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404 Genus Cerastoderma Poli 1795

Cerastoderma pinnulatwn Conrad Northern Dwarf Cockle Plate 30c

Labrador to off North CaroHna.

^ to /4 inch in length, thin, with 22 to 28 wide, flat ribs which have delicate, arched scales on the anterior slope of the shell. Scales missing on the central portion of the valve. Externally cream; interior glossy and white, rarely tinted with orange-brown. Commonly dredged from 7 to 100 fathoms.

Super jamily VENERACEA

Family VENERIDAE

The classification of the family of Venus clams has been one of continual debate and rearranging for some years. Our presentation here is no better than has been suggested before, but at least it is in a form which is conservative and most likely to be accepted by the majority. Rather than accept a separate family Chionidae or consider it a subfamily remotely related to the Venerinae, we have allied it as an artificial group in the subfamily Venerinae. I suspect that an anatomical study of the soft parts will support this course.

Siibfamily VENERINAE

Sculpture usually both radial and concentric; anterior lateral present, especially in the left valve, but often extraordinarily vestigial.

Genus Antigona Schumacher 1817 Subgenus Dosina Gray 1835 Antigona listen Gray Princess Venus Plate 32m

Southeast Florida and the West Indies.

2 to 4 inches in length, oblong-oval, obese. Resembling Mercejiaria campechiensis, but characterized by numerous, fine, radial riblets which cause the sharp, concentric ribs to be serrated or beaded. Each side of the lunule is bounded by a long, deep, narrow furrow. Posterior muscle scar usually stained brown. Moderately common in shallow water in sand.

Subgenus Circojnphahis Morch 1853

Antig07ia strigillina Dall Empress Venus

Plate 3 81; figure 8 id

Southeast Florida and the West Indies.