J 



CONTENTS Xvii 



PACK 



CHAPTER XXI 



Subphylum Vertebrata: Class VII. Mammalia . . . 632 



1. The Rabbit ....... 633 



2. A Brief Classification of Living Mammals . . . 641 



3. A Review of the Principal Orders and Families of Living 



Mammals 64; 



4. General Remarks on the Mammalia .... 676 



a, Integumentary Structures, 676 ; b, The Teeth of Mam- 

 mals, 678; c, The Development of Mammals, 680;^ 

 d, Hibernation, 682 ; e, Migration, 683 ; f, Domesti- 

 cated Mammals, 684 ; g, Fossil Mammals, 685 ; h,T'he 

 Economic Importance of Mammals, 688.^ 



CHAPTER XXII 



I*HE Ancestors and Interrelations of the Vertebrates 691 



1. The Relations between Vertebrates and Invertebrates . 691 



2. The Phylogenesis of Vertebrates ..... 693 



3. The Fossil Remains of Vertebrates ..... 696 



a, Succession of Life in General, 696; b, The Evolu- 

 tion of the Horse, 6q8. 



