"^"^ CONTENTS "^^"^ 



CHAPTER XII 

 More About Fossils io6 



CHAPTER XIII 

 The Dual Relationship of Animals 114 



CHAPTER XIV 

 What is a Species? 130 



CHAPTER XV 

 Animal Forms 149 



CHAPTER XVI 



The Continuity of Life 155 



CHAPTER XVII 



Life 164 



CHAPTER XVIII 

 Developmental Lines and Trees — Evolution 170 



CHAPTER XIX 

 Gaps in the Evolutionary Lines — Mutations 180 



CHAPTER XX 

 The Origin of the Earliest Animals — Eogenesis 189 



CHAPTER XXI 

 Summary io8 



Appendix A 13 5 



Appendix B 2.61 



[vi] 



