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CARDIIDAE 397
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
Alaska to Lower California.
Figure Sob
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 periostracum
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
North Carolina to Florida, Texas and the West Indies.
Plate 39P
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 Shuttleworth Prickly Cockle
North Carolina to south Florida and the West Indies.
Plate 39-0
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.