CONTENTS 



PAGE 



2 



UThe Proteus Animalcule {Amoeba) . .... 



'The Slipper Animalcule {Paramecium) ..... 6 



MONOCYSTIS ......... 10 



ySpoNGES {Porifera) ... i .... 14 



\/The Fresh- Water Polyp {Hydra) ... . . 26 



©The Sea-Anemone {Actinia) ....... 34 



^The Liver-Fluke {Fasciola or Distoma) . . ■ . 40 



\y The Tape- Worm {Taenia) ....... 46 



uThe Earth- Worm {Lumbricus) . . . . 54 



The Medicinal Leech {Hirudd) .... 64 



The Cockroach {Periplaneta) ....... 74 



The Fresh-Water Crayfish {Astacus) and the Cape Crawfish {Jasus) 88 



The SNArfL {Helix) . . . . . . .114 



1. The Fresh- Water Mussel {Anodonta) and the Common Marine Mussel 



{Mytilus) ......... 126 



The Lancelet {Amphioxus, syn. Branchiostoma) . . ' . 142 



The Spiny Dogfish {Acanthias, syn. Squalus), or the Spotted Dogfish 



{Scyllium), and the Skate {Raia) ..... 152 



The Frog {Pana) and the Platana or Clawed Toad {Xenopus) . 188 



The Pigeon {Columba) .... . . 236 



The Rabbit {Lepus) ... .... 266 



A Classification of the above Types . . . 316 



Index ......... 319 



vn 



