348 ANNALS OF THE CARNEGIE MUSEUM. 
anodontoides (my specimens from Texas are typical and undoubted 
anodontoides), and it is not at all ‘“‘horny,’’ and corresponds to the 
flap described above. 
Lampsilis luteola (Lamarck). 
Many specimens from the Lake Erie and Ohio drainages in western 
Pennsylvania, and also from Kansas and Arkansas, have been in- 
vestigated. 
Bradytictic, and may be found gravid practically all the year round. 
The breeding season begins at the beginning of August, and ends in 
July, and may overlap with the next toward the end of July. But in 
July there is an indication of an interim, gravid specimens being quite 
rare. In the Ohio drainage, the females have generally discharged 
their glochidia by the beginning of July, and only single belated in- 
dividuals are met with later. In Lake Erie, discharging females were 
found more frequently in July, as late as July 12. No gravid females 
have ever been found between July 12 and August 4 by myself. 
The soft parts have been described by Lea (Obs., X, 1863, p. 402) 
and Simpson (in Baker, 1898, p. 104). 
Mantle-connection between anal and supra-anal of medium length, 
shorter than anal. Anal crenulated, branchial with papilla. In 
front of branchial the female has on the inner edge of the mantle a 
typically developed flap (see Ortmann, I91Ib, p. 321). It has the 
shape of a ribbon-like keel, with irregular, rather distant teeth, but 
no papille,®® and its anterior end projects considerably, even when 
contracted, and has great powers of expansion. The marginal teeth 
are largest at the free lobe, which appears lacerated. There are a 
number of irregular teeth on the edge of the mantle in front of the 
lobe, but soon the edge becomes smooth. On the inner side of the 
flap there is a broad streak of black pigment. Eye-spot (in alcoholic 
material) indistinct. The flap extends over about one-third of the 
lower margin. 
Posterior margins of palpi connected for about one-fourth of their 
length. Gills and diaphragm normal. Inner lamina of inner gills 
entirely connected, rarely a very small hole remaining at the posterior 
end of the foot. 
Marsupium kidney-shaped, occupying about the posterior half of 
53 When strongly contracted by the action of alcohol, the teeth become thicker, 
and appear like papilla, but when expanded, they are flat (not sub-cylindrical). 
