OF THE UNITED STATES. 317 



Breadth two and three-twentieths of an inch. 



Inhabits (he southern coast. 



Cabinet of the Academy and Philadelphia Mu- 

 seum. 



A common shell. The hinge is formed upon the 

 same plan with that of the S. vagina and truncatus, 

 but it differs from those species, in being much more 

 rounded at each extremity, and in being narrowed at 

 the anterior tip. I think it probable, however, that 

 this species has been regarded as a variety of S. 

 truncatus. 



SOLEMYA, Lam. 



Species. 



S. *velum. Shell remarkably thin and fragile, 

 transversely-oblong, rather longer at the posterior 

 end ; hinge edentulous, placed near the anterior end, 

 with a slightly prominent cartilage, and an interior 

 elevated callus, which is fornicated beneath ; valves 

 radiated with about fifteen double lines, which are 

 sparse towards the middle of the valves ; epidermis 

 pale yellowish-brown, extending much beyond the 

 basal and lateral edges of the valves, and at the 

 hinge margin, connecting them together nearly the 

 whole length of the shell ; within bluish-white ; um- 

 bo destitute of the slightest elevation ; anterior and 

 posterior margins rounded ; superior and inferior 

 margins rectilinear, parallel. 



Length seven-twentieths of an inch. 



