8iiicc which, on a journey with Mr. JMaclurc, we obtain- 

 ed two or three others on the coasts of Georgia and Flori- 

 da ; so that it may be said to inhabit all our southern and 

 middle coast. 



The inner edge of the hinge margin of one valve, closes 

 over that of the other. 



This species differs from those previously made kno-svn, 

 more particularly hy its teeth, by having the hinge placed 

 much further back and consisting of a mere angle, not at 

 all prominent, the rostrum also has a direction more up- 

 ward, and the dilierence in the convexity of the valves is 

 not very considerable. 



REFERENCE TO THE PLATE. 



Tlic ui)pcr ligurcb exhibit tiic inside view. 

 Tlic lower figures tlio exterior view. 

 PLATE II. K 



