UPPER TENNESSEE DRAINAGE. 573 



6i. ToxoLASMA LiviDUM (Rafinescjue) , 1831. 



Unio llvidus Rafinesque, '31. — Unio moestn's Lea, '41. — Unio cylin- 

 drellits Lea, '68. — Unio glaiis Lewis, '71. — Unio glans Pilsbry & 

 Rhoads, '96.^ — Lampsilis (Carnncidiiia) cylindrclla and moesta 

 Simpson, '14, pp. 155, 156. — Toxolasma livida Frierson, '14a, 

 p. 7. 



The upper Tennessee form is not the real U. glans of Lea ('43), 

 as already hinted at by Pilsbry & Rhoads. The latter is more swol- 

 len, and has more inflated beaks, and possibly, it is the big river and 

 lowland form of Toxolasma lividiiiii. 



What Lea has described as U. nioestiis (from French Broad 

 River, Tenn.) undoubtedly is this: I have specimens from Little 

 Pigeon River (tributary to French Broad), which are fully identical 

 with moestus. U. cylindrellns Lea (Duck River, Tenn.) is in shape 

 absolutely identical with T. lividum ; however, it dififers by paler 

 color of epidermis and nacre. Such pale specimens occasionally are 

 found in the upper Tennessee drainage as individual variations. 

 Yet it might be, that elsewhere (Tennessee drainage in northern 

 Alabama, and Alabama drainage in Alabama and Georgia) this pale 

 form becomes a distinct race. 



U. pnllus Conrad, '38, from the original locality, Wateree River, 

 S. Car., may be a different species. But it is rather sure that the 

 specimens from "Warm Springs, N. Car." (=Hot Springs, Madi- 

 son Co., N. Car., on the French Broad) are actually T. lividum. 



There is great variation in the color of the nacre: it may be en- 

 tirely dark purple, or may have (generally) a whitish margin along 

 the edge of the shell; or it may (very rarely) have a pale, yellowish, 

 color. The epidermis is mostly blackish or blackish brown, but it 

 may become pale brown or greenish brown. 



This species seems to have a wide range over the upper Ten- 

 nessee drainage, but, on the othe'r hand, it seems to be rather local. 

 I know it from the following localities : South Fork Powell River, 

 Big Stone Gap, Wise Co., Va. (Walker coll.) ; Powell River, Jones- 

 ville, Lee Co., Va. (Walker coll.) ; Shawanee, Claiborne Co., Tenn. 

 (Walker coll.) ; Green's Ford, L'nion Co., Tenn. (Walker coll.) ; 

 Clinch River, Speer's Ferry, Scott Co., Va. ; Emory River, Harri- 



