SUPPLEMENT TO ISAAC LEA'S PAPER ON UNIONID^. 59 



My cabinet, and cabinet of J. C. Plant. 

 Diam. M, Length 1-6, Breadth 3-8 inches. 



Shell smooth, very transverse, subcylindrical, very inequilateral, obtusely bian- 

 gular behind, obliquely rounded before ; substance of the shell thick, somewhat 

 thicker before ; beaks a little prominent ; ligament long, rather thick and light 

 brown ; epidermis yellowish-green, much radiated and with rather distant marks 

 of growth ; umbonial slope very obtusely angular ; posterior slope scarcely raised, 

 narrow elliptical, with two impressed lines in each valve from the beaks to the 

 posterior margin; anterior cicatrices distinct, rather large and well impressed; 

 posterior cicatrices confluent and well impressed ; dorsal cicatrices placed above 

 the cavity of the beaks ; cavity of the shell wide and somewhat deep; cavity of the 

 beaks very shallow, scarcely observable; nacre white, purple or salmon color and 

 very iridescent. 



Remarks. — There are four specimens before me, all of different ages. Three are 

 from Mr. Plant and one, the youngest, from Mr. Postell. None of them are perfect 

 enough to present the undulations of the beaks. In outline it is nearest to exacutus 

 (nobis), but it is a stouter species and not quite so transverse. 



Unio corneus. pi. 20, fig. 58. 



Testa Iffivi, oblonga, subcompressa, ad latere parum planulata, insequilaterali, postice biangulari, aiitice 

 rotundata; valvulis crassiusculis ; natibus prominulis ; epidermide cornea, perradiata ; dentibus 

 cardinalibus crassiusculis et in utroque valvule duplicibus; lateralibus longis, crassis subcurvisque; 

 margarita pallido-purpurea vel salmonis colore tincta et iridescente. 



Shell smooth, oblong, somewhat compressed, at the side slightly flattened, ine- 

 quilateral, biangular behind and rounded before ; valves somewhat thick ; beaks 

 slightly prominent; epidermis horn color, very much radiated; cardinal teeth some- 

 what thick and double in both valves ; lateral teeth long, thick and somewhat 

 curved; nacre pale purple or salmon and iridescent. 

 Proc. Acad. Nat. Sci., 1873, p. 423. 



Jlab. — Columbus, Georgia, G. Hallenbeck ; Abbeville District, South Carolina, 

 Dr. Barratt ; Marietta, Georgia, J. C. Anthony. 



My cabinet and cabinet of Mr. Anthony. 

 Diam. '8, Length 1-4, Breadth 2-1 inches. 



Shell smooth, oblong, somewhat compressed, at the side slightly flattened, ine- 

 quilateral, biangular behind and rounded before ; substance of the shell somewhat 

 thick ; beaks slightly prominent ; ligament rather long, narrow and light brown ; 

 epidermis horn color, nearly covered with green rays, with rather distant marks of 



