QUADRULA 845 
of the right valve somewhat double; beak cavities deep, com- 
pressed; muscle scars impressed; nacre whitish, thinner and 
slightly iridescent behind. 
Length go, height 80, diam. 47 mm. 
Alabama to Texas, in streams flowing into the Gulf of 
Mexico. | 
Type locality, Fayette Co., Texas. 
Umo forsheyi Lwa, Pr. Ac. N. Sci. Phila., III, 1859, p. 155; 
i Ac, Nose Phila. 9 V, re60, p. 357, pl. Lx, fig. 182; Obs., 
VIII, 1860, p. 39, pl. Lx, fig. 182—RerEve, Conch. Icon., 
XVI, 1864, pl. vi, fig. 21. 
Margaron (Unic) forsheyt Lea, Syn., 1870, p. 32. 
Ouadrula forsheyi StMPSON, Syn., 1900, p. 778. 
This species varies much in the degree of smoothness or 
roughness of its surface. Young specimens are more tuber- 
culous than old ones. The tubercles usually extend over the 
whole surface and in this it differs from the ordinary mani- 
festation of /achrymosa and fragosa where they are usually 
wanting on the anterior end. I am inclined to think that it 
may run into Q. speciosa. 
QUADRUILA SPECIOSA (Lea). 
Shell long rhomboid or long quadrate, subcompressed, in- 
equilateral, subsolid; beaks rather high but not full, their 
sculpture sharply doubly-looped ridges; posterior ridge single 
and angled above, becoming double below, ending in a bian- 
gulation at the base of the shell; in front of and behind it 
there is a faint radial depression; surface densely covered with 
rather small, uneven pustules, which are arranged on the pos- 
terior slope in curved, subradial lines; epidermis greenish ; 
pseudocardinals elevated, two in the left valve and one with 
two vestigial ones in the right; left valve with two laterals; 
right valve with one double one; beak cavities rather deep, 
compressed; anterior scars impressed, rough; nacre bluish- 
white, silvery. 
Length 62, height 45, diam. 20 mm. 
Kansas, south to Texas. 
