1888.] NATURAL SCIENCES OF PHILADELPHIA, 191 



to the skin on the under surface of the penis. It has already been 

 mentioned that an early stage in the development of the mammalian 

 embryo the rectum, bladder, Mullerian ducts (the latter in the female 

 becoming the vagina and uterus) pass into the cloaca, and that as 

 development advances the rectum sepai-ates from the cloaca, open- 

 ing by the anus. With a still further advance in development the 

 uterus separates from the uro-genital canal and opens by a distinct 

 canal, the vagina, the bladder opening through the urethra. While 

 such is the normal order of develoiDmeut of the female generative 

 apparatus in the mammalia, it may be readily conceived that, should 

 the develoi^ment be arrested at the stage in which the uterus and the 

 bladder still pass together into a uro-genital sinus and should the 

 latter traverse the clitoris in the same manner as the urethra does in 

 the case of Capromys etc., a disposition precisely similar to that found 

 by Prof. Watson and the author, in the female of Hyaena crocuta 

 would result. If the above view be admitted, then the peculiar ar- 

 rangement of the female generative apparatus in Hyoena ei^ociUa 

 may be regarded as due to an arrest of development. One of the 

 most remarkable peculiarities of the female generative apparatus of 

 Hycena crocuta, to which we have hitherto only incidentally alluded, 

 is the entire absence of a vagina, the uterus passing directly into 

 the urogenital canal in which respect the animal differs from 

 all other mammalia, except perhaps the elephant. In the latter an- 

 imal in both the Indian and African species, as observed by the 

 author^ a long and capacious urogenital canal leads into the bladder 

 on the one hand and on the other into a cavity which the author 

 regarded either as corresponding to a vagina or to the neck of 

 the uterus, this cavity leading in turn into the body of the uterus. 

 Should the latter view be accepted, that is if the cavity in question be 

 regarded morphologically as uterine, then the vagina would be ab- 

 sent in the elephant, as it is without doubt in the hysena. In con- 

 clusion it may be mentioned that the fact of the vagina being undoubt- 

 edly absent in Hyeena crocuta and probably also in the elephant 

 settles definitely, at least for these animals, the question as to whether 

 the utriculus or sinus pocularis of the male should be regarded as 

 the homologue of the uterus or the vagina of the female, since if the 

 vagina be absent in the female hysena and elephant the utriculus of 

 the male of these animals must necessarilv be homolocrous Avith the 

 uterus of the female. 



1 On the Placenta and female generative apparatus of the Elephant. Toumal 

 of Acad, of Nat. Sci. of Philad., n. s. VIII p, 413. 



