864 ; QUADRULA 
Animal with the marsupium occupying all four leaves of 
the gills; inner gills the larger, free from the abdominal sac 
only part of their length; anal opening without papille. . 
I have been puzzled as to the relationship of this group and 
have been strongly inclined to place it near chickasawhensis, 
but I now believe it is more closely allied to the pustulosa 
group. Its posterior truncation, the prominent angle behind 
the ligament, and beak sculpture lead me to place it here. The 
general sculpture of QO. petrina approaches that of these species. 
QuADRULA INFUCATA (Conrad). 
Shell subrhomboid, convex or subinflated, solid, somewhat 
inequilateral ; beaks high, rather full, their sculpture consisting 
of strong, irregular ridges, which curve up sharply behind, 
and behind these there are a few radial, subnodulous ridges; 
anterior end a little narrower and rounded; base line curved; 
posterior end obliquely subtruncate; posterior ridge full, nar- 
rowly rounded, ending in a blunt point on the base line; sur- 
face sometimes nearly smooth, but usually sculptured with 
low, nodulous ridges arranged in zigzag or chevron-shaped 
patterns; epidermis greenish in young shells, thick, black and 
subshining in old ones; pseudocardinals considerably split ; two 
laterals in the left valve and one, which is often somewhat 
double, in the right; beak cavities not very deep, compressed ; 
anterior scars small; nacre purplish, iridescent behind. 
Length 38, height 30, diam. 17 mm. 
Chattahoochee and Flint Rivers, Georgia. 
Type locality, Flint River, Ga. 
Unio infucatus Conrap, New F. W. Shells, 1834, p. 45, pl. 
ut, fig. 2—CuHENU, Bib. Conch., Ist ser., III, 1845, p. 22, 
pl. u, fig. 6—Kuster, Conch. Cab. Unio, 1861, p. 176, pl. 
Lv, fig. 5.—-Sowxrrpy, Conch. Icon., XVI, 1866, pl. xt, fig. 
221.—Simpson, Pr. U. S. Nat. Mus., XV, 1892, p. 409, pl. 
MNIK, Mes: cae, 10: 
Margarita (Unio) infucatus Lea, Syn., 1836, p. 34; 1838, p. 23. 
Margaron (Unio) infucatus Lea, Syn., 1852, p. 20; 1870, p. 30. 
Unio securiformis Conrap, Ann. and Mag., IV, 1849, p. 300; 
Pr. Ac. Nat. Sci. Phila., I, 1850, p. 275, pl. xxxvu, fig. 1. 
Generally a little smaller, solider and smoother than klein- 
iana and having a darker epidermis. 
