Page:American Seashells (1954).djvu/479

a single specimen, is much more oblique in shape, resembling the equally rare Erycina jernmidina Dall from off Florida. My sella tu77tida Carpenter Fat Pacific Lepton Figure Sob Alaska to Lower California. Vq to %6 of an inch in length, moderately compressed, somewhat tri- angular in shape. The tiny beaks are almost at the very posterior end. Shell dull-white, but commonly covered with a light-brown, smoothish periostra- cum which is faintly marked with concentric, microscopic wrinkles. The hinge teeth are large in comparison to those in other species. Common from low water to 99 fathoms. Has been found in duck stomachs. Superfamily CARDIACEA Family CARDIIDAE Subfamily TRACHYCARDIINAE Genus Trachycardium Morch 1853 Trachycardium muricatum Linne Yellow Cockle Plate 39P North Carolina to Florida, Texas and the West Indies. 2 inches in height, subcircular, with 30 to 40 moderately scaled, radiating ribs. Externally light-cream with irregular patches of brownish red or shades of yellow. Interior commonly white, rarely yellow-tinted especially in Flor- ida. A very common, shallow-water species. Compare with eginontianum and magnum which are both more elongate. Trachycardium egmontianum Shuttle worth Prickly Cockle Plate 39-0 North Carolina to south Florida and the West Indies. 2 inches in height, with 27 to 31 strong, prickly, radial ribs. Externally whitish to tawny-gray with odd patches of weak yellow, brown or dull- purple. Interior glossy, commonly brightly hued with salmon, reddish and purple. Do not confuse with muricatum which is more oval, has more ribs which are not sharply scaled at the center of the shell and is commonly only yellowish inside. A common shallow-water species, especially on the Gulf side of Florida. Trachycardium isocardia Linne from the West Indies has larger and slightly different scales, 32 to 37 ribs and has not been recorded from Florida. Trachycardium magnum Linne Magnum Cockle Lower Florida Keys and the West Indies.