OF THE UNITED STATES. 67 



Venilia, (S.G. M.) 



Generic character. An equivalve bivalve ; hinge with three 

 robust cardinal teeth in each valve, and an elongated, thick, 

 lateral tooth on the posterior side, similar to that of Unio: an- 

 terior muscular impression profound. 



V. Conradi, (S. G. M.) PL viii, fig. 1 and 2. 



Specific character. Trigonal, ventricose, thick, concentric- 

 ally sulcated ; beaks long and incurved. 



Diameter, one inch and a half. 



This singular marine shell, so different from any of the 

 hitherto known genera, was discovered at Arneytown, 

 New Jersey, by my friend Mr. T. A. Conrad, in whose 

 name I gladly introduce it to notice. He has since found 

 it at Prairie Bluff, Alabama. It is possible that the As- 

 tarte trigonalis, of Sowerby, (Min. Conch, pi. ccccxliv,) 

 may belong to this genus. 



Cytherea. 



C. excavata, (S. G. M.) PI. v, fig. 1. 



Specific character. Suborbicular, compressed; posterior 

 slope deeply excavated ; posterior side with an obsolete fold ; 

 margin angular. 



Diameter, about an inch and a half. 



Found by Mr. T. A. Conrad, at Arneytown, New 

 Jersey. 



Lutraria? 



Casts are occasionally found seemingly belonging to this 

 genus. One from the marl of Delaware strongly resem- 





