CHAP. VII , MARSU PIALIA——-POUCH iE 
No 
on the whole in the Polyprotodont forms, such as the Thylacine, 
Dasyures, etc., but is found in.so many of them that the 
two divisions of the Marsupials, the Diprotodonts and the Poly- 
protodonts, cannot be raised to distinct orders on this and other 
grounds. The marsupial pouch of the Marsupials must not, as 
has been already pointed out, be confounded with the pouch of the 
Fig. 59.—Rock Wallaby (Petrogale xanthopus), with young in pouch. ~ #. 
(After Vogt and Specht. ) 
Monotreme mammals. Distinct teats are found in the marsupiun 
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 Polyprotodonts. Its walls are supported by 
a pur of bones diverging from each other in a V-shaped manner ; 
these are cartilaginous and vestigial in the Thylacine. They 
