OUTLINES OF ZOOLOGY 
CHAPTER I 
GENERAL SURVEY OF THE ANIMAL 
KINGDOM 
In beginning the study of Zoology, it is natural and useful 
to try to get a bird’s-eye view of the “ Animal Kingdom.” 
Without this, one is apt to miss the plan in studying the 
details. But the survey can be of little service unless the 
student has the actual animals in his mind’s eye. 
VERTEBRATES, OR BACKBONED ANIMALS 
Mammals.—We begin our survey with the animals which 
are anatomically 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 quad- 
rupeds ; 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 distinguishable from Birds and Reptiles. 
These distinctive characters include 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 
brain, the occurrence of a muscular partition or diaphragm 
between the chest and the abdomen, and so on, as we shall 
I 
