Chapter XXVII: Introduction: General Characters and Terminology—brown Bodies—history (4)

Haberlandt, on _Convoluta_, 43
Habits, of Platyhelminthes, 3, 7, 21, 35, 43;
of Nemertinea, 114;
of Gordiidae, 170 f.;
of Chaetognatha, 189;
of Rotifers, 206, 226;
of Gastrotricha, 232, 234, 235;
of Polychaeta, 285;
of Oligochaeta, 366;
of Gephyrea, 426, 433, 442;
of _Phoronis_, 451
_Haemadipsa_, _408_;
eye, 394
Haemal fluid, 252
_Haematocleptes_, parasitic, 297
_Haementeria_, _407_
Haemerythrin, 416;
in _Magelona_, 252
Haemoglobin, in Nemertinea, 107, 108;
in Chaetopoda, 252, 253, 291, 356;
in Gephyrea, 437;
in _Phoronis_, 456
_Haemopis_, 393, _407_
_Halicryptus_, _432_, 433;
anatomy, 430
Hallez, on Turbellaria, 7, 21, 40
_Halosydna_, 298
Hamann, on Nematoda, 131, 133, 136 n.;
on Acanthocephala, 176, 180
_Hamingia_, 435 f., _442_;
males of, 438
_Haplobranchus_, _339_;
gills, 261
_Haplodiscus_, 43, _49_
Haplodrili, 241
Hares, parasites of, 141, 145
Harker, on Oligochaeta, 369
Harmer, on Polyzoa, 465 f.
Harris, on Rotifera, 197
Hartog, on Rotifera, 197 f.;
on Gastrotricha, 231 f.;
on Kinorhyncha, 236 f.
Haswell, on Temnocephalidae, 53;
on _Phoronis_, 451
Hatschek, on affinities of Polyclads, 28 n.;
on nature of Cestodes, 76;
on Trochophore, 229;
on development of Gephyrea, 419, 447
Head, of _Nereis_, 246, 248;
of Polychaeta, 259 f.;
regeneration of, 283;
of _Tomopteris_, 315;
of _Aphrodite_, 260;
of Chlorhaemidae, 334;
of _Eunice_, 262;
of _Nephthys_, 262;
of _Phyllodoce_, 262;
of _Polydora_, 261;
of Polynoid, 262;
of _Sabella_, 261;
of _Sabellaria_, 263;
of Syllid, 262;
of _Trophonia_, 262
_Hedruris_, 163
_Hekaterobranchus_, _326_
_Heliodrilus_, 359, 380
_Heliopora_, containing _Polydora_, 298
Heller, on human parasites, 139
Hemichordata, 462
_Hemilepidia_, colour of, 292
_Hemistomum_, _73_
_Hemitubifex_, _378_
_Henlea_, 369
_Hermadion_, 299
Hermaphrodite, Nemertinea, 109;
Polychaeta, 273 f.
Hermellidae, _258_, _341_
Hermelliformia, _258_, _306_, 341
_Hermione_, _312_;
chaetae, 266, 267
Hermionina, 309, _311_
Herpobdellidae, _407_
Hertwig, O., on Chaetognatha, 187 n.
Hesionidae, _258_, _308_;
segments, 258;
head, 263;
swim-bladder, 272;
genital organs, 274;
parasitic, 297
_Hesperodrilus_, 352 f., 369, _378_ f.
Hesse, on nervous system of Nematoda, 127
_Heterakis_, 131, _139_ {546}
Heterocotylea, _73_
_Heterodera_, _155_, 160, 164
Heterogamy, 66 n.
Heteronemertini, _113_
Heteronereid phase, 276 f.;
chaetae, 246, 276;
parapodia, 276, 277
Heteronereis, 276, 281—see Heteronereid
_Heteropora_, 520 n.
Heterosyllis, 278, 279, 281
_Hexacotyle_, _73_
_Hexarthra_, _223_, 226
Hibernaculum, 501, 502
Hincks, on Polyzoa, 475, 500, 508, 516, 519, 523
_Hippothoa_, 528
_Hippuraria_, 533
Hirudinea, _241_, 392 f.;
external characters, 392;
British species, 393;
eyes, 395;
branchiae, 395;
alimentary canal, 396;
vascular system, 396;
body-cavity, 397;
nephridia, 399;
reproductive organs, 401;
cocoons, 404;
classification, 405
Hirudiniculture, 393
_Hirudo_, 393, 396 f., 399, 403, 405, _407_;
nephridium, 400
_Hislopia_, 492
_Histioderma_, 302
_Histriobdella_, 242 n.
_Histriodrilus_, 242 n.
Holloway, on Rotifers, 227
Holomyarii, _137_
Holostomatidae, 63, 64, _73_
_Holostomum_, _73_;
_H. excavatum_, 63
Holothurian, as host, 298
_Homalogaster_, _73_
Hood, of _Sabellaria_, 263, 306
Hooks, of Trematodes, 53, 56, 57;
of Cestodes, 75, 85;
of Cestode-larvae, 87, 88;
taxonomic value in Cestodes, 90 f.
Hoplonemertea, _106_, 109, _110_;
auditory organs, 106, 110;
British species, 110;
characters, 110;
development, 113;
proboscis, 110
_Hornera_, _518_, 532
Horse, parasites of, 68, 83, 90, 125, 140, 142, 163
Horse-leeches, 393 f.
