84 Couthouy's New Species of Mollusca 
Hab. waters of Mass. Bay. 
My own Cabinet, and that of the Bost. Soc.Nat. Hist., 
Geo. B. Emerson Esq., and A. A. Gould, M. D. 
Description. Shell oval, convex, somewhat com- 
pressed anteriorly; color a dull ashy white, nearly 
covered by a thin pergamineous integument, appa- 
rently formed by an extraordinary prolongation of the 
coriaceous margin, and coated with a thick, short, dirty- 
blackish pubescence; valves posteriorly arcuated, late- 
rally rounded, not angular in any part, sub-carimate, 
their apices slightly produced ; in the centre of each is a. 
cordiform elevation, formed by very delicate, concentric, 
granulate lines, five or six in number, and occupying ' 
rather more than one fifth of their breadth ; lateral areas 
defined by a feebly elevated line, usually rendered bi- 
carinate by a suture or sulcation in its middle, and ex- 
tending obliquely and posteriorly from the apices to the 
margins, where the suture deepens into a slight fissure ; 
terminal valves entire, without either laminz or denticu- 
lations at their insertion; anterior one marked with 
elevated radiating lines; posterior, disproportionately 
smaller than the rest, emarginate and strongly arcuated 
„or scooped out at its extremity; intermediate valves, 
except in the centre, quite smooth ; margin coriaceous, 
having the same external downy coating as the rest of 
the shell, and surrounded by two parallel ranges of fasci- 
culi, composed of shining yellowish hairs, about an 
eighth of an inch in length, situated one above the other, 
to the number of two on each of the intermediate, and 
six or eight round the terminal valves ; internal color a 
dead white. 
OssERvaTIONS. This. remarkable species was ob- 
tained, like the preceding, from the stomachs of cod, 
