CONTENTS 



Page 



TlTLEPAGE i 



Preface iii 



Contents ix 



Systematic Index xv 



List of Plates xxix 



CHAPTER I. 



Classification of Birds. 



Position of the Charadriidae. — Anseriformes. — Cuculiformes. — Passer iformes. — Charadri- 

 formes. — Struthioformes. — Principles of Classification 1 



CHAPTER II. 



The Evolution of Birds. 



Natural Selection the guide, not the cause of Evolution. — Fortuitous variations. — Use 

 and Disuse. — Inherited habits. — Definite variations. — Isolation. — Evolution the result of a 

 force . . 7 



CHAPTER III. 



The Differentiation of Species. 



Geographical Isolation. — Romanes's theory of Physiological Isolation. — Causes of Varia- 

 tion. — Summary of the facts of Evolution. — Laws of Evolution only apply to organic matter . 16 



CHAPTER IV. 



The Glacial Epoch. 



CrolPs Theory. — Eccentricity of the Earth's orbit. — Fossil Birds. — Prse-Pliocene Glacial 

 Epoch. — Return of Birds to the Polar Basin. — Post-Pliocene Glacial Epoch. — Post-Glacial 



modification 25 



b 



