990 MESSRS. LISTER AND FLETCHER ON THE [DeC. 13, 



exhibits a rather peculiar structure. The thin median septum — the 

 remains of the coalesced inner walls of the primitively distinct canals 

 — remains more perfect than usual ; and at a point rather behind the 

 middle of the median chamber the septum leaves the middle line 

 and becomes joined to the right side, thus forming a right cul-de-sac. 

 The left part of the chamber, however, is continued onward, becomes 

 more spacious where the right-hand one has ceased, and opens by a 

 distinct orifice in the usual position. The lateral canals are long, 

 and show the constriction distinctly. The cross fold, though not 

 prominent, is visible. 



It may be remarked that when the lateral canals were opened they 

 were found to be filled %vith a yellowish custard-like substance, in 

 which lay several fibrous irregular structures. Similar hard bodies 

 were found in the lateral canals of a specimen (2740 b) in the 

 Museum of the Royal College of Surgeons. Microscopic examination 

 showed no trace of spermatozoa. 



The specimen b had a young one (measuring 8| in. from the 

 snout to the root of the tail) in its pouch. The young was also a 

 female. 



The condition of the vaginal canals of the mother was just as 

 in specimen a, except that the median septum was less distinct, and 

 the lateral canals were empty. 



The minute generative organs of the young (c) (which of course 

 had not bred) were dissected ; and the median canal was found to end 

 in two csecal pouches separated from the urogenital chamber by a 

 thiir partition. Externally there is no indication whatever of separa- 

 tion between the end of the median chamber and the urogenital 

 canal. 



The sj)ecimen of Dendrolagus inuslus was obtained young by the 

 Society, and had lived alone in the Gardens for nearly three years. 

 In all probability, then, it had not born young. 



In this animal (fig. 3) the lateral vaginal canals are so closely applied 

 to the median canal that dissection is required to separate them. They 

 exhibit the constriction and cross fold very distinctly. The median 

 canal has a well-marked median fold along its ventral wall ; and 

 delicate trabeculse traversing the chamber complete the septum 

 here and there. Posteriorly the canal terminates blindly in two 

 lateral caeca, which are bounded by a thin wall at the sides, where 

 they abut against the part where the lateral canals open into the 

 urogenital chamber. The middle line is occupied by a short parti- 

 tion formed by the coalesced inner walls of the converging lateral 

 canals, see p. 989. 



The specimen of Hypsiprymnus gaimardi had undoubtedly born 

 young. The uteri open on prominences into the anterior end of the 

 median vaginal canal ; but the orifices are situated near one another 

 on the dorsal wall, not at the sides as in other forms. The anterior 

 part of the median septum is complete, and separates the two open- 

 ings. The median canal is long and narrow, and passes down with 

 a median ridge, but no further septum, and ends in two lateral culs- 

 de-sac, one on either side of the middle line ; but there is no opening. 



