LIST OF ILLUSTRATIONS. XI 



PAOB 



Whiptail 289 



Skeleton Wheel-Bearer 243 



Sword-Bearer 247 



Tripod Wheel-Bearer 249 



Two-Lipped Tube-Wheel 252 



Wheels of Tcbe-Wheel 253 



Foot of Nais 262 



Throat of Leech Laid Open 269 



Jaw of Leech 270 



Pushing Poles of Serpula 273 



Hooks of Serpula 274 



Spine of Echinus 281 



Head of Pedicellaria Tridens 284 



Sucker of Urchin 289 



Pores of Urchin 289 



Sucker-plate of Urchin 292 



Dumb-Bells in Holothuria 298 



Wheel in Chirodota 298 



Anchor-plate in Stkapta 299 



Larva of Sea-Urchin 303 



Young Sea-Urchin: Development of Disk .... 305 



Ctdippe 310 



Sarsia 316 



Thaumanttas ... 319 



Otolithes of Thausiantias 320 



Turris and its Young ........ 324 



Laomedea 328 



Tentacle of Laomedea 329 



Stauridia 342 



Lares 345 



Polypes of Cow's Pap 351 



Spicula of Cow's Pap 353 



Portion of Acontium 357 



Cincliiies 358 



Cnida of Madrepore 364 



Cnida of Tealia 367 



Cnida of Cortnactis 370 



Forms of Amozba 379 



