234 



FIRST LESSORS IN ZOOLOGY. 



CHAPTEE XXXIII. 

 THE MARSUPIALS OR POUCHED MAMMALS. 



ALTHOUGH the spiny ant-eater has a brood-pouch, the 

 true pouched mammals are represented by the opossum 

 (Fig. 235), kangaroo (Fig. 236), and a number of other 

 kinds, all of which, except the opossum, live in Aus- 

 tralia. The pouch is supported by two long slender 

 bones (Fig. 235, M) attached to the front edge of the 



FIG. 235. Opossum, and side-view of pelvis, with the marsupial bone, M. 



pelvis, and projecting forwards. In the opossum, the 

 kangaroo, and probably most marsupials, the young, 

 which are very rudimentary and small when born, live 

 in the pouch attached to the nipple, which fills the 

 mouth. "To this it remains attached for a consid- 

 erable period, the milk being forced down its throat by 

 the contraction of the cremaster muscle. The danger of 

 suffocation is avoided by the elongated and conical form of 

 the upper extremity of the larynx, which is embraced by 



