300 NEW UNIONID^, MELANID^, ETC., 



the deposit of epidermal matter, so that the whole interior of the disk becomes 

 cloudy. The lines of growth in each of the three specimens are four, and they are at 

 nearly equal distances and very strong!}' marked. 



Unio dorsatus. pi. 45, fig. 112. 



Testa ]£evi, triangulari, ad latere planulata, insequilaterali, postice subbiangulari, antice rotundata- 

 valvulis subtenuibus, antice crassiusculis ; natibus prominentibus ; epidermide rufo-fusca, sub- 

 squamosa, obsolete radiata ; dentibus cardinalibus parvis corrugatisque ; lateralibus longis, 

 lamellatis subcurvisque ; margarita vel alba vel purpurea vel salmonea et valde iridescente. 



Shell smooth, triangular, flattened at the sides, inequilateral, subbiangular behind 

 and rounded before ; valves rather thin, thicker before ; beaks prominent; epidermis 

 reddish-brown, subsquamose, obtusely radiated ; cardinal teeth small and corrugate ; 

 lateral teeth long, lamellar and somewhat curved ; nacre white, purple or salmon 

 color and very iridescent. 



Proc. Acad. Nat. Sci. 1868, p. 160. 



5"a5.— Catawba River, N. C, C. M. Wheatley. 



My cabinet and cabinet of Mr. Wheatley. 

 Diam. -9, Length l-o. Breadth 2-2 inches. 



Shell smooth, triangular, flattened at the sides, inequilateral, subbiangular behind, 

 rounded before; substance of the shell rather thin, thicker before; beaks prominent; 

 ligament short, thick and dark brown ; epidermis reddish-brown, somewhat squamose, 

 obscurely radiate, with distant lines of growth ; umbonial slope raised and obtusely 

 angular; posterior slope raised into a carina; cardinal teeth small and corrugate; 

 lateral teeth long, lamellar and somewhat curved ; anterior cicatrices distinct and 

 well impressed; posterior cicatrices confluent and moderately impressed; dorsal 

 cicatrices placed above the cavity of the beaks; cavity of the shell rather deep and 

 wide; cavity of the beaks rather deep and subangular; nacre white, purple or 

 salmon color and very iridescent. 



Remarhs. — Several specimens are belore me which differ slightly. They have all 

 more or less color of purple ; some are mixed with salmon color. One is clouded 

 with purple and white. In outline it is nearest to ovatus, Say, but it differs very 

 much in size, inflation, color of the nacre, epidermis, and flatness of the posterior 

 slope. The epidermis in ovatus is yellowish, smooth and polished. In this species it 

 is rubiginose and squamose. The beaks, as usual in nearly all the specimens sent 

 from this part of North Carolina, are eroded, and therefore the apicial undulations 

 are unknown. Some of the specimens are wrinkled on the posterior slope. 



