PRINCIPLES OF ZOOLOGY: 



TOUCHING 



THE STRUCTURE, DEVELOPMENT, DISTRIBUTION, 

 AND NATURAL ARRANGEMENT 



RACES OF ANIMALS, LIVING AND EXTINCT 



WITH NUMEROUS ILLUSTRATIONS. 

 PART I 



COMPARATIVE PHYSIOLOGY. 



FOR THE USE OF SCHOOLS AND COLLEGES. 

 BY 



LOUIS AGASS1Z AND A. A. GOULD, 



REVISED EDITION. 



BOSTON: 

 OOULD AND LINCOLN, 



50 WASHINGTON STREET. 



NEW YOKK: SHELDON AND COMPANY. 

 CINCINNATI : GEO. S. BLANCUAKD. 



1869. 



