116 



HUMAN EMBRYOLOGY AND MORPHOLOGY. 



except man it retains this form. By the beginning of the 6 th 

 month in the female foetus (Fig. 92 B) it will be seen that the 



uterus 



cord.-i : i'" : 



uterus 



bladder 

 Cir rectum 

 vagina 



uro-gen. canal 



symph. 



clitoris 



A. 



uro-gen. canal 



B. 



Flo. 92.— Section showing the Uro-genital Sinus. 

 A. In the 4th month female human foetus. B. In the 5th month female human foetus. 



vesicovaginal septum (a in Fig. 92) has grown down towards the 

 pudenal cleft, and all that remains of the uro-genital sinus is 

 the small space of the female pudendal cleft from the fossa 



cord 



symphSgj^: --uterus and 



vagina 



rectum 



uro-gen. canal 

 iriang. lig. 



penile urethra 



Fig. 03. — Section showing the Uro-genital Sinus in the male foetus. 



a indicates the part corresponding to the vesico-vaginal septum of the female. It is 



occupied by the 3rd lobe of the prostate. 



navicularis behind to the vestibule of the vulva in front. 

 The vagina (Miillerian ducts) thus comes to open in the 

 pudendal cleft in the female. In the male (Fig. 93) the early 

 foetal form is retained, and the uro-genital sinus becomes that 

 part of the male urethra between the sinus pocularis and the 



