TWENTIETH CENTURY TEXT-BOOKS 



ANIMAL STUDIES 



A TEXT- BOOK OF ELEMENTARY ZOOLOGY 

 FOR USE IN HIGH SCHOOLS AND COLLEGES 



DAVID STARR JORDAN 



PRESIDENT OF LELAND STANFORD JR. UNIVERSITY 



VERNON LYMAN KELLOGG 



PROFESSOR OF ENTOMOLOGY 



AND 



HAROLD HEATH 



ASSOCIATE PROFESSOR OF INVERTEBRATE ZOOLOGY 

 IN LELAND STANFORD JR. UNIVERSITY 



NEW YORK 



D. APPLETON-CENTURY COMPANY 



INCORPORATED 



