xii CONTENTS 



VI. EVOLUTION AND ADAPTIVE RADIATION OF ELASMOBRANCHS 

 i. Characteristics of elasmobranchs, 175; 2. Classification, 175; 3. Palaeozoic 

 elasmobranchs, 176; 4. Mesozoic sharks, 180; 5. Modern sharks, 180; 6. Skates 

 and rays, 182; 7. Chimaera and the bradyodonts, 184; 8. Tendencies in elasmo- 

 branch evolution, 185; 9. The earliest Gnathostomes, Placoderms, 186. 



VII. THE MASTERY OF THE WATER. BONY FISHES 



1. Introduction: the success of the bony fishes, 190; 2. The trout, 191; 3. The 

 skull of bony fishes, 193; 4. Respiration, 196; 5. Vertebral column and fins 

 of bony fishes, 199; 6. Alimentary canal, 201 ; 7. Air-bladder, 201 ; 8. Circulatory 

 system, 201 ; 9. Urinogenital system and osmoregulation, 202; 10. Races of trout 

 and salmon and their breeding habits, 204; 1 1. Endocrine glands of bony fishes, 

 206; 12. Brain of bony fishes, 209; 13. Receptors for life in the water, 212; 

 14. Eyes, 212; 15. Ear and hearing of fishes, 216; 16. Sound production in 

 fishes, 218; 17. The lateral line organs of fishes, 218; 18. Chemoreceptors. 

 Taste and smell, 220; 19. Touch, 222; 20. Autonomic nervous system, 222; 

 21. Behaviour patterns of fishes, 225. 



VIII. THE EVOLUTION OF BONY FISHES 



1. Classification, 228; 2. Order 1. Palaeoniscoidei, 228; 3. Order 2. Acipen- 

 seroidei, 234; 4. Superorder 2. Holostei, 234; 5. Superorder 3. Teleostei, 236; 



6. Analysis of evolution of the Actinopterygii, 237. 



IX. THE ADAPTIVE RADIATION OF BONY FISHES 



I. Swimming and locomotion, 244; 2. Various body forms and swimming habits 

 in teleosts, 248; 3. Structure of mouth and feeding-habits of bony fishes, 251; 

 4. Protective mechanisms of bony fishes, 252; 5. Scales and other surface armour, 

 252; 6. Spines and poison glands, 253; 7. Electric organs, 253; 8. Luminous 

 organs, 254; 9. Colours of fishes, 255; 10. Colour change in teleosts, 258; 



II. Aerial respiration and the air-bladder, 261; 12. Special reproductive 

 mechanisms in teleosts, 265. 



X. LUNG-FISHES 



1. Classification, 268; 2. Crossopterygians, 268; 3. Osteolepids, 268; 4. Coela- 

 canths, 271; 5. Fossil Dipnoi, 273; 6. Modern lung-fishes, 275. 



XI. FISHES AND MAN, 280 



XII. TERRESTRIAL VERTEBRATES: AMPHIBIA 



1. Classification, 296; 2. Amphibia, 296; 3. The frogs, 298; 4. Skin of Amphibia, 

 298; 5. Colours of Amphibia, 299; 6. Vertebral column of Amphibia, 303; 



7. Evolution and plan of the limbs of Amphibia, 307; 8. Shoulder girdle of 

 Amphibia, 309; 9. Pelvic girdle of Amphibia, 312; 10. The limbs of Amphibia, 

 313; 1 1. The back and belly muscles of Amphibia, 318; 12. The limb muscles of 

 Amphibia, 322; 13. The skull of Stegocephalia, 325; 14. The skull of modern 

 Amphibia, 328; 15. Respiration in Amphibia, 332; 16. Respiration in the frog, 

 333; I 7- Respiratory adaptations in various amphibians, 334; 18. Vocal appara- 

 tus, 334; 19. Circulatory system of Amphibia, 335; 20. Lymphatic system of 

 Amphibia, 338; 21. The blood of Amphibia, 339; 22. Urinogenital system of 

 Amphibia, 340; 23. Digestive system of Amphibia, 342; 24. Nervous system 

 of Amphibia, 344; 25. Skin receptors, 349; 26. The eyes of Amphibia, 350; 27. 

 The ear of Amphibia, 353; 28. Behaviour of Amphibia, 354. 



