FRESHWATER AND LAND SHELLS. 73 



Continuation of Mr Lea's Paper. Mead, Nov. 4thj 1836. 



Unio Dorfeuillianus. Plate XVII. fig. 54. 



Testa subtriangulari, inflate, tuberculata, incBquilaterali ; valvulis prcecrassis ; natibus 

 magnis elevatisque; dentibus cardinalibus magiiis erectisque; lateralibus brevibus curvisque; 

 margaritd alba. 



Shell subtriangular, inflated, tuberculate, inequilateral; valves very thick ; beaks 

 large and elevated ; cardinal teeth large and erect ; lateral teeth short and curved ; 

 nacre white. 



Hab. Ohio River. Mr Dorfeuille, Cincinnati. 



My Cabinet. 

 Diam. 2-2, Length 2-6, Breadth 2-9 inches. 



Shell subtriangular, inflated, tuberculate on the umbones ; substance 

 of the shell very thick ; beaks large, very prominent and recurved ; 

 ligament short and thick ; epidermis dark brown and transversely stri- 

 ate ; cardinal teeth large and erect; lateral teeth short, thick and curved ; 

 anterior cicatrices distinct, the great one forming a very deep pit ; pos- 

 terior cicatrices distinct ; dorsal cicatrices situated on the inferior part 

 of the cardinal tooth ; cavity of the shell deep ; cavity of the beaks deep 

 and angular; nacre white. 



Remarks. — A single specimen of this species belonged to the Mu- 

 seum of Mr Dorfeuille, who very obligingly presented it to me. I do 

 not know from what part of the Ohio it was obtained, and although a 

 single specimen, and resembling two species, I have considered it pro- 

 per to propose it as a new species, being unable to class it with any 

 one known to me. In general outline and thickness it resembles 

 U. trigonus (nobis), but, having higher beaks and being tuberculated, 

 cannot be classed with that species. In the possession of tubercles it 

 resembles U. pustulatus (nobis), but differs from it in having very ele- 

 vated thick beaks, in having very few tubercles (these are scattered over 



VI. — T 



