Oe Te! a a er re ee ei fy ee aoe ae 
‘ 
Mr. Barnes on the Genera Unio and Alasmodonta, 263 
hind, sub-cylindrical, disks somewhat compressed ; anterior 
side very much produced; beaks flat ; ent ‘elevated; 
anterior dorsal margin depressed and flattened; basal m 
gin nearly straight 5; epidermis blackish brown, finely stria- 
ted and deeply wrinkled transversely; naker purple of dif- 
ferent shades, often with a purple centre and white m ; 
Teeth crenate; lateral tooth rough, very thick, bentlial 
downward, terminating abruptly and folded over pire: 
the interior of the shell. 
Remarxs.—This shell in many respects resembles the 
preceding, but it differs from it in being less, thicker in pro- 
portion to the size, more attenuated before ; and it may be 
distinguished from all others by the unusual thickness of 
the /ateral tooth. Itis also more depressed immediately be- 
hind the beaks, and the thickness of the anterior part of the 
shell is very unusual, being in some specimens greater than 
that of the posterior. In one specimen the lateral tooth of 
the left valve measures two lines in thickness, and the chan- 
nel of the opposite valve is two and a half lines broad. 
UNIO CUNEATUS.—Shell ovate wedge-shaped, 
thick, gibbous ; disks swelled, anterior lunule fur- 
rowed ; lateral tooth thin ; inside purple. 
Inhabits the Ohio. Mr. S. B. Collins. 
Mr. Collins’s collection. 
Diam h 2.3 Breadth 3.8 
Shell ane and sub-triangular, thick and ponderous; 
anterior side narrowed, thin, angulated, wedge-shaped, 
compressed ; umbones large and somewhat elevated; beaks 
low and distant; anterior lunule long-heart-shaped, large, 
distinct with an elevated ridge and longitudinally furrowed ; 
posterior lunule small aiid deep; basal margin slightly 
rounded ; anterior margin narrow and angulated ; anterior 
dorsal, rapidly narrowed ; posterior dorsal impressed ; “3 
dermis blackish brown, somewhat ferruginous ; surface 
ly wrinkled, an elevated ridge extends from the beaks to ee 
anterior basal margin, and terminates in an angle on.the 
fore part. Cardinal teeth deeply divided and sulcated ; lat- 
eral tooth long, curved, and not very thick; cicatrices deep ; ; 
cavity of the beaks small and not angular; naker browgish 
purple, iridescent. 
