CONTENTS 



CHAPTER I 



PAGE 



What is Life and Whence it Comes 1 



CHAPTER II 

 Species — their Numbers, Variety, and Distribution ... 12 



CHAPTER III 



The Numerical Distribution of British Plants : Temperate 

 Floras Compared 24 



CHAPTER IV 

 The Tropical Floras of the World • . . 43 



CHAPTER V 

 The Distribution of Animals 89 



CHAPTER VI 



The Numerical Distribution of Species in Relation to Evolu- 

 tion 100 



CHAPTER VII 

 Heredity, Variation, Increase 109 



CHAPTER VIII 



Illustrative Cases of Natural Selection and Adaptation . . 134 



ix 



