LIST OF ILLUSTKATIONS. XI 



Page 



Sword-Beaeer 285 



Tkipod Wiieel-Beaeer 286 



Two-LipPED Tube-Wheel 290 



Wheels op Tube-Wheel 291 



Foot of Nais i 301 



Theoat of Leech laid Open 3]0 



Jaw of Leech 311 



Pdshing-poles of Serpdla 314 



Hooks of Serpula 316 



Spine op Echinus 323 



Head op Pedicellaeia , 326 



Sucker of Urchin 332 



PoEES of XJuchin 332 



SuCKEE-PLATE OF UrCHIN 335 



Dumb-bells in Holothueia 342 



Wheel in Chieodota 343 



Anchok-plate isStnapta 344 



Laeva of Sea-Ueciiin 347 



Development op Disk 350 



Ctdippe 357 



Saksia 364 



Thaumantias 367 



Otolithes of Thaumantias 368 



TuEEis and its Young 372 



Lao>iedea 377 



Tentacle of Laomedea 379 



Staueidia 393 



Laees 396 



Polypes of Cow's Pap 403 



Spicula of Cow's Pap 406 



poetion of acontium 409 



CiNCLIDES 411 



Cnida OF Madrepoee 417 



Cnida of Teaua Ceassicoenis 420 



Cnida op Coeynaotis 424 



FoEMS of Am<eba 434 



Section of Sponge 442 



Theee-sided Euglena 447 



Swan-neck and its Divisions 450 



Paeamcecium 454 



