vi PREFACE 



must find his nature elucidated 

 through evolution if this doctrine is 

 to maintain itself. What its value is 

 in this respect must be judged by 

 each reader. 



That the illustrative examples and 

 other like materials in the present vol- 

 ume are chiefly from zoological 

 sources is due to the fact that the 

 writer is a zoologist. It is scarcely 

 necessary to add that botanical ma- 

 terials afford the same kind of evi- 

 dence as that given in the body of 

 this text and might have been utilized 

 in the same way that the zoological 

 examples have been. 



It is the object of this volume to 

 present a brief, readable account of 

 the main facts of evolution, that the 

 ordinary reader may acquaint him- 

 self with what may be called the ele- 

 ments of the subject. That so large a 

 topic as evolution can be adequately 



