CONTENTS 



INTRODUCTORY . 



CLASSIFICATION 



MORPHOLOGY 



EMBRYOLOGY 



PALEONTOLOGY 



CHAPTER I. 



CHAPTER II. 



CHAPTER III. 



CHAPTER IV. 



CHAPTER V. 



CHAPTER VI. 



GEOGRAPHICAL DISTRIBUTION . 



CHAPTER VII. 



THE THEORY OF NATURAL SELECTION 



PAGE 



i 



98 



CHAPTER VIII. 

 EVIDENCES OK THE THEORY OF NATURAL SELECTION 



204 



251 



285 



