TABLE OP CONTENTS. 



INTRODUCTION, . . . . . . .1 



CHAPTER I. PROTOZOA. 



1. Amoeba (Proteus Animalcule), . . . . .7 



2. Vorticella (Bell Animalcule), . . . . .11 



3. Gregarina, . . . . . . .17 



CHAPTER II. CCELENTERATA. 



4. Hydra (Fresh Water Polype), . . . . ,19 



Further remarks on Hydrozoa, ..... 27 



CHAPTER III. PLATYHELMIA (Flat- worms). 



5. Distoma' (Liver-fluke), ...... 28 



Further remarks on Flukes, . .... 39- 



6. Tsenia (Tapeworm), . . . . .39 



Further remarks on Tapeworms, . . . .46 



CHAPTER IV. NEMATHELMIA (Thread-worms). 



7. Ascaris (Round-worm), . . . ... 47 



Other Thread- worms, ...... 53 



CHAPTER V. ANNELIDA (Segmented Worms). 



8. Lumbricus (Earthworm), . . . . .54 



Sexual reproduction, . . . . . .71 



9. Hirudo (Leech), .... . 75 



