DESCRIPTION OF NEW 



Remarks. — A single valve only of this species could be obtained, 

 and that many years ago. Several attempts to procure more have 

 proved abortive, and I now venture from it to establish the species. 

 This valve has a greater area than any of the Naiades which I have 

 yet seen, and its capacity is also greater. It diflfers in outline, as well 

 as in size, from any species yet described, being broader before and more 

 angular behind. 



Anodonta ovata. Plate II. fis;. 2. 



&• 



Testa ovata, subcompressa, transversa, incBquilaterali ; valvulis subtenuibus ; natibus pro- 

 minulis ; margarila alba. 



Shell ovate, somewhat compressed, transverse, inequilateral; valves rather ihin ; 

 beaks somewhat prominent ; nacre white. 



Hab. near Marietta, Ohio. Dr Hildreth. 



My Cabinet. 



Cabinet of Mr Hyde. 



Diam. 1-5, Length 2-2, Breadth 4 inches. 



Shell ovate, somewhat compressed, transverse, inequilateral; sub- 

 stance of the shell rather thin: beaks somewhat prominent and granu- 

 late at tip ; ligament rather short ; epidermis greenish brown, wrinkled, 

 apparently without rays; anterior and posterior cicatrices both conflu- 

 ent ; dorsal cicatrices placed in the centre of the cavity of the beaks ; 

 cavity of the shell deep; cavity of the beaks shallow; nacre white, 

 sometimes bluish. 



Remarks. — Very recently this shell has been sent to me by Dr 

 Hildreth. I presume it is from the vicinity of Marietta, where he 

 resides. It is certainly distinct from any species with which I am ac- 

 quainted. It perhaps most resembles the cataratta (Say), but diflfers 

 in being more elliptical. It also diflfers in the beaks, the cataracta 

 being undulated, while this shell is rather granulate at tip. 



