﻿LAMPSILIS 121 



specimens are subsolid, but it is often rather frag^ile. Unio dif- 

 Hcilis Lea, placed in the synonomy of nebulosa in the Synopsis,. 

 may be a form of L. planca Lea. 



Lampsilis muhlfeldiana (Lea). 



Shell irreg-ularly long: elliptical, solid in front, thin behind, 

 scarcely snbinflated, with low, compressed beaks sculptured 

 beautifully with numerous, somewhat irregularly doubly-looped 

 ridges ; surface with rather rude growth lines ; dirty greenish- 

 yellow with a few faint rays ; there is a slight elevation extend- 

 ing from the beaks to a point on the base one-third of the dis- 

 tance from the posterior end, and from this point to the some- 

 what elevated posterior end the shell is somewhat truncated ; 

 left valve with two roughened, equal pseudocardinals and two 

 lamellar laterals ; right valve with one pseudocardinal and one 

 lateral ; muscle scars distinct ; nacre whitish, shaded salmon in 

 the cavity, iridescent behind. 



Length 60, height 34, diam. 20 mm. 



Type locality, Cumberland River. Tenn. Also. Watauga 

 River near Johnson City, Tenn. 

 Unio muhlfeldianus Lka, Tr. Am. Phil. Soc, VL 1838, p. 41, 



pi. XII, fig. 36; Obs., n, 1838, p. 41, pi. XII, fig. ^6. — Hanley, 



Biv. Shells, 1843, P- I9<^' pl- xxn, fig. 60. — Chenu, 111. 



Conch., 1858, pi. XVII, figs. 5. 50. 5&. — Sowerby, Conch. 



Icon., XVI, 1866, pi. XXXVIII, fig. 211. 

 Margarita (Unio) miihlfeldianus Lea, Syn., 1836, p. 27: 1838, 



p. 20. 



Margaron (Unio) miihlfeldianus Lea^ Syn., 1852, p. 30; 1870, 



p. 48. 

 Lampsilis miihlfeldianus Simpson, Syn., 1900, p. 555. 



I have only seen a single specimen of this, the type, and I 

 am dbuhtful whether it is a valid species, yet I cannot refer it 

 to any other. Its coloration is something like that of adult 

 specimens of L. :;ieglcriana, but the shell is difTerently shaped, 

 being somewhat truncated at the posterior base. 



