404 American Seashells 



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 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 



Plate 3 81; figure 8 id 



Southeast Florida and the West Indies. 