Horst, on Oligochaeta, 354
Hubrecht on Nemertinea, affinities, 120;
classification, 109;
excretory system, 108;
nervous system, 105
Hudson, on Rotifera, 197, 198, 215 n., 220 n., 223 n., 228
_Hudsonella_, _224_
Huxley, on Rotifers, 198, 229;
on Polychaeta, 246;
on Molluscoidea, 475
_Huxleya_, 525, 527
_Hyalinoecia_, 299, 318, _319_;
tentacles, 262;
composition of tube of, 290
_Hydatina_, 199, 200, 202, 204, 213, _224_, 226, 228
Hydatinidae, _224_
_Hymenolepis_, _91_;
generic characters, 91;
_H. diminuta_ (= _Taenia flavopunctata_), life-history, 83;
specific characters, 91;
_H. murina_ (= _Taenia murina_), 70;
life-history, 83, 89, 91;
_H. nana_, 80;
life-history, 83;
specific characters, 91
_Hyocrinus_, as host, 342
_Hyperiodrilus_, 363 f.;
reproductive organs, 363
Hypodermic impregnation, 27, 218
Hypodermis (= Epidermis) of _Gordius_, 165;
of Rotifera, etc., 205, 232
_Hypophorella_, 478, _518_, 533;
larva, 510
_Hyporhynchus_, _49_
_Hystrichis_, _147_, 149, 163

_Ichthydium_, _235_
Ichthyobdellidae, _406_
_Ichthyonema_, 131, _147_, 149, 163
_Ichthyotaenia_, _91_
Ichthyotaeninae, 85, _91_
_Idmonea_, _518_, 532
Iguana, parasites of, 142
Iijima, on yolk-glands, 38 n.
Illoricata, _223_
_Ilyodrilus_, _378_;
chaeta, 350
_Ilyogenia_, _388_
_Imogine_, _19_
Inarticulata, _517_, _518_
Incudate, 210, 211
Incus, in Rotifers, 210
Inermia, 445
Infusoriform embryos, 93
Insects, parasites of, 142, 150, 152, 153, 154, 160, 163, 179, 183, 184,
185
Internal sac, 509, 511
Internode, 525
Interproglottidal glands, 90
Intertentacular organ, 469, 473, 508
Introvert, in Polychaeta, 249, 250;
in Gephyrea, 412, 424
Investing membrane, in ectoparasitic Trematodes, 57;
in Cestodes, 85
Ioda, form of head, 278
_Isacis_, 163

Jammes, on skin of Nematoda, 126
Jaws, of _Nereis_, 248, 250, 270;
of Polychaeta, 269 f.;
of Eunicidae, 270;
of Polynoid, 270;
of _Autolytus_, 270;
fossil, 302;
of _Glycera_, 270
Jelly, Miss, on Polyzoa, 523
_Jensenia_, _50_
Jimenez, on Leeches, 407
Joblot, on Rotifers, 197
Johnston, on Hirudinea, 393
Joliet, on development of Rotifers, 218;
on Polyzoa, 508
Jungermanniaceae, inhabited by Rotifers, 227 {547}
Jurassic, Serpulids, 301;
Polyzoa, 520 f.

Kaiser, on Acanthocephala, 177
Kamptoderm, 469, 470
Keferstein, on Polycladida, 7, 10
Kennel, von, on Nemertinea, 108;
on _Malacobdella_, 101 n., 119
_Kerria_, _384_
Kinorhyncha, 236 f.
Kleinenberg, on Trochophore, 229
_Koellikeria_, _73_
Kölliker, on _Distomum okenii_, 71
Koren and Danielssen, on Gephyrea, 442, 443
Kowalevsky, on Hirudinea, 397;
on _Phoronis_, 458
Kraepelin, on Polyzoa, 493, 502
Krause, on parasites, 163
Krohn, on Nemertine development, 99
_Krohnia_, _186_;
species, 192, 194;
American species, 534
Krukenberg, on haemerythrin, 416
_Kynotus_, _386_

_Labrorostratus_, 297
_Lacinularia_, 200, 213, 215, _221_, 226
_Lacrymaria_, 235
_Laetmonice_, _312_
_Lagenipora_, 528
Lamarck, on Gephyrea, 411
Land, Planarians, 4, 30, 33, 34, 36;
Nemertines, 101, 117;
Oligochaeta, 347 f.;
Leeches, 408
Lang, on Polyclads, 7, 17, 21 f., 27, 28 n.;
on nature of Cestodes, 76
_Lanice_, 328;
_Hypophorella_ in tubes of, 478, 533
Lankester, on Trochosphere, 229;
on Earthworms, 347;
on Hirudinea, 397;
on Gephyrea, 430, 437, 439;
on Podaxonia, 461
Larva, Müller's, 29;
of _Polystomum_, 59;
of _Diplozoon_, 60;
of _Gyrodactylus_, 61;
of Holostomatidae, 63, 64;
of _Distomum_ 64, 65, 67;
hosts of larvae of digenetic Trematodes, 71 f.;
of _Calliobothrium_, 77;
of Cestodes, 79 f.;
table of Cestode larvae, 83, 85, 87;
of _Schistocephalus_, 84;
of _Bothriocephalus_, 87;
of _Dipylidium_ (Cysticercoid), 83, 88 f.;
of Mesozoa, 92, 93;
of Nemertinea, 113;
Trochosphere, 229, 274, 439, 510;
of _Polygordius_, 245;
of Polychaeta, 274, 275;
of _Chaetopterus_, 325;
of _Myzostoma_, 344;
of Gephyrea, 419, 439;
of _Phoronis_, 458;
of Polyzoa, 466, 509, 511, 520
Lateral organs, of Capitellidae, 343—see also Ciliated pits
Laurer's Canal (= Laurer-Stieda canal), 57, 87
_Leaena_, 300, 327 n.
