CONTENTS xiii 



XIII. EVOLUTION AND ADAPTIVE RADIATION OF AMPHIBIA 



i. The earliest Amphibia, 356; 2. Terrestrial Palaeozoic Amphibia. Embolomeri 

 and Rhachitomi, 357; 3. Aquatic Amphibia of the later Palaeozoic, 359; 

 4. Tendencies in the evolution of fossil Amphibia, 362; 5. Newts and Salaman- 

 ders. Subclass Urodela, 364; 6. Frogs and Toads. Subclass Anura, 365; 7. Sub- 

 class Apoda (— Gymnophiona = Caecilia), 366; 8. Adaptive radiation and 

 parallel evolution in modern Amphibia, 366; 9. Can Amphibia be said to be 

 higher animals than fishes ? 367. 



XIV. LIFE ON LAND: THE REPTILES 



1. Classification, 369; 2. Reptilia, 371; 3. The organization of reptiles, 372; 

 4. Skin of reptiles, 373; 5. Posture, locomotion, and skeleton, 373; 6. Feeding 

 and digestion, 378; 7. Respiration, circulation, and excretion, 378; 8. Reproduc- 

 tion of reptiles, 380; 9. Nervous system and receptors of reptiles, 383. 



XV. EVOLUTION OF THE REPTILES 



1. The earliest reptile populations, Anapsida, 386; 2. Classification of reptiles, 

 391; 3. Order 1. Chelonia, 392; 4. Subclass *Synaptosauria, 399; 5. Order 

 *Ichthyopterygia, 401 ; 6. Subclass Lepidosauria, 401 ; 7. Order Rhynchocephalia, 

 402; 8. Order Squamata, 404; 9. Suborder Lacertilia, 407; 10. Suborder 

 Ophidia, 411; 11. Superorder Archosauria, 416; 12. Order *Pseudosuchia, 417; 

 13. Order *Phytosauria, 417; 14. Order Crocodilia, 418; 15. The 'Terrible 

 Lizards', Dinosaurs, 421; 16. Order *Saurischia, 422; 17. Order *Ornithischia, 

 424; 18. Order *Pterosauria, 426; 19. Conclusions from study of evolution of the 

 reptiles, 429. 



XVI. LIFE IN THE AIR: THE BIRDS 



1. Features of bird life, 431 ; 2. Bird numbers and variety, 431 ; 3. The skin and 

 feathers, 432; 4. Colours of birds, 436; 5. The skeleton of the bird. Sacral and 

 sternal girders, 437; 6. The sacral girder and legs, 440; 7. Skeleton of the wings, 

 447; 8. Wing muscles, 449; 9. Principles of bird flight, 450; 10. Wing shape, 

 452; 1 1. Wing area and loading, 452; 12. Aspect ratio, 453; 13. Wing tips, slots, 

 and camber, 453; 14. Flapping flight, 455; 15. Soaring flight, 458; 16. Soaring 

 on up-currents, 458; 17. Use of vertical wind variations, 460; 18. Speed of 

 flight, 461; 19. Take-off and landing, 462; 20. The skull in birds, 464; 21. The 

 jaws, beak, and feeding mechanisms, 464; 22. Digestive system of birds, 468; 

 23. Circulatory system, 470; 24. Respiration, 471; 25. Excretory system, 474; 

 26. Reproductive system, 475; 27. The brain of birds, 477; 28. Functioning of the 

 brain in birds, 479; 29. The eyes of birds, 482; 30. The ear of birds, 488; 31. 

 Other receptors, 490. 



XVII. BIRD BEHAVIOUR 



I. Habitat selection, 491; 2. Food selection, 491; 3. Recognition and social 

 behaviour, 492; 4. Bird migration and homing, 493; 5. The stimulus to migra- 

 tion, 495; 6. The breeding-habits of birds, 496; 7. Courtship and display, 497; 

 8. Bird territory, 503; 9. Mutual courtship, 504; 10. Nest-building, 505; 



I I. Shape and colour of the eggs, 507; 12. Brooding and care of the young, 507. 



XVIII. THE ORIGIN AND EVOLUTION OF BIRDS 



1. Classification, 509; 2. Origin of the birds, 510; 3. Jurassic birds and the 

 origin of flight, 510; 4. Cretaceous birds. Superorder Odontognathae, 513; 



