370 



ZOOLOGY. 



male opening ; near the ootype the oviduct forms a small 

 dilatation, the receptaculum seminis, in which the sperma- 

 tozoa received in copulation are stored. 



The genital papilla is situated on the margin of the pro- 

 glottis, but not always on the same side ; it is sometimes 

 on the left side, sometimes on the right, but not in regular 

 alternation. 



The above description applies to the fully-developed 

 genital organs, which in Taenia solium are found in the 

 450th and following proglottids. In the youngest pro- 

 glottids immediately following the neck no trace of 

 genital organs can be detected : as they grow older and 

 farther removed from the point of origin the organs 

 begin to develop, the male organs first and afterwards the 

 female. 



6. Process of Reproduction. The process of copula- 

 tion is not completely understood, but it is believed that 



the penis protruded from 

 the male aperture is in- 

 serted into the vagina of 

 the same or a neigh- 

 bouring proglottis, and 

 spermatozoa are thus 

 conveyed to the recepta- 

 culum. As in Trema- 

 todes, the ova derived 

 from the ovaries are 

 fertilised in the ootype, 

 surrounded by yolk cells 

 from the vitellarium or 

 yolk gland, and then en- 

 closed in an egg-shell 

 secreted by the shell- 

 glands. 



The eggs when complete pass successively into the uterus, 

 in which they accumulate, and as the number of perfect 

 eggs increases the uterus enlarges and develops lateral 

 caeca, as shown in fig. 22, until at last it occupies nearly 

 the whole of the proglottis, and the rest of the reproductive 



Ut- 



Fig. 191. HALF-RIPE PROT.LOTTIS OF 



SHOWING BRANCHED UTERUS. 



Ut, uterus. 



