TABLE OF CONTENTS 
CHAPTER I 
PAGE 
INTRODUCTION . : é ; 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- 
Protozoa, 25; Metazoa, 28. 
CHAPTER III 
Toe Germ-ceLL CyYcLE IN THE Pa#pDOGENETIC FLy, 
Miastor . : A ‘ é : : » 6h 
CHAPTER IV 
Tue SEGREGATION OF THE GERM CELLS IN SPONGES, Caz- 
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 ‘ : 3 . : ‘ 3 . 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. 
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