CONTENTS 



CHAPTER I 



PAGE 



ONTOGENY 1 



CHAPTER II ^ 



I/ THE CELL AND CELL DIVISION 31 S/ 



CHAPTER III 



/- THE GERM CELLS AND THEIR FORMATION 85 



CHAPTER IV 

 MATURATION 131 



CHAPTER V 

 FERTILIZATION 164 }C_ 



CHAPTER VI 

 CLEAVAGE 219 



CHAPTER VII 



THE GERM CELLS AND THE PROCESSES OF DIFFERENTIATION, HEREDITY, 



AND SEX DETERMINATION 260 



CHAPTER VIII 



THE BLASTULA, GASTRULA, AND GERM LAYERS. MORPHOGENETIC 

 PROCESSES 329 



INDEX . 367 



