MARSUPIALIA POUCH 



I 2 - 



on the whole in the Polj'prutodont forms, such as the Thylacine, 

 Dasyures, etc., but is found in so many of them that the 

 UxQ divisions of the ]\Iarsupials, the Diprotodonts and the I'oly^ 

 protodonts, cannot be raised to distinct orders on this and other 

 grounds. Tlie marsupial pouch of the Marsupials must not, as 

 has been already pointed out, be confounded with the pouch of the 



Fig. 59. — Eock "Wallaby [Prtrogale, xanthopus), with young in pouch. 

 (After Vogt and Specht.) 



]\Ionotreme mammals. Distinct teats are found in the marsupiuni 

 of the Marsupials, while there are none in the mammary pouch of 

 the Monotreme, the pouch itself indeed representing an un- 

 differentiated teat, of which the walls have not closed up. The 

 pouch opens forward in the Kangaroos, and backwards in the 

 Phalangers and in the Polyin'otodonts. Its walls are supported by 

 a pair of bones diverging from each other in a V-shaped manner ; 

 these are cartilaginous and vestigial in the Thylacine. They 



