Xll 



TABLE OF CONTENTS 



E.' Direct or Amitotic Division 



1. General Sketch ...... 



2. Centrosome and Attraction-sphere in Amitosis 



3. Biological Significance of Amitosis 



F. Summary and Conclusion ..... 

 Literature, II. . . • 



PAGE 



80 

 80 

 81 



82 



85 



86 



CHAPTER III 

 The Gekm-Cells 



A. The. Ovum 



1. The Nucleus 



2. The Cytoplasm . 



3. The Egg-envelopes 



B. The Spermatozoon 



1. The Flagellate Spermatozoon 



2. Other Forms of Spermatozoa 



3. Paternal Germ-cells of Plants 



C. Origin and Growth of the Germ-cells . 



D. Growth and Differentiation of the Germ-cells 



1. The Ovum ..... 



(«) Growth and Nutrition . 



(^) Differentiation of the Cytoplasm. 



(<r) Yolk- nucleus .... 



2. Formation of the Spermatozoon 



E. Staining-reactions of the Germ-nuclei . 

 Literature, III. . ...... 



Deposit of Deutoplasm 



90 

 92 



94 

 96 

 98 



99 

 106 

 106 

 108 

 113 

 "3 

 "3 



"5 

 118 



I 22 



127 

 128 



CHAPTER IV 

 Fertilization of the Ovum 



A. General Sketch 



1. The Germ-nuclei in Fertilization 



2. The Centrosome in Fertilization 



B. Union of the Germ-cells ..... 



1. Immediate Results of Union 



2. Paths of the Germ-nuclei .... 



3. Union of the Germ-nuclei. The Chromosomes 



C. Centrosome and Archoplasm in Fertilization 



D. Fertilization in Plants ...... 



E. Conjugation in Unicellular Forms 



F. Summary and Conclusion ..... 

 Literature, IV. ........ 



130 

 132 



135 



145 

 149 



151 

 153 

 156 

 160 

 163 

 170 

 171 



B. 



C. 

 D. 



CHAPTER V 

 Reduction of the Chromosomes, Oogenesis and Spermatogenesis 



General Outline ....... 



1. Reduction in the Female. The Polar Bodies 



2. Reduction in the Male. Spermatogenesis . 



3. Theoretical Significance of Maturation 

 Origin of the Tetrads ...... 



1. General Sketch ...... 



2. Detailed Evidence ..... 

 The Early History of the Germ-nuclei . 

 Reduction in the Plants ...... 



•74 



175 

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 186 

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 187 

 193 

 '95 



