24 DESCRIPTIONS OF 



proininulis; epidermidc tenebroso-fusca, polita ; dentibus cardinalibus parvis crenulatisque ; lateralibus 

 longis curvisque ; margarita casruleo-alba. 



Shell furrowed, elliptical, rather inflated, inequilateral, obtusely angular behind ; 

 valves rather thick ; beaks a little prominent ; epidermis dark brown and polished; 

 cardinal teeth small and crenulate ; lateral teeth long and curved ; nacre bluish white. 

 Proc. Acad. Nat. Sci. Vol. 8, p. 94. 



Hab.—Braiil. B. W. Budd, M. D. 



Cabinet of Dr. Budd, New York. 

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



Shell transversely furrowed, elliptical, rather inflated, inequilateral, obtusely angular 

 behind and regularly rounded before ; substance of the shell rather thick, thicker 

 before ; beaks a little prominent ; ligament thin and rather short ; epidermis dark 

 chestnut brown, highly polished, apparently without rays ; umbonial slope rounded 

 and but slightly elevated ; cardinal teeth small, slightly compressed and crenidate ; 

 lateral teeth long, rather thin and curved ; the two inferior anterior cicatrices confluent, 

 the superior one distinct ; posterior cicatrices confluent, dorsal cicatrices placed in the 

 cavity of the beaks ; cavity of the shell shallow ; cavity of the beaks very shallow 

 and rounded ; nacre bluish white. 



Eemarks. — A single specimen of this species only was submitted to me by Dr. Budd, 

 but it difiers so much from any described shell I am acquainted with that I have not 

 hesitated to give it a name. In general aspect it resembles U. eUipticus, (Diplodou 

 ellipticum, Spix), but it is not transverse, seems to be without folds and has more 

 marked transverse strige ; the lateral teeth are more curved and the epidermis is more 

 highly polished. The beaks of the specimen above described are eroded, and more 

 perfect ones may be found to have undulations at the tips. 



Unio Shuttleworthii. pi. 28, fig. 19. 



Testa sulcata, oblonga, transversa, valdfe in£equilaterali, subcompressa, postice obtuse biangulata, ad latus 

 planulata ; valvulis subcrassis ; natibus prominulis ; epidermide brunneo-nigricante ; dentibus cardi- 

 nalibus parvis ; lateralibus longis subcurvisque ; margarita purpurea et iridescente. 

 Shell sulcate, oblong, transverse, very inequilateral, rather compressed, obtusely 

 biangular behind, flattened on the sides ; valves rather thick ; beaks a little prominent ; 

 epidermis blackish brown ; cardinal teeth small ; lateral teeth long and slightly 

 curved ; nacre purple and iridescent. 



Proc. Acad. Nat. Sci. Vol. 8, p. 94. 

 Hah. — Australia. K. J. Shuttleworth, Berne, Switzerland. 

 My cabinet, cabinets of Mr. Shuttleworth, W. A. Haines, New York, and H. Cu- 

 ming, London. 

 Diam. 1-1, Length 2, Breadth 4 inches. 



Shell sulcate, oblong, transverse, very inequilateral, rather compressed, obtusely 



