﻿I<AMPSII,IS 



107 



worthy of even varietal rank. Unio copei is a little thinner 

 and shorter than the ordinary manifestation of the species, and 

 I am doubtful whether it is normal. 



LAMPS11.1S OBSCURA (Lea). 



Shell long- elliptical, subsolid, subintiated, rounded in front 

 and pointed or slightly biangulate behind about midway up 

 from the base; beaks rather low, with fine, double-looped 

 sculpture; growth lines irregular, sulcated in front, the rest 

 periods well marked; epidennis dirty greenish-yellow or yel- 

 lowish-green, with very delicate, scarcely shining rays; there 

 are two subcompressed pseudocardinals in each valve, the 

 upper one in the right valve the smaller; one lateral in the 

 right valve and two in the left ; beak cavities shallow ; muscle 

 scars not deep ; nacre whitish at the edge, becoming purple in 

 the cavity of old shells. All the shells ] have seen that are 

 adult appear to be males. 



Length 51, height 28, diam. 19 mm. 



'Tennessee and Cumberland River systems ; Lower Ohio and 

 its tributaries. 



Type locality, Nashville. Tenn. 

 Unio obscuriis Lka, Tr. Am. Phil Soc, VL 1839, P- 7, pl- m, 



fig. 7 ; Obs., n, 1838, p. 7, pi. Ill, fig. 7.— Hanley, Biv. Shells, 



1843, P- 194, pl- XXII, fig. 58.— Chenu, 111. Conch., 1858, pi. 



XVII, figs. I, la, lb.— Kusrm, Conch. Cab. Unio, 1861, p. 



220, pl. LXXIV, fig. 3. 



Margarita (Unio) obscurus Lea, Syn., 1836, p. 26; 1838, p. 20. 

 Margaron (Unio) obscurus Lea, Syn., 1852, p. 29; 1870, p. 45. 

 Lampsilis obscurus Simpson, Syn., 1900, p. 549. 

 Margarita (Unio) zeiglerianus Lea, Syn., 1836, p. 26; 1838, 



p. 20. 

 Unio zeiglerianus Lea, Tr. Am. Phil. Soc, VI, 1838, p. 32, pl. 



X, fig. 27 ; Obs., II, 1838, p. 32, pl. X, fig. 27.— Hanley, Biv. 



Shells, 1843. P- 193. pl- XXII, fig. 57._Chenu, 111. Conch.. 



1858, pl. XXIV, figs. 2, 2a, 2&.— SowERBY, Couch. Icon., XVI, 



1866, pl. XXXVI, fig. 19. 

 Margaron (Unio) aeiglerianus Lea, Syn., 1852, p. 29. 

 Margaron (Unio) sieglerianm Le.-v, Syn., 1870, p. 45. 



