﻿LAMPSILIS 3Q^ 



A large, rather coarse species, which bears some resemblance 

 io I. hiangularis. It is rather more compressed and thinner at 

 the edges than L. ligamentina. It has very wide prismatic 

 border. 



Lampsilis vp;nusta (Lea). 



Shell irregularly long elliptical, solid, subinflated, with rather 

 compressed but pointed beaks, which are sculptured with fine, 

 distinct, doubly-looped ridges ; with a low posterior ridge ; with 

 irreguilar growth lines ; greenish-yellow with narrow and wide, 

 somewhat broken, wavy rays ; left valve with two equal, erect 

 pseudocardinals and two straight laterals ; right valve with one 

 pseudocardinal and a small one above it, with one lateral and 

 sometimes a vestige of another below it ; beak cavities shallow ; 

 nacre white, scarcely thickened in front. Both male and female 

 shells are full at or behind the middle and somewhat narrowed 

 at the ends. Both are bluntly pointed behind, that of the male 

 midway up from the base, that of the female a little higher up. 

 There is a feeble marsupial swelling just behind the center of 

 the base. 



Length 57, height 32, diam. 21 mm. 

 Type locality, Potosi, Missouri. 

 Umio 2'enustus Lea, Tr. Am. Phil. Soc, VI, 1838, p. 4. pi. 11,. 

 fig. 4; Obs., II, 1838, p. 4, pi. 11, fig. 4.— Hanley, Biv. Shells, 

 1843, P- 192, pl. XXIII, fig. 5.— Chenu, 111. Conch., 1858, pi.. 

 XXII, figs. I, la, lb. 

 Margarita fUnio) 7'eniistNs Lea. Syn., 1836, p. 24; 1838, p. 19. 

 Mar gar on fUnio) 7'emtstus Lea. Syn., 1852, p. 2y\ 1870. p. 43. 

 I.ampsilis venustus Simpson. Syn., igcx), p. 543. 



In some respects this shell approaches L. ellipsiformis, in 

 others it has characters of the ligamentina group. I hardly 

 know where to place it. There are specimens, which seem close 

 to L. iris. 



Group of l^ampsilis anodontoides. 



Shell elongated, inflated, moderately solid, sharply pointed 

 behind ; that of the female much produced at the posterior base, 

 behind v/hich it is diagonally truncate : epidermis ver^- bright. 



