DESCRIPTION OF FIFTY-TWO SPECIES OF UNIONID^. 45 



Shell smooth, somewhat oblong, rather compressed, somewhat flattened at the 

 sides, very inequilateral, obtusely biangular behind, rounded before ; valves rather 

 thick, thicker before ; beaks slightly prominent, undulate at the tips ; epidermis 

 olivaceous or brown, obscurely rayed ; cardinal teeth rather large, somewhat com- 

 pressed, sulcose and double in both valves ; lateral teeth long, somewhat lamellar 

 and slightly curved; nacre white, purple or salmon colored and very iridescent. 

 Proc. Acad. Nat. Sci., 1872, p. 159. 



Jjdb. — Irwin's Creek, North Carolina, C. M. Wheatley. 



My cabinet and cabinet of C. M. Wheatley. 

 Diam. 1, Length 1-8, Breadth 3'1 inches. 



Shell smooth, somewhat oblong, rather compressed, somewhat flattened at the 

 sides, very inequilateral, obtusely biangular behind, rounded before ; substance of 

 the shell rather thick, thicker before ; beaks slightly prominent, undulate at the 

 tips; ligament rather short, thick and brown; epidermis olivaceous or brown, 

 obscurely rayed, with distinct and somewhat close marks of growth; umbonial 

 slope raised and obtusely angular; posterior slope carinate, narrow elliptical; car- 

 dinal teeth rather large, somewhat compressed, sulcose and double in both valves ; 

 lateral teeth long, somewhat lamellar and slightly curved ; anterior cicatrices dis- 

 tinct and deeply impressed ; posterior cicatrices confluent, large and slightly im- 

 pressed; dorsal cicatrices placed above the centre of the cavity of the beaks; cavity 

 of the shell somewhat deep and wide ; cavity of the beaks shallow ; nacre white, 

 purple or salmon colored and very iridescent. 



Remarks. — Quite a number of specimens were sent to me by my friend Mr. 

 Wheatley. In outline this species is near to rufusculus (nobis), but it is not so 

 compact. Some specimens had ventral cicatrices and obscure rays. It reminds 

 one of Gastonensis (nobis), but it is not so high in the wing. 



Unio exacutus. pi. 15, fig. 43. 



Testa Iffivi, praelata, subcompressa, ad latere planulata, valde insequilaterali, postice exacuta, subbian- 

 gulari, antiee oblique rotundata ; valvulis crassiusculis ; natibus prominulis, fere terminalibus, ad 

 apices minute undulatis ; epidermide tenebroso-fusca, perradiata ; dentibus cardinalibus parvis 

 sulcatisque ; lateralibus longis, rectis lamellatisque ; margarita vel alba vel purpurea et valde 

 iridescente. 



Shell smooth, very wide, somewhat compressed, flattened at the sides, very ine- 

 quilateral, pointed and subbiangular behind, obliquely rounded before; valves some- 

 what thick ; beaks a little prominent, nearly terminal, minutely undulate at the 

 tips ; epidermis dark brown, very much rayed ; cardinal teeth small and sulcate ; 

 lateral teeth long, straight and lamellar; nacre white or purple and very iridescent. 



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