346 DR D. BERRY HART. 



Three of my specimens were available for studying this ques- 

 tion. The first was a male foetus between the second and third 

 months ; the second, a male at the third and a half month ; and 

 the third, one at the fourth month. 



In the first and second the closure was going on, but there 

 was no perforation of the glans ; in the third the perforation of 

 the glans was going on (tigs. 24, 25, and 2G). In regard to the 

 closure of the inferior aspect of the spongy portion of the 

 urethra, it can be noted that the greater part of the posterior 

 closure was due to a gradual growth forwards of epidermis and 

 deeper tissue towards the frtenum, and probably forming a solid 

 closure. Behind the frsenum the deep and superficial layers of 

 the epidermis passed in and back, the superficial cells being 

 central and tunnelling back to meet the higher part of the 

 urethra. These appearances are illustrated by figs. 24, 25, and 

 26. The posterior part of the urethra thus seemed to be closed 

 as usually described, but certainly tunnelling goes on from before 

 backwards, the active epidermis passing in and back, and by 

 central desquamation forming a lumen. The changes closing in 

 the posterior part are more difficult to follow, but those in front 

 are certain. 



Sections at the fourth and a half month show the prepuce in 

 course of formation, as I have already described. There is, 

 however, a remarkable condition to be noted at the apex of the 

 glans, where the epidermis passes in as a solid plug to cause 

 perforation of the glans there and tu meet the canal behind 

 (fig. 20). 



Thus, in the male urethra the canal is formed down to the 

 perineum by the urinogenital sinus : below this we get the canal 

 completed by a gradual and apparently solid closure of the ridges 

 from behind forwards. Immediately posterior to the freeimm 

 the epidermis passes in and back, making a lumen, as already 

 described ; finally, the glans is perforated by an epidermal plug, 

 and thus the continuous canal formed. 



Further observation is, however, needed on these points, which 

 are subsidiary to the present inquiry. 



