LIST OF ILLUSTRATIONS 



FIG. PAGE 



1. OVUM OF A THREADWORM (FROM CARNOY) .... 5 



2. DIAGRAM OF CELL DIVISION (AFTER BOVERI) .... 31 



3. DIAGRAM OF CELL STRUCTURE (AFTER WILSON) 33 



4. " COMET-FORM " OF STARFISH (AFTER HAECKEL) 35 



5. ASEXUAL REPRODUCTION OF A SEA-WORM (AFTER MC!NTOSH) . 36 



6. DIAGRAM OF OVUM AND SOMATIC CELL (AFTER CARNOY) facing 38 



7. VOLVOX GLOBATOR t 39 



8. FORMS OF SPERMATOZOA 41 



9. DIAGRAM OF GERMINAL CONTINUITY (AFTER WILSON) . . 43 



10. PARALLELISM OF SPERM ATOGENESIS AND OOGENESIS (AFTER 



BOVERI) 47 



11. DIAGRAM OF REDUCTION AND AMPHIMIXIS (AFTER ZIEGLER) facing 48 



12. FERTILISED OVUM OF ASCARIS (AFTER BOVERI) .... 49 



13. DIAGRAM OF MATURATION AND FERTILISATION (FROM ZIEGLER). 



facing 51 



14. CHROMATIN ELEMENTS OF NUCLEI (AFTER PFITZNER) . . 59 



15. DIAGRAM OF FERTILISATION IN ASCARIS (AFTER BOVERI) . 60, 61 



16. A POLLEN GRAIN WITH ITS NUCLEI (FROM CARNOY) ... 63 



17. DIAGRAM TO ILLUSTRATE THE DIFFERENCE BETWEEN MODIFICA- 



TIONS AND VARIATIONS *.*.... 7! 



18. VARIETIES OF WALL-LIZARD (AFTER EIMER) .... 74 



19. VARIATIONS IN WASP (AFTER KELLOGG AND BELL) . facing 76 



20. VARIATIONS IN BEETLE (AFTER TOWER) ... ,,76 



21. MUTATION IN MEDUSOIDS ..... 89 



22. MUTATIONS OF HART'S TONGUE FERN (AFTER LOWE) . facing 98 



23. KARYOKINESIS (AFTER FLEMMING) . . 102 



24. LEAVES OF WILLOW (AFTER WIESNER) in 



25. DEVONSHIRE PONY WITH STRIPES (FROM DARWIN) . . .121 



26. VARIETIES OF DOMESTIC PIGEON (AFTER DARWIN) . . 139 

 27. BRINE-SHRIMP, ARTEMIA SALINA . . . . . .213 



27a. TAIL-LOBES OF ARTEMIA SALINA (AFTER SCHMANKEWITSCH) . 213 



a8> HALF-LOP RABBIT (FROM DARWIN) ...... ,289 



xv 



