THE COMMON OYSTER, (Ostrea edulis),
Has long been in favour with man for its delicacy as an article of food; the Lucrine lake used to be as much in renown among the Romans for the choicest kind of Oysters, as Cancalle Bay with the French, and the Colchester beds with us. The two shells of the Oyster are generally unequal in size; the hinge is without teeth, but furnished with a somewhat oval cavity, and generally with lateral transverse grooves. Oysters sometimes grow to a very large size; in the East Indies they are said sometimes to measure nearly two feet in diameter.
The principal breeding season of oysters is in the months of April and May, when they cast their young, which are enveloped in slime, and in this state called spats by the fishermen, 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 end of a candle, but 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, Oysters are said to be sick; but by the end of August they become perfectly recovered; from May till August they are out of season and unwholesome. 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, 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.
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. The gills, through which the Oyster breathes, are what is commonly called the beard, and are very indigestible. The scallop is nearly allied to the Oyster.