LIST OF ILLUSTRATIONS. 



1 . Diagrammatic expression of classification in a genealogical tree, 1 1 



2. Structure of the cell. (CARNOY), .... 44 



3. Fertilised ovum of Ascaris. (BovERi), ... 44 



4. Diagram of cell division. (BovERi), ... 45 



5. Karyokinesis. (FLEMMING), .... 47 



6. Diagrammatic expression of alternation of generations, . 55 



7. Diagram of ovum, showing diffuse yolk granules, . . 57 



8. Forms of spermatozoa, ..... 5^ 



9. Diagram of maturation and fertilisation. (GEDDES and 



THOMSON), ...... 59 



10. Spermatogenesis and polar bodies. (HERTWIG and 



WEISMANN), ...... 61 



11. Fertilisation in Ascaris megalocephala. (BovERi), . . 62 



12. Modes of segmentation, ..... 64 



13. Life history of a coral, Monoxenia Darwinii. (fLECKEL), 66 



14. Embryos ( I ) of bird ; (2) of man. (His). ... 69 



15. Gradual transitions between Paludina Neumayri and Palu- 



dina Hcernesi. (NEUMAYR), . . . 77 



16. Life history of A mceba, ..... 87 



17. End-to-end union of Gregarines. (FRENZEL), . . 88 



18. Life history of Gregarina. (BtJTSCHLi), ... 89 



19. Life history of Monocystis. (BiJTSCHLl), ... 90 



20. Paramcecium. (BuTSCHLi), . . . .91 



21. Conjugation of Paramctciiun aurelia four stages. 



(MAUPAS), ...... 92 



22. Diagrammatic expression of process of conjugation in Para- 



mcecittm aurelia. ( MAUPAS), .... 93 



23. Vorticella. (BiJTSCHLT), ..... 95 



24. Volvox globator. (COHN), . , . . . 96 



25. Diagram of Protomyxa aurantiaca. (H^CKEL), . . 99 



26. Formation of shell in a simple Foraminifer. (DREYER), . 100 



