QUADRULA 829 
Unio stolli von Martens, Biol. Cent. Amer., Moll., 1900, p. 
492; (pl: SxXix,- fie’ 2. 
Quadrula stolli Simpson, Syn., 1900, p. 771. 
I am inclined to believe that this is a valid species. It seems 
to be uniformly more elongated than Q. nickliniana, the nacre 
is not so suddenly or greatly thickened in front and it lacks 
a swelling just back of the middle of the shell generally seen 
in that species. The sculpture near the beaks is considerably 
corrugated and broken. von Martens believes that Kuster’s 
Unio nicklianus (Conch. Cab. Unio, p. 217, pl. Lxxitt, fig. 3) 
is not the nicklinianus of Tea, but his species. I cannot agree 
with him in this. 
QUADRULA NEISLERII (Lea). 
Shell subquadrate, inflated, solid, inequilateral ; beaks mod- 
erately full and high; posterior ridge high, narrowly rounded, 
sometimes slightly double, ending at the base in a feeble bian- 
gulation or a blunt point; anterior end narrower and rounded ; 
base line nearly or quite straight; post-dorsal slope scarcely 
winged above, almost squarely truncated behind; surface with 
the usual concentric sculpture of the group and having, often, 
throughout all the shell, except the extreme anterior end, a 
series of nearly horizontal, moderate folds, these sometimes 
descend a very little in front and behind and on the dorsal slope 
they curve slightly upward; in the umbonal region the sculp- 
ture is corrugated somewhat as in Q. heros; epidermis brown- 
ish to blackish; pseudocardinals radially striate, often radially 
split up; laterals short; beak cavities moderately deep, com- 
pressed; anterior scars partly filled with rough nacre; nacre 
whitish or purplish, iridescent and slightly thicker behind. 
Length 80, height 65, diam. 43 mm. 
Type locality, Flint River, amer Co., and Macon, Georgia. 
Unio neislerii Lea, Pr. Ac. N. Sci. Phila., I, 1858, p. 165; Jl. 
Ac WN. Sci. Phila, DY; 1859: \p. 212, pl. xxvi, fig. 93; Obs., 
VII, 1859, p. 30, pl. xxvt,. fig. 93. 
Margaron (Unio) neislerti Lea, Syn., 1870, p. 29. 
Quadrula neislerii Simpson, Syn., 1900, p. 771. 