_Lecanocephalus_, 131, 133
Leckenby, on _Priapulus_, 433
Leeches, _241_, 392 f.—see also Hirudinea
Leeuwenhoek, on Rotifera, 197
Legrain, on Nematodes in deserts, 156
Legros, on _Trichina_, 146
Lehnert, on _Bipalium_, 36, 37
Leidy, on Rotifers, 198
_Leimacopsis_, 37, _42_
Lemnisci, 176
_Lepas_, as host, 298
_Lepidasthenia_, 293, _311_
_Lepidoderma_, _235_
_Lepidonotus_ (subgenus of _Polynoe_), eye, 255
_Lepralia_, 516, _518_, 528, 530, 531 n.;
_L. foliacea_, 478, 527;
larva, 511
_Leprea_, _328_
_Leptodera_, 129, 131, 133, 160
_Leptoplana_, 7, 8, 9, 11, 14, 17;
British species, _19_;
habits, 8 f.;
anatomy, 11 f.
Leptoplanidae, _19_
_Leptostoma_, 396
Lesson, on Polyclads, 24
_Leuciscus_, parasites of, 173, 182
Leuckart, on Platyhelminthes, 6, 64 f., 70, 76;
on Nemertinea, 99;
on Nematoda, 136, 139, 140, 142, 146, 163;
on Hirudinea, 395
_Leucochloridium_, 65, 66
Leucocytes, of Polychaeta, 252
_Leucodore_—see _Polydora_
Leydig, on Rotifers, 198
Lias, Serpulids in, 301
_Libyodrilus_, 364, 385, 386
_Lichenopora_, _518_, 531
Life-history, of Trematodes, 4;
of Polystomatidae (_Polystomum_, _Diplozoon_, _Gyrodactylus_), 58 f.;
of digenetic Trematodes, 63 f.;
table of, 71;
of Cestodes, 5 f., 87;
table of life-histories of Cestodes, 83;
of _Dipylidium_, 88;
of Dicyemidae, 93;
of Nematoda, 159;
of _Gordius_, 170;
of Acanthocephala, 179—see also Development
_Ligula_, _91_;
occurrence, 85
Ligulinae, _91_
Lim Boon Keng, on Earthworms, 349
_Lima_, nests of, 298
Lime, secreted by Serpulidae, 290
_Limnaea truncatula_, host of larvae of _Distomum hepaticum_, 67, 72
_Limnatis_, _407_
_Limnias_, 205, _221_;
early description of, 197
_Limnodrilus_, _378_
_Lineus_, _111_;
_L. marinus_ (= _L. longissimus_), 99, 100, _111_, 114;
Borlase on, 99;
size of, 100;
_L. gesserensis_ (= _L. obscurus_ = _L. sanguineus_), recuperative
powers of, 116
Linguatulida, affinities of, 344 {548}
Linnaeus, on Cestodes, 78;
on Gephyrea, 411;
on Polyzoa, 474
Linstow, von, on classification of Nematodes, 137;
on life-history of _Ascaris lumbricoides_, 140;
on parasitism, 162;
on _Gordius_, 166, 171, 173
Lip, lip-membrane, lip-processes, of Sabellidae, 261, 337
_Lipobranchius_, _334_;
shape of body, 259
Lipochromes, in Polychaeta, 292
Lister, on Polyzoa, 497
Lithodomous, Polychaeta, 287
Lithographic slate, fossil Polychaeta from, 301, 302
Liver, -fluke, 51;
-rot, 68
Locomotion, of Planarians, 9, 10, 36;
of Polyclads, 22 f.;
of Nemertinea, 114, 115;
of Chaetognatha, 190;
of Rotifers, etc., 206, 235;
of _Dinophilus_, 243;
of Phylactolaemata, 496
Looss, on Trematoda, 62 n., 66, 70
Lopadorhynchina, _314_
_Lopadorhynchus_, _314_;
_L. erythrophyllum_, colour of, 292
_Lophochaeta_, 351;
chaeta, 350
_Lophohelia_, with _Eunice_, 298, 319
Lophophore, in _Phoronis_, 453;
in Polyzoa, 476, 476, 495
_Lophopus_, 494, 499, 504, 505, _518_, 519;
movements, 496, 497;
fission, 496, 506;
statoblast, 502, 503
Lorica, in Rotifers, 205
Loricata, 205, _224_
_Lota_, parasites of, 182
_Loxosoma_, 489 f., 489, 490, 506, _518_;
on Polychaeta, 299, 489;
on other animals, 489;
buds, 489, 490, 506;
larva, 509
Lug-worm, castings of, 285;
as bait, 297
_Lumbricaria_, 302
Lumbricidae, 362, 371 f., _388_
_Lumbricobdella_, 392
_Lumbriconereis_, 318, _320_;
from fresh water, 284
_Lumbriconereites_ (misprinted in text), 302
Lumbriculidae, 350, 361, _379_
_Lumbriculus_, _379_;
as host of Rotifer, 211 n.
_Lumbricus_, 349, 351, 356, 367, 368, 371, 389 f., 403 f.;
generative organs, 362;
cocoon, 365
_Lunulites_, _518_;
vibracula, 487
Lurg, 317
Lycoridae, _315_
_Lysidice_, 297, _320_

MacGillivray, on Polyzoa, 519
M‘Intosh, on Nemertinea, 110 n., 115, 116;
on _Phoronis_, 454
_Macraspis_, _73_
_Macrobdella_, 393, _406_;
sense-body, 394
_Macrorhynchus_, 44, 47;
British species, _49_
_Macrostoma_, 44, 47;
British species, _49_
Macrostomatidae, _49_
_Magelona_, _325_;
haemerythrin in, 252
Magelonidae, 258, _325_
Main-gut, of _Leptoplana_, 8, 13;
of Polyclads, 17
_Malacobdella_, 101;
description of, 119;
_M. grossa_, _110_, 119;
excretory system of, 108
Malacocotylea (= Digenea), _73_
Maldanidae (= Clymenidae), _258_, _332_;
shields, 259;
anal funnel, 259;
chaetae, 266, 267, 268;
colour, 293
Male, of Rotifers, 199, 200, 217, 223 n.;
of Echiuroids, 438
Malleate, 210
Malleoramate, 210, 211
Malleus, 210
Mammals, Trematodes of, 62, 63, 67-70, 71 f.;
Cestodes of, 77-84, 89-91;
Nematodes of, 163;
Acanthocephala of, 183, 184
Man, Trematode-parasites of, 63, 68-70;
Cestodes of, 74, 78-81, 83, 89 f.;
Nematodes of, 125, 139, 140, 143, 145, 147, 163;
_Gordius_ of, 173;
_Echinorhynchus_ of, 183
Man, De, on free-living Nematodes, 157
_Manayunkia_, 284, _339_ n.
