CONTENTS. ix 



PAGE 



Vermes 178 



Plathelminthes 178 



Nemathelminthes. . . ". 182 



Annelida 183 



Molluscoidea 189 



Summary. , 190 



Mollusca 193 



Amphineura 197 



Gasteropoda 197 



Acephala . . 202 



Cephalopoda 208 



Summary 212 



Arthropoda 215 



Crustacea 218 



Acerata 231 



Merostomata 231 



Arachnida 232 



Insecta 235 



Chilopoda 235 



Hexapoda 236 



Summary. 270 



Echinoderma 273 



Asteroidea 276 



Ophiuroidea 278 



Crinoidea v 279 



Echinoidea 280 



Holothuroidea 282 



Summary , 284 



Chordata 286 



Tunicata 287 



Leptocardii 289 



Vertebrata 290 



Cyclostomes 315 



Pisces 317 



Amphibia 336 



Reptilia 342 



Aves 350 



Mammalia 363 



Summary 392 



