FRESHWATER AND LAND SHELLS. 19 



Continuation of Mr Lea's Paper. Read, January 2c?, 1835. 



Unio lamellatus. Plate VI. fig. 16. 



Testa subovata, transversa, subinflata, nitida; valvulis tennuissimis ; natibus vix prominu- 

 lis, undulatix ; dentibus cardinalibus longis, tenuibus et laminatis ; lateralibus longis, tenui- 

 bus subrectisque ; margarita ccerulea. 



Shell subovate, transverse, somewhat inflated, shining; valves very thin ; beaks 

 scarcely prominent, undulated ; cardinal teeth long, thin and lamellar ; lateral teeth 

 long, thin and nearly straight ; nacre bluish. 



Hab. Bengal. Captain Lang. 



My Cabinet. 

 Diam. 1, Length 1-5, Breadth 2-6 inches. 



Shell subovate, transverse, somewhat inflated, carinate behind ; dor- 

 sal line nearly straight; substance of the shell very thin; beaks some- 

 what prominent, with minute undulations following the umbonial 

 slope ; umbonial slope furnished with two capillary raised lines, run- 

 ning nearly parallel ; ligament rather short ; epidermis dark brown 

 .ind finely polished; rays none; cardinal teeth long, thin, lamellar, 

 single in the left valve and double in the right ; lateral teeth long, thin, 

 and nearly straight; anterior cicatrices distinct; posterior cicatrices 

 confluent; dorsal cicatrices situated nearly in the cavity of the beaks; 

 cavity of the shell somewhat deep; cavity of the beak shallow; na- 

 cre bluish. 



Remarks. — Several specimens of this shell, with the animal, were 

 brought by Captain Lang in his late voyage to Calcutta. In the con- 

 formation of the animal I could perceive no difference from that of 

 our common species. It may be considered to be most nearly allied to 

 U. Corrianus (nobis). It differs from that shell in its most remarkable 

 character, its cardinal teeth, which are longer and more lamelliform 

 than in any species I am acquainted with. The teeth of this species 



