6 AMERICAN CORBICULAD-^. 



smooth, at times glossy. The interior of the valves is either white 

 or deep violet. Found not unfrequently. 



I have never seen an original specimen of the Tellina limosa, 

 but have no doubt, from an examination of the description given 

 of it and of its figure, that it is the Cyrena variegata, D'OrV). 

 With regard to the Corhunda semisuJcafa, Desh., with the habitat 

 New Holland, of which I have received authentic specimens from 

 Mr. Cuming, I can find no diiference between it and the species 

 under examination. I am convinced that the habitat assigned to 

 the Co7-h. semisulcafa is incorrect, from the fact that it has a 

 sinus, a peculiarity confined to the Corbiculadse of this continent. 



This species is distinct from all other American ones of the 

 genus in its elliptical and compressed shape. 



Fig. 5. 



C. euntata. 



6. CorlJiCUla ClUieaia. Deshayes. — Shell trigonal, very inequila- 

 teral, cuneiform, anterior side short, sloping, rounded ; 

 posterior side longer, subangular, inferior margin 

 slightly rounded ; beaks tumid, opposite, inclined to- 

 wards the anterior, often eroded ; valves solid, inte- 

 rior orange, pink or violet ; striae regular though deep ; 

 epidermis dark blackish or brownish-green, glossy ; 

 hinge-margin thick, three strong cardinal teeth ; late- 

 ral teeth lightly striated, anterior curved, a little the 

 shorter ; palleal impression terminating in a small 

 narrow sinus. 

 Long. .78 ; Lat. .G8: Diam. .50 inch. 

 " 20 ; " 17 ; " 13 mill. 



Hah. South America, in the Orinoco River. (Cabinets of Jonas, Cu- 

 ming, Smithsonian Institution, Jay and Prime.) 



Cyrenn ameata, JovAS, Zeit. Malak. 1844, 186.— Phil. Abb, II, 1846, 



77, pi. 1, f. 6. 

 Ci/rrna glohulus, JoxAS, in litter. 



Cnrhicula incrassata, Desh.wes, Proc. Zool. XXII, 1S54, 342. 

 Corhiciila cuneata, DEsnAYES,'Biv. Brit. Mus. 1854, 231. 



This is a remarkably well characterized species not likely to be 

 confounded with any other, the outline recalling somewhat that of 

 the Cyrena antiqua of the Basin of Paris. I know of no recent 

 species to which it is at all allied. 



I have not seen any original specimen of the Cyrena cuneata, 

 Jonas, but judging from the descrii)tion and figure given of it in 

 Fhilippi, I have no doubt that the specimens from which this de- 



