OUTLINES OF ZOOLOGY. 



CHAPTER I. 



GENERAL SURVEY OF THE ANIMAL KINGDOM. 



AT the outset of our study of Zoology it is useful to take 

 a general survey of the " animal kingdom." Without some 

 such bird's eye view necessarily very superficial one is 

 apt not to see the wood for the trees. 



Mammals. 



We naturally begin a survey with the animals which are 

 most like man the monkeys. But neither we nor the 

 monkeys are separated by any structural gulf from the 

 other four limbed, hair bearing animals, to which Lamarck 

 gave the name of Mammals. For although there are many 

 different types of Mammals such as monkeys and men ; 

 horses, cattle, and other hoofed quadrupeds ; cats, dogs, 

 and bears ; rats, mice, and other rodents ; hedgehogs, 

 shrews, and moles, and so on the common possession of 

 certain characters unites them all in one class, readily dis- 

 tinguishable from Birds or Reptiles. 



Among these characters we rank the milk giving of the 

 mother mammals, the growth of hair on the skin, the 

 general presence of convolutions on the front part of the 



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