TABLE OF CONTENTS xiil 



PAGE 



The Fauna of Oceanic Islands. George John Romanes . . . . 172 

 The Fauna of Continental Islands — Madagascar and New Zealand. 



A.R.Wallace 181 



The Distribution of Marsupials. .-4 ./?. M''a//ace 182 



The Distribution of Birds. ^. 2?. lFfl//ace 183 



Summary of Mammalian Dispersal. Hans Gadow 185 



Summary of the Argument for Evolution as Based on Geographic 



Distribution 186 



PART III. THE CAUSAL FACTORS OF 

 ORGANIC EVOLUTION 



Chapter XIV. Introductory Statement igi 



What We Owe to Darwin 192 



Chapter XV. The Background of Darwinism: Adaptations . . 194 



The Nature of Adaptations . . . 194 



Two Categories of Adaptations 198 



Adaptations Classified 199 



Some Special Adaptations 200 



Parasitism and Degeneration 201 



Adaptations of Deep-Sea Animals and of Cave Animals .... 204 



Color and Pattern in Animals 205 



Osborn's Laws of Adaptation 211 



Chapter XVI. The Background of Darwinism — Continued . . 215 /^ iX 



The Web of Life. J . Arthur Thomson 215 



Chapter XVII. Natural Selection. Charles Darwin 228 



Foundation Stones of Natural Selection 228 



Darwin's Own Estimate as to the Role of Natural Selection in 



Evolution 228 



Effects of Habit and of the Use or Disuse of Parts; Correlated 



Variation; Inheritance 229 



Darwin's Idea of the Causes Responsible for the Origin of Domes- 

 tic Races 230 



Darwin's Idea of the Origin of Varieties, Species, and Genera in 



Nature 230 



The Term "Struggle for Existence" Used in a Large Sense . . 231 



Geometrical Ratio of Increase 232 



Natural Selection; Or the Survival of the Fittest 232 



Sexual Selection 239 



Illustrations of the Action of Natural Selection, or the Survival 



of the Fittest 241 



Summary of Chapter on Natural Selection 242 



Difficulties and Objections to Natural Selection as Seen by Darwin 245 



