94 DEVELOPMENT AND LACTATION OP MAMMALIA. 



vorcus animals, they are situated on the abdomen as well as the 

 thorax ; and in the Horse, Cow, and Sheep, &c., they are placed 

 still farther back, near the hip-joint. 



*<* Sometimes the young are born with their eyes open, and 

 cap immediately run about, and procure their own food ; but a 

 great number of the Mammalia come into the world with their 

 eyes shut, and in a state of such weakness that they can scarcely 

 move. There are even some, that appear as if born prematurely; 

 for their body is hardly formed, and they could not live if they 

 did not become grafted, as it were, on the breast of their mother, 

 where they remain suspended for a considerable time. It is also 

 to be remarked, amongst the greater part of the animals which 

 are born in this extreme state of imperfection, that the skin of 

 the abdomen, in front of the mammary glands, forms a pouch, 



Fis. 48. OPOSSUM. 



which contains and protects the young. This peculiarity of 

 structure characterises the Opossums (Fig. 46), the Kangaroos, 



