424 DR. M. WATSON ON THE MALE [Apr. 16, 



called spongy portion of the male urethra with that portion of the 

 urino-genital canal which, in the female, lies in relation to the clitoris, 

 is manifest. The erectile organ is of the same size, and constructed 

 upon the same plan, in both sexes, the only difference being that in 

 the female the urino-genital canal is not surrounded by the erectile 

 tissue of the corpus spongiosum as is the case in the male, this dif- 

 ference being due to the fact that in the latter the essentially bilateral 

 spongy bodies have coalesced in the middle line, whilst in the female, 

 in accordance with physiological requirements, they remain distinct 

 throughout life, and do not surround the sexual canal. In the 

 female, moreover, and associated with this arrangement, there is a 

 complete absence of the elevator urethrse and bulbo-cavernosi 

 muscles. 



It may be well now to ascertain whether the examination of this 

 animal throws any light upon the subject of the probable homo- 

 logues of the vagina and uterus in the male mammal. The majority 

 of embryologists (among whom I may mention the names of Leuckart, 

 Kolliker, and Allen Thomson) are now agreed that the so-called 

 utriculus of the male mammal represents both the uterus and vagina 

 of the other sex, these organs being formed by the coalescence of 

 the ducts of Miiller. I have, however, in a previous paper remarked 

 concerning the corpus uteri of the female H. crocuta, " That the 

 whole of this is to be regarded as corpus uteri, and not as consti- 

 tuting any portion of the vagina, is proved by the absence of any 

 constriction in its interior which might correspond to an os uteri, 

 the tubular body of the uterus remaining of the same calibre, and 

 having the walls of uniform thickness down to its opening into the 

 urino-genital canal." It is evident therefore that in the female H. 

 crocuta, the vagina being altogether absent, we must conclude that 

 in the male of this species the utriculus represents the uterus alone, 

 and not the uterus and vagina together. The same remark holds 

 good, so far as I can ascertain, of only one other placental mammal — 

 that is, of the Indian Elephant, in the female of which, as Mayer 1 

 pointed out, the vagina is altogether absent, and the uterus opens 

 directly into the urino-genital canal. In the male, therefore, of that 

 animal, as in that of H. crocuta, the utriculus, as shown by Leuckart 2 , 

 clearly corresponds to the uterus, and to the uterus alone, of the 

 female. With reference to the homologue of the prostate gland in 

 the female mammal, this, according to Prof. Allen Thomson 3 , is to 

 be looked for in tissue uniting the urethra with the vagina. We 

 might therefore be justified in expecting that in those animals in the 

 female of which the lower ends of the Mullerian ducts unite to form 

 the uterus and not the vagina, the prostate gland would be absent in 

 the male. Such is certainly the case in H. crocuta ; but that it 

 would be erroneous to accept this as a general law is proved by a 

 reference to the Elephant, in which, although the vagina is absent in 

 the female, the male nevertheless possesses prostate glands of con- 



1 Nova Acta Acad. Cajs. Leop.-Car. torn. xxii. p. 38. 



2 ' Cyclopaedia of Anatomy,' vol. iv., Art. '•Vesicula prostatica.'' 



3 Quain's ' Anatomy,' 8th edit. vol. ii. p. 826. 



