4U THE VOYAGE OF II. .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 cceca. 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 broughl 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 (PL 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 1 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 cceca 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 maybe 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. ccecum 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 ovigcrms 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 tin- large 

 ovarian eggs, each having a nucleus with a, sparkling nucleolus (PI. \ I. fig. 2) about 



' ZooL Chall. Exp., part sxv. p. 12, pi. i. 6 



