xxvi LIST OF ILLUSTRATIONS 



FIG. PAGE 



324. Apical system of young Starfish 385 



325. Echinus esculentus, peristome 386 



326. Strongylocentrotus 387 



327. Corona of Sea-urchin 388 



328. Apical disc of Sea-urchin 389 



329. Echinus, lantern of Aristotle 390 



330. Sea-urchin, anatomy, lateral view 390 



331. Echinoid, transverse section of ambulacra! zone . . . .391 



332. Sea-urchin, anatomy, oral view 392 



333. Cucumaria planci 393 



334. Anatomy of a Holothurian 395 



335. Antedon 397 



336. Aboral view of Antedon 397 



337. Antedon disc 398 



338. ,, transverse section of pinnule 399 



339. ,, sagittal section . . . ' 400 



340. Anthenea, ventral view 410 



341. Ophioglypha lacertosa 411 



342. Astrophyton arborescens 412 



343. Diagram of spine of Sea-urchin . .413 



344. Pedicellaria of Arbacia punctulata 413 



345. Hemipneustes radiatus 414 



346. Clypeaster sub-depressus 414 



347. Metacrinus interruptus . . .415 



348. Development of Echinoderms 422 



349. ,, Antedon 423 



350. Stalked larva of Antedon ^. 424 



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



dermata 428 



352. Nereis dumerilii 430 



353. ,, ,, parapodium 431 



354. setae 431 



355. Nereis diversicolor, proboscis 433 



356. Nereis dumerilii, anatomy 434 



357. transverse section 435 



358. ,, ,, nervous system 436 



359. eye 437 



360. ,, ,, nephridium 438 



361. ,, development 440 



362. 442 



363. Lumbricus 444 



364. setse 445 



365. transverse section 446 



366. ,, sagittal section 447 



367. nervous system 448 



368. nephridium 450 



369. ,, reproductive organs 451 



370. development 453 



