﻿156 I.AM PSI LIS 



sIkH differs bill very little from that of the male, having a 

 faint marsupial swelling- near the posterior part of the base and 

 both are nearly evenly round beliind. 



Lengib 2,7 > beigbt 20, diam. 16 mm. 



Tennessee River drainage. 



Type locality, Duck River, Tenn. : Swamp Creek, Wbitfield 

 Co.. Ga. : northern Alabama. 

 Unio cylindreUus Li-a, Pr. Ac. N. Sci. Phila., XII, 1868, p. 144; 



fl. Ac. N. Sci. Phila., VIII, 1869, p. 308, pi. xi.viii, fig. 121 ; 



— Obs.. XII, 1869, p. 68, pi. xLviii, fig. 121. 

 Margaron (Unio) cylindreUus Lea, Syn., 1870, p. 49. 

 Lampsilis cylindreUus Simi'son, Syn., 1900, p. 565. 



The .solid, long, almost cylindrical shell and the coppery 

 nacre, bordered with lighter color, distinguish this from allied 

 species. The specimens I take to be females differ but very 

 little from the males, being only a very little fuller in the post- 

 basal region. 



Lami'Sii.is mcesta (Lea). 



Shell long elliptical or subrhomboid, subinflated, rather solid, 

 with a very faint posterior ridge ; beaks probably full ; surface 

 concentrically striate, having an olive-brown epidennis, rayless ; 

 left valve with two stumpy pseudocardinals and two short lat- 

 terals : right valve with one pseudocardinal and one lateral ; 

 beiik cavities not deep, having a few deep pits ; nacre dirty„ 

 dark purple, somewhat thinner and iridescent behind. 



Length 47, height 26, diam. 18 mm. 



Type locality, French Broad River, Tennessee. 

 Unio mccstns T,f,a, Pr. Am. Phil. Soc, II, 1841, p. 82: Tr. Am. 



Phil. Soc, VIII, 1842, p. 244, pi. XXVI. fig. 60: Obs., III. 



1842, p. 82, pi. XXVI, fig. 60. — Chenu, 111. Conch., 1858, pi. 



XXVIII, figs. 3, 3a, 36. — KusTER, Conch. Cab. Unio, 1861, p. 



226, 1)1. Lxxvi, fig. 5. 

 Mari^aron (Unio) mocstus Lea, Syn., 1852, p. 31 ; 1870. p. 49. 

 l.ampsilis tmrstus Simpson, Syn., 1900, p. 565. 



