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THE VOYAGE OF H.M.S, CHALLENGER. 
VI. THE FEMALE GENITAL APPARATUS. 
According to Darwin, the female genital apparatus consists of the true ovaria, or 
glandular bodies seated on each side, not far from the basal edge of the labrum ; the 
main or unbranched ovarian ducts ; and the ovarian branching tubes and coeca. The 
latter in the pedunculated Cirripedia are placed high up in the peduncle, and in all sessile 
Cirripedia lie between the calcareous or membranous basis and the inner basal lining of 
the sack. After the most careful and repeated examination of various Lepadidse 
and Balanidse, Darwin became convinced that there were no oviducts ; he therefore 
supposed that the ova were brought to the surface by the formation of a new membrane 
round the sack underneath them, and by the subsequent exuviation of the old membrane. 
This supposition of Darwin’s has proved to be erroneous. What Darwin called the main 
or unbranched ovarian duct is in reality the oviduct ; it does not run up to the glandular 
bodies (which I have described in one of the foregoing chapters), but it passes at some 
distance beneath them (PI. VI. figs. 7 and 8); it describes a curve and then enters the basal 
segment of the first cirrus, at the foot of which it opens. 1 Krohn was the first to describe 
the female genital apparatus accurately ; Kossmann, though in the main agreeing with 
Krohn, differs from him with regard to the significance of the little shoe-shaped sack 
which is placed in a swelling of the oviduct near its opening. I studied the female genital 
apparatus in Lepas, Scalpellum vulgare and Scalpellum regium, in Conchoderma 
virgatum and in Balanus. In all essential points the results of my researches tend to 
confirm those of my predecessors ; in detail I think I am able to add to our knowledge. 
From the existence of two oviducts we may conclude that there are also two ovaries 
present. In the full-grown animals their numerous and strongly ramified cceca are 
united so intimately that they seem to form a single mass only. The coeca of the 
right side, however, communicate with the right oviduct, the others with that on the 
left. 
A study of the way in which the ova are formed has given the following results. 
The oviduct itself is lined by a very distinct and well-developed epithelium ; where the 
limits of the cells are not distinct, which may be due to the condition of the material 
at command, the nuclei are placed so regularly along the wall that even the dimensions of 
the epithelial cells can still be made out. Where the oviduct passes over into a coecum of 
the ovary, the epithelium of the wall is no longer so distinct, and in its place nuclei 
are seen rather irregularly along the wall ; of the true body of the cell there are only 
traces here and there. The ovigerms or future ovarian eggs are seen in the interior along 
this wall. When the ovary is mature or nearly so, we observe in the first place the large 
ovarian eggs, each having a nucleus with a sparkling nucleolus (PI. VI. fig. 2) about 
1 Zool. Chall. Exp., part xxv. p. 12, pi. i. fig. 2. 
