TABLE OF CONTENTS 



CHAPTER I 



PAGE 



INTRODUCTION 1 



The Cell, 2 ; Cell Division, 13 ; Methods of Repro- 

 duction, 17 ; The Germ Cells, 19 ; The Life Cycles of 

 Animals, 22. 



CHAPTER II 



GENERAL ACCOUNT OF THE GERM-CELL CYCLE IN ANI- 

 MALS 25 



Protozoa, 25 ; Metazoa, 28. 



CHAPTER III 



THE GERM-CELL CYCLE IN THE P^DOGENETIC FLY, 



MIASTOR 51 



CHAPTER IV 



THE SEGREGATION OF THE GERM CELLS IN SPONGES, CCE- 



LENTERATES, AND VERTEBRATES ... 69 

 1. Porifera, 69. 2. Coelenterata, 80. 3. Verte- 

 brata, 98. 



CHAPTER V 



THE SEGREGATION OF THE GERM CELLS IN THE ARTHRO- 



PODA 106 



1. The Keimbahn in the Insects, 106 ; Diptera, 107 ; 

 Coleoptera, 109 (In Chrysomelid Beetles, 109 ; Origin 

 of Nurse Cells, 119; Cyst Formation in Testis, 125; 

 Amitosis, 133 ; Differentiation of Nuclei in Egg, 141) ; 

 Hymenoptera, 143. 2. The Keimbahn in the Crusta- 

 cea, 163. 



