QUADRULA 875 
plate. Nacre rose-color, with blotches of yellow surrounded 
by brown. Cavity nearly always studded with numerous pearly 
excrescences. 
Flesh of the animal whitish or salmon-colored exteriorly, 
but shows scarlet when cut. Eggs carried in all four gills, 
very red, and the gravid animal thus presents a striking ap- 
pearance. 
Length 3.2, height 2.3, diam. 1.5 inches.” (Frierson). 
Type locality, Lanana Creek, also Banita Creek, near Na- 
cogdoches, Texas. 
Quadrula lananensis FRIERSON, Naut., XV, 1901, p. 75, pl. Iv. 
Fusconaja lananensis ORTMANN, Ann. Car. Mus., VIII, 1912, 
Pp. 244. 
“Q. lananensis is closely allied to Q. askewi Marsh, both by 
its conchological and anatomical characteristics. It may be 
differentiated from that shell by being longer, more compress- 
ed, more oblique, and its shell is never so inflated and thick- 
ened in front as askew? and not so acutely angled on the pos- 
terior ridge. Internally, Jananensis is rose-colored nearly in- 
variably and the color is uniformly spread over its surface. 
Askew is mostly white, and, when colored (pink) the color 
is almost always confined exterior to the pallial line. Finally, 
Q. askewi never possess those peculiar pearly excrescences, 
which seem to belong to lananensis.” 
Group of Quadrula undata. 
Shell triangular, generally inflated, with high, full beaks, 
which are incurved and turned forward over a well-developed 
lunule; anterior end obliquely truncate above, often with a 
curved, shallow depression in each valve, running from the 
beaks to midway down the anterior end, and forming a sort 
of secondary Junule ; posterior base, usually incurved ; the pos- 
terior ridge ending in a rather sharp point; beak sculpture, a 
few coarse, concentric ridges turned upward behind, and often 
swollen on the posterior ridge, sometimes becoming finer and 
broken or irregular on the upper disk; hinge solid but not very 
wide; psetidocardinals triangular and radial, torn; there is a 
