NEW I'NIOXin.E OF TUT, IJN'iriCD STATRS. C,'} 



Shell smooth, oblong, subcompressed, flattened at the side, swollen and biangular 

 behind, very inequilateral ; substance of the shell rather thick ; l)eaks prominent, 

 slightly pointed; ligament long, thin and brown ; epidermis blackish, striate, without 

 rays, with rather distant marks of growth ; umbonial slope swollen and subbiangular; 

 posterior slope narrow, slightly raised, with slightly impressed lines on each valve 

 from the beaks to the margin ; cardinal teeth rather small, crenulate, striate, disposed 

 to be double in both valves ; lateral teeth very long, somewhat curved, lamellate and 

 corrugate ; anterior cicatrices distinct, very large and well impressed ; posterior cica- 

 trices confluent, large and well impressed ; dorsal cicatrices placed nearly in the centre 

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

 very shallow ; nacre purple or salmon color and iridescent. 



liemarJcs. — In outline this species is very near to Roanokemis, (nobis,) but it is 

 much smaller and more inflated. It belongs to the group of which complanatns is the 

 type. In one of the specimens before me there is a well defined cicatrix of the attach- 

 ment of a ventral muscle, like that in trapezoides, but it is more anterior. 



Unio purus. pi. 4, fig. 209. 



Testa laevi, elliptica, subcompressa, posticc rotundata, injequilaterali ; valvulis subcrassis, antico spissatis; 

 natibus subpromincntibus; epidermide luteo-oliva, glabra, ad umbones politfi, obsolete radiata; dentibus 

 cardinalibus subgrandibus, acuminatis, crcDulatis, in utroque valvule subduplicibus; lateralibus sub- 

 longis, lamellatis subcurvisque ; margarita alba ct iridescente. 



Shell smooth, elliptical, rather compressed, rounded behind, inequilateral ; valves 

 rather thick, thickened before ; beaks rather prominent ; epidermis yellowish-olive, 

 smooth, polished towards the beaks, obsoletely radiate; cardinal teeth rather large, 

 pointed, crenulate and double in both valves ; lateral teeth rather long, lamellar and 

 somewhat curved; nacre white and iridescenf. 

 Proc. Acad. Nat. Sei. 1858, p. 41. 



Ilah. — Neuse River, six miles from Raleigh. N. C. Prof. Emmons. 



My cabinet and cabinet of Prof. Emmons. 

 Diam. -8, Length, 1-5, Breadth, 2-6 inch. 



Shell smooth, elliptical, rather compressed, flattened at the sides, rounded behind, 

 inequilateral ; substance of the shell rather thick, thickened before ; beaks rather 

 prominent ; ligament rather short, thick, brownish ; epidermis yellowish-olive, smooth, 

 polished toAvards- the beaks, obscurely rayed; umbonial slope swollen and sub- 

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

 pointed, crenulate and double in both valves; lateral teeth rather long, lamellar and 

 somewhat curved ; anterior cicatrices distinct, somewhat large and well impressed ; 

 posterior cicatrices confluent, large and slightly impressed; dorsal cicatrices placed 



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