56 FEMALE UROGENITAL ORGANS OF PERAMELES, 



opens on the ventral wall of the cloaca by a small aperture 

 (Plate i., fig. 1, O.U.S.), situated from 3 '5 to 5 mm, within the 

 margin of the cloacal opening. Its lining is thrown into longi- 

 tudinal ridges. The vaginal canals open together into its anterior 

 end dorsally, while a short distance posteriorly the urethra opens 

 on its floor under a slight median papilla. Also situated on 

 the floor of the sinus some distance behind the urethral opening is 

 the small clitoris. It lies in a distinct longitudinal depression, 

 justwithin the margin of the openingof the sinus, and is bounded by 

 lateral preputial folds which may be continued beyond the margin 

 of the opening. In form the clitoris is bluntly cone-shaped, and 

 measures from 1-5 to '2 mm. in length b}' about 1 mm. in greatest 

 breadth. It is attached over its whole extent, though exception- 

 ally its apex maybe free and slightly bifid. It is stated by Owen 

 and Brass that where the glans penis is bifurcate in the male, in 

 the female the clitoris is likewise bifid, but this statement does 

 not hold for Perameles. 



I am unable to discover any reference in the literature to the 

 minute structure of the clitoris in Marsupials; the following facts 

 may therefore be of interest. Shortly in front of the clitoris two 

 ducts leave the floor of the urogenital sinus and run back in the 

 ventral wall of the latter to enter the clitoris proper. The 

 lumina of these canals may be continuous or interrupted, or the 

 ducts may even be entirely solid in difi"erent females. They run 

 back enclosed below by a horse-shoe-shaped band of erectile 

 tissue. Posteriorly, towards its apex, the clitoris is divided into 

 two halves by a median septum (Plate v., fig. 9, m.s.) each half 

 containing one of the canals below which is a horse-shoe-shaped 

 mass of erectile tissue [e.t.). Eventually the canals open on the 

 surface of the organ shortly behind its apex (fig. 9, c.d.). 



In view of the above, it is interesting to note that according to 

 Owen (8, p. 312) "in the Perameles lagotis not only is the glans 

 [penis] bifurcate, but each division is perforated and the urethral 

 canal is divided by a vertical septum for about half an inch 

 before it reaches the forked glans." 



