MOEPHOLOGY OF THE HUMAN UKINOGENITAL TEACT. 345 



moulded on this central fact I have not yet had time to deter- 

 mine exactly, but it might be considered in the case of some of the 

 lower animals first— c.r/., in the dog. I may point out, however, 

 that the pudic artery and nerve supply the lower end of the 

 genital tract and external genitals, but the exact upper boundary 

 of this supply I have not had time to look into. It is probable, 

 however, that the urinogenital and rectal tract may be divided 

 into two great parts, an upper and lower. The latter comprises 

 external genitals, lower end of urethra, lower third of vagina 

 and anus: the former, the rest of urethra, the bladder, upper 

 two-thirds of vagina, uterus and tube, and rectum. Herman 

 records a remarkable case where from nerve or vascular 

 influence this lower part alone seems to have sloughed. Von 

 Lingen has also drawn attention to a number of cases where a 

 cast of the upper part of the vagina and vaginal portions of the 

 cervix, comprising mucous membrane, submucous and some 

 muscular fibre, has sloughed off. He points out that this part 

 is supplied by the cervico-vaginal branch of the uterine artery^ 

 and one supposes that thrombosis of this branch must have 

 occurred. Tliese pathological cases form an interesting comr 

 ment on the view I have given. 



3. The formation of the female and male urethra and the chcv7ujes 

 at the urethral orifice. — In the female the urethra is developed 

 from the lower end of the anterior division of the primitive gut. 

 It is possible, as I have already suggested, that during the for- 

 mation of the hymen the urinogenital sinus becomes blocked, 

 and the urethra at its lower end perforated from below again 

 {v. p. 344). 



The male urethra is formed from the primitive gut in the 

 same way down as far as the colliculis seminal is, the hy- 

 meneal analogue. Below this, where the adult female is, as 

 it were, hypospadic, the male urethra is closed. As, however, 

 this same hypospadias exists in the embryo in both sexes, the 

 question arises as to how the male urethra becomes ultimately 

 closed on its inferior aspect. The usual statement is that the 

 parts analogous to the labia minora in the female unite by their 

 edges and thus close in the canal. Of this method of closure 

 there is only a fair amount of proof, and it does not explain how 

 the male glans becomes perforated. 



