66 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XIV. 



levator muscle. The divided glans and the well-developed levator muscle 

 are doubtless both to be regarded as generalized conditions and it may 

 be concluded that if C&nolestes has retained one it is at least in a secon- 

 dary stage as regards the other. It is by no means certain that any of 

 the small paired muscles on the cephalo-ventral surface of the bulbous 

 urethra are homologous with the levator penis, but if not, then that 

 muscle, which is so well developed in Didelphis and some other polypro- 

 todonts, is entirely absent in Ccenolestes as it is in the Macropodidae. 



FEMALE ORGANS. 



Plate VIII. 



The female specimen dissected was a virgin. The ovaries were found 

 lying entirely exposed on the latero-ventral surface of the colon slightly 

 clasped by the fimbriated funnel of the oviduct. They are smooth and 

 disklike, about 2 mm. in diameter. The Fallopian tubes are rather 

 short and heavy as compared to those of the opossum. The uterine 

 bodies also are relatively short and less flattened than in Didelphis. They 

 appear simply as gradual expansions of the Fallopian tubes with only 

 a slight line of division. They are shorter than the outstretched vaginal 

 canals and measure approximately 6 mm. in length from the end of the 

 oviduct to the base of the median vaginae. The general relations of the 

 peritoneal folds forming the uterine fossa and the broad ligament are 

 as in other marsupials. 



The round ligament is well developed. In gross dissection its rela- 

 tions to the ovary and the uterus could not be determined positively. 

 Apparently it does not extend directly to the uterus but is lost in the 

 thickened part of the broad ligament to which the ovary is attached and 

 from which a well-defined branch runs to the anterior part of the 

 uterus. Possibly this branch is a continuation of the round ligament, but 

 this could not be determined. This round ligament is attached by a 

 membranous fold which extends in directly transverse relation to the 

 broad ligament and thence to the dorso-parietal wall of the body cavity. 

 Its antero-yentral border is rounded and about equal in diameter to the 

 oviduct. Seen from the ventral side it passes at right angles beneath 

 (dorsad) the folds of the oviduct and the broad ligament and makes a 

 sharp turn craniad to join the thickened mass upon which the ovary 

 rests. It is so distinct and well-developed that it does not seem likely 

 that it can be anything other than the homologue of the round ligament 

 of higher mammals. Its occurrence is one of the most noteworthy fea- 

 tures of the female urinogenital system of Canolestes. I am unable to 

 detect any trace of a similar ligament in Marmosa. A round ligament, 



