xii LIST OF ILLUSTRATIONS. 



FIG. 1 



34. Gradual transitions between Paludina neumayri (a), the 



oldest form, and Paludina Juzrnesi (j ) from Neumayr 

 34A. Structure of Am&ba proteus after Lucy A. Carter . Facing 



35. Life history of Amoeba .... 



36. Actinophrys sol (Sun-animalcule) after Grenacher . 



37. Polystomella, megalospheric form, with large central chamber 



(M) and one nucleus (N] after Lister . 



38. Polystomella, microspheric form, with large central chamber 



(c.c. ), numerous nuclei (N), bridges of protoplasm 

 between chambers (B) after Lister 



39. Paramczcium in longitudinal optical section, and dividing 



after Biitschli ...... 



40. Conjugation of Paramc&cium aurelia four stages after 



Maupas ..... 



41. Diagrammatic expression of process of conjugation in Para- 



m&cium aurelia after Maupas .... 



42. Vorticella after Biitschli ..... 



43. Volvox globator after Klein and Janet 



44. Life history of Monocystis after Biitschli 



45. Life history of Gregarina after Biitschli 



46. End-to-end union of Gregarines after Frenzel 



47. Life history of Coccidium after Schaudinn. . 



48. Diagram of Protomyxa aurantiaca after Haeckel . 



49. Formation of shell in a simple Foraminifer after Dreyer 



50. A Foraminifer (Polystomella) showing shell and pseudopodia 



after Schultze . . . 



51. A pelagic Foraminifer Hastigerina (Globigerina} Murray i 



after Brady ...... 



52. Optical section of a Radiolarian (Actinomma) after Haeckel 



53. Glossina palpalis^ tse-tse fly . 



54. Trypanosoma gambiense ..... 



55. A colonial flagellate Infusorian Proterospongia haeckelii 



after Saville Kent . . . . 



56. Simple sponge (Ascetta primordialis) after Haeckel 



57. A sponge colony ..... 



58. Sponge spicules . . 



59. Section of a sponge after F. E. Schulze 



60. Diagram showing types of canal system after Korschelt and 



Heider. The flagellate regions are dark throughout, the 

 mesogloea is dotted, the arrows show the direction of the 

 currents. All the figures represent cross-sections through 

 the wall ....... 



61. Development of Sycandra raphanus after F. E. Schulze 



62. Diagrammatic representation of development of Oscarella 



lobularis after Heider ..... 



63. A, Young Dicyema after Whitman. B, Female Orthonectid 



(Rhopalura giardii} after Julin .... 



64. Salinella after Frenzel ... 



65. Diagram of Ccelenterate structure, endoderm darker through- 



out ....... 



66. Colony of Hydractinia on back of a Buccinum shell tenanted 



by a hermit-crab ...... 



