PART 1V Contents xi 



CHAPTER XV 



BACKBONELESS ANIMALS 



i. Sponges 2. Stinging - animals or Ccelenterata 3. "Worms" 

 4. Echinoderms 5. Arthropods 6. Molluscs . Pages 222-247 



CHAPTER XVI 



BACKBONED ANIMALS 



i. Balanoglossus 2. Tunicates 3. The Lancelet 4. Round-mouths 

 or Cyclostomata 5. Fishes 6. Amphibians 7. Reptiles 8. 

 Birds 9. Mammals . . . . 248-272 



PART IV 



THE EVOLUTION OF ANIMAL LIFE 



CHAPTER XVII 



THE EVIDENCES OF EVOLUTION 



i. The idea of evolution 2.. Arguments for evolution : Physiological, 

 Morphological ', Historical 3. Origin of life , . 273-281 



CHAPTER XVIII 



THE EVOLUTION OF EVOLUTION THEORIES 



T. Greek philosophers 2. Aristotle 3. Lucretius 4. Evolutionists 

 before Darwin 5. Three old masters : Buffon, Erasmus Darwin, 

 Lamarck 6. Darwin 7. Darwin s fellow - workers 8. The 

 present state of opinion . . . .282-302 



CHAPTER XIX 



THE INFLUENCE OF HABITS AND SURROUNDINGS 



i. The influence of function 2. The influence of surroundings 3. 

 Our own environment . .... 303-319 



