PIL.EUROPEMA 
“I 
~ 
cn 
Group of Plewrobema nuv. 
Shell oval, inflated, moderately solid, with a low posterior 
ridge, swollen at the post-basal part; posterior end pointed at 
the termination of the posterior ridge; beaks full, rather high, 
considerably removed from the anterior end; epidermis pale 
to dark brown, rest lines very distinct; pseudocardinals small, 
stumpy, radiate, rough; laterals straight; nacre brilliantly iri- 
descent posteriorly; front part of shell heavy, suddenly be- 
coming thinner behind. 
Animal unknown. 
PLEUROBEMA VERUM (Lea). 
Shell subovate or subtriangular, subinflated, subsolid, inequt- 
lateral; beaks elevated, moderately full; anterior end rounded 
or slightly truncated above; base line curved; outline of dor- 
sal slope curved, subangulate just behind the ligament; pos- 
terior vidge well developed, narrowly rounded, ending in a 
blunt point above the base; surface with uneven growth lines ; 
epidermis dull tawny-brown to greenish-brown, generally 
showing the rest marks; pseudocardinals small, two in the left 
valve and one to three in the right; two laterals in the left 
valve and a double one in the right; muscle scars impressed ; 
beak cavities rather shallow ; nacre whitish. 
Length 50, height 40, diam. 23 mm. 
Black Warrior and Cahawbha rivers, Alabama. 
Type locality, Cahawba River, Perry Co., Ala. 
Unio verus Lea, Pr. Ac. N. Sci. Phila., V, 1860, p. 140; Jl. Ac. 
Ne Sct) Phila 1862; -p.' 83, phix1 fie. 231 ;- Obs.,. VIL, 
[o62) p87 .pl. SL, fe! 230 
Margaron (Unio) verus Lea, Syn., 1870, p. 38. 
Pleurobema vera SIMPSON, Syn., 1900, p. 757. 
The type is a young shell, and seems to stand between the 
troschelianum and nux groups, and to show some relation to 
that of Pleurobema argenteum. The shell is only moderately 
solid and inflated. 
