viii LIST OF ILLUSTRATIONS 



PAGE 



FIG. 13. The Freshwater Jelly-fish, Limnocodium 97 



FIG. 14. Polyp of Limnocodium ... ... ... ... ... 97 



FIG. 15. Sense-organ of Limnocodium ... 97 



FIG. 1 6. The Freshwater Jelly-fish of Lake Tanganyika ... 98 



FlG. 17. Sir Harry Johnston's specimen of the Okapi 99 



FlG. 1 8. Bandoliers cut from the striped skin of the Okapi ... 99 



FlG. 19. Skull of the horned male of the Okapi 100 



FIG. 20. The metamorphosis of the young of the common Eel... 101 

 FIG. 21. A unicellular parasite of the common Octopus, pro- 

 ducing spermatozoa 102 



FlG. 22. The Cocctdium, a microscopic parasite of the Rabbit, 



producing spermatozoa 102 



FlG. 23. Spermatozoa of a unicellular parasite inhabiting a 



Centipede 103 



FlG. 24. The motile fertilizing elements (antherozoids or sper- 

 matozoa) of a peculiar cone-bearing tree, the Cycas 



revoluta ... ... ... ... ... ... ... 104 



FlG. 25. The gigantic extinct Reptile, Triceratops 106 



FlG. 26. A large carnivorous Reptile from the Triassic rocks of 



North Russia 107 



FIG. 27. The curious fish Drepanaspis, from the Old Red Sand- 

 stone of Germany 107 



FIG. 28. The oldest Fossil Fish known 108 



FlG. 29. The skull and lower jaw of the ancestral Elephant, 



PalcEomastodon, from Egypt ... ... ... ... 109 



FIG. 30. The latest discovered skull of Palceomastodon ... no 

 FlG. 31. Skulls of Meritherium, an Elephant ancestor, from the 



Upper Eocene of Egypt in 



FlG. 32. The nodules on the roots of bean-plants and the nitro- 

 gen-fixing microbe, Bacillus radicola, which produces 

 them ... ... ... ... ... ... ... 114 



FIG. 33. The continuity of the protoplasm of vegetable cells ... 1 16 

 FlG. 34. Diagram of the structures present in a typical organic 



'cell' 117 



FIG. 35. The Number of the Chromosomes 119 



FIG. 36. The Number of the Chromosomes , ,,, ... 120 



