528 FEMALE UROGENITAL ORGANS IN THE MARSUPIALIA, 



From these two quotations it will be seen that, according to 

 Brass, the median vaginal apparatus consists of two completely 

 separated halves; according to Forbes, of a single chamber with 

 only slight traces of a median partition. My own observations 

 show that both conditions occur. In the organs of undoubted 

 virgin animals, the apparatus consists, as Brass describes, of two 

 cul-de-sacs completely separated by a thin, often semi-transparent 

 partition. The two cul-de-sacs terminate in the connective tissue 

 ventral to the converging posterior portions of the lateral vaginae, 

 between the latter and the neck of the bladder and some distance 

 in front of the anterior end of the long urogenital sinus. In the 

 organs of females which have given birth to young, on the other 

 hand, I find that the median partition has over by far the greater 

 portion of its extent disappeared, thus placing the two cul-de- 

 sacs in wide and open communication. In such females, remnants 

 of the septum are present, usually in the form of dorsal and 

 ventral median folds of slight though varying width. Occa- 

 sionally the two folds may meet in front and behind, and excep- 

 tionally I have found the two cul-de-sacs in communication 

 through a large aperture in the posterior portion of the septum, 

 here largely persistent. 



The question now arises, at what period does the vaginal 

 septum break down ? What little definite evidence I possess 

 points to the conclusion that the rupture and consequent dis- 

 appearance of the greater portion of the septum is contempo- 

 raneous with the first act of parturition and probably is brought 

 about by the passage of the young one into one or other of the 

 cul-de-sacs In the organs of a female which had quite recently 

 had young (a, below), I find the two vaginal cul-de-sacs in open 

 communication, but very considerable remnants of the septum 

 are present in the form of wide dorsal and ventral folds. Not 

 only so, their free margins present a torn and quite irregular 

 appearance, forcibly suggesting that the septum had only recently 

 been ruptured. 



In view of the above and the fact that while in late pregnant 

 females the septum may be found complete, such is never the 

 case so far as I have observed in multipara, and further from 



