PREFACE. 



THE PLAN. The general plan of the book is to introduce each of 

 the larger groups of animals by the careful study of a typical repre- 

 sentative. It is the aim to present a fairly complete picture of the life 

 of this type, its place of living ; its manner of securing food ; its 

 enemies and its means of protection ; its mode of locomotion ; the 

 processes of digestion, circulation, and respiration ; its sense organs ; 

 its development ; its relations to the plant world, to other animals, and 

 to man. Following the study of the type is a general account of 

 representative forms The characteristics of the group are given in 

 summarized form. Each chapter closes with a tabular classification 

 of the group. 



TIME FOR THE STUDY OF ZOOLOGY. Of the three seasons during 

 which school is in session, winter is the least desirable for the study 

 of animals. Many of the birds have migrated ; most of the insects 

 have been killed ; those that remain alive are in close hiding and are 

 hard to find, and still more so are their eggs, larvae, or pupae. A large 

 number of animals are hibernating. Animal life is at low ebb. The 

 choice of time, then, is practically limited to fall and spring. While 

 there is an abundance of life in the spring and some forms can better 

 be studied then, on the whole animal life is at its highest activity in the 

 fall. Again, since spring is preferred for botany, the fall seems the 

 best time for zoology. 



THE ORDER OF STUDY. The chief aim is to understand the lives 

 of animals. To know them it is necessary to study them in relation to 

 their surroundings. To do this to the best advantage they should be 

 studied when at the hight of their activity. These points, then, must 

 largely determine the order of study. For instance, if zoology is begun 

 in the fall, one finds insects active and abundant. Many forms are 

 laying their eggs to produce the generation of the following spring. 



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