LIST OF ILLUSTRATIONS xxv 



FIG. I'M, I 



376. Hirudo, diagram of blood-channels ... . . 472 



377. ,, section of eye . . . 473 



378. ,, cocoon ... . 474 



379. Three Rhynchobdellida . . 475 



380. Proboscis of Clepsine . . 477 



381. Transverse sections of three Leeches . . . 478 



382. Pontobdella, nephridial system . . . 479 



383. Clepsine, development .... . . 47-' 



384. Diagram of origin of metamerism 482 



385. Diagram illustrating the relationships of the Annulataand Trochel- 



minthes 483 



386. Apus cancriformis, dorsal aspect . ... 485 



387. Lepidurus kirkii, side view . . 486 



388. Apus glacialis, ventral aspect 487 



389. ,, appendages 488 



390. Lepidurus kirkii, sagittal section . 491 ) 



391. Apus, transverse section 492 



392. ,, shell-gland ... 493 



393. ,, cancriformis, nervous system .... . 494 



394. ,, structure of paired eye ... 495 



395. ,, development 496 



396. Astacus fluviatilis, male . . . 499 



397. ,, ,, appendages .... . 501 



398. ,, ,, articulations and muscles of leg . . 503 



399. Section of skin and exoskeleton of Lobster . . 504 



400. Articulations and muscles of abdomen of Crayfish . . 505 



401. Astacus fluviatilis, dissection from right side 506 



402. ,, ,, gills ... . 508 



403. ,, ,, kidney 510 



404. ,, ,, transverse section of thorax . . . 511 



405. ,, ,, diagram of circulation . ... 512 



406. ,, ,, nervous system . . . 513 



407. ,, ,, reproductive organs . . . 515 



408. ,, ,, formation of the blastoderm . . . 515 



409. ,, ,, early embryo . 516 



410. ,, ,, nauplius 517 



411. ,, ,, section of embryo . . . 518 



412. ,, ,, advanced embryo .... 519 



413. Three Euphyllopoda . . ... 526 



414. ,, Cladocera . ... 527 



415. Cypris ... . 528 

 41(J. Cyclops and Calocalanus . 529 



417. Various forms of parasitic Eucopepoda . . . 531 



418. Argulus foliaceus . . 532 



419. Lepas anatifera . . ... . 533 



420. Balamis . . 534 



421. Sacculina carcini . . . 535 



422. Nebalia geoft'royi . . . 536 



423. Mysis oculata . ... 537 



