LIST OF^FIGURES 



XIX 



FIG. 



8i. Ova.na.n eggs oi Limti/tis and Po/yzoniuf/i .... 



82. Formation of the spermatozoon in Ajiasa .... 



83. Transformation of the spermatids of the salamander 



84. P'ormation of the spermatozoon in Salamandra and Amphinma 



85. The same in Helix and in elasmobranchs .... 



86. The same in mammals ....... 



87. Formation of spermatozoids in cycads ..... 



88. Formation of spermatozoids in cryptogams .... 



PAGE 



CHAPTER IV 



89. Fertilization of Physa . 



90. Fertilization of Ascaris 



91. Germ-nuclei of Nematodes , 



92. Fertilization of the mouse . 



93. Fertilization of Pterotrachea 



94. Entrance and rotation of sperm-head in Toxopneustes 



95. Conjugation of the germ-nuclei in Poxopnensies . 



96. Diagrams of fertilization ..... 



97. Fertilization of Nereis ...... 



98. Fertilization of Cyclops ..... 



99. Fertilization and persistence of centrosomes in Thalassema 



100. Entrance of spermatozoon into the egg 



101. Pathological polyspermy .... 



102. Polar rings of Clepsine .... 



103. Paths of the germ-nuclei in Toxopneustes 



104. Fertilization of Myzostoma .... 



105. Fertilization of Pihilaria .... 



106. Penetration of the pollen-tube in angiosperms 



107. Fertilization of the lily .... 



108. Fertilization in Zamia .... 



109. Diagram of conjugation in Infusoria 



110. Qoxi]\xgzX\ox\ oi Pa ramie ciiim 



111. Conjugation of Vorticella .... 



112. Con]\xgz\.\on o( Noctiltcca .... 



113. Co\\]\xg2ii\on oi Spirogyra .... 



180 



184 

 185 

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 187 

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 190 

 191 



193 

 195 

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 199 



201 

 203 

 209 

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 22 ? 

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CHAPTER V 



114. Polar bodies in Toxopneustes 



115. Genesis of the egg 



116. Diagram of formation of polar bodies 



117. VoXaxhoCixtsm. Ascaris 



118. Genesis of the spermatozoon 



119. Diagram of reduction in the male 



120. Spermatogenesis of .'^5<r<7;-?5 



121. Diagrams illustrating tetrad-formation 



122. Tetrads of Gryllotalpa 



123. Tetrads and polar bodies in Cyclops 



o 

 o 



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 239 



240 

 242 



244 



247 



249 



250 



