VERTEBRATA, 3829 
that of a Duck, and webbed feet. The latter is covered 
with spines, has a long toothless snout, like the Ant-eater’s, 
and the feet are not webbed. Both burrow, and feed upon 
ea 
Fig. 321.—Ornithorhynchus. 
Insects. The brain is smooth in the Ornithorhynchus, and 
folded in the Echidna. In both, the cerebral hemispheres 
are loosely united by transverse fibres, and do not cover 
the cerebellum and olfactory lobes.’” 
2. Marsupials are distinguished by the fact that the 
young, always born premature, are transferred by the 
mother to a pouch on the abdomen, where they are at- 
tached to the nipples, and the milk is forced into their 
mouths by special muscles.” They have “ marsupial 
bones” projecting from the pelvis, which may serve to 
support the pouch; but as the Monotremes have the same 
bones, but no pouch, they doubtless have some other fune- 
tion. ‘These bones are peculiar to animals having no pla- 
centa, namely, to Monotremes and Marsupials. The brains 
of Marsupials resemble those of the Monotremes, except 
that the cerebrum of the Kangaroo covers the olfactory 
lobes. All have the four kinds of teeth, and all are coy- 
