CONTENTS. 



Branch V. — Vekmes 185 



Class I. — Platuelminthka 187 



Sub-Class I. — Tukbellaria 188 



Sub-Class II. —Tkematoda 191 



Sub-Class III. — Cestoda 198 



Class II. — Kotifeba 202 



Class III. — Gasteotkicha 206 



Class IV. — Nematoda 207 



Class V. — Acanthocephali 213 



Class VI. — Ch^tognathi 213 



Class VII. — Nemeetea 215 



Class VIII. — Gephybea 217 



Class IX. — Annelida . 218 



Sub-Class I. — Akchiannelida 219 



Sub-Class II. — Ch^topoda 219 



Sub-Class III. — Enteeopneusti 231 



Sub-Class IV. — Discophoei 232 



Branch VI. — Molluscoidea 236 



Class I. — Polyzoa 236 



Sub-Class I. — Entopeocta 239 



Sub-Class II. — Ectopeocta 240 



Sub-Class III. — Podostomata 244 



Class II. — Brachiopoda 244 



Branch VII. — Mollusca 248 



Class I. — Acephala 252 



Class II. — Cephalophora 287 



Sub-Class I. — Scaphopoda , , . 291 



Sub-Class II. — Gasteropoda 292 



SUPKR-OKDEB I. — ISOPLEURA 292 



Order I. — ChvETOdeem^ 292 



Order II. — Neomenoidea 292 



Order III. — Polyplacophora . 293 



Super-Order II. — Anisopleura 294 



Order I. — Opisthobranchiata 295 



Order II. — Pulmonata 303 



Order III. — Zygobranchia 319 



Order IV. — Scutibranchia . 322 



Order V. — Ctenobeanchia 324 



Oeder VI. — Heteropoda 353 



Sub-Clas.s III. — Pteropoda 356 



Order I. — Thecosomata 357 



Order II. — Gymnosomata 359 



Class III. — Cephalopoda . . 3g0 



Sub-Class I. — Teteabeanchiata 307 



Sub-Class II. — Dibranchiata 309 



Order I. — Octopoda 3g9 



Order II. — Decaceba 3^2 



