14 



NEW UNIONID.'E OF THE 



being very much larger, more ponderous, and totally in the color of the epidermis, 

 that species being almost jet black. It is also allied to sordichis (nobis), having 

 nearly the same colored epidermis, but that species is elliptical, is not enlarged over 

 the umbonial slope, nor is it emarginate. 



UXIO SALEBROSUS. PI. 52, fig. 157. 

 Testa laevi, oblonga, subcompressa, ad latere planulata, postice biangulata, anticfe subtruncata, Talde insequi- 

 laterali ; valvulis subcrassis, antioe paulisper crassioribus ; natibus subprominentibus, ad apices crebre 

 et concentrice uudulatis; epidermide vel rufo-fusca vel luteo-fusca et vald6 striata; dentibus cardinali- 

 bus subgrandibus, striatis, subelevatis crenulatisque ; lateralibus prtelongis subcurvisque ; margarit^ vel 

 alba vel salmonia, rare purpurea et iridesceDtc. 



Shell smooth, oblong, rather compressed, flattened at the sides, biangular behind, 

 subtruncate before, very inequilateral ; valves rather thick, slightly thicker before ; 

 beaks slightly prominent, closely and concentrically undulate at the tips ; epidermis 

 reddish brown or yellowish brown and very much striate ; cardinal teeth rather large, 

 striate, somewhat raised and crenulate ; lateral teeth very long and somewhat curved ; 

 nacre white or salmon color, rarely purple, iridescent. 

 Proc. Acad. Nat. Sci. 1359, p. 170. 



jjah. — Flat Rock Creek, Bull Creek, G. Hallenbeck and Chattahoochee River near 

 Columbus, Georgia. Bishop Elliott. 



My cabinet and cabinets of Bishop Elliott and Mr. Hallenbeck. 

 Diam. -9, Length 1-6, Breadth 3-1 inches. 



Shell smooth, oblong, rather compressed, flattened on the sides, biangular behind, 

 somewhat truncate before, very inequilateral, nearly straight on the basal margin ; , 

 substance of the shell rather (hick, slightly thicker before; beaks slightly prominent, 

 with close and concentric undulations at the tips, the undulations being transverse 

 and parallel on the sides ; ligament long, somewhat thick and light brown ; epider- 

 mis reddish brown or yellowish brown, sometimes with greenish rays, usually without 

 rays, with rather distant marks of growth ; umbonial slope somewhat raised and ob- 

 tusely angular ; posterior slope narrow, raised into a carina, with an obscure groove 

 from the beaks to posterior margin on each valve; cardinal teeth rather large, striate, 

 somewhat raised, crenulate, single in the right and double in the left valve; lateral 

 teeth very long, somewhat curved, thickened towards the posterior end, anterior 

 cicatrices distinct, large and well impressed ; posterior cicatrices confluent, large and 

 slightly impressed ; dorsal cicatrices placed over the centre of the cavity of the beaks ; 

 cavity of the shell rather shallow and wide ; cavity of the beaks very shallow and 

 rounded ; nacre usually white, sometimes salmon color, rarely purple, iridescent. 



Soft Parts. — Branchial uterus occupies the whole leaf of the outer branchiae. 

 Brancldoi very wide, very short, slightly curved below, inner ones being very much 

 the larger, free two-thirds the length of the abdominal sack. Palpi small, ovate, 



