57 



whose unpublished manuscript I have seen. As I 

 am ignorant whether Mr. Gray ever published his 

 genus, I am compelled to adopt the name since given 

 it by Des Moulins. 



The hinge of this shell is similar to that of Mac- 

 TRA ; and like that genus, each valve possesses a car- 

 tilage of its own, much resembling a small grain of 

 maize ; and the ligament is strong, having to attach 

 the valves without any assistance from the cartilage. 



RANGIA CYRENOIDES. 



SPECIFIC CHARACTER. 



Tab. XIII. 



Shell subtriangular, or subcordate, thick and pon- 

 derous, convex ; somewhat undulated ; beaks very 

 prominent, distant, posterior side subcuneiform ; epi- 

 dermis concentrically wrinkled ; lunule broad cor- 

 date, defined by an obtusely indented line. 



observations. 



This shell has long been familiar to conchologists in 

 this city, but its history and most interesting characters 

 have not attracted the attention they merit. I have oc- 

 casionally found worn valves on the sea beach, but 



H 



