

MAMMARY ORGANS IN MARSUPIALIA. 



771 



sphincter muscle. The interior of the pouch is almost naked : a 

 few hairs grow around the nipple : it is lubricated by a brown 

 sebaceous secretion. The mouth of the pouch is directed for- 

 wards in most Marsupials : the reversed position in the Perameles, 

 and Chseropus, where the 



605 



mouth is directed towards 

 the vulva, has been already 

 noticed. 



In the male Thylacine 

 the rudimental marsupium 

 is retained, in the form of 

 a broad triangular depres- 

 sion or shallow inverted 

 fold of the abdominal in- 

 tegument, from the middle 

 of which the peduncle of 

 the scrotum is continued. 

 In the female the orifice of 

 the capacious pouch is situ- 

 ated nearer the posterior 

 than the anterior boundary 

 of that receptacle. 



From experiments and 

 observations made at the 

 London Zoological Gar- 

 dens in 1833, I inferred 

 that in the case of the 

 Kangaroo the fore paws 

 were not used for the trans- 

 mission of the foetus, but 

 to keep open the pouch 

 ready for its reception, the 

 new-born animal being de- 

 posited therein by the 

 mouth, and so held over a 

 nipple until the mother 

 had felt it grasping the 

 sensitive extremity of the nipple. 



This means of removal is consistent with analogy ; dogs, cats, 

 mice, all transport their young from place to place with the 

 mouth. In the case of the Kangaroo, it may be supposed that 

 the foetus would be held by the lips only, not the teeth, on 

 account of its delicate consistence. There is no internal passage 



Female Didelphys dorsigera, with young and pouch. 