Mandible, of avicularium, 482, 524
Manson, on _Filaria_, 149
Manubrium, 210
Marginal groove, of _Leptoplana_, 15
Maricola, 30, 32, _42_
Marine, Rotifers, 226;
Oligochaeta, 366;
Leeches, 406
_Marphysa_, 276, _319_;
as bait, 297;
as host, 297
Mastax, of Rotifers, 199, 210
Masterman, on Chaetognatha, 190;
on _Phoronis_, 461
_Mastigocerca_, _225_
_Mastigophora_, _518_, 529;
vibraculum, 484
_Mastobranchus_, gill of, 268, _331_
Matzdorf, on Leeches, 369
Maupas, on Rotifers, 217
Mbalolo, 297
_Meckelia asulcata_, _111_
_Mecynostoma_, _49_
Median pore, in Cheilostomata, 484, 524
Megadrili, _373_, 374, _380_ f.
_Megalotrocha_, _221_
_Megapora_, 530
_Megascolex_, 351, 372, _381_, 383
_Megascolides_, 349, 358, 372, _382_;
body-wall and nephridia, 357
Mégnin, on parasites, 164
Meissner, on Polyzoa, 493
_Melania_, _Coabangia_ in shell of, 284
Melanin, 292
_Melicerta_, 202, 205, 206, 210, 215, 218, 219, 221, 226; {549}
early description of, 197
Melicertaceae, 203, _221_
Melicertidae, 201, 203, 205, 211, 213, _221_
_Melinna_, _330_
_Membranipora_, 481, 492, _518_, 519, 523, 528, 530;
phosphorescence, 478;
function of aperture, 500;
larva, 509, 510;
variation, 516
_Membraniporella_, _518_, 524, 528
_Menipea_, _518_, 526, 527
_Mermis_, 131, _150_, 160, 163
Mermithidae, _150_, 163
Meromyarii, 129, _137_, 142
Mertens, on Polyclads, 6, 23
_Mesobdella_, _407_
_Mesocestoides_, _91_;
_M. lineatus_, life-history, 84;
specific characters, 90
Mesonemertini, _112_
_Mesostoma_, 44, 45;
reproduction, 48;
British species, _49_
Mesostomatidae, _49_
Mesotrochal larva, 325
Mesozoa, 92 f.
Metamerism, 249
Metamorphosis, in Polycladida, 16, 28;
in Trematodes, 5, 66 f.;
in Cestodes, 5, 74, 76, 87-89;
in _Phoronis_, 459;
in Polyzoa, 512
Metanemertini, _112_
Metastatica (= Holostomatidae), _73_;
life-histories, 64
_Metopidia_, 200, _225_
Metschnikoff, on Orthonectida, 94;
on Nemertines, 99;
on Chaetosomatidae, 158
Meyer, on Polychaeta, 261
Michaelsen, on Earthworms, 349, 353, 359, 370 f., 375, 385
_Microchaeta_, 362
_Microcodides_, _224_
_Microcodon_, 202, 215, _224_, 230
Microcodonidae, 202, _220_ n., _224_
_Microcotyle_, _73_;
eggs of _M. labracis_, 58
Microcotylinae, _73_
Microdrili, 373, 374 f.
_Microplana_, 34, _42_
_Micropora_, _518_, 530;
zooecium, 523
_Microporella_, 516, _518_, 519, 529;
avicularia, 484, 485;
median pore, 501
_Microscolex_, 372, _382_, 383, 384
_Microstoma_, 44;
asexual reproduction, 44;
sexual organs, 47;
British species, _49_
Microstomatidae, _49_
_Micrura_, 101, 114;
British species, _111_
Migrations, of Trematode-larvae, 5, 52, 63 f.;
of Cestode-larvae, 5, 74, 83, 87
Millson, on Oligochaeta, 368, 387
_Millsonia_, _382_ f.
Milne-Edwards, on Polyzoa, 475
Mimicry, in Polychaeta, 293 f.
