256 ENTOZOA. 



the joint ? And wliy need there be any external outlet, sphincter, 

 or papilla ? It is extremely difficult to believe in tins notion of 

 self-impregnation, notwithstanding Leuckart's clear descriptions 

 and the figure wherein he represents (s. 339 /. c.) the "Penis in Be- 

 gattung." In the hermaphroditic flukes, self-impregnation has 

 likewise been supposed to be the sexual method, but, since my dis- 

 covery of two distomes in the very act of coitus, I have ceased to 

 believe in the generally-received notion of a self-impregnation. It 

 may be, however, that I am wrong, and I cannot but respect 

 Leuckart's authority. 



The female reproductive apparatus consists of the ordinary 

 elements, but their relative degree of development and arrange- 

 ment is somewhat peculiar. According to Leuckart, the vaginal 

 passage is enlarged near the middle of its course, after which (pro- 

 ceeding inwards) it enlarges to form a pouch, which I take to be 

 the internal seminal vesicle. N'ear this point one would naturally 

 look for a communication with the dendriform uterus, but, if 

 Leuckart's description can be relied on, it is very different. Im- 

 mediately after forming this pouch (which contains a ball of sper- 

 matozoa rolled together) the vaginal canal — if such it may be called 

 — subdivides, one branch forming the main passage going to or 

 coming from the yelk-forming glands, the other going to or coming 

 from the ovary and the great uterine rosette. The glands in ques- 

 tion form two small lobulated organs, one on either side of the 

 lower part of the proglottis, the single ovarium, of about equal 

 size, being placed in the central line a little below these organs. 

 As the connections of this second or inferior division of the so-called 

 vaginal canal are so peculiar, I shall transcribe Leuckart's own 

 description, which runs as follows : — " The second canal divides 

 into two passages, of which one is continued on to the sac-like sin- 

 gle ovarium, and is consequently the true oviduct, whilst the other 

 probably communicates with the uterus. The latter passage seems to 

 constitute a wide cavity from the comniencement, for one recognizes 

 it rather late after the yelk-glands have emptied their contents into 



