MAY, 1921. AMERICAN MARSUPIAL, C^NOLESTES OSGOOD. 67 



apparently of similar character, is recorded by Hill (Proc. Linn. Soc. 

 N. S. W., XXIV, p. 46, 1899) for Perameles and Macropus. 



The bladder in its posterior half and the adjoining part of the uro- 

 genital sinus have their ventral surfaces connected with the abdominal 

 wall at the linea alba by a vertical membrane, the "Ligamentum vesicae 

 medium" of Brass and Hill. The bladder is also attached at the base 

 laterally by a fold on each side running forward into the broad ligament. 

 The ureters pass dorsad of the uteri and dorso-laterad of the uterine 

 neck, enveloped in the broad ligament, and enter the base of the bladder 

 dorso-laterally, passing between the vaginal cul de sac and the lateral 

 vaginal canals and parallel to them. 



The uterine necks are very closely attached to each other along the 

 median line but may be separated without destruction of their walls 

 to the beginning of the median vaginae. The os tincae, however, are 

 completely coalesced and in the virgin female examined they are of 

 extraordinary size, extending the full length of the vaginal cul de sac 

 and having thick, slightly rugose walls. They are attached dorsally and 

 ventrally by strong septa, forming two distinct lateral vaginal chambers. 

 In an older female they were found to be relatively much smaller. 



The thin-walled vaginal cul de sacs extend nearly to the base of 

 the bladder on its dorsal surface and are attached to it and to the 

 urogenital sinus by connective tissue, but without direct communication 

 in the virgin female specimen examined. In a pregnant and probably 

 multiparous female a possible connection was observed between the 

 median vaginae and the urogenital sinus. An irregular opening was 

 found but some destruction of tissue had occurred before the specimen 

 was examined, so the point needs verification. If this should prove to 

 be of regular occurrence it would be an important indication of rela- 

 tionship to the diprotodonts, for it is essentially characteristic of most 

 of them. 



The lateral vaginal canals leave the median vaginae in a dorsal direc- 

 tion and turn sharply caudad and then craniad in several convolutions, 

 nearly to their origin, where they again turn and run directly caudad to 

 their endings on the lateral walls of the urogenital sinus posterior to the 

 ureters. The length of one of the canals fully extended is 10 mm. or 

 two-thirds longer than the uteri. In this respect, therefore, C&nolestes 

 shows some approach to the condition in Macropus, where the vaginal 

 canals are always longer than the uteri. The urogenital sinus from the 

 base of the ureters to the cloaca is 9 mm. long in a young female. 



The rectum and the urogenital sinus open into the common cloaca 

 at about the same level, 3 mm. from the lips of the external orifice. The 

 clitoris is situated in a pocket of membrane on the dorsal wall of the 



