NEW FRESH WATER AND LAND SHELLS. 239 



Unio Rajahensis. Plate 23, Fig. 53. 



Tesld triangulari, inflata, incequilaterali, postice angulatd; valvulis crassis; natihus valde prominen- 

 tibus; epidermide tenebroso-fuscd ; dentibus cardinalibus magnis; lateralibus sublongis curvisque; 

 margaritu alba et valdk iridescente. 



Shell triangular, inflated, inequilateral, angular behind; substance of the shell thick; beaks very promi- 

 nent; epidermis dark brown; cardinal teeth large; lateral teeth rather long and curved; nacre white and 

 very iridescent. 



Hab. The Rajah's Tank, Calcutta. Dr. Jay. 



My Cabinet, and Cabinets of Dr. Jay and Dr. B. W. Budd of N. Y. 

 Diam. .8, Length 1.1, Breadth 1.4 inches. 



Shell triangular, inflated, inequilateral, angular behind; posterior slope much 

 flattened, cordate, with two curved impressed lines; umbonial slope carinate; 

 beaks very prominent and solid; ligament short, thick and light brown; epider- 

 mis dark brown; cardinal teeth large, double in both valves; lateral teeth curved, 

 being more bent near the cardinal tooth, disposed to be double in the right and 

 to be treble in the left valve; anterior cicatrices distinct; posterior cicatrices 

 distinct; dorsal cicatrices placed under the plate between the cardinal and 

 lateral teeth ; cavity of the shell rather deep and triangular ; cavity of the beaks 

 deep and triangular ; nacre beautifully pearly white and very iridescent. 



Remarks. — Two specimens of this species only were received from Calcutta 

 by Dr. Jay. One is rather large and more inflated than the other. The beaks 

 of both are eroded. When perfect they may be found to be undulate at tip like 

 U. corrugatus, Lam. In the nacre it is very much like that shell, but differs 

 totally in the outline, in its beaks and in being more inflated and more solid. The 

 cleft of the cardinal tooth is nearly parallel with the dorsal line ; the lateral teeth 

 are remarkable for their dupKcation in one valve and triplication in the other. 



Unio callosus. Plate 23, Fig. 54. 



Testa elUpHcu, compressd, inaquilaterali, postice angulatd; valvulis crassis; natibus prominentibus ; 

 epidermide luleo-fuscd, nitidd; dentibus cardinalibus parvis; lateralibus longis curvisque; margaritd 

 alba et iridescente. 



VIII. — 3 L 



