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fallopian tubes into the upper attached portion of the uterus, — no 

 doubt, in consequence of the ova having been impregnated during 

 their transit through that portion of the uterus into which the 

 testicles open as already described. From this point downwards 

 the progressive development of the ova can be readily followed. But 

 as this communication has already extended beyond the limits I had 

 marked out for it, instead of giving my readers a detailed descrip- 

 tion of the process of development, I shall take the liberty of refer- 

 ring them to the accompanying figures, which accurately represent 

 the different appearances observed in the ova from the time of their 

 exit from the ovary till their arrival in the vagina (PI. XL VI. fig. 7, 

 PI. XL VII. figs. 9, 10, 11 and 12). I may here only further re- 

 mark, that impregnation evidently takes place from above down- 

 wards, and that no spermatozoa in any stage of development could 

 be detected in any part of the uterus ; thus forbidding the idea of the 

 animals having received the vivifying fluid from a separate male 

 organ after the uterus had been filled with ova. 



Having now completed my remarks upon the anatomy of the en- 

 tozoon, I shall proceed to say a few words upon the important ques- 

 tion of its sex, and I may premise these words by observing that it 

 appears to me that some naturalists are at present running to extremes 

 in attempting to find separate sexes in all animals, and to prove that 

 there is no such thing as hermaphroditism in nature. Ultra views 

 are at all times to be condemned, and I think in no case more so 

 than the present, when the obstacles besetting the path to a definite 

 conclusion are as complicated as they are numerous. A few years 

 ago several members of the genus Pentastoma were regarded as true 

 hermaphrodites by the most distinguished naturalists ; and now since 

 some of the species have been ascertained to have separate sexes, a 

 recent writer has ridiculed the idea of a single example of this large 

 genus having male and female organs of generation united in one 

 individual. I do not intend to say that he has erred in jumping too 

 hastily to his conclusion, but merely to remark that the entozoon 

 which I have described in the foregoing pages, if not strictly belong- 

 ing to the genus Pentastoma, is yet in many of its characters very 

 closely allied to it, and that it still remains to be shown that this 

 animal is not a hermaphrodite. As there are two sides to every 

 question, and as it is wrong to give an opinion before both have been 

 examined, I shall briefly state my reasons for thinking it possible that 

 the animal we have just been considering is a female, and that the 

 true male organs of generation are to be sought for in another indi- 

 vidual. 



The Linguatula tcenioides, which is the nearest allied species to 

 my entozoon, was described by naturalists of the very highest stand- 

 ing, such as Owen, Valentin, Von Siebold, Dujardin and others, as a 

 hermaphrodite, in consequence of their finding that it possessed, in 

 each individual, organs containing the female and organs containing 

 the male reproductive materials in different stages of their develop- 

 ment ; and that these organs were not only so arranged as to allow 

 of the vivifying contents of the one coming into contact with those 



