OF THE UNITED STATES. 315 



Length two-fifths of an inch. 



Width thirteen twentieths of an inch. 



Thickness one-fourth of an inch. 



Cabinet of the Academy and Philadelphia Mu- 

 seum. 



This species does not appear to be very common. 

 SOLEN, Lam. 

 Species. 



1. S. *costatus. Shell transversely elongate- oval, 

 concentrically wrinkled, very much compressed, ve- 

 ry thin and fragile, rounded at each end ; hinge 

 nearly equidistant from the posterior termination of 

 the shell, and the middle of the hinge margin; teeth 

 two, sometimes none, in each valve, the posterior one 

 upright, the other inclining forward ; a strong, broad, 

 elevated line within, passes from the hinge towards 

 the base and becomes obsolete near that part; colour 

 pale violaceous, with about three whitish rays. 



Breadth one inch and a half. 



Inhabits Great Egg Harbour, New Jersey. 



Cabinet of the Academy. 



Rather rare, I have obtained but few and incom- 

 plete specimens. The internal costa is somewhat 

 similar to that of S. legumen, but it is much more 

 elongated, and does not incline obliquely forward, 

 as in that shell ; it probably approaches nearest to 

 jS». minimus of Tranquebar. 



