PRACTICAL ZOOLOGY 



BY 



ROBERT W. HEGNER, Ph.D. 



ASSISTANT PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF MICHIGAN : 

 FORMERLY TEACHER OF NATURE STUDY IN THE SCHOOL OF EDUCA- 

 TION, UNIVERSITY OF CHICAGO, AND PROFESSOR OF BIOLOGY IN 

 THE STATE NORMAL SCHOOL AT RIVER FALLS, WISCONSIN ; 

 AUTHOR OF " INTRODUCTION TO ZOOLOGY," " COLLEGE 

 ZOOLOGY," AND " THE GERM-CELL CYCLE IN ANIMALS " 



Nefo Iforfe 



THE MACMILLAN COMPANY 



1915 



All rights reserved 



