BY JAS. P. HILL. • 67 



following conclusions: — The young in Ferameles reach the exterior 

 by way of a direct median passage, constituted in front by a 

 comparatively short epithelially lined tube a few millimetres in 

 length, formed by the union of the posterior portions of the 

 median vaginal canals — the common median vagina — and behind 

 by a relatively very long, cleft-like space 3-4 cms. in length— the 

 pseudo-vaginal passage — lying in the connective tissue between 

 the lateral vaginal canals and leading back from the posterior end 

 of the former but, unlike it, " wholly destitute of any epithelial 

 lining or any other specialised wall" (3, p. 429). Although I 

 have not been able to demonstrate the presence of an opening 

 from the pseudo-vaginal passage into the urogenital sinus in any 

 of the specimens examined, there is not the slightest doubt but 

 that such an opening must exist before parturition can be com- 

 ])leted. Once that process is over, the opening, which must 

 simply be of the nature of a rupture or breaking thi'ough by the 

 young of the epithelial lining of the sinus, apparently rapidly 

 heals up and must be reformed anew at every act of parturition 

 as a temporary opening place for the exit of the young. The 

 closure of this ojjening after each act of parturition is, without 

 doubt, simply a necessary result of the fact that the median 

 pseudo-vaginal passage is merely a solution of continuity entirely 

 destitute of any epithelial lining with which the ruptured epithe- 

 lium of the margin of the opening could become continuous. Its 

 edges simply have to unite with each other with the consequent 

 healing up and obliteration of the opening. 



When the pseudo-vaginal passage is once formed, it persists 

 throughout at least the greater portion of the posterior part of 

 its extent as an empty cleft-like space which no doubt serves for 

 the transmission of the young of successive gestations. But 

 anterioi^ly, immediately behind the posterior end of the common 

 median vagina, the pseudo-vaginal passage more or less completely 

 loses its continuity with the lumen of the latter after 

 each parturition owing to its becoming blocked up by the per- 

 sistent remains of allantoic stalks, surrounded and enveloped by 

 connective tissue sheaths. It is thus evident that in this region 



