50 



NEW UNIONIl).^. OF THK 



Smithsonian Institution. This species belongs to the group of which muUiradiattis 

 (nobis), may be considered the type, and the outline is very nearly the same, but it 

 differs in the color of the epidermis b%ing brown and not black, in the undular 

 tions of the beaks being smaller and more numerous, and in having the carina 

 of the posterior slope a little more raised. It will at once remind one of 

 Nhklinianus (nobis), but may be distinguished by its less elevated carina, by 

 the outline being quadrate and by the greatest diameter being towards the beaks, while 

 in the NkMinianus it is quite central, being lenticular. One of the specimens from 

 twenty-eight miles east of San Antonio, Texas, has a rich pearly nacre, the other from 

 Sabinas River, New Leon, has a very white nacre. I name this species after Dr. 

 James Eights, who procured the specimens some years since when travelling through 

 these countries. 



Unio cognatus. pi. G5. fig. 193. 



Testa lifivi, elliptica, crassa, subinflata, valde inaequilaterali, postice obtuse angulata, antice rotundata ; val- 

 vulis crassis, antic6 crassioribus ; natibus subprominentibus ; epidermide luteola radiataque ; dentibus 

 cardinalibus grandibus, crassis, pyramidatis, rogoso-striatis ; lateralibus subeurtis, subcurvis crassisque ; 

 margarita alba et valde iridescente. 



Shell smooth, elliptical, thick, somewhat inflated, very inequilateral, obtusely 

 angular behind and rounded before ; valves thick, thicker before ; beaks somewhat 

 prominent ; epidermis yellowish and rayed ; cardinal teeth large, thick, pyramidal 

 and rugosely striate ; lateral teeth rather short, somewhat curved and thick ; nacre 

 white and very iridescent. 



Proc. Acad. Nat. Sci. 1860, p. 306. • 



Eah. — Rio Salado, New Leon, Mexico. L. Berlandier, M. D. 



Cabinet of the Smithsonian Institution. 

 Diam. '7, Length 11, Breadth IT inch. 



Shell smooth, elliptical, thick, somewhat inflated, very inequilateral, obtusely 

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

 beaks somewhat prominent ; ligament rather long ; epidermis yellowish, radiate, 

 with rather distant lines of growth ; umbonial slope somewhat raised and obtusely 

 angular ; posterior slope rather wide and but slightly raised ; cardinal teeth large, 

 thick, pyramidal and rugosely striate ; lateral teeth rather short, somewhat curved 

 and thick ; anterior cicatrices distinct and deeply impressed ; posterior cicatrices dis- 

 tinct, large and well impressed ; dorsal cicatrices well imj^ressed and placed on the 

 upper part of the cavity of the beaks ; palleal cicatrices well impressed ; cavity of the 

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

 white and very iridescent. 



Remarks. — A single valve only — the left one — was received by the Smithsonian 



