LIST OF ILLUSTRATIONS. 



FIGUKB PAGB 



1. Figure illustrating osmosis . . 



2. Figure illustrating osmosis .... 42 



3. Diagram of the intestinal walls .... 43 



4. Diagram of a single villus ..... 44 



5. Enlarged figure of four cells in the villns membrane . 44 



6. A bit of muscle showing blood-vessels ... 49 



7. A bit of bark showing cellular structure . . ,75 



8. Successive stages in the division of the developing egg , 78 



9. A typical cell ,80 



10. Cells at a root tip 81 



11. Section of a leaf showing cells of different shapes , . 81 



12. Plant cells with thick walls, from a fern . . . 82 



13. Section of potato 82 



14. Various shaped wood cells from plant tissue . . ,83 



15. A bit of cartilage ....... 83 



16. Frogs' blood . .... 84 



17. A bit of bone .... 84 



18. Connective tissue ...... 85 



19. A piece of nerve fibre ...... 85 



20. A muscle fibre ....... 86 



21. A complex cell, vortlcella ..... 87 



22. Amoeba 89 



23. A cell as it appears to the modern microscope . . 103 



24. A cell cut into pieces, each containing a bit of nucleus . 107 



25. A cell cut in pieces, only one of which contains any nucleus 108 



26. Different forms of nuclei! . ... Ill 



27 and 28. Two stages in cell division 

 29 and 30. Stages in cell division . 

 31 and 32. Latest stages in cell division 

 An egg 



115 

 116 

 118 

 122 



34 and 35. Stages in the process of fertilization of the egg . 123 



36 and 87. Stages in the process of fertilization of the egg , 124 

 38, 39, and 40. Stages in fertilization of the egg . . .125 



41 and 42. Latest stages in the fertilization of the egg . . 128 

 43 and 44. Two stages in the division of the egg . . .130 



45. A group of cells resulting from division, the first step in 



machine building ...... 156 



46. A later step in machine building, the gastrula . . 157 



47. The arm of a monkey ...... 167 



48. The arm of a bird ...... 167 



49. The arm of an ancient half-bird, half-reptile animal . . 167 



50. Diagram to illustrate the principle of heredity . 179 



8 



