﻿272 Nl'PIIRONAIAS 



Croup of Nephronaias scamnata. 



Slicll elliptical to elongate, compressed, strongly sulcate, 

 rather solid, subbiangular behind; that of the female inHated 

 at post-base ; epidermis olive to brown, sometimes feebly rayed ; 

 beak sculpture delicate and but slightly marked, consisting 

 of faint parallel ridges, which show a tendency to fall into 

 two rounded loops ; hinge rather solid ; pseudocardinals 

 stumpy, ragg-ed, laterals straight ; front part of the shell solid 

 and suddenly becoming thinner behind ; nacre bluish-white, 

 salmon, or purple. 



Animal unknown. 



Nephronaias scamnata (Morelet). 



Shell elongate rhomboid or long elliptical, compressed, ine- 

 quilateral, subsolid, with a low, generally double posterior 

 ridge ending in a feeble biangulation ; beaks not high but sharp, 

 their sculpture consisting of fine, scarcely doubly-looped ridges, 

 which differ little from the close, concentric sculpture that 

 covers the entire shell ; ligament long, narrow ; epidermis 

 blackish, brownish or olive, sometimes with a few faint, wide 

 rays and occasionally having concentric tawny or light brown 

 bands ; left valve with two subtriangular, ragged pseudocar- 

 dinals and two slender, nearly straight laterals ; right valve 

 with one strong pseudocardinal, a vestige of a second above 

 it and one lateral ; muscle scars superficial ; dorsal scars numer- 

 ous under the posterior part of the pseudocardinals ; nacre 

 reddish or jnirplish, sometimes nearly white, slightly thicker 

 in front. Male shell straight on the base or a little arcuate ; 

 that of the female .somewhat produced at the posterior base, 

 the two shells scarcely differing behind. 



Length 55, height 30, diam. 15 mm. 



Cuba; Honduras? 

 Unio scauniatns Morklkt. Test. Nov., Xo. i, 1849, P- 3^^- 

 Margaron (Unio) scamnatus Lka. Syn.. 1852, p. 40; 1870, 



P- .3.S- 

 Nephronaias scamnatus Simp.son, Syn., 1900, p. 595. 



