NERILLA AN ARCH! ANNELID. 
413 
The Genital Organs of the Female. 
Ifc lias already been mentioned that nephridia occur in 
segments 2, 5, 6, and 7 of the female Nerilla, but neither in 
segment 9, nor in segment 7. In the living worm two 
slender oviducts can be detected occupying the place of the 
nephridia in segment 7. They are delicate tubes, lined with 
fine closely set cilia, passing backwards from the septum 
between segments 6 and 7, to open separately on the ventral 
surface near the base of the parapodium, at a point corre- 
sponding to the nephridiopores in other segments (fig. 11). 
Towards the external pore, which is elongated and oblique, 
converge a number of granular unicellular gland-cells (figs. 
11, 18, 34). The internal opening of the oviduct is in the 
form of a small funnel piercing the septum, and spreading out 
on its anterior face (fig. 11). Sections show the funnel as a 
small patch of ciliated epithelium with a central opening 
leading into the duct (fig. 32). The oviducts seem extra- 
ordinarily small as compared with the ripe ova ; in sections the 
diameter is actually less than that of the nucleus of the ovum 
and even than that of its nucleolus. But it is possible that 
the duct enlarges just before the eggs are laid, as in so many 
worms ; moreover the egg is very soft, and no doubt capable 
of squeezing through a small aperture. A similar dispro- 
portion is often found in the Oligocheeta. 
The ovaries are situated in segment 6 (figs. 18, 30). Each 
pear-shaped ovary is attached at its anterior narrow end to 
the septum in front not far from the middle line. Sometimes 
the two almost fuse below the gut (fig. 36). Towards the 
free posterior end of the ovary the cells increase in size, form- 
ing a compact chain of growing ova with granular cell-bodies 
and large vesicular nuclei (fig. 31). A right and a left 
ovarian sac enclose the ovaries (figs. 1, 29-34). A blood- 
vessel runs over the outer surface of the ovarian sac, the inner 
lining of which is composed of large granular cells forming a 
very conspicuous deeply staining epithelium (fig. 14). These 
cells appear to build up yolky material for the nourishment 
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