122 NOTKS ON M XKSUl'IALIAN ANATOMY. 



we have in T. caninus the internal lining raised into a 

 number of large, rounded folds, separated bv deep grooves, 

 the whole having a reticulate appearance. In T. vulpecula, 

 on t.lie other hand, the reticulate appearance is confined to 

 ♦lit- area around the os uteri, and even in tliis region is 

 not very conspicuous, the remainder cf the cul-de-sac being 

 occupied by a scries of slightly raised long, narrow folds. 

 The presence of the strong septum as well as the other 

 points mentioned give the median vaginal apparatus in T. 

 caninus an appearance of strength absent in other members 

 ■of the genus. 



A study of the table given by Van den Broek (5) 

 summarising the existing knowledge of the changes occur- 

 ring in the median vaginal apparatus consequent on parturi- 

 tion, brings strongly forward the general rule that where 

 the young are borne through a direct median passage, the 

 septum between the two cul-de-sacs is more or less incom- 

 plete. A possible exception to this is Sarcophilus (6), but 

 it is as yet doubtful whether the young are here not borne 

 through the lateral canals, although the main evidence 

 points to the median passage as theii' means of exit- At 

 first, as stated in his work on the anatomy of the female 

 organs in Per-ameles, Hill (7) believed that the young of 

 Trichosurus were borne thi'ough the lateral canals, "here 

 comparatively short and simple in their course," but later 

 lie communicated the discovery of a pseudo-vaginal passage 

 in that genus similar to that in Perameles and Dasvurus 

 viverrinus (8). These -^oints may be summarised as fol- 

 lows : — 



(1.) Marsupials which possess in the virgin completely 

 separated median vaginal cul-de-sacs, and in which, after 

 parturition, these cul-de-sacs are in communication, bear, so 

 far as is known, their young through a direct median 

 passage. 



(2.) In some genera of marsupials (e.g.. Didelphys and 

 Trichosurus) one species may still have an entire septum 

 after parturition, while another mav not- 



Hence, it is possible that in a genus of marsu])ials in 



5. I.oc. cit., p. •27<<-'i7S. 



6. FIvnn.T. T " Cdtitiil.iil i'.iis 1 .1 ;i luKiwlcil^e of tlie Aivit. .iiid Dev of the 

 ■Marsnpiiilia." I. I'.L.S., N.S.W., idio. 



7. I^oc. i-it 



(S. Hi'l, .1.1*. '•(•<.iitiiliiiti..ii t<i ibc .Mdinli. .-iiul Dov. of llic Keiii Uioji. 

 OiRaiis in tlic .Miiisiii-iiilia ' II. \'. I'.L S., N.v.W., v.tm, j.. .•, (i. 



