and then soused into the water, for the purpose of clearing them of such sand as has been dug up along with them.

OF THE OYSTER TRIBE*.

There are few tribes of shell-fish more numerous or more generally dispersed over submarine rocks and sands, in all parts of the world, than these. The greater number of them are wholesome and extremely palatable food.

From a similarity in the structure of the hinge, the Oysters and Scallops have been united into one tribe. But they differ very essentially, both in their habits and external appearance. The Oysters adhere to rocks, or, as in two or three species, to roots of trees on the shore; while the Scallops are always detached, and usually lurk in the sand.

THE COMMON OYSTER†, AND GREAT SCALLOP‡.

It is the nature of Oysters in general to have their lower valve fixed to rocks or loose stones, and frequently even to each other. Some of them, however,

* Oysters are bivalve shell-fish, having the valves generally unequal. The hinge is without teeth, but furnished with a somewhat oval cavity, and mostly with lateral transverse grooves.

+ SYNONYMS. Ostrea edulis.

Bosc. Cuvier.

Linn.-Huître commune.

SYNONYMS. Ostrea maxima. Linn.-Pecten Maximus. Montagu.-Peigne Gigantesque. Cuvier.

are loose; these have very thin shells, and are more regularly shaped than the others.

Most of our rocky coasts produce Oysters in great abundance; but those chiefly celebrated for them are the coasts of Essex and Suffolk. Here they are dredged up by a kind of net, (with an iron scraper at the mouth,) which is dragged by a rope from a boat, over the beds. As soon as they are taken from their native beds, they are stored in pits formed for the purpose, and furnished with sluices; through which, at spring tides, the water is suffered to flow. This water, being stagnant, soon becomes green in warm weather, and after a few days the Oysters acquire the same tinge, which renders them of greater value in the market: but they do not acquire their full quality, and become fit for sale, till the end of six or eight weeks.

The principal breeding-time of Oysters is in the months of April and May, when they cast their spawn, or spats, as the fishermen call them, upon rocks, stones, shells, or any other hard substance that happens to be near the place where they lie; and to these the spats immediately adhere. Till they obtain their film or crust, they are somewhat like the drop of a candle, but are of a greenish hue. The substances to which they adhere, of whatever nature, are called cultch. From the spawning-time till about the end of July, the Oysters are said to be sick; but by the end of August they become perfectly recovered. During these months they are out of season, and are bad eating.

The Oyster-fishery of our principal coasts is regulated by a court of admiralty. In the month of May the fishermen are allowed to take the Oysters, in order to separate the spawn from the cultch, the latter of which is thrown in again, for the purpose of preserving the bed for the future. After this month it is felony to carry away the cultch, and otherwise punishable to take any Oyster, between whose shells, when closed, a shilling will rattle. The reason of the heavy penalty on destroying the cultch is, that when this is taken away, the ouse

will increase, and muscles and cockles will breed on the bed, and, by gradually occupying all the places on which the spawn should be cast, will destroy the Oysters.

Oysters are not reckoned proper for the table until they are about a year and a half old; so that the brood of one spring are not to be taken for sale till at least the September twelve months afterward. When younger ones than these happen to be caught in the dredge, they are always thrown into the sea again. The fishermen know the age of Oysters by the broader distances, or interstices, among the rounds or rings of the convex shell.

The Oysters in the pits, of course, always lie loose, but on their native beds they are in general fixed by their under shell; and their goodness is said to be materially affected, by their being laid in the pits, with the flat shell downward; not being able, in this position, to retain a sufficient quantity of water in the shell for fattening them.

The Oyster has been represented, by many authors, as an animal destitute not only of motion, but of every species of sensation. It is able, however, to perform movements which are perfectly consonant to its wants, to the dangers it apprehends, and to the enemies by which it is attacked. Instead of being destitute of sensation, Oysters are even capable of deriving some knowledge from experience. When removed from situations that are constantly covered with the sea, they open their shells, lose their water, and die in a few days. But, when taken from similar situations, and laid down in places from which the sea occasionally retires, they feel the effect of the sun's rays, or of the cold air, or perhaps apprehend the attacks of enemies, and accordingly learn to keep their shells close till the tide returns. Oysters breathe by means of gills. They draw the water in at their mouth, a small opening in the upper part of their body, drive it down a long canal that constitutes the base of the gills, and so out again, re

taining the air that is requisite for the functions of the body.

The Great Scallop.-The Scallop has the power of progressive motion upon land, and likewise of swimming on the surface of the water. When this animal happens to be deserted by the tide, it opens its shell to the full extent, then shuts it with a sudden jerk, often rising five or six inches from the ground. In this manner it tumbles forward, until it regains the water. When the sea is calm, it is said that troops or little fleets of Scallops are sometimes to be observed swimming on the surface. They raise one valve of their shell above the surface, which becomes a kind of sail, while the other remains on the water, and, by steadying the animal, and thus preventing its being overset, answers the purpose of a keel. When an enemy approaches, these animals instantly close their shells, plunge to the bottom, and the whole fleet disappears. By what means they are enabled to regain the surface, we are totally ignorant. Scallops are frequently sold for the table; and, in some parts of Europe, are much esteemed.

OF THE MUSCLES IN GENERAL*.

Some of the Muscles penetrate into the interior of calcareous rocks, where they reside out of the reach of danger. Others adhere by their beard to the exterior of rocks or stones; and so tenacious is their hold, that, in the larger species, they cannot be separated without considerable exertion. One species is gathered from the depths of the sea, on account of the pearls which are found within its shells.

The Muscle tribe is distinguished by the shell being bivalve, without any tooth in the hinge, but in having the hinge marked with a longitudinal hollow line; and by the animal's being generally fixed to some substance by a byssus or silky beard..

THE COMMON OR EDIBLE MUSCLE *.

By the silky threads which it forms from its body, this species adheres to rocks, both in the European and Indian seas; but it grows to a much larger size between the Tropics, than in the northern climates. It abound's on the British shores, and is one of the commonest of our shells.

This

All the Muscles have, for an instrument of motion, a tongue or foot, capable of considerable elongation, and also of being shortened into the form of a heart. is marked with a longitudinal furrow, and is completely enveloped in a sheath formed of transverse and circular fibres, of an obscure purple colour. When the animal is inclined to change its place, it thrusts the foot out of the shell, and raises itself on its edge; then, by extending this forward, it uses it as a kind of arm, drawing the body up to it, and thus it proceeds until it has found a convenient situation. If the Muscle be inclined to continue at the spot to which it has removed, the instrument of its motion is put to a very different employment; it is now employed in spinning those silky threads which fix it firmly to the spot, and which, like a ship at anchor, enable it to brave all the agitations of the water. All this it accomplishes by seizing with its point the gluten that is supplied by a gland situated under its base, and drawing it out, through the furrow, into threads. When the Muscle is thus fixed, it lives upon the little earthy particles, or upon the bodies of such smaller animals, as the water transports to its shells.

These Muscles are generally esteemed a rich and wholesome food; but to some constitutions they occasion disorders, the symptoms of which are great swellings, eruptions of blotches or pimples, shortness of breath, convulsive motions, and sometimes even deli

SYNONYMS. Mytilus edulis. Linn.--La Moule commune. Bosc. Cuvier.