LIST OF FIGURES 



1. Epidermis of larval salamander 2 



2. Amoeba Proteus 



3. Cleavage of the ovum in Toxopneustes 



4. Diagram of inheritance. n 



5. Diagram of a cell 14 



6. Spermatogonium of salamander 



7. Group of cells, showing cytoplasm, nu- 



cleus, and centrosome 



8. Alveolar or foam-structure of proto- 



plasm, according to Biitschli 



9. Living cells of salamander, showing 



fibrillar structure 



10. Nuclei from the crypts of Lieberkiihn. 



11. Special forms of nuclei 



12. Diffused nucleus in Trachelocerca. . . . 



13. Ciliated cells 



14. Nephridial cell of Clepsine 



15. Nerve-cell of frog 



16. Diagram of dividing cell 



17. Diagrams of cell-polarity 



18. Remak's scheme of cell-division 



19. Diagram of the prophases of mitosis. . 



20. Diagram of later phases of mitosis. . . . 



21. Prophases in salamander cells 54 



22. Metaphase and anaphases in salaman- 



der cells 



23. Telophases in salamander cells 56 



24. Middle phases of mitosis in Ascaris- 



e ggs , 



25. Mitosis in pollen-mother-cells of lily. . 



26. Heterotypica! mitosis 



27. Mitosis in Infusoria 



28. Mitosis in Pluglypha 63 



29. Mitosis in Euglena 



30. Mitosis in Noctiluca 



31. Mitosis in Actinosphcerium 66 



32. Pathological mitoses in cancer-cells.. . 



33. Pathological mitosis caused by poisons 



34. Mechanism of mitosis in Ascaris 



35. Leucocytes 72 



36. Pigment-cells 73 



37. Mitosis in the egg of Toxopneustes. ... 76 



38. Nuclei in the spireme-stage 78 



39. Early division of chromatin in Ascaris 79 



40. Amitotic division 81 



41. Volvox 89 



42. Ovum of Toxopneustes 91 



I 78. 



79- 



80. 

 81. 

 82. 



PAGE 



Ovum of Nereis 95 



Insect-egg 96 



Micropyle in Argonauta 97 



Germ-cells of Volvox 98 



Diagram of the flagellate spermatozoon 99 

 Spermatozoa of fishes and amphibia. . 100 

 Spermatozoa of birds and other ani- 

 mals 102 



Spermatozoa of mammals 104 



Unusual forms of spermatozoa 105 



Spermatozoids of Chara 106 



Spermatozoids of various plants 107 



Germ-cells of Hydractinia 109 



Primordial germ-cells of Ascaris no 



Primordial germ-cells of Cyclops 112 



Egg and nurse-cell in Ophryotrocha. . . 114 



Ovarian eggs of insects 115 



Young ovarian eggs of various animals lib 

 Young ovarian eggs of birds and mam- 

 mals 1 18 



Young ovarian eggs of earthworm. . . , 120 



Formation of the spermatozoon 124 



Transformation of the spermatids of 



the salamander 125 



Fertilization of Physa 131 



Fertilization of Ascaris 133 



Germ-nuclei of nematodes 134 



Fertilization of the mouse 136 



Fertilization of Pterotrachea 137 



Entrance and rotation of sperm-head 



in Toxopneustes 138 



Conjugation of the germ-nuclei in Tox- 

 opneustes 139 



Fertilization of Nereis 141 



Fertilization of Cyclops 142 



Continuity of centrosomes in 'Ihalas- 



sema 144 



Entrance of spermatozoon into the egg 146 



Pathological polyspermy 147 



Polar rings of Clepsine 150 



Paths of the germ-nuclei in Toxo- 

 pneustes 152 



Fertilization of Myzostoma 158 



Fertilization of Pilularia 160 



Fertilization of the lily 161 



Diagram of conjugation in Infusoria. . 164 

 Conjugation of Paramasciitm 166 



