526 FEMALE UROGENITAL ORGANS IN THE MARSUPIALIA, 



the common mass of connective tissue, to open by a single aper- 

 ture into the urogenital sinus. The sinus has a length of about 

 5 mm. It opens with the rectum into a distinct cloaca. The 

 clitoris, situated ventrally at the junction of sinus and cloaca, is 

 attached throughout its length; it is deeply grooved dorsally and 

 markedly bifid at its apex. Two pairs of anal glands are present. 

 The cloacal opening is narrow, somewhat spout-like, and ventrally 

 directed. 



In Petaurus breviceps the uteri and lateral vaginas arc related 

 very much as in Acrobates. The median vaginal apparatus, how- 

 ever, consists of a single and quite short undivided canal, which 

 ends blindly in the connective tissue, at a considerable distance 

 from the anterior end of the urogenital sinus. According to 

 Forbes* in P. sciureus " there are apparently two small cul-de- 

 sacs ; but the specimen examined does not allow me to say 

 whether or no they unite." 



V. On the Existence at Parturition of a Pseudo-Vaginal 

 Passage in Trichosurus vulpecula. 



(PL xxix , fig. 9). 



In Contribution I.,f while discussing the general significance 

 of the occurrence of a direct median passage for the birth of the 

 young in Marsupials, the following remark occurs : " As regards 

 other forms, there are some, e.g., Trichosurus vulpecula, in which 

 the young are almost certainly born through the lateral vaginal 

 canals, here comparatively short and simple in their course " 

 (p. 74). Since the date of writing the above I discovered that 

 in Dasyurus viverrinus a pseudo-vaginal passage essentially 

 similar to that described for Perameles exists at parturition and 

 serves for the outward passage of the young, t The wholly 



* Forbes, W. A. "On some Points in the Anatomy of the Koala (Plms- 

 colarctos cinereus)." P.Z.S. 1881, p. 190. Footnote. 

 + Proceedings, 1899, Part i. 



J Hill, J. P. " On the Foetal Membranes, Placentation and Parturition 

 of the Native Cat (Dasyurus viverrinus)." Proc. Eoy. Soc. 1900. 



