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 >: 



||orfe 



THE MACMILLAN COMPANY 

 1927 



All riphts rrservtd 



