ORTMANN: FAMILIES AND GENERA OF NAJADES. 551 
Mantle-connection, anal, branchial, and gills like those of L. luteola. 
Inner lamina of inner gills entirely connected, or with a small hole at 
posterior end of foot. Posterior margins of palpi connected for one- 
third, or slightly more, of their length. 
Marsupium occupying the posterior half (more or less) of the outer 
gill, greatly swollen, kidney-shaped, with pigment on margin. Ovisacs 
numerous, up to thirty or more. Glochidia (figured by Lea, Obs., 
VI, 1858, pl. 5, fig. 15)°4 large, subovate; length 0.24, height 0.28 mm. 
Color of soft parts like that of L. ventricosa, generally paler, with the 
orange tints prevailing on the margin of the mantle and flap. Black 
line on inside of flap sometimes wanting. 
Lampsilis ventricosa (Barnes). 
Numerous specimens have been investigated from western Penn- 
sylvania, and a gravid female from Hurricane Creek, Gurley, Madison 
Co., Alabama (H. E. Wheeler coll., Sept. 13, 1910). 
Bradytictic; the breeding season commencing at the beginning of 
August, and ending in July, so that the species is gravid ‘‘all the year 
round,’ with the seasons possibly slightly overlapping in July. But 
the majority of the females discharge their glochidia in May and 
June, and in July only a few belated ones are found. The Lake Erie 
form (canadensis Lea) has about the same breeding season, but gravid 
females were not found in July. 
The soft parts have been described (as occidens) by Lea (Obs., X, 
1863, p. 418), and Simpson (in Baker, 1898, p. 95). The flap of the 
mantle has been figured rather well by Lea (Obs., VII, 1860, pl. 30, 
fig. 107) and by Ortmann (1911), pp. 319 and 320, figs. 7 and 8). 
The anatomy is in every respect like that of L. ovata, of which this 
is probably only a variety. 
Color grayish white, gills pale brownish, foot pale yellow or brown. 
Marsupium white, with black edge. Margin of the mantle mottled 
black and brown, the brown often shading to orange. Mantle-flap 
gray on outside, inside pale orange or brownish, with a black longitu- 
dinal line, and an eye-spot (black in white field) at posterior end. 
54 Here again a mistake occurs in Lea’s figures. In fig. 13 of the same plate he 
figures the glochidium of occidens (= L. ventricosa), and the latter is considerably 
larger than that of L. ovata. The fact is, however, that the glochidia of these two 
forms are practically indistinguishable in size and shape, and the slight differences 
in our measurements may easily be regarded as matters of personal equation in the 
case of the observer. 
