72 DESCRIPTION OF NEW 



Hab. Altamaha, Liberty County, Geo. Lewis Leconte, Esq. 



My Cabinet. 

 Cabinet of Major Leconte. 

 Diam. 1-6, Length 1-7, Breadth 2-2 inches. 



Shell plicate, triangular, very much inflated ; substance of the shell 

 very thin ; umbones very large ; umbonial slope acutely carinate ; pos- 

 terior slope very much flattened, having an indistinct furrow along the 

 edge of the carina; folds about eight, large on the beaks, and diminish- 

 ing along the edge of the carina ; ligament small ; epidermis dark green, 

 with numerous green rays over the whole disk ; teeth lamellar, irregu- 

 lar ; anterior cicatrices confluent ; posterior cicatrices not perceptible ; 

 dorsal cicatrices not perceptible; cavity of the shell very deep, acutely 

 angular under the carina, having two furrows leading from the beak to 

 the posterior margin ; cavity of the beak very deep and angular ; nacre 

 very thin, bluish, often tinted with pink. 



Remarks. — I owe to the kindness of Major Lecinte the possession 

 of this very interesting species. It is entirely distinct from any I am 

 acquainted with, and is peculiar for the folds which are placed along 

 the umbonial slope, and lie at right angles with it. It is among the 

 most inflated species of the family, and the substance of the shell is 

 thinner than in any species of its size which I know. The posterior 

 slope is so flat, that the valves when placed on that part will rest there. 

 In the folds it has some resemblance to the »Alas. undulata (Say), but 

 in this species they are larger and more numerous than in the undulata. 

 In outline it resembles U. triangularis (Barnes). Taking a posterior 

 view of it, one is reminded, by the outline, of Cardium cardissa. 



