Vlll CONTENTS. 



CHAPTER IX. 



TOE CHARACTERS OF GENERA 136 



CHAPTER X. 



SPECIES Alto BREEDS 184 



CHAPTER XI. 



FORMATION OF CORAL REEFS , 148 



CHAPTER XII. 



AGE OF CORAL REEFS AS SHOWING PERMANENCE OF SPECIES 175 



CHAPTER XIII. 



HOMOLOGIES 201 



CHAPTER XIV. 



ALTERNATE GENERATIONS ....... 233 



CHAPTER XV. 



THE OVARIAN EGG 269 



CHAPTER XVI. 



EMBRYOLOGY AND CLASSIFICATION ...... 296 



