CONTENTS xv 



XXVI. WHALES, 666. 



XXVII. CARNIVORES 



i. Affinities of carnivores and ungulates: Cohort Ferungulata, 677; 2. Classifica- 

 tion, 679; 3. Order Carnivora, 680; 4. The Cats, 680; 5. *Suborder Creodonta, 

 683; 6. Suborder Fissipeda, 684; 7. Suborder Pinnepedia, 691. 



XXVIII. PROTOUNGULATES 



1. Origin of the ungulates, 694; 2. Ungulate characters, 695; 3. Classification, 699; 



4. Superorder Protoungulata, 700; 5. South American ungulates. *Order Notoun- 

 gulata, 701; 6. *Order Litopterna, 703; 7. *Order Astrapotheria, 703; 8. Order 

 Tubulidentata, 704. 



XXIX. ELEPHANTS AND RELATED FORMS 



1. 'Near-ungulates', superorder Paenungulata, 706; 2. Classification, 706; 

 3. Order Hyracoidea, 707; 4. Elephants. Order Proboscidea, 709; 5. *Order 

 Pantodonta (Amblypoda), 717; 6. *Order Dinocerata, 718; 7. *Order Pyro- 

 theria, 718; 8. *Order Embrithopoda, 718; 9. Order Sirenia, 720. 



XXX. PERISSODACTYLS 



1. Perissodactyl characteristics, 722; 2. Classification, 723; 3. Perissodactyl 

 radiation, 724; 4. Suborder Ceratomorpha, tapirs and rhinoceroses, 727; 



5. Rhinoceroses, 728; 6. *Brontotheres (*Titanotheres), 730; 7. *Chalicotheres 

 (= *Ancylopoda), 731; 8. Palaeotheres, 732; 9. Horses, 732; 10. Allometry in 

 the evolution of horses, 737; 11. Rate of evolution of horses, 738; 12. Conclu- 

 sions from the study of the evolution of horses, 739. 



XXXI. ARTIODACTYLS 



1. Characteristics of artiodactyls, 741; 2. Classification, 745; 3. The evolution 

 of artiodactyls, 746; 4. Pigs and hippopotamuses, 748; 5. *Oreodonts, 750; 



6. Camels, 751; 7. Ruminants, 753; 8. Chevrotains, 754; 9. Pecora, 755; 

 10. Cervidae, 755; II. Giraffidae, 757; 12. Antilocapridae and Bovidae, 760. 



XXXII. CONCLUSION. EVOLUTIONARY CHANGES OF THE LIFE OF 

 VERTEBRATES 



1. The life of the earliest chordates, 765; 2. Comparison of the life of early 

 chordates with that of mammals, 767; 3. The increasing complexity and variety 

 of vertebrates, 768; 4. The variety of evidence of evolutionary change, 769; 

 5. Rate of evolutionary change, 770; 6. Vertebrates that have evolved slowly, 

 771; 7. Varying rates of evolutionary changes, 774; 8. Vertebrates that have 

 disappeared, 774; 9. Successive replacement among aquatic vertebrates, 775; 

 10. Successive replacement among land vertebrates, 776; 11. Is successive re- 

 placement due to climatic change?, 776; 12. Convergent and parallel evolution, 

 777'. ! 3- Some tendencies in vertebrate evolution, 779; 14. Evolution of the 

 whole organization, 780; 15. Summary of evidence about evolution of verte- 

 brates, 781; 16. Conservative and radical influences in evolution, 783; 17. The 

 direction of evolutionary change, 784; 18. The influences controlling evolutionary 

 progress, 785. 



REFERENCES 787 



INDEX 797 



