QUADRULA 8 
ios) 
“I 
Var. sparsa (Lea). 
Shell smaller than twberosa, generally not nodulous. 
Length 47, height 38, diam. 22 mm. 
Holston and Clinch rivers, Tennessee. 
Type locality, Holston river, Tennessee. 
Umo sparsus Lea, Pr. Am. Phil. Soc., II, 1841, p. 82; Tr. Am. 
Phi ode. UL, 1642, p:-242, pl xxv, fig. 58; Obs., ITT, 
1842, p. 80, pl. xxv, fig. 58—CHENU, Ill. Conch., 1858, pl. 
XXVI, figs. 2, 2a, 2b.—RreEveE, Conch. Icon., XVI, 1864, pl. 
IV, fig. 14. 
Margaron (Umio) sparsus Lea, Syn., 1852, p. 22; 1870, p. 33. 
Quadrula sparsa SIMPSON, Syn., 1900, p. 775. 
After critically comparing large series of this and tuberosa, 
it does not seem to me that it can take any higher rank than 
that of a variety of the latter. It is smaller and generally a 
little less nodulous, but the coloring, texture, form and general 
characters are practically the same. I am very strongly in- 
clined to believe that both should be considered mere varieties 
of metanevra. 
QuADRULA INTERMEDIA (Conrad). 
Shell subelliptical, suborbicular or subquadrate, convex to 
subinflated ; beaks moderately high but not full; posterior ridge 
scarcely elevated above the outline of the shell, but having 
above it a deep, wide, radial depression, so that on its upper 
side it is well defined; the depression ends in a deep, rounded 
sinus: surface covered, except on the anterior end, with large, 
elevated warts, which are sometimes double; epidermis green- 
ish-yellow or yellowish-green, variegated with fine, angular 
green spots or zigzags, sometimes with imperfect rays; pseu- 
docardinals radial, radially striate; lateral of right valve dou- 
ble; beak cavities deep, much compressed ; muscle scars small, 
impressed; nacre white or straw-color, thinner and iridescent 
behind. 
Length 59, height 51, diam. 29 mm. 
Tennessee River system. 
Type locality, Nolachucky River, Tenn. 
