goo QUADRULA 
flattened; pseudocardinals triangular; laterals strong, second- 
ary lateral of right valve well developed; beak cavities deep, 
compressed; muscle scars very deep, smooth; nacre dirty 
straw-color. 
QUADRULA GLANDACEA (Lea). 
Shell subrhomboid, or rhomboid-oval, somewhat inflated, 
rather solid, inequilateral; beaks probably full and high; pos- 
terior ridge well developed, usually narrowly double, ending 
below in a blunt point or a biangulation ; anterior end rcunded, 
sometimes slightly truncate above; base line straight; outline 
of dorsal slope curved or raised into an angle behind the liga- 
ment; surface with rude, irregular growth lines; epidermis. 
wrinkled, tawny, scarcely shining; pseudocardinals triangular, 
strongly radially striated; muscle scars small, impressed; beak 
cavities deep and compressed: nacre whitish or straw-colored, 
thinner and iridescent behind. 
Length 50, height 38, diam. 26 mm. 
Coosa and Cahawba Rivers, Alabama. 
Type locality, Cahawba River, Ala. 
Unio glandaceus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 593. 
Ji. Ac. N. Sc.) Phila. "V, 1862, p:.77,. pl. 1%, n¢.2220; taps. 
VILE: p. Sty pl. rx, fas. 226, 
Margaron (Unio) glandaceus Lea, Syn., 1870, p. 38. 
Quadrula glandacea SIMPSON, Syn., 1900, p. 793. 
I have seen but a limited amount of material of this peculiar 
species. It has the texture, form and coloring of many of the 
members of the genus Pleurobema, but the beak cavities of all 
the specimens I have seen are deep and compressed and this 
would indicate that it is a Quadrula. In two of the shells ex- 
amined there is a slight, radial groove on the dorsal slope but 
I do not know whether this is a constant character. There is 
a somewhat eroded valve in the national museum collection 
donated by Dr. Powell, labeled “Arkansas” which is marked 
“Unio glandaceus” by Dr. Lewis. While it may be that species, 
I am a little in doubt concerning it. 
