xxviii LIST OF ILLUSTRATIONS 



FIG. 



414. Proboscis of Clepsine . .518 



415. Nephridium of Herpobdella ... 519 



416. Pontobdella, nephridial system 520 



417. Clepsine, development . .... 521 



418. Diagram of origin of metamerism . 524 



419. Diagram illustrating the relationships of the Annulata and 



Trochelminthes . . .... 525 



420. A pus cancriformis, dorsal aspect 527 



421. Lepidurus kirkii, side view . 528 



422. Apus glacialis, ventral aspect 529 



423. ,, appendages . . 530 



424. Lepidurus kirkii, sagittal section . 532 



425. Apus, transverse section 534 



426. ,, shell-gland ... .535 



427. ,, cancriformis, nervous system 536 



428. ,, structure of paired eye 537 



429. ,, development 538 



430A. Astacus fiuviatilis, male ... ... . 540 



430 B. ,, ,, transverse section of abdomen .... 540 



431. ,, ,, appendages . . . 543 



432. ,, ,, articulations and muscles of leg .... 545 



433. Section of skin and exoskeleton of Lobster 546 



434. Articulations and muscles of abdomen of Crayfish .... 547 



435. Astacus fluviatilis, dissection from right side . . . 548 



436. ,, gills . . . . 550 



437. ,, kidney ... .552 



438. ,, ,, transverse section of thorax 553 



439. ,, ,, diagram of circulation 554 



440. ,, ,, nervous system 555 



44 1 . , , , , reproductive organs .... . 557 



442. ,, ,. formation of the blastoderm 557 



443. ,, ,, early embryo 558 



444. ,, ,, nauplius 559 



445. ,, ,, section of embryo 560 



446. ... ... 560 



447. ,, ,, advanced embryo 501 



448. Three Branchiopoda 571 



44 J. ,, Cladocera . 572 



450. Cypris .... . .... 573. 



451. Cyclops and Calocalanus 574 



452. Various forms of parasitic Eucopepoda 576 



453. Argulus foliaceus . . 577 



454. Lepas anatifera . .... . . 578 



455. Balanus . .... 579 



456. Sacculina carcini . 580 



457. Nebalia geoffroyi 581 



458. Paranaspides 582 



459. Mysis oculata . . 582 



460. Diastylis 583 



