TWENTIETH CENTURY TEXT-BOOKS 



ANIMALS 



A TEXT-BOOK OF ZOOLOGY 



BY 



DAVID S. JORDAN, M. S., M. D., PH. D., LL. D. 



PRESIDENT OF LELAND STANFORD JUNIOR UNIVERSITY 



VERNON L. KELLOGG, M. S. 



PROFESSOR OF ENTOMOLOGY IN LELAND STANFORD JUNIOR UNIVERSITY 



AND 



HAROLD HEATH, PH.D. 



PROFESSOR OF ZOOLOGY IN LELAND STANFORD JUNIOR UNIVERSITY 



OF THE 



UNIVERSITY 



OF 



NEW YORK 



D. APPLETON AND COMPANY 

 1907 



