FAMILY VENERIDA — CYPRINA. 215 
FAMILY VENERIDA:. 
SHELLs with three cardinal teeth at least, on one valve ; the other having as many or fewer : 
rarely with lateral teeth; usually solid. Epidermis often scanty or entirely wanting. 
Tubes elongated, unequal. Foot wide, prominent. Marine. 
Oss. This family corresponds with the Conques marines of Lamarck, and comprises at 
present four genera. 
GENUS CYPRINA. Lamarck. 
Animal with the edges of the mantle undulated, and furnished with a series of tentacular 
cirri; tubes short, separated. Mouth small; labial appendices small; gills wide; foot 
wide; compressed, trenchant. Shell obliquely heart-shaped, solid; beaks prominent. 
Hinge with three unequal diverging cardinal teeth, and a remote lateral one; palleal im- 
pression simple. 
CypRINA ISLANDICA. 
PLATE XXVI. FIG. 269 (apuLt). FIG. 268 (youna). 
(STATE COLLECTION.) 
Venus islandica. Lin. Syst. Nat. p. 1131. 
Cyprina id. Russet, Essex Jour. Vol. 1, p. 37. 
Cc. id. Gou cp, Invertebrata of Mass. p. 82. 
Description. Shell large, thick and ponderous, ventricose ; beaks prominent, incurved, con- 
tiguous. Ligament stout and prominent: basal margin simple, rounded. Cardinal teeth stout 
and diverging: three in each valve, or the largest one bipartite in the right valve ; lateral tooth 
inconspicuous : palieal impression distinct. Epidermis coarse and wrinkled. 
Color. Epidermis blackish, becoming olivacecous towards the margin; interior chalky 
white ; faint purple on the margin. 
Vertical axis, 2°8; transverse ditto, 3°3. Diameter, 1°4. 
It rarely attains a greater size than this specimen, which J derived from Mr. Couthouoy, 
who obtained it on the northern coast. Although a northern shell, it may possibly be detected 
on the shores of this State. The young shell (fig. 268), which I obtained from fishes, has 
numerous minute concentric elevated ridges, becoming obsolete on the highly polished beaks; 
an obsolete ridge extends from the beaks to the basal margin. It may however prove to be a 
new species of Astarte. 
