LIST OF FIGURES 



XIX 



FIG. 



8i. Ovarian eggs of Limn/us 2ind Pofyzonium .... 



82. Formation of the spermatozoon in Anasa .... 



83. Transformation of the spermatids of the salamander 



84. Formation of the spermatozoon in Salajuandra and Atnphiuma 



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 



159 



162 

 164 



166 

 168 



169 



173 

 174 



CHAPTER IV 



89. Fertilization of PJiysa . 



90. Fertilization of Ascaris 



91. Germ-nuclei of Nematodes . 



92. Fertilization of the mouse . 



93. Fertilization of Pterotiuxchea 



94. Entrance and rotation of sperm-head in Toxoptieustes 



95. Conjugation of the germ-nuclei in Toxoptieustes . 



96. Diagrams of fertilization ..... 



97. Fertilization of /Vereis ...... 



98. Fertilization of Cyclops ..... 



99. Fertilization and persistence of centrosomes in Thah 

 100. Entrance of spermatozoon into the egg 

 loi. Pathological polyspermy .... 



102. Polar rings of Clepsine .... 



103. Paths of the germ-nuclei in Toxopneustes 



104. Fertilization of Myzostoma .... 



105. Fertilization of Pilularia .... 



106. Penetration of the pollen-tube in angiosperms 



107. Fertilization of the lily .... 



108. Fertilization in Zamia .... 



109. Diagram of conjugation in Infusoria 

 no. Conjugation of /'(7;77;«(i'<r/«/« 



111. Conjugation of Vorticella .... 



112. Con]\i.g3X\on oi A^octiluca .... 



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



assema 



180 



183 

 184 



185 

 186 

 187 

 189 

 190 

 191 

 193 



195 

 197 



199 



201 



203 



209 



216 



217 



219 



220 



223 



225 



226 



227 



2^28 



CHAPTER V 



114. Polar bodies in Toxopneustes 



115. Genesis of the egg 



116. Diagram of formation of polar bodies 



117. Polar bodies in Ascaris 



118. Genesis of the spermatozoon 



119. Diagram of reduction in the male 



120. Spermatogenesis of ^45Cr7;-?> 



121. Diagrams illustrating tetrad-formation 



122. Tetrads of Gryllotalpa 



123. Tetrads and polar bodies in Cyclops 



234 

 235 

 237 

 239 

 240 

 242 

 244 

 247 

 249 

 250 



