and Shells of Massachusetts Bay. 61 
CARDIUM PUBESCENS. 
Plate HI. fig. 6 
C. testå mediocri, obliquè rotundatà, sub-æquilaterali, cinerescente ; 
costellis 36, ciliatis; umbonibus tumidis; natibus approximatis; mar- 
gine crenato ; intus albo-lutescente. 
Long. sixteen twentieths, lat. eleven twentieths, alt. 
fourteen twentieths, of an inch. 
Hab. waters of Mass. Bay. 
My cabinet, and that of Bost. Soc. Nat. History. 
Description. Shell rounded obliquely, very nearly 
equilateral, thin: external color dull ashy white ; pos- 
teriorly depressed, sub-cordate ; margin rounded, also 
rounded anteriorly and a little narrowed ; umbones some- 
what inflated, summits incurved, approximate ; anterior 
dorsal area inconspicuous, feebly impressed, sub-cordate, 
the posterior almost null, striated by the origin of the 
coste, which are 36 in number, rounded, smooth, their 
upper edges covered with a short, downy ciliation of a 
dirty brown color ; margins crenated internally ; anterior 
lateral teeth conspicuous, posterior ones nearly obsolete ; 
interior a brilliant yellowish-white, nearly a straw color 
at the margins. 
OssrnvarioNs. Only four specimens of this shell 
were ever found by me, and those were obtained near 
Egg rock, off Lynn. 
It is closely allied to C. pinnuldtum, Conrad, in form 
and coloration, but the number of the ribs is much 
greater, that having but 27, and it is without the imbrica- 
tions. on the coste, the number of which also distinguish 
it from C. édule, Lin. which has but 26. This last has 