_Mimosella_, _518_, 532;
movement of zooecia, 481
Molluscoidea, 475
_Molops_, host of _Gordius_, 172
_Monhystera_, 160
Moniez, on Cestodes, 84 n., 85;
on Earthworms, 369
_Moniezia_, 83, _91_;
characters of genus, 90;
_M. alba_, _M. benedeni_, _M. denticulata_, 90;
_M. expansa_, 83, 90;
_M. neumani_, _M. oblongiceps_, _M. planissima_, _M. trigonophora_, 90
_Moniligaster_, 359, _380_, 402
Moniligastridae, 361, 373, _380_
Monkey, parasites of, 145
_Monocotyle_, _73_
Monocotylinae, _73_
Monogenea (Monogenetic Trematodes), 5, 53;
classification, 73
_Mononchus_, _154_
_Monoophorum striatum_, _50_
_Monopora vivipara_, 117
_Monoporus rubropunctatus_, _49_;
reproductive organs of, 47
Monostomatidae, _73_
_Monostomum_, 71, _73_;
life-history, 72
_Monostyla_, _225_, 226
Monotidae, _50_
_Monotus_, 36;
British species, _50_;
_M. fuscus_, 45;
habits, 46
Monozoa, _91_
Montgomery, on _Stichostemma eilhardii_, 118
_Monura_, _225_
Morren, on Earthworms, 347
Moseley, on Land Planarians, 7, 35 n., 37;
on _Pelagonemertes_, 101, 114
Movements, in Rotifers, etc., 206, 235
Moxon, on Rotifers, 198
Mucro, 522, 525
_Mucronella_, _518_, 522, 528, 529, 530, 531
Müller, F., on Triclads, 37;
on Polyzoa, 493
Müller, O. F., on Turbellaria, 6;
on Rotifers, 197;
on Oligochaeta, 348, 352
Müller's larva, 16, 28, 29
Muscles, of _Leptoplana_, 12;
of intestine in Polyclads, 24;
of Nemertinea, 102, 103;
of Nematoda, 128;
of Gordiidae, 165;
of Chaetognatha, 187;
of Rotifers, etc., 206, 233, 237;
of _Nereis_, 247, 249 f.;
of Polyzoa, 469, 470, 472, 499, 500—see also Body-wall
Musculo-glandular organ, in Triclads, 39, 40
_Myrianida_, 280, _308_;
gemmiparity, 279, 280;
markings, 293
_Myrianites_, 302
_Mytilia_, _225_, 226
_Myxicola_, _338_; {550}
tori uncinigeri, 268;
eyes, 272;
otocyst, 273;
tube, 285;
supposed mimicry, 294
_Myzostoma_, anatomy, 342 f.;
_M. cirriferum_, 343;
_M. glabrum_, 342
Myzostomaria, _241_;
structure and affinities, 342 f.
Myzostomatidae, _342_

Naidomorpha (= Naididae and Naids), 348, 352, 375 f., _377_, 378, 400;
chaetae, 350, 367;
reproductive organs, 361;
asexual reproduction, 281, 377
_Nais_, 348, _377_;
chaetae, 350
_Nannodrilus_, _382_ f.
Natatory chaetae, of Nereidae, 277;
of Syllidae, 278, 307
Nathusius, on parasites, 63, 163
_Nauphanta_, 314, _315_
_Nebalia_, Rotifers parasitic on, 225
_Nectochaeta_, 291
_Nectonema agile_, 164, 168, _169_, 173
Nemathelminthes, 123 f., 168
_Nematobothrium_, 4, 55, 71, _73_
Nematoda, _123_;
anatomy, 124 f.;
embryology, 135;
classification, 136;
life-history of, 159 f.
Nematogen, 94;
Secondary Nematogen, 94
Nematomorpha, _123_, 164 f.
_Nematoxys_, _139_, 142, 161, 163
Nematozoa, _137_
_Nemertes_, British species, _110_;
deposition of ova and spermatozoa in, 116
Nemertinea, affinities, 119;
anatomy, 102;
body-wall, 102;
breeding, 116;
cephalic slits and cerebral organs, 107, 273;
circulatory system, 106, 107;
classification, 109 f.;
colour, 102;
contractility, 102;
development, 113;
diagram, 104;
digestive system, 103;
excretory system, 108, 108;
external characters, 101;
food, 115;
fresh-water forms, 101, 118;
generative organs, 109;
geographical distribution, 117;
habitat, 100;
habits, 114;
land forms, 101, 117;
locomotion, 114, 115;
nervous system, 105, 106;
parasitic forms, 101, 119;
pelagic forms, 101, 114;
proboscis, 100, 101 f., 103, 104, 110, 115;
regeneration, 115;
sense organs, 101, 106, 107;
size, 100
_Nemertodrilus_, 360
_Nemertoscolex_, 444
_Neodrilus_, _384_
Neorhynchidae, _184_
_Neorhynchus clavaeceps_, 178, 181, _184_;
_N. agilis_, _184_
_Nephelis_, 392 f., 397, 399, 401, 403, 405
Nephridium, of Archiannelida, 243, 244;
of _Nereis_, 253;
of _Arenicola_, 253, 254;
of Polychaeta, 253;
dimorphism of, in Polychaeta, 269;
thoracic, of Sabelliformia, 306;
of Terebellidae, 327;
of Chlorhaemidae, 334;
of _Myzostoma_, 344;
of Oligochaeta, 356 f., 381 f., 400;
of Leeches, 399;
of Gephyrea—see Brown tubes;
of _Phoronis_, 456
Nephthydidae, _258_, _317_
_Nephthys_, _317_;
nephridium, 254;
prostomium, 259, 260;
head, 262;
tentacles, 262;
peristomium, 263;
parapodium, 264, 265;
cirrus, 265;
gill, 268;
jaws, 270;
habitat, 286;
as bait, 297
Nereidae, _258_, _315_;
palps, 260;
colour, 292
Nereidiformia, _258_, _303_;
vascular system, 252;
anal cirri, 259;
prostomium, 259, 260;
tentacles, 262;
peristomial cirri, 263;
parapodium, 264 f.;
cirri, 265;
chaetae, 266;
jaws, 269;
eyes, 272;
ciliated organ, 273;
regeneration in, 283;
food, 296;
fossil, 301 f.
_Nereilepas_, 317
_Nereis_, 246, 299, 301, _316_ f.;
anatomy, 245 f., 247 f.;
transverse section, 247;
parapodium, 246, 247, 265, 317;
chaetae, 246;
head, 246, 248, 316;
alimentary canal, 249 f., 251;
jaws, 248, 250, 270, 316;
nervous system, 254, 255;
eye, 255;
vascular system, 247, 251;
dorsal ciliated organ, 247, 254, 256;
nephridium, 253;
reproduction, 256;
sexually mature, 276, 276 f.;
sexual dimorphism and Heteroneid phase, 276 f.;
epitokous (= epigamous) and atokous phase, 277 n.;
from fresh water, 284;
burrow, 286;
pigment, 292;
as bait, 297;
commensalism, 298;
as host, 299;
British species, 316 f.
