103 
and as far sontli as Bast Florida. Cabinet of tbe Academy and 
Philadelphia Museum. 
Very distinct from the preceding species, and probably approaches 
L. crassiplica of Lamarck. 
CoRBULA CONTRACTA. — Shell transversely subovate; valves 
subequal, regularly and profoundly striated transversely ; beaks 
not prominent, nearly central, one side rounded and the other sub- 
acute ; basal margin contracted near the middle, and one half of 
the length of the edge of one valve concealing one half of the 
edge of the opposite valve. 
Length one-fourth of an inch. Breadth two-fifths of an inch. 
Thickness one-fifth of an inch, nearly. Inhabits the coasts of 
G^eorgia and East Flarida. Cabinet of the Academy and Phila- 
delphia Museum. 
I found two specimens of this shell. The striae are precisely 
similar to those of the larger valve of Mya insequivalvis of Mon- 
tague ((7. nucleus of Lam.) 
Mya acuta. — Shell oblong-subovate, narrowed behind, rather 
strongly wrinkled ; posterior hinge margin and posterior basal mar- 
gin subequally arquated ; tip of the posterior margin equidistant 
from the apex and middle of the base ; tooth moderate, with a 
small, not prominent, tooth on its posterior side. 
Length one inch and a half. Breadth twoTnches and four-fifths. 
Inhabits the southern coast. Cabinet of the Academy and Phila- 
delphia Museum. 
I have but two valves, which are old and bleached. It resem- 
bles M. arenaria, but is much smaller at the posterior termination, 
than the corresponding part of that shell, as figured by Bruguiere, 
One of the valves alluded to is more than four inches in breadth ; 
it corresponds very well in the outline with Pennant’s fig. of 
avenaria. My decorticated specimens have an obsoletely radiated 
appearance. 
Mya mercenaria. — Shell subovate, convex, somewhat un- 
equal, transversely wrinkled; posterior hinge margin curving 
abruptly downward to the tip of the posterior margin, which is 
much nearer to the middle of the base than to the apex; tooth 
robust, prominent, very convex within, and with a small tooth on 
its posterior side ; within white. 
