CONTENTS. 



PART II. 



SOME INVERTEBRATE TYPES. 



CHAP. PAGE 



XII. The Crayfish, ...... 231 



XIII. The Cockroach, 257 



XIV. The Earthworm, 278 



XV. The Snail, 291 



XVI. The Fresh-water Mussel, .... . 305 

 XVII. The Liver-Fluke and Tapeworm, . . .322 



XVIII. The Hydra, 335 



XIX. Vorticella and Paramoecium, .... 347 



XX. The Amoeba, .... . 354 



APPENDIX. 



Classification of Types, ...... 361 



Glossary, ........ 365 



Index, ......... 379 