_Nereites_, 302
_Nerine_, 299, _322_;
habitat, 286;
_N. vulgaris_, head, 322
Nerve plexus of Nemertinea, 103, 105
Nervous system, of _Leptoplana_, 13, 14;
of Polyclads, 26, 30;
of _Planaria lactea_, 39;
reduced in parasitic Rhabdocoels, 45;
of _Temnocephala_, 54;
of Polystomatidae, 56;
of Cestodes, 75, 86;
of Nemertinea, 105, 106;
of Nematoda, 127;
of Gordiidae, 166;
of Acanthocephala, 177;
of Chaetognatha, 187;
of Rotifera, etc., 215, 234, 237;
of Archiannelida, 243, 244;
of Polychaeta, 254;
visceral, of Polychaeta, 255;
of Oligochaeta, 353, 374;
of Gephyrea, 416, 431, 437, 440, 445;
of _Phoronis_, 456;
of Polyzoa, 471
Neumann, on parasites, 164
Neuropodium, 246, 247, 264, 266, 268
Newton, on zoo-geographical regions, 372
_Nicolea_, _328_;
gill, 329
_Nicomache_, _332_;
tail, 332;
tube, 287;
_N. lumbricalis_, colour, 292;
distribution, 299
Nitsche, on Polyzoa, 475 n., 478, 500
_Nitzschia_, 56, _73_ {551}
Norman, on Polyzoa, 475
_Norodonia_, 492
_Notamia_, _518_, 526
_Noteus_, _225_
_Notholca_, _225_, 226
_Notocotyle_, _73_
_Notomastus_, _331_;
chaetae, 268
_Notommata_, 217, _224_, 226
Notommatidae, 200, 205, 207, 215, 223, _224_
_Notophyllum_, colour, 293
Notopodium, 246, 247, 264, 265, 268
_Notops_, 200, _224_
_Notopygos_, 259
Nuchal cirri of Eunicidae, 318;
Nuchal organ—see Ciliated pits

_Ocnerodrilus_, _383_
_Octobothrium_, 56, _73_
_Octochaetus_, 358, _384_
Octocotylinae, _73_
_Octotrocha_, _221_
_Odontosyllis_, reproduction of, 278;
as host, 297.
_Oecistes_, 205, 206, _221_
_Oenonites_, 302
Oesophageal glands, 271, 358
_Ogmogaster_, _73_
Oka, on Hirudinea, 399 f.;
on Polyzoa, 500
Olfactory pits, in Polyclads, 26;
in Triclads, 36
_Oligocelis_, _42_
Oligochaeta, _241_, 347 f.;
external characters, 348;
body-wall, 349;
chaetae, 350, 351;
branchiae, 352;
nervous system, 353;
sense-organs, 354;
coelom and vascular system, 355;
excretory organs, 356;
alimentary canal, 358;
reproductive organs, 360;
habitat, 365;
phosphorescence, 368;
distribution, 369;
classification, 373;
Rotifers parasitic on, 227
_Oligocladus_, _19_, 22
_Oligognathus_, 297
_Ollulanus_, _142_;
_O. tricuspis_, 144, 161
_Omalostoma_, _49_
_Onchnesoma_, 422, 423, _426_, 430, 447
_Onchocotyle_, _73_
_Oncholaimus_, _157_
Onchosphaera-larva of Cestodes, 87, 88
Onuphin, 290
_Onuphis_, 290, 318, _319_;
_O. conchylega_, tube, 287
_Onychochaeta_, _388_;
chaeta, 351
_Onyx_, 131
Ootype, in _Polystomum_, 59.
Operculum, of Serpulidae, 261, 276, 339;
of _Spirorbis_, as brood-pouch, 261, 276;
of Cheilostomata, 466, 477, 481, 482, 522, 524
Opesia, 524
_Ophelia_, 299, _332_;
eggs, 275;
coelomic corpuscles, 252
Opheliidae, _258_, _331_;
gill, 265;
ciliated pits, 272
_Ophiodromus_, _308_;
_O. flexuosus_, parasitic, 297
_Ophryotrocha_, 310, _320_;
pelagic, 291;
genital organs, 274
_Opisthotrema_, _73_
_Opistoma_, _50_
Orbigny, D', on Polyzoa, 519, 520
Orifice, of zooecium, 466, 469, 470, 524;
secondary, 522, 524
Örley, on classification of Nematodes, 137
Orthonectidae, 13, 92, 94 f.
