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 pinmile . ... 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 racliatus . . 414 



346. Clypeaster sub-depressu.:; . . . 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. setse . .... 431 

 3,")."). Nereis diversicolor, proboscis ... . 433 



356. Nereis dumerilii, anatomy . . 434 



357. ,, ,, transverse section . . 435 



358. ,, ,, nervous system . ... . 436 



359. eye . 437 



I!'')". nephridium . . ... 438 



361. ,, development . . 449 



362. .442 



363. Lumbricus .... 444 



364. ,, setae . . 445 



365. ,, t ninsverse section . . . 44(5 



366. ,, sagittal section . 447 



367. ,, nervous system . . 44$ 



368. ,, nephridium ... . 450 



369. reproductive organs . 4,-)l 



370. ,, development . . . 453 



