277. _The COCKLE_ (Cardium edule, Fig. 80) _is a small and well-known testaceous animal with a double convex shell, somewhat deeper on one side than the other; and marked by twenty-eight depressed ribs, which are streaked or slightly furrowed across._ Cockles are perhaps more generally eaten in England than in any other country of the world: and they are a wholesome and, to many persons, an agreeable food, but, if eaten raw, they are supposed to produce poisonous effects. Cockles are generally found on sea coasts, immersed at the depth of two or three inches in the sand. They are dug up at low water, and the places where they are concealed are known by small, circular, and depressed spots in the sand. Cockles are chiefly in request during the winter months. They are sometimes pickled, and sometimes converted into ketchup. 278. _The GREAT PINNA, or SEA WING_ (Pinna nobilis) _is a testaceous animal with a double or bivalve shell, of nearly triangular shape, open at the broader end, longitudinally striated, the scales channelled and tubular, and somewhat imbricated._ _Its length is sometimes more than fourteen inches, and its greatest breadth six or seven inches._ _These animals are found in great abundance in the Mediterranean; and in the sea near some parts of the coast of America._ From the most remote periods of antiquity the _byssus_, as it has been denominated, or silky threads by which these animals affix their shells to rocks or stones at the bottom of the sea, has been spun and woven into different articles of dress. For this purpose the shells are dragged up by a kind of iron rake with many teeth, each about seven inches long, and three inches asunder; and attached to a handle proportionate to the depth of water in which the shells are found. When the byssus is separated, it is well washed, to cleanse it from impurities. It is then dried in the shade, and straightened with a large comb; the hard part from which it springs is cut off, and the remainder is properly carded. By these different processes it is said that a pound of byssus, as taken from the sea, is reduced to about three ounces. This substance, in its natural colour, which is a brilliant golden brown, is manufactured in Sicily and Calabria (with the aid of a little silk to strengthen it) into stockings, gloves, caps, waistcoats, and other articles of extremely fine texture. All these, however, are to be considered rather as curious than useful; and the manufacture of them is every day declining. 279. _The EDIBLE SNAIL_ (Helix pomatia), _is a shell animal distinguished by its large size, nearly globular shape; being of brownish white colour with usually three reddish horizontal bands, somewhat striated longitudinally; and having a large and rounded aperture with thickened and reflected margin._