Otocyst (and Otolith), of Turbellaria, 26;
of Nemertinea, 106, 110;
of Polychaeta, 273
_Otomesostoma_, 46, _49_
_Otoplana_, _50_
Oudemans, on Nemertinea, 108
Ovary (and Oviduct), of _Leptoplana_, 11, 14, 16;
of Polyclads, 27;
of _Planaria_, 38, 39;
of Rhabdocoelida, 47;
of _Temnocephala_, 54;
of Polystomatidae, 57;
of _Diplozoon_, 60;
of _Gyrodactylus_, 61;
of _Distomum macrostomum_, 65;
of _Calliobothrium_, 75;
of _Archigetes_, 76;
of _Schistocephalus_, 86;
of _Rhopalura_, 95;
of Myzostoma, 343—see also Reproductive organs
Ovicell, in Cheilostomata, 466, 466, 468, 481, 482, 484, 522 f., 525;
in Cyclostomata, 479, 480, 521, 525
Oviduct—see Ovary
_Owenia_, _325_
Ox, parasites of, 79, 83, 125, 139, 140, 143
_Oxysoma_, _139_, 142
_Oxyuris_, 129, 131, 135, _139_, _141_, 160;
_O. ambigua_, 141;
_O. curvula_, 141, 163;
_O. diesingi_, 141, 142;
_O. vermicularis_, 141, 163;
_O. blattae_, _O. blatticola_, _O. hydrophili_, _O. megatyphlon_,
_O. spirotheca_, 142

Paddle worm, _313_
Paedogenesis, 151
Pagenstecher, on Nemertinea, 99
_Palaemonetes_, host of _Nectonema_, 174
Palaeonemertea, _109_, 112;
characters, 111;
development, 113
Palaeozoic, Serpulidae, 301;
Eunicidae, 302;
Polyzoa, 520
Paleae, of _Sabellaria_, 267
_Palmicellaria_, 527, 528
_Palolo viridis_, as food, 297
Palps, of _Nereis_, 248, 255;
nerves to, 254;
of Polychaeta, 260 f.;
development of, in Sabelliformia, 275;
of Hermelliformia, 306;
of Syllidae, 307
_Paludicella_, 492, 494, 501, 502, 505, _518_
Paludicola, 30, _42_ {552}
_Panthalis_, _313_
Paragnaths, 248, 250, 316
Parapodium, of _Nereis_, 246, 247;
of Polychaeta, 264 f.;
of Heteronereid, 276, 277;
muscles of, 247;
glands of, 249, 314;
of _Myzostoma_, 342
_Paraseison_, 212, 225, _226_
Parasitic, Turbellaria, 51;
Polyclads, 22;
Triclads, 32;
Rhabdocoela, 45, 51;
Nemertinea, 101, 119;
Rotifers, 204, 227;
Polychaeta, 297;
Leeches, 406
Parasitism, effect on the parasite, 161, 177;
effects on the host, 162
Parenchyma, in _Leptoplana_, 11, 12;
of Müller's larva, 29;
in Triclads, 41;
in Acoela, 42;
in Cestodes, 85, 86
Parovaria, of _Phagocata_, 38 n.
Parthenogenesis, amongst Rotifers, 200
_Pectinaria_, _330_;
body, 259;
tube, 285, 287;
_P. auricoma_, tube, 288;
_P. belgica_, 330
_Pectinatella_, 496, 497, 505, 512, _518_;
statoblast, 502
_Pedalion_, 200, 201, 206, 211, 216, _223_, 224, 225, 228, 230
Pedalionidae, _223_
_Pedetes_, _224_
_Pedicellina_, 487, 488, 490, 506, 507, _518_;
larva, 510, 513;
budding, 514;
on Polychaeta, 299
Pelagic, Nemertinea, 101, 114;
Chaetognatha, 189; Rotifera, 226;
Polychaeta, 291, 294, 314;
larvae of Polychaeta, 300, of Polyzoa, 520
_Pelagobia_, _314_
_Pelagonemertes_, 101, 114
_Pelodera_, 129, 131, 133
_Pelodrilus_, 369, _377_
_Pelodytes_, 134
Penis, of _Leptoplana_, 14, 15;
of Polyclads, 27;
of _Planaria_, 38, 39;
of Rhabdocoelida, 47;
of _Temnocephala_, 54;
of _Calliobothrium_, 75;
of _Schistocephalus_ (cirrus-sac), 86
Pennant, on Hirudinea, 406 n.
Pereyaslawzewa, on Acoela, 44 n.
Pergens, on Polyzoa, 500
_Perichaeta_, 351, 357, 358, 372, 381, 381 f., 388, 394, 403
Perichaetidae, 357, 362, _380_
Perienteric, blood-sinus, 252
_Perionyx_, _381_
_Perissogaster_, _383_
Peristome, 481, 482, 522, 524
Peristomial (tentacular) cirri, of _Nereis_, 248;
of Polychaeta, 263;
nerves to, 254
Peristomium, of _Nereis_, 248;
of Polychaeta, 263;
of Sabellidae, 336
Perrier, on Oligochaeta, 367, 385
_Petalostoma_, 422, _426_, 430, 447
_Petromyzon_, host of _Gordius_, 173
_Petta_, intestine of, 271
_Phagocata_, 31, 32
_Phalacrophorus_, _314_
Phanerocephala, _258_, _303_
Pharynx, 4;
of _Leptoplana_, 8, 9, 12, 14;
of Polyclads, 17, 24;
of _Discocelis_, 23;
development of, in Polyclads, 29, 30;
of Triclads, 31, 37, 39;
of _Temnocephala_, 53, 54;
of Polystomatidae, 56;
of Digenea, 62, 64;
of _Nereis_, 249, 250, 251;
of Polychaeta, 269
_Phascolion_, 423, _425_, 428
_Phascolosoma_, 416, 420, 423, _425_, 428, 447;
as host of _Loxosoma_, 489
Philippi, on Hirudinea, 406
_Philodina_, 208, _222_, 227
Philodinidae, _222_
_Phoronis_, 450 f., 451, 452, 453, 455;
habits, 451;
anatomy, 453 f., 457;
development, 458, 458;
species, 460;
affinities, 461, 512
Phosphorescence (and light-producing organs), in Rotifers, 226;
in Polychaeta, 272, 295, 296;
in Oligochaeta, 368;
in Polyzoa, 478
_Photodrilus_, 368, _383_
