BLAKISTON'S SCIENCE SERIES 



ZOOLOGY 



A TEXT-BOOK FOR 

 UNIVERSITIES, COLLEGES 

 AND NORMAL SCHOOLS 



BY 



THOMAS WALTON GALLOWAY, PH. D., Lrnr. D. 



'ROFESSOR OF ZOOLOGY, BELOIT COLLEGE, BELOIT, WISCONSIN; FORMERLY PROFESSOR 

 OF BIOLOGY IN THE JAMES MILLIKIN UNIVERSITY, DECATUR, ILLINOIS 



THIRD EDITION, REVISED 

 WITH 255 ILLUSTRATIONS 



PHILADELPHIA 



P. BLAKISTON'S SON & CO. 



1012 WALNUT STREET 



