32 DESCRIPTION OF NEW 



Shell smooth, elliptical, somewhat inflated, inequilateral, obtusely angular behind; valves thick, beaks some- 

 what prominent; epidermis dark-olive, rough, very much striate, obsoletely radiated ; cardinal teeth large, oblique, 

 compressed and much crenulated; lateral teeth long, rather thick and curved; nacre white and iridescent. 



Hab. Columbia river, Oregon, Mr. C. M. Wheatley. 

 Diain. .8, Length 1.2, Breadth 2.1 inches. 



Shell smooth, elliptical, somewhat inflated, inequilateral, obtusely angular behind; sub- 

 stance of the shell thick, thinner behind; beaks somewhat prominent, submedial; ligament 

 rather short and somewhat thick ; epidermis dark-olive, very rough, and striate over the 

 whole disk, with very obscure, rather thin rays; posterior slope somewhat compressed; 

 umbonial slope obtusely angular; cardinal teeth large, oblique, compressed and much 

 crenulated, double in the left and single in the right valve; lateral teeth long, rather thick, 

 curved, enlarged at the posterior end and separated from the cardinal tooth; anterior 

 cicatrices distinct; posterior cicatrices distinct; dorsal cicatrices placed obliquely on the 

 inner portion of the cardinal tooth and under the plate; palleal cicatrix impressed; cavity 

 of the shell rather shallow; cavity of the beaks shallow and subangular; nacre white and 

 iridescent. 



Remarks. — I owe to the kindness of Mr. Wheatley one of the two specimens before 

 me. It is a species very distinct from any I am acquainted with. The roughness of the 

 exterior is remarkable, and would indicate its inhabiting near to brackish waters. It is 

 not usual to see a rough shell like this with rays. In those specimens which are eroded 

 and old, they are indistinct; but I suspect that when perfect the rays might be very dis- 

 tinct. In outhne, it is somewhat like a young U. Ugamentinus, Lam., {crassus, Say,) and 

 the nacre is of the same pure white, but the surface is totally different, being rough, and 

 the form more transverse. In its elliptical outline it comes closer to U. Sapotalensis, 

 (Nobis,) but is a smaller shell, and differs much in the rays and the surface. 



Unio RuMPHiANus. PI. XXII. Fig. 34. 



Testa tubermlata, quadrata, subinjlald, subinxqtnlaterali, postice truncal a, ad basim emarg;inata; valvuHs 

 percrussis; natihus crassis, prominentibus; epidermide rufofuscd, svbstriatd; dentibus curdinalibus percraasis 

 striatisgite; lateralibus brevibus rectisqiie; margaritd argented et iridescente. 



Shell tuberculate, quadrate, somewhat inflated, rather inequilateral, truncate behind, emarginate at the basal 

 margin; valves very thick; beaks thick and prominent; epidermis reddish-brown, substriate; cardinal teeth very 

 thick and striate; lateral teeth short and straight; nacre silver wiiite and iridescent. 



Hab. West Georgia? Dr. Budd. 



Cabinet of Dr. Budd, New York. 

 Diam. 1.1, Length 1.7, Breadth 2 inches. 



Shell tuberculate, quadrate, somewhat inflated, rather inequilateral, truncate behind, 

 emarginate at the basal margin, raised over the umbonial slope and grooved from beaks 

 to basal margin; substance of the shell very thick, thinner behind; beaks thick, submedial 

 and prominent; ligament short and thick; epidermis reddish-brown, somewhat striate, 

 with distinct, proximate marks of growth; posterior slope compressed, raised into a carina 

 and covered with curved rows of tubercles; umbonial slope raised into a widening ridge. 



