xviii LIST OF FIGURES 



FIG. PAGE 



33. Mitosis in Erysiphe <.. 83 



34. Mitosis in pollen- mother-cells of lily, according to Guignard 84 



36. Mitosis in spore-cells of Equisetum . . . . . . . . .85 



37. Heterotypical mitosis 87 



38. Mitosis in Infusoria 89 



39. Mitosis in Euglypha 90 



40. Mitosis in Euglena . 91 



41. Mitosis in Acanthocystis . . . .92 



42. Mitosis in Noctiluca ..." 93 



43. Mitosis in Paramceba . . . \ 95 



44. Mitosis in Actinospharium . ' . . .96 



45. Mitosis in Actinosph&rium ...........97 



46. Pathological mitoses in cancer-cells 98 



47. Pathological mitosis caused by poisons ......... 99 



48. Van Beneden's account of astral systems in Ascaris . . . . . .100 



49. Leucocytes 102 



50. Pigment-cells . 103 



51. Heidenhain's model of mitosis . . . .104 



52. Mitosis in the egg of Toxopneustes 107 



53. Pathological mitoses in polyspermy . . . e . . .109 



54. Nuclei in the spireme-stage . .112 



55. Early division of. chromatin in Ascaris . 113 



56. Amitotic division ... 115 



CHAPTER III 



57. Volvox 123 



58. Ovum of Toxopneustes 126 



59. Ovum of the cat .127 



60. Ovum of Nereis 1 29 



.61. Germinal vesicles of Unto and Epeira 130 



62. Insect-egg 132 



63. Micropyle in Argonauta 133 



64. Germ-cells of Volvox 134 



65. Diagram of the flagellate spermatozoon 135 



66. Spermatozoa of fishes and amphibia . . . . . . .136 



67. Spermatozoa of birds and other animals . . , 138 



68. Spermatozoa of mammals . . . . 140 



69. Unusual forms of spermatozoa . . . .141 



70. Spermatozoids of Char a 142 



71. Spermatozoids of various plants 143 



72. Germ-cells of Cladonema 146 



73. Primordial germ-cells of Ascaris 147 



74*. Primordial germ-cells of Cyclops . . . . . . . . .149 



75. Ovarian ova and follicles of Helix . . . . . . . . J 5! 



76. Egg and nurse-cells in Ophryotrocha 152 



77. Ovarian eggs of insects . 153 



78. Young ovarian eggs of various animals . . . . . . .154 



79. Young ovarian eggs of birds and mammals . .'"*". . . . . 155 



80. Ovarian eggs of spider, earthworm, ascidian, showing yolk-nucleus . . 157 



