LIST OF ILLUSTRATIONS 



FIG. PAGE 



1. Amoeba proteus . . . 16 



2. Difflugia urceolata 20 



3. Arcella discoides ......... 21 



4. Gromia oviformis 23 



5. Polystomella crispa 24 



6. Heliosphaera inermis 27 



7. Chondrioderma diforme 29 



8. Actinophrys sol ......... 30 



9. Actinosphaerium eichhornii ....... 31 



10. Euglena viridis 32 



11. Vorticella microstoma 36 



12. Diagram of Vorticella . . . . . . . . 37 



13. Paramecium caudatum 40 



14. Opalina ranarum ......... 42 



15. Clepsidrina long a .43 



16. Hydra fusca ...... 50 



17. Longitudinal section through the body of Hydra ... 51 



18. Transverse section of Hydra fusca 53 



19. Cnidoblast with large nematocyst from the body -wall of 



Hydra fusca 54 



20. Section through body- wall of Hydra fusca ... 56 



21. Preparation of part of the body -wall of Hydra to show the 



nerve-cells 56 



22. Diagram of Hydra to show the arrangement of the nerve- cells 57 



23. Obelia helgolandica .58 



24. Part of a branch of Obelia 59 



25. Free-swimming Medusa of Obelia .60 



26. Bougainvillia fructuosa 61 



27. (1) Eye of Lizzia koellikeri ; (2) Kadial section through the 



edge of the umbrella of Carmarina hastata showing sense 



organ and velum 63 



28. The ciliated larva or Planula of a Hyclromedusan, Clava 



squamata 65 



29. Part of a colony of Alcyonium digitatum . . . 69 



