Ortmann: Families and Genera of Najades. .';~>l 



Mantle-connection, anal, branchial, and gills like those of L. luteola. 

 Inner lamina of inner gills entirely connected, or with a small hole al 

 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, pi. 5, fig. 15) 64 large, subovate; length 0.24, height 0.2S 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). 



Brady tictic; 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, i860, pi. 30, 

 fig. 107) and by Ortmann (19H&, pp. 319 and 320, figs. 7 and 8). 

 The anatomy is in every respect like that of L. ovata, of which this 

 i> 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. 



M Here again a mistake occurs in Lea's figures. In fig. 13 of the same plate he 

 figures the glochiclium 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 I) I as matters of personal equation in the 



case of the observer. 



