NEW FRESH WATER AND LAND SHELLS. 227 



Anodonta Couperiana. Plate 20, Fig. 46. 



Testa ellipticd, valde inflatd, gibbosd; valvulis tenuibus ; natibus planulatis, undulatis; epidermide 

 virido-luted, obsolete radiatd; margaritd cmruleo-albd et iridescente. 



Shell elliptical, very much inflated, gibbous; valves thin; beaks flattened and undulated; epidermis 

 greenish-yellow, obsoletely radiate; nacre bluish-v^^hite and iridescent. 



Hab. Hopeton, near Darien, Georgia. J. H. Couper, Esq. 



My Cabinet. 

 Diam. .9, Length 1.5, Breadth 2.1 inches. 



Shell elliptical, smooth, polished, very much inflated, gibbous and swollen 

 from the beaks to the basal margin, flattened behind the beaks; basal margin 

 much rounded; substance of the shell very thin; beaks flattened and finely 

 undulate; ligament rather long and very thin; epidermis greenish-yellow, with 

 numerous small rays, darker on the posterior slope, where the rays are very 

 distinct and capillary; anterior cicatrices confluent; posterior cicatrices con- 

 fluent; dorsal cicatrices none; cavity of the shell very deep and rounded; 

 cavity of the beaks very small; dorsal line slightly curved; nacre bluish- white 

 and iridescent. 



Remarks. — This is a very distinct species, and I dedicate it to my friend Mr. 

 Couper, who has done much to elucidate the Natural History of his vicinity. 

 It is remarkable in its form, and more nearly allied to An. gihhosa, Say, than 

 any other species with which I am acquainted. It differs in being more trans- 

 verse, being less inflated, having flatter beaks, in being smaller and in having 

 the swell of the inflation more towards the basal margin. Indistinct capillary 

 rays covering the whole disk, diverge from the beaks, and are more distinct on 

 the posterior slope where there are generally two yellow rays. The beaks are 

 so much flattened as scarcely to rise above the dorsal margin.* 



* Accompanying this species I received from Mr. Couper several specimens of an Anodonta which so 

 closely resembles my specimens of Anodonta incerta, from the Ohio, that I conclude they must be the 

 same species. If it prove so, it will be the first which I have seen coming from the eastern side of the 

 Allegheny range. 



VIII. 3 H 



