214 DESCRIPT10]N OF 



Shell elliptical, inflated, very small; valves thick; beaks somewhat prominent; epidermis nearly black; 

 cardinal teeth small; lateral teeth long and curved; nacre white and iridescent. 



Hab. Chattahoochee River, Columbus, Georgia. Dr. Boykin. 



My Cabinet. 

 Diam. .4, Length .6, Breadth .9 inches. 



Shell elliptical, inflated, very small; substance of the shell thick, thinner 

 behind; beaks somewhat prominent; ligament short and thin; epidermis nearly 

 black; cardinal teeth small, disposed to be double in both valves; lateral teeth 

 long and curved; anterior cicatrices distinct ; posterior cicatrices confluent ; dor- 

 sal cicatrices placed on the inferior part of the tooth; cavity of the shell deep ; 

 cavity of the beaks very small ; nacre white, pearly and beautifully iridescent 

 on the posterior part. 



Remarks. — A single specimen only of this species was received. It seems to 

 be most nearly allied to U. parvus, Barnes, but differs in being a smaller species 

 and having a thicker nacre. 



More recently I received from J. H. Couper, Esq., of Hopeton near Darien 

 three specimens of this species, one of which is sub-carinate on the umbonial 

 slope. A second one is enlarged posteriorly exhibiting the female character. 

 All of the three are rather smaller than that received from Dr. Boykin. 



Unio Edgarianus. Plate 15, Fig. 30. 



Testa triangulari, compressd, emarginata ; valoulis crassis, natihus elevatis; epidermide luted, valde 

 radiatd; dentibus cardinalibus magnis, later alihus rectis; margaritd alba et iridescente. 



Shell triangular, compressed, emarginate; valves thick; beaks elevated ; epidermis yellow, much radiated; 

 cardinal teeth large ; lateral teeth straight ; nacre white and iridescent. 



Hab. Holston River, Tenn. Prof Troost and Dr. Currey. 



" Tennessee River, at Florence, Ala. Mr. Dutton. 

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



Diam. .S, Length 1.2, Breadth 1.3 inches. 



Shell triagular, compressed, emarginate at base, flattened or widely furrowed 



before the umbonial slope; substance of the shell thick; beaks elevated and 



