244 



ZOOLOGY. 



link between birds and mammals, the tongue is long and 

 slender, like that of the ant-eater, while the body is armed 

 with quills like those of a porcupine, as well as hairs. The 

 claws are very large and strong, adapted for tearing open 

 ant-hills in order to devour the ants. Its eggs are 2 cm. long. 



Sub-Class II. — Marsupialia. 



General Characters of Marsupials. — These are singular 

 forms, represented by the opossum in this country, and the 

 kangaroo, with a number of other forms, in Australia. 

 They differ from all other mammals in having a pouch 



Fig. 385.— Opossum, with side view of pelvis, with the marsupial bone, M. 



(marsupium) for the reception of the young immediately 

 upon birth, where they are attached to the nipples at the 

 bottom of the pouch. This large pouch (which is however 

 absent in certain opossums and in the "Tasmanian devil") 

 is supported by two long slender bones (Fig. 285, M) attached 

 to the front edge of the pelvis, and projecting forwards. 



In the opossum, the kangaroo, and probably most mar- 

 supials, the young, which are very rudimentary and small 

 when born, remain in the pouch attached to the nipple, 

 which fills the month. " To this it remains attached for a 

 considerable period, the milk being forced down its throat 

 by the contraction of the cremaster muscle. The danger 



