xxiv LIST OF ILLUSTRATIONS 



PAOE 



327. Nereis development . . . 415 



328. Lumbricus agricola . 418 

 :!2<l. setre . .419 



330. ,, transverse section . 41 ( .> 



331. ,, herculeus, sagittal section . 420 



332. ,, nervous system . . . 422 



333. ,. nephriclium . . 423 



334. ,, agricola, reproductive organs . . 424 



335. ,, development ... . 426 



336. Polynoe setosissima . 429 



337. Vermilia ccespitosa . . 430 



338. Setfe of various Polychreta ... . . 431 



339. Section of setigerous sac of an Oligochrete . . 431 



340. Polynoe extenuata, anterior end . 432 



341. Tubifex . . 433 



342. Terebella . 434 



343. Aphrodita, enteric canal . . 436 



344. Saccocirrus, transverse section . . , 438 



345. Diagram illustrating development of gonad of Polyclueta . . 441 



346. Spirorbis kevis .... . . 444 



347. Eupomatus, development of trochosphere . . 445 



348. Autolytus cornutus, budding ... . 446 



349. Serpuhe with their tubes . 447 



350. Myzostomum . . 449 



351. ,, anatomy ... . 450' 



352. Sipunculus nudus, anterior extremity . . . . . 451 



353. ,, ,, tentacular fold . . 452 



354. ,, ,, anatomy . . 453^ 



355. ,, ,, nervous system . 453^ 



356. Bonellia viridis, female . . . 456 



357. Echiurus . . 456 



358. Priapulus . . . 457 



359. Bonellia, anatomy . . 458 



360. Echiurus, ciliated funnel . . 458 

 3(51. ,, anatomy . . 459 



362. ,, nervous system . . 459 



363. Bonellia, male . . 460 



364. Echiurus, trochosphere . . 460 



365. Polygordius neapolitanus . . . 462 



366. Protodrilus . .463 



367. Polygordius neapolitanus, transverse section . 463 



368. ,, ,, trochosphere . . 464 



369. ,, ,, ,, later stage . . . 464 



370. Hirudo medicinalis . . 466 



371. ,, ,, transverse section . . . 468- 



jaw . . . 468 



">7-"'. ,, quinquestriata, dissection from dorsal aspect . . . 469 



374. ,, ,, ,, ,, left side . 470- 



375. ,, medicinalis, nephridiuni . . . 471 



