210 DESCRIPTION OF 



Hab. French, Broad and Holston Rivers, East Tenn. S. M. Edgar. 

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

 Diam. .1, Length 1.4, Breadth 1.6 inches. 



Shell rounded, inflated, solid; substance of the shell very thick; beaks ele- 

 vated; ligament rather short and thick; epidermis with indistinct rays, striate, 

 dark brown, becoming squamose towards the margin; lines of growth approxi- 

 mate; cardinal teeth rather large; lateral teeth rather long, thick, nearly straight; 

 anterior cicatrices distinct; posterior cicatrices distinct, the smaller one being 

 placed on the end of the lateral tooth; dorsal cicatrices placed on the under 

 side of the cardinal tooth; cavity of the shell shallow, rounded; cavity of the 

 beaks rather deep and angular; nacre milky white. 



Remarks. — Mr. Edgar brought this species from East Tennessee, and kindly 

 submitted several specimens to me. It seems to be naturally placed betw^een 

 U. ehenus and U. subrotundus (nobis,) and to resemble U. maculatus, Con. Mr. 

 Edgar informs me that the animal is colourless. 



Unio tuberosus. Plate 14, Fig. 25. 



Testa nodosa, triangulari, emarginatd; valvulis crassis; natibus elevatis; epidermide luted, striata; 

 dentibus cardinalibus magnis; lateralibus parvis rectisque; margaritd alba. 



Shell nodulous, triangular, emarginate; valves thick; beaks elevated; epidermis yellow, striate; cardi- 

 nal teeth large; lateral teeth small and straight; nacre white. 



Hab. Cany Fork and Cumberland Rivers, Middle Tenn. S. M. Edgar. 

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

 Diam. .1, Length 1.9, Breadth 2.2 inches. 



Shell tuberculate nearly all over, triangular, emarginate at the posterior 

 margin, depressed behind the umbonial slope; substance of the shell very thick 

 before, thinner behind ; beaks elevated; ligament rather short and thick; epi- 

 dermis yellow, striate; cardinal teeth very large and double in both valves; 

 lateral teeth very short, thick and straight; anterior cicatrices distinct; posterior 

 cicatrices distinct; dorsal cicatrices placed on the under side of the cardinal 

 tooth; cavity of the shell shallow; cavity of the beaks very deep and angular; 

 nacre white and silvery. 



