LIST OF ILLUSTRATIONS 



FIGURE 



1 . Variation Curve of the Disc-breadth of Ophiocoma nigra 



2. Uniaxial System . . 



3. EuastropsiSy Pediastrum .... 



4. Pseudochcete gracilis ..... 



5. A Hair consisting of Four Cells (Erodium moschatum) 



6. Prasiola parietina ..... 



7. Pleurococcus vulgaris .... 



8. Regular Chess-board System .... 



9. Epidermis {Allium cepa) . 



10. Ilea . ...... 



11. Prasiola . . . . . . 



12. Human Epidermis ..... 



13. (i) Regular Chess-board System 



13. (2) Effects of Gradation in a Chess-board System 



14. Allium porrum \ Epidermis .... 



15. Chess-board System in Leaves of Mosses 



16. Mnium punctatum '. Cells of the Leaf 



17. Bryum argenteum : Cells of the Leaf 



18. Curve of Errors (fl! + <^)io .... 



19. Curve of Committed Errors ; Curve of Observed Effects 



20. Curve of Growth ..... 



21. Curve of Growth ..... 



22. Curve of Development : Red, Hesitation, Blue 



23. Curves of Development of Three Primordia . 



24. Symmetrical Variation Curve 



25. Relation between Temperature and Growth . 



26. Gradation Curve ..... 



27. Gradation Curves of Four Primordia . 



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