Other Worms.
Classification, [135.]—Earthworms and leeches (Oligochætæ), [136.]—Flat worms (Platyhelminthes). [137.]—Round worms (Nemathelminthes), [140.]—Wheel-animalcules (Rotifera), [142.]
XX.—BRANCH ARTHROPODA: THE CRUSTACEANS, CENTIPEDS, INSECTS, AND SPIDERS.
Class Crustacea: Crayfishes, crabs, lobsters, etc.
Example: The crayfish (Cambarus sp.). Structure, [146.]—Life-history and habits, [146.]
Other Crustaceans.
Body form and structure, [147.]—Water-fleas (Cyclops), [148.]—Wood-lice (Isopoda), [150.]—Lobsters, shrimps, and crabs (Decapoda), [151.]—Barnacles, [155.]
XXI.—BRANCH ARTHROPODA (CONTINUED).
Class Insecta: The Insects.