LIST OF ILLUSTRATIONS 



Volvox globator Ehrenberg . . . Frontispiece 



FIG. PAGE 



1. Diagram of the life-history of the Liver-fluke . . 22 



2. Portion of colony of Bougainmllea fruticosa . . 37 



3. Hydra 39 



4. Stylonychia my til us . . . . . . . 41 



5. Pilidium with young Nemertine enclosed . . 73 



6. Clathrina coriacea, histology 91 



7. Gonium 103 



8. Haplozoon macrostylum 108 



9. Probable evolution of the Catenata . . . .111 



10. Part of a colony of Hydr actinia . . . .117 



11. Diphyes campanulata 121 



12. Physcia parietina 123 



13. The Yucca and its Moth 129 



14. Development of a nerve- cell 139 



15. Regeneration in Planaria lugubris . . . .145 



16. Elementary Structure in plants 159 



Figs. 2, 10, and 11 are reproduced from the Encyclopaedia 

 Britannica (eleventh edition) ; figs. 6 and 12 are from 

 Lankester's Treatise on Zoology, Vol. n, and Scott's Struc- 

 tural Botany respectively, by kind permission of Messrs 

 A. & C. Black ; fig. 7 is from West's British Freshwater 

 Algae (Camb. Univ. Press) ; and fig. 13 is from Weismann's 

 Evolution Theory, by permission of Mr Edward Arnold. 



