ORTMANN: FAMILIES AND GENERA OF NAJADES. 313 
from Portsmouth had eggs only, and thus the beginning of the breeding 
season is shown to be in autumn. 
The soft parts have been described and figured by Lea (Obs., I, 
1834, pl. 5, figs. 6 and 7; and Obs., X, 1863, p. 433), but the figure is 
very poor.*® 
Branchial, anal, and supra- 
anal as usual, the latter two 
separated by a very short 
mantle-connection. Brarich- 
ial with papille, anal finely 
crenulated. In front of the 
branchial, the inner edge of 
the mantle has a series of fine 
crenulations which soon di. - 
appear, this edge becoming 
smooth. Palpi normal, pos- ieee 
A . P 1 | EiGes ize Cyprogenia irrorata (Lea). 
terior margins connected at 
Gravid female, from Ohio River, Ports- 
base only. mouth, Scioto Co., O. (Carn. Mus., No. 
Gills short and broad, the 61, 4,763.) 
inner much wider than the 
outer throughout its whole length. Diaphragm normal, inner lamina 
of inner gills free from abdominal sac, except at the anterior end. 
Anterior attachment of gills as usual. 
Septa and water-tubes in both gills normally developed, the latter 
moderately wide in the male and the non-marsupial gills of the female. 
Marsupium formed by a section in the middle of the outer gill; in 
fact this section is a little more toward the anterior end of the gill. 
Ovisacs few (three to eight in my specimens; up to eleven reported 
by other authors; Simpson gives for the genus twenty-three as maxi- 
mum), hardly different in width from the rest of the water-tubes, 
that is to say in the longitudinal direction. But, when charged, they 
swell somewhat in the transverse direction, so as to become subcylin- 
drical. The ovisacs project to an extreme degree beyond the edge of the 
gill. Although they begin near the base of the gill, and although a 
considerable part is enclosed between the original lamine of the gill, 
38 Lea’s figures are quite characteristic of the marsupium itself, but the position 
of the latter in the animal (fig. 7) is wrong. Apparently the anterior and posterior 
ends of the body are inter-changed. The marsupium does not coil forward, as this 
figure shows, but backward. 
