NEW FRESH WATER AND LAND SHELLS. , 223 



Margaritana Curreyiana. Plate 18, Fig. 40. 



Testa triangulari, subcompressd, emarginatd, sulcata; valvulis crassis; natibus subprominentibus, ad 

 apices undulatis; epidermide luteo-fusca ;' dentibus cardinalibus magnis; margaritd alba et iridescente. 



Shell triangular, somewhat compressed, emarginate, sulcate; valves thick; beaks rather prominent, un- 

 dulated at the tip; epidermis yellowish brown; cardinal teeth large; nacre white and iridescent. 



Ilab. Stone's River, Tenn. Dr. Currey of Nashville. 



My Cabinet, and Cabinets of Dr. Currey, Dr. Troost and Mr. Edgar. 

 Diam. .5, Length .7, Breadth 1 inch. 



Shell triangular, somewhat compressed or flattened on the side, emarginate at 

 the basal and posterior basal margins, furrowed on the posterior slope; substance 

 of the shell thick, thinner before ; beaks rather prominent, with large undula- 

 tions at the tip, nearly medial; ligament short and rather thick; epidermis yel- 

 lowish brown ; umbonial slope carinate ; posterior slope flattened ; cardinal teeth 

 large, one closing in behind the other ; anterior cicatrices distinct ; posterior 

 cicatrices confluent; dorsal cicatrices placed under the cardinal tooth; cavity 

 of the shell very small; cavity of the beaks angular and shallow; nacre white 

 and iridescent. 



RemarJcs. — A single specimen of this species of Margaritana was among 

 the shells from Dr. Currey. He had found two or three only, all of vs^hich M^ere 

 of the same diminutive size, and, like mine, much eroded. It is about the size of 

 the U.fahalis, (nobis,) and has some resemblance to it. If it were not separated 

 generically from it, the furrow on the posterior slope causing two oblique folds 

 would at once distinguish it. It is a very solid shell, and the teeth are robust. 

 I name it after Dr. Currey, to whose kindness I am indebted for the possession 

 of the shell. 



Anodonta argentea. Plate 19, Fig. 41. 



Testa ellipticd, inflatd, transversd; valvulis tenuibus; natibus prominulis ; apicibus minute undulatis; 

 epidermide fused, radiatd; margaritd argentea et iridescente. 



Shell elliptical, inflated, wide; valves thin; beaks rather prominent ; apices minutely undulate; epidermis 

 brown, radiated; nacre silvery and iridescent. 

 VIIL — 3 G 



