62 



OBSERVATIONS. 



This shell is well represented by the figure quoted 

 from Chemnitz. The M. dealbata is considered by 

 several authors to be the same species, but the remark- 

 able lines in the fragilis are not represented in any 

 of the figures of the former, although the outline is 

 the same in both. 



Mr. Say found this species on one of the sea islands 

 of Georgia. It is not uncommon on the coast of South 

 Carolina. 



MACTRA LATERALIS. 

 Tab. XIV, ^g. 4, 5. 



SPECIFIC CHARACTER. 



Shell triangular, very convex, of a smooth appear- 

 ance, but with minute concentric wrinkles j lateral 

 margins flattened, cordate, with a rectilinear, some- 

 times concave profile ; one margin rounded at the 

 extremity, the other longer and less obtuse ; umbo 

 nearly central, prominent. 



SYNONYME. 



Mactra lateralis, Sai/f Journ. Acad. JVat. Sci. 

 vol. 2, p. 309. 



