10 NEW UNIONID.E OF THE 



/7;,7,._Flint River, near Macon, Goo. J. C. Plant and H. M. Neisler, M. D. 



Mv cabinet and cabinet of Mr. Plant. 

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



Shell .smooth, oblique, very much inflated, very inequilateral, obtusely angular 

 behind and regularly rounded before ; substance of the shell thicker before ; beaks 

 swollen and raised; ligament short, thick and brown; epidermis nearly black, 

 shining above and striate towards the margin, without rays, with obscure distant 

 lines of growth ; umbonial slope much raised and angular ; posterior slope flattened, 

 slightly wrinkled, with two obscure impressed lines on each valve ; cardinal teeth 

 rather large, somewhat i>yramidal, slightly compressed and crenulate ; lateral teeth 

 short, rather thick, nearly straight and corrugate ; anterior cicatrices distinct and 

 well impressed ; posterior cicatrices distinct ; dorsal cicatrices placed under the plate 

 within the cavity of the beaks and deeply impressed ; cavity of the shell rather 

 deep and rounded ; cavity of the beaks rather shallow and rounded ; nacre either 

 white or salmon color and iridescent. 



Soft Parts. — Branchial uterus not charged, but ova were found in the ovarium. 

 Branchioi very large, quite semicircular, inner one a little the larger, free two-thirds ' 

 the length of the abdominal sack. PaJj>i large, pendant, suboval, united nearly lialf 

 way down the jiosterior edges. Mantle thin, slightly thickened on the posterior 

 border. BrancJdal ojxning small, with small brownish papillce. Anal openinj rather 

 large, with numerous small, brownish papillae on the inner edges. Super-anal 

 openhnj rather small, colored on the inner edges, united below. Color of the mass 

 whitish. 



Remarks. — Two specimens only were received by me. That which is figured is the 

 more imperfect of the two. The better one was received from Dr. Neisler after the 

 drawing was made. In both, the points of the beaks for some distance are worn 

 square off, so that the character of this portion cannot be given. It is evident they 

 were high and massive. The si^ecimen from Dr. Neisler has a rich salmon colored 

 nacre, quite satin-like ; that from Mr. Plant is white, with a slight disposition to a 

 salmon tint near the margin. It is near to Ilanleyanus (nobis) in outline, but is 

 rather more triangular, has a higher and more angular umbonial slope, has a black 

 and polished epidermis, and is without colored spots or bands. 



Unto Plantii. PI. 21, fig. 76. 



Testa laevi, regulariter elliptica, valdc compressa, inequilaterali ; valvulis subcrassis, anticfe crassioribus ; 

 natibus prominulis ; epidermide tenebroso-castanea, micante, eradiata ; dentibus cardinalibus parvi- 

 usculis, subdepressis, obtuso-coiiicis crenulatisque ; lateralibus prselongis, subcrassis curvisque ; mar- 

 garita salmonis colore tincta et valde iridcscente. 



Shell smooth, regularly elliptical, very much compressed, inequilateral; valves 



