44 DESCRIPTION OF NEW 



Margaritana fabula. Plate XIII. fig. 39. 



Testa suboblongd, transversa, incequilaterali, ad bashn emarginata, ad lalus planulatd ; 

 valvulis subcrassis ; natibus prominulis; epidermide subviridi ; dentibus cardinalibus parvis 

 erectisque; margarita salmonis colore tincta. 



Shell somewhat oblong, transverse, inequilateral, emarginate at base, flattened on 

 the side ; valves somewhat thick; beaks rather prominent ; epidermis greenish ; cardi- 

 nal teeth small and erect ; nacre salmon colour. 



Hab. Cumberland River, Ten. Professor Troost. 



My Cabinet. 



Cabinet of Professor Troost. 



Diam. '4, Length '5, Breadth '8 of an inch. 



Shell somewhat oblong, transverse, inequilateral, somewhat inflated, 

 emarginate at base, flattened on the side, raised at the umbonial slope ; 

 substance of the shell rather thick, thinner behind ; beaks rather pro- 

 minent; epidermis greenish, with indistinct rays ; ligament short; car- 

 dinal teeth small and erect; anterior cicatrices confluent; posterior 

 cicatrices distinct; dorsal cicatrices placed on the under part of the 

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

 gular ; nacre salmon colour, lighter before. 



Remarks. — This curious and interesting shell I owe, with many 

 others, to my friend Professor Troost. It is much smaller than any 

 species which has been heretofore described, and does not seem to ap- 

 proach very closely any other species in its general characters. The 

 two specimens which are now before me, the only ones I have seen, 

 are much eroded. This prevents my knowing if the beaks be, in a 

 perfect state, furnished with undulations. 



