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404 American Seashells
Genus Cerastoderma Poli 1795
Cerastoderma pinnulatwn Conrad Northern Dwarf Cockle
Labrador to off North CaroHna.
Plate 30c
^ 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.
Superjamily 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 conserva-
tive 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
Southeast Florida and the West Indies.
Plate 3 81; figure 8 id