3;W ON PARTURTTION IS' MARSUPIALS. 



of tlie digits of the foot. Tlie early initiation of the lip-fusion, 

 leading to the establishment of the sucking mouth, was demon- 

 sti'ated in a series of embryos of Trichosurus, and an interesting 

 comparison was instituted between the recentlj^ hatched young of 

 Oniithorhynchus and the new-born Marsupial. 



The remarkable and unique mode of parturition which occurs 

 in certain Marsupials was explained and illustrated by a series of 

 micro-photographs. It was shown that in Perameles, Dasyurus, 

 and Trichosurus the young reach the exterior, not through one or 

 other of the latei'al vaginal canals, but by way of a direct median 

 passage, constituted in front by the epithelially lined median 

 vagina and behind by a cleft-like " pseudo- vaginal passage," 

 actually formed at the time of parturition as a tear in the 

 connective tissue situated behind the median-, and between the 

 lateral vaginje. The occurrence of the same mode of parturition 

 was demonstrated for Phascolarctos (the fact being recorded here 

 for the first time), and lantern-slides were shown indicating that 

 the same mode of birth also holds good for the Gambd, {Didelphys 

 auritci). The bearing of these facts on the patent condition of 

 the median vagina in certain Macropods was brieily discussed. 



