xxvi LIST OF ILLUSTRATIONS 



FIG. PAGE 



320. Echinus esculentus, peristome 394 



321. Strongylocentrotus 395 



322. Corona of Sea-urchin 396 



323. Apical disc of Sea-urchin 397 



324. Echinus, lantern of Aristotle 397 



325. Sea-urchin, anatomy, lateral view 398 



326. Echinoid, transverse section of ambulacral zone .... 399 



327. Sea-urchin, anatomy, oral view 400 



328. Cucumaria planci 401 



329. Anatomy of a Holothurian 403 



330. Antedon 405 



331. Aboral view of Antedon 406 



332. Antedon disc 406 



333. ,, transverse section of pinnule 407 



334. ,, sagittal section 408 



335. Anthenea, ventral view 419 



336. Ophioglypha lacertosa 420 



337. Astrophyton arborescens 421 



338. Diagram of spine of Sea-urchin 422 



339. Pedicellaria of Arbacia punctulata 422 



340. Hemipneustes radiatus 423 



341. Clypeaster sub-depressus 423 



342. Metacrinus interruptus 424 



343. Development of Echinoderms 431 



344. ,, ,, Antedon 432 



345. Stalked larva of Antedon 433 



346. Diagram to illustrate the relationships of the classes of Echino- 



dermata 437 



347. Nereis dumerilii 440 



348A. ,, ,, parapodium 441 



348B. ,, ,, setae - . . .441 



349. Nereis diversicolor, proboscis 443 



350. Nereis dumerilii, anatomy 444 



351. ,, transverse section 445 



352. ,, ,, nervous system 446 



353. ,, eye 447 



354. ,, ,, nephridium 448 



355. ,, ,, development 451 



356. 453 



357. Lumbricus herculeus 454 



358. ,, setae 455 



359. ,, transverse section 456 



360. ,, sagittal section 457 



361. ,, nervous system 459 



362. ,, nephridium 460 



363. ,, reproductive organs ,. 462 



364. ,, development 463 



365. Polynoe setosissima 467 



