206 NEW-YORK FAUNA — MOLLUSCA. 
CarDIUM ISLANDICUM. 
PLATE XXIII. FIG. 252. Youne. 
Cardium islandicum. Linn. Syst. Nat. p. 1124. 
Cc. pubescens. Courtuovy, Bost. Jour. Vol. 2, p. 60, pl. 3, fig. 6 (young). 
Cc. islandicum. GovuLp, Invertebrata of Massachusetts, p. 89, fig. 58. 
Description. Shell large and rather thin, rounded, inflated, nearly equilateral. Beaks pro- 
minent, incurved, contiguous: anterior dorsal area feebly impressed, subcordate. Surface 
with thirty-six to thirty-eight sharp ribs, which are covered with a stiff fringe-like epidermis 
in the young shells. Margin of the shell crenate internally, and the surface impressed by 
the ribs. 
Color. Epidermis dull yellowish brown ; within, straw-colored, or brilliant yellow in the 
young. 
Length, 1:0-2+5. Width, 0°9-2°3. Diameter, 0-9 - 1:0. 
This shell occurs from Cape Cod, near which it is obtained plentifully from the stomachs 
of fishes, along the coast of Maine, where it is found on the shores, to the Arctic circle, and 
on both sides of the Atlantic. 
CaRDIUM GRGNLANDICUM. 
PLATE XXIII. FIG. 250. 
(STATE COLLECTION.) 
Cardium grenlandicum. GMELIN, Syst. Nat. p. 3232. 
Aphrodita columba. Lea, Trans. Am. Phil. Soc. Vol. 5, p. 110, pl. 18, fig. 54: 
Cardium grenlandicum. Gov.D, Invertebrata of Mass. p. 92, 
Description. Shell large ; the adult very thick and robust, heart-shaped, somewhat com- 
pressed. Beaks submedial, prominent, incurved, contiguous. Surface with concentric in- 
cremental lines, crossed by numerous almost obsolete elevated radiating lines. Hinge liga- 
ment small: margin entire, gaping behind. Cardinal teeth almost obsolete ; lateral teeth 
small and distinct. 
Color. Epidermis thin, pale olivaceous or drab : the young with occasionally zigzag darker 
lines ; beneath this, dingy white. Interior opake white, flesh or salmon-colored. 
Length, 1°5-2+3. Width, 1°6-2+°7. Diameter, 1+3. 
This shell has not yet been found south of the shores cf Maine, except in the stomachs of 
fishes. It has much the external configuration of a Mactra, for which it has been mistaken ; 
and the occasional absence of the cardinal teeth has led Mr. Lea to arrange it under a new 
genus. 
