ILLUSTRATIONS 



no. PAGK 



1. Amoeba pfoteus (highly magnified) . . . . . .2 



2. Paramecium caudatum (highly magnified) . . . . .6 



3. Life-history Stages of Monocystis agilis (highly magnified) . . .10 



4. Transverse Section through a part of the wall of Sycon gelatinosum . . 14 



5. Types of Sponge Spicules . . . . . . .18 



6. Transverse Section of an Asoon Sponge (diagrammatic) . . .20 



7. Transverse Section of a Syoon Sponge . . . . . .22 



8. Transverse Section of a part of the wall of a Leucon Sponge . . .22 



9. Transverse Section of a Khagon Sponge . . . . . .24 



10. Hydra viridis. Longitudinal Section of Hydra . . . . .26 



11. Transverse Section of Hydra viridis, etc. . . . . . .30 



V2. Transverse Section of a Sea-anemone . . . . . .34 



13. Longitudinal Section of a Sea-anemone . . . . . .38 



14. Dorsal and Ventral View of the Liver-fluke (Fasciola) . . . .42 



15. Transverse Section through the body of a Liver-fluke . . .44 



16. The Beei Tape-worm {Taenia saginata) . . . . . .46 



17. A Mature Proglottis of Taenia solium . . . . . .48 



18. Transverse Section through a proglottis of Taenia solium . . .50 



19. Earth-worm (Lumbricus terrestris) . . . . . .54 



20. Alimentary, Vascular, Nervous and Reproductive Systems of the Earth-worm . 58 



21. Transverse Section (diagrammatic) through the middle of the body of the Earth- 



worm {Lumbricus) . . . . . . . .62 



22. The Leech {Hirudo medicinalia) . . . . . . .68 



23. Transverse Section (diagrammatic) through the middle of the body of the Leech 



{Hirudo) ......... 70 



24. The Cockroach {Periplaneta americana). Male . . . . .76 



25. The Cockroach.. Front, side and dorsal views of the head . . .78 

 28. Appendages of the Cockroach {Periplaneta) . . . . .80 



27. Alimentary and Nervous System of the Cockroach . . . .84 



28. The European Fresh-water Crayfish {Astacus) . . . . .90 



29. The Cape Crawfish or Kreeft {Jasus lalandii) . . . . .92 



30. Appendages of the Fresh-water Crayfish {Astacus) . . . .96 



31. Appendages of the Cape Crawfish {Jasus) . . . . .100 



32. The Fresh-water Crayfish {Astacus). General Structure and Nervous System . 108 



33. The Cape Crawfish {Jasus). General Structure and Nervous System . .110 



34. PhyllosomalnxYS. of the Crawfish ....... 112 



35. The Snail (Hdix aspersa) . . ■ ■ • . .114 



36. The Snail (Helix). Dorsal view after removal of shell . . . .116 



37. Dissection of the Snail {Helix) . . . . . . .118 



38. The Nervous System of the Snail {Helix) ..... 122 



39. Inner view of the left half of the head region (odontophore, etc.) of the Snail . 124 



40. The Fresh-water Mussel {Anodonta cygnea) ..... 126 



IX 



