BT T. THOMSON FLVNN. 



883 



portions of the Miillerian ducts remain permanently embedded 

 in tlie persistent genital cord of the embryo. In the position 

 where the median vaginal cul-de-sacs disappear, there remains, 

 •occupying tlie central portion of the cord, a mass of deeply 

 •staining tissue, in the lateral portions of which the lateral vaginal 

 •canals are enclosed. Sectioning further back, the lateral vaginal 

 canals are found to diverge and lose connection with this central 

 mass of tissue. They soon come to lie at the surface, and the 

 central, deeply staining mass has become of rhomboidal shape, 

 as shown in Fig.9, where are also seen, between this mass and 

 the lateral vaginal canals, the inpassing ureters. 



The divergence of the lateral canals is still greater in Fig. 10, 

 somewhat behind Fig.9, and the central mass has still further 

 changed its shape, as shown in the figure. After the ureters 

 have entered tlie bladder, the lateral vaginal canals quickly 

 converge, to enter the short cylinder of tissue continuous 

 externally with the wall of the urogenital sinus, and correspond- 

 ing to the urogenital strand of Perameles. The lateral vaginae 

 now come again into relation with the central mass, and, shortly 

 .after this, become quite obliterated without any lumen. These 



closed canals can be seen 

 to come into relation with 

 the urogenital sinus. The 

 deeply staining mass above 

 spoken oi{x) represents the 

 path of the pseudovaginal 

 passage. The presence of 

 this passage is indicated 

 by various breaks or splits 

 in the tissue, some of 

 which extend through a 

 considerable number of 

 sections. At the anterior 

 -and posterior ends, however, the passage has quite healed 

 «up. The central mass(a;) comes into relation with the lateral 

 canals at the point where these canals 



Fig. 10. 



vaginal 



become- ^ ,■ 





^ -^9^^ 



V' 



LIBRARY -x-}] 



