LIST OF ILLUSTRATIONS. XI 



Pagb 



Sword-Bearer 285 



Tripod Wheel-Bearer 286 



Two-Lipped Tube- Wheel 290 



Wheels op Tube-Wheel 291 



?"ooT OF Nais 301 



Throat OF Leech laid Open 310 



Jaw OF Leech 311 



Pushing-poles of Serpula 314 



Hooks of Serpula 316 



Spine of Echinus 323 



Head op Pedicellaria 326 



Sucker of Urchin 332 



Pores of Urchin 332 



Sucker-plate of Urchin 335 



Dumb-bells in Holothuria 342 



Wheel in Chirodota 313 



Anchor-plate in Synapta 311 



Larva of Sea-Urchin 347 



Development of Disk 350 



Cydippe 357 



Sarsia 364 



Thaumantias 367 



Otolithes op Thaumantias 368 



Turris and its Young 372 



Laosiedea 377 



Tentacle of Laomedea 379 



Staubidia 393 



Lares 396 



Polypes of Cow's Pap 403 



Spicin^ op Cow's Pap 406 



Portion of Acontium 409 



Cinclides 411 



Cnida of Madrepore 417 



Cnida of Tealia Crassicornis 420 



Cnida of Cortnactis 424 



FoRAis of Amcbba 434 



Section of Sponge 442 



Three-sided Euglena 447 



Swan-neck and its Divisions 450 



Pabaikecium 454 



