DESCRIPTION OF FIFTr-TWO SPECIES OF TJNIONID.E. 33 



Hab. — Yadkin River, near Salisbury, North Carolina, C. M. Wheatley, Esq. 



My cabinet, and cabinets of Mr. Wheatley and Dr. Hartman. 

 Diam. I'l,- Length 1-9, Breadth 3 inches. 



Shell smooth, oblong, compressed, very inequilateral, flattened at the sides, sub- 

 biangular behind, rounded before ; substance of the shell thick, very slightly thicker 

 before; ligament rather large and dark brown; epidermis dark brown, without 

 rays, slightly sulcate before and rugose behind, with very distant marks of growth; 

 umbonial slope very obtusely angular ; posterior slope carinate, narrow elliptical ; 

 cardinal teeth rather small, compressed, crenulate, corrugate and double in both 

 valves; lateral teeth long, lamellar, corrugate and somewhat curved; anterior cica- 

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

 and slightly impressed; dorsal cicatrices placed nearly in the centre of the cavity 

 of the beaks; ventral cicatrices very small; cavity of the shell rather shallow and 

 wide ; cavity of the beaks very shallow and rounded ; nacre salmon colored or 

 purplish and very iridescent. 



JRemarhs. — Mr. Wheatley received quite a number of this species from the 

 Yadkin River, and I owe to him a fine suite of them. It is of the complanatus 

 group, but is not so wide as complanatus, and is higher on the umbonial slope. It 

 difi'ers from jjlanilateris Con. from the same river in being less wide and having a very 

 difi'erent epidermis. It is very near to quadrilateris and humerosiis (nobis), but is less 

 quadrate than the former and not so long as the latter. The remarkable character 

 of possessing a ventral muscular attachment, leaving a small cicatrix, is worthy of 

 notice. All the specimens before me have it more or less developed. The nacre 

 of these specimens is salmon more or less deeply colored, except one, which is 

 pale purplish. None of them have a white nacre. The beaks, being much eroded, 

 present only the remains of undulations at the tips, very like those of complanatus. 



Unio Conasaugaensis. pi. 10, fig. 30. 



Testa Isevi, snboblonga, subinflata, insequilaterali, postice subbiangulata, antice rotnndata; valvulis 

 percrassis, antice crassioribas ; natibus subprominentibus ; epidermide rufo-fusca, eradiata ; 

 dentibus cardinalibus parviusculis, subcompressis crenulatisque ; lateralibus curtis, crassis, obli- 

 quis rcctisque ; margarita alba et aliquanto iridescente. 



Shell smooth, rather oblong, somewhat inflated, inequilateral, subbiangular be- 

 hind and rounded before; valves very thick, thicker before; beaks somewhat prom- 

 inent; epidermis reddish-brown and without rays; cardinal teeth rather small, 

 somewhat compressed and crenulate; lateral teeth short, thick, oblique and straight; 

 nacre white and somewhat iridescent. 



