280 DESCRIPTION OF NEW 
Remarks.—A single specimen only of this species is. before me.—Other specimens 
may vary in some characters. It is most nearly allied to U. crassidens, (Lam.,) but is a 
shorter species, and not so thick. The purple and white colour of the nacre in this speci- 
men gives it a livid appearance—other specimens may be found of a salmon colour. It 
has a fine nacre with a blackish margin. No rays are visible on this specimen. 
Unio AHENEUS, Pu. 41. Fie. 9. 
Testé valde transversd, compressd, valde inequilaterali, postice biangulatd; valvulis tenuibus; natibus vix prominentibus 
7 ip 7 q oP ee y ) 
undulatis; epidermide tenebroso-fuscd, radiatd; dentibus cardinalibus minimis; lateralibus longissimis rectisque; margarité 
cupred. 
Shell very wide, compressed, very inequilateral, biangular behind; valves thin; beaks scarcely prominent, 
undulated ; epidermis dark-brown and rayed ; cardinal teeth very small; lateral teeth very long and straight; nacre 
copper- coloured. 
Hab. Black Creek, Florida. S. B. Buckley. 
My cabinet and cabinets of Dr. Budd and Mr. Buckley. 
DTA. Oy Length .9, Breadth 2.1 inches, 
Shell very wide, compressed, very inequilateral, biangular behind; umbonial slope 
angular and straight; substance of the shell very thin; beaks scarcely prominent, undu- 
lated at the tip; ligament very long and thin; epidermis dark-brown, with numerous 
dark-green oblique rays on the whole disk; cardinal teeth very small and granulate; 
lateral teeth very long, thin, and straight; anterior cicatrices distinct; posterior cicatrices 
confluent; dorsal cicatrices placed under the anterior end of the lateral tooth; cavity of 
the shell shallow; cavity of the beaks very small and angular; nacre dark copper-colour 
and iridescent. 
Remarks.—This is a very distinct species, belonging to that group of which the compla- 
natus may be considered to be the type. It is remarkable for its dark copper-coloured 
nacre, which is very splendent. Indistinct undulations may be observed at the tip of the 
beaks, although the specimens are both eroded there. The cardinal teeth are remarkable 
in being so small and in being granular, and the position of the dorsal cicatrices is 
farther removed from the cardinal tooth than usual—even more so than in the Unio 
Shepardianus, (Nobis.) The posterior slope is elevated, compressed, and made very 
dark by thick green rays. ‘The flattening behind the umbonial slope causes a second 
angle at the posterior margin. 
Unio nEGLEcTUS. PL. 42. Fig. 10. 
Testa oblonga, inflata, inequilaterali; valvulis tenuibus; natibus subprominentibus; epidermide luteold, radiata ; 
dentibus cardinalibus parvis ; lateralibus longis, tenuibus subcurvisque; margaritéd subaured et iridescente. 
Shell oblong, inflated, inequilateral; valves thin; beaks rather prominent; epidermis yellowish, rayed ; cardinal 
teeth small; lateral teeth long, thin, and somewhat curved; nacre somewhat golden and iridescent. 
Hab. North Alabama. Dr. Budd. 
My cabinet and cabinet of Dr. Budd. 
Diam, .8, Length 1.2, Breadth 2 inches. 
