61 



compressed and sinuous ; lateral teeth distinct on one 

 valve, on the other obsolete. 



SYNONYME. 



Mactra tellinoides, nobis, Journ. Acad. J^at, 

 Sciences, vol. 6, p, 258, pi, 11, jig. 2, 3. 



OBSERVATIONS. 



Inhabits the whole coast, and is a fossil of the Plio- 

 cene strata of Virginia. Its exterior is not unlike a 

 Tellina. 



MACTRA FRAGILIS. 



Tab. XIV, /^. 3. 



SPECIFIC CHARACTER. 



Shell oblong-oval, very slightly wrinkled, except- 

 ing upon the margin ; umbo hardly prominent ; two 

 strong distant lines from the apex to the posterior ex- 

 tremity ; epidermis pale brownish yellow, tinged 

 with ferruginous ; within white, highly polished. 



SYNONYMES. 



Mactra fragilis, Chem.v. 6,/>. 236, t. 24,Jig.235. 

 Mactra oblonga, Say, Journ. Acad. JVat. Sci. 

 vol. 2, p. 310. 



