XX 



LIST OF FIGURES 



FIG. 

 124. 



»25- 



126. 

 127. 



128. 

 129. 

 130. 



131- 



132. 



133- 

 134- 

 135- 

 136. 

 137- 

 138. 



139- 

 140. 



141. 

 142. 



Diagrams of tetrad-formation in arthropods 



Germinal vesicles and tetrads 



Maturation in Anasa .... 



Maturation in Atiasa .... 



Diagrams of reduction 



Maturation in Thalasscnia . 



Maturation in Thalassema and Zirphaa 



Maturation in Salaniandra . 



The maturation-divisions in angiosperms 



Maturation in Liliuni .... 



Maturation in Lilium .... 



Diagrams of reduction in the flowering plants 



Ovary of Canthocamptus .... 



Polar spindles without centrosomes 



Polar bodies in Actinophrys 



Polar bodies in Actinosphcerium . 



Conjugation and reduction in Closterium 



First type of parthenogenetic maturation in Artemia 



Second type of parthenogenetic maturation in Artemia 



PAGE 



251 

 252 



254 

 255 

 259 

 260 

 261 

 262 

 264 

 266 

 268 

 270 



273 

 276 

 278 

 278 

 279 

 282 

 283 



143- 

 144. 

 145. 

 146. 

 147. 

 148. 

 149. 

 150. 



151- 

 152. 



153- 

 154. 



155- 

 156. 



CHAPTER VI 



Abnormalities in the fertilization of Ascaris 



Giant eml^ryo of Ascaris ...... 



Individuality of chromosomes in Ascaris 



Independence of chromosomes in fertilization of Cyclops 



Hybrid fertilization of Ascaris 



Mitosis with intranuclear centrosome in Ascaris . 

 Abnormal mitoses in Ilemerocallis .... 

 Centrosomes in ChcFtopterus and Cerehratidus 

 Artilicially produced asters and centrosomes in echinoderms 

 Diagram of different types of centrosome and centrosphere 



Polar mitoses in Diaulula 



Astral systems in Unio ....... 



Astral systems in Cerebratiilus and Thalassema . 

 Structure of the aster in spermatogonium of salamander 



295 

 296 

 297 

 298 

 300 



305 

 306 



307 

 308 

 310 

 312 



313 

 320 

 326 



CHAPTER VII 



157. History of chromosomes in the germinal vesicle of sharks 



158. Nucleated and enucleated fragments of Stylonychia 



159. Regeneration in Stenlor ..... 



160. Nucleated and enucleated fragments o{ Ainceba . 



161. Nucleated and enucleated fragments of plant-protoi)lasm 



162. Position of nuclei in plant-cells .... 



163. Ovary of Forficula ...... 



164. Normal and dwarf larv;Te of sea-urchins 



165. Supernumerary centrosome in Ascaris 



166. Cleavage of disperniic egg of Toxopneusles . 



167. Centrosomes and cilia ...... 



339 

 342 

 343 

 344 

 345 

 347 

 349 

 352 

 355 

 356 

 357 



