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Family Veneridae

SHELL sub-orbicular or oblong, regular, closed; ligament external; hinge with three divergent teeth; two muscle scars oval, polished; pallial line sinuate. Animal free, active, rarely burrowing, or forming a byssus for attachment; mantle with large anterior opening; siphons unequal, more or less united; foot tongue-like, compressed, rarely grooved; gills large, sub-quadrate, dorsally united.

Bivalves whose tropical forms are remarkable for elegance of shape, finish and coloration, frequently with chevron-shaped markings; texture very hard. A large family in tropical and temperate zones. The genera are variously arranged by authors who disagree.

Genus VENUS, Linn.

Shell thick, ovate, smooth, ridged or cancellated; margins minutely crenulated; cardinal teeth, three; ligament prominent, lunule distinct; mantle margin fringed; siphons unequal, separated; fringed, foot slim. A world wide genus.

The Round Clam or Hard-shelled Clam (V. mercenaria, Linn.) is the "Quahog" and "Little Neck," the chief commercial clam of our east coast. In Chapter I. of Part IV. this species is fully described as a typical bivalve. The obliquely round shells are familiar in the markets.

When the tide goes out the clam-digger may be seen in the mud flats and in shallow coves raking the clams to fill his boat or basket. He has a special tool called a "clam rake." It is not a romantic enterprise-"clamming" in the quagmires of Cape Cod or elsewhere, but it is profitable. The men usually wear high boots and do not mind wading in the clinging mud. Flat-bottomed boats are used in shallow water.

"Outside clams" with thinner shells, but of the same species, are found on sandy bottoms of bays, or off exposed coasts. These are taken by rakes or by tongs such as oystermen use. The clammer goes out in a boat for them.

"Treading clams" is a method used in warm waters of the southern shores, where the gigantic variety, Mortoni, reaches six inches in diameter, and a weight of five pounds. The bare feet of the wading man range under the surface of the sandy mud, and rout out the individual clams one at a time.

The young clams of the typical species are almost as tender and fine flavoured as oysters. Adult specimens are tougher. Var. Mortoni is tough and coarse and too strong in flavour to be a popular shell fish except to people who have known no better clams. They are used extensively for chowders on the Florida coast.

The northern hard-shell reaches three inches in length and a width of two and a half inches. It ranges from Nova Scotia to the West Indies. The season lasts from April to September, coinciding with the oyster's closed season. Clams live a long time out of water, if kept cool, and are shipped in quantities in the shell to mid-continental cities.

V. Kennicottii, Dall, a lamellate clam resembling the quahog in size and form, is rarely found off the California coast and northward.

Sub-genus CHIONE, Megerle

The Cross-barred Venus (V. cancellata, Linn.) is one of the very abundant bivalves on the west coast of Florida. Narrow elevated ridges cross on the surface of the valves, which range in colour from white to cloudy yellow and brown. The white lining is tinged with violet. Length, 1 to 1 1/2 inches.

Habitat.-Cape Hatteras to West Florida.

Chione includes also two or three compact little cross-barred clams on the west coast.

Genus CYTHEREA, Lam.

Shell ovate, smooth, thick; hinge with three cardinal teeth; siphons united half-way.

The Japanese Cytherea (C. petechialis, Lam.) is handsomely painted with brown chevrons and obscurely rayed on the neutral, olive ground. Over the smooth, white shell substance is laid a shiny epidermis, like a coat of lacquer. It is brittle and, scaling off, removes all the colour. Length, 2 to 4 inches.

Habitat.-Japan Sea to Indian Ocean.

The Convex Cytherea (C. convexa, Say) is a smooth little round clam, with a convexity behind its prominent beaks. Length, 2 inches.

Habitat.-Nova Scotia to Cape Hatteras, west coast of Florida.

Sub-genus CALLISTA, Morch

The Giant Callista (C. gigantea, Gmel.) is shaped and painted like a sunset shell, but the plaid pattern is oftenest developed in dull blue, lilac or gray, on a pale ground. A brown band of some width is set a little back from the margin. The hinge is nearer the anterior end. The posterior end is elongated, and pointed to a slight degree. The china-like shell is covered with a livid or pink epidermis. This species is especially abundant on the beaches of western Florida. Length, 5 to 6 inches; width, 3 inches.

Habitat.-Cape Hatteras to Texas.

The Spotted Callista (C. maculata, Linn.) is oval, ventricose, with a shiny surface, fawn-coloured, with broken radiating bands of violet-brown, and chevron prints in the spaces between the bands. A horny epidermis covers the shell. The flesh is edible as is also the giant Callista's, but both have a peppery taste one must learn to like. Length, 4 inches; width, 3 inches.