Photogen (light-producing organ), of _Polyophthalmus_, 272;
of _Tomopteris_, 296, 315
_Phreodrilus_, 369, _379_
_Phreoryctes_, 367, _377_
Phreoryctidae, _376_
_Phylactella_, 528, 530
Phylactolaemata, _476_, 493 f., _518_;
lophophore, 476, 495;
occurrence, 493;
movements, 494, 496 f.;
reproduction, 501, 506, 507;
larva, 511, 512;
distribution, 493, 504;
affinities, 512
Phyllacanthinae, _91_
Phyllobothrinae, _91_
_Phyllobothrium_, 76 n., _91_
_Phyllocotyle_, _73_
_Phyllodoce_, _313_, 314;
head, 262, 263:
eggs, 275, 314 n.;
colours, 291, 292;
parapodium, 264;
chaeta, 267
Phyllodocidae, _258_, _313_;
parapodial cirri, 266;
as food, 297;
eggs, 314;
colours, 292, 293
_Phyllodocites_, 302
_Phyllonella_, _73_
_Phymosoma_, 413, 420, 421, 423 f., _425_, 426
_Physaloptera_, 163
Pig, parasites of, 68, 79, 139, 147, 184
Pigments, of Polychaeta, 291 f.;
of Gephyrea, 435
Pike, Trematode of, 62;
Cestode of, 81, 84
Pilidium larva, 113, 113, 229, 230
_Pionosyllis_, _308_
_Piscicola_, 393, _406_
_Pista_, _328_;
gill of, 329
Pits, ciliated, of Polychaeta, 272, 273
_Placostegus_, colour, 292; {553}
from deep sea, 300
_Placunella_, _73_
_Plagiochaeta_, 358, _381_, _384_
_Plagiostoma_, 46;
British species, _50_
Plagiostomatidae, _50_
_Planaria_, 30, 31 f., 39;
British species, _42_
Planarians, 3, 7;
_Dinophilus_, compared with, 242, 243
Planariidae, _42_
_Planctoplana_, _19_
Plankton, Rotifers in, 225
_Planocera_, 18, _19_, 20
Planoceridae, _19_, 23
_Planorbis_, host of _Gordius_, 173
Plants, parasites on, 154, 155, 157, 160
Plasmodium, nature of, in Orthonectids, 94
Plate, on Rotifers, 198, 225 n.
_Platyaspis_, _73_
_Platycotyle_, _73_
Platyhelminthes, 3 f.;
Nemertinea classed with, 119
_Plectanocotyle_, _73_
_Plectus_, 160
_Pleionogaster_, _381_
Plerocercoid larva, 84
Plessis, du, on _Tetrastemma lacustre_, 101 n., 118
_Pleurocotyle_, _73_
_Pleurotrocha_, _224_, 226
_Ploesoma_, 212, _225_
Ploima, 202, 203, 212, 213, 216, _220_, _223_, 226, 227
_Plumatella_, 493, 494, 499, 503-505, _518_, 519;
protrusion of polypides, 499;
statoblasts, 499, 502, 503;
larva, 512
Podal membrane, of Spionidae, 322
Podaxonia, 461
_Polyarthra_, 201, _224_, 226
Polybostrichus, 280
_Polycelis_, 30, 31, 40, _42_
Polychaeta, _241_, 245 f.;
classification, 257, 258, 303 f,;
head, 248, 259 f.;
parapodium, 246, 264 f.;
chaetae, 246, 266 f.;
coelomic fluid, 252;
nervous system, 254;
sense-organs, 255, 272;
ciliated pits, 272;
alimentary canal, with pharynx, 249, 250, 251, 269, 270, 271;
oesophageal glands, 271 f.;
nephridium, 253, 254, 269, 274;
genital duct, 254, 269;
genital cells, 256, 273 f.;
hermaphrodite, 273;
regeneration, 278, 282;
habits, 285;
carnivorous, 304;
distribution, 299;
from fresh water, 284;
from deep sea, 300;
pelagic, 291, 314;
boring, 287;
tubes, 287;
pigments, 291;
colours, 291 f.;
warning colours, 294;
protective devices and mimicry, 293;
phosphorescent, 295;
food of, 296, 299;
as bait, 296, 297;
as food for man, 297;
commensalism, 297 f.;
parasitic, 297 f.;
as hosts, 299;
extinct, 301, 302;
larva, 274, 276, 300;
provisional chaetae, 274
_Polychoerus_, _49_;
development of, 44 n.
_Polycirrus_, _330_;
habits of, 285;
_P. aurantiacus_, warning colours, 294;
phosphorescence, 295;
_P. haematodes_, coelomic corpuscles, 253
Polycladida (Polyclads), 4 f., 7;
classification, 16 f.;
development, 28 f.;
British species, 19, 20, 22
_Polycladus_, 42
_Polycotyle_, _73_
_Polydora_ (= _Leucodore_), _323_;
frontal ridge, 260;
head, 261;
special chaetae, 267;
with _Heliopora_, 298;
_P. ciliata_, borings, 287
Polydoridae, 258, _323_
_Polygordius_, 242, 244;
development, 245
_Polymnia_, 328
Polymorphism, of _Nereis_, 277
Polymyarii, _137_, 142
_Polynoe_ _310_;
segments 258;
parapodium, 265;
jaws, 270;
anus, 259;
nephridium, 254;
habits, 286;
as ectoparasites or commensals, 294, 298, 325;
distribution, 299, 300;
British species, 299, 310 f.;
_P. squamata_, 309;
elytron, 310;
_P. clava_, elytron, 310;
_P. imbricata_, elytron, 311
Polynoina (= Polynoids), _309_;
head, 262;
chaetae, 266, 267;
jaw, 270;
intestine, 271; eggs, 275;
sexual dimorphism, 276 n.;
tubes, 285;
colours, 291, 292;
protective resemblance, 294;
phosphorescence, 295, 296;
food, 296;
parasitic and commensal, 297, 325;
elytra, 275, 294, 295, 299, 309 f.
_Polyodontes_, _313_ n.
_Polyophthalmus_, _332_;
segmