



a- 



^ ?z 



PRINCIPLES OF 



ANIMAL BIOLOGY 



BY 



A. FRANKLIN SHULL 



Professor of Zoology in the University of Michigan 



WITH THE COLL-IBORATION OF 



GEORGE R. LARUE 



Professor of Zoology in the University of Michigan 

 AND 



ALEXANDER G. RUTHVEN 



President of the U niversity of Michigan 



i 



Sixth Edition 

 Second Impression 



McGRAW-HILL BOOK COMPANY, Inc. 



NEW YORK AND LONDON 

 1946 



