CONTENTS ix 



PAGE 



SECTION X 



PHYLUM ARTHROPODA 211 



I. The Crustacea 212 



II. The Onyehophora 236 



III. The Insecta 239 



IV. The Myriapoda 251 



V. The Arachnida 253 



SECTION XI 



PHYLUM MOLLUSCA 263 



I. The Pelecypoda 264 



II. The Amphineura 280 



III. The Gastropoda 284 



IV. The Cephalopoda ... 296 



SECTION XII 



PHYLUM CHORDATA 309 



I. The Adelochorda 310 



II. The Urochorda 313 



III. The Vertebrata 321 



A. The Acrania 322 



B. The Craniata 327 



I. Cyclostomi 359 



II. Pisces 364 



I. Elasmobranchii 365 



3. Teleostomi 391 



4. Dipnoi 402 



III. Amphibia 404 



IV. Eeptilia 431 



V. Aves " 454 



VI. Mammalia 487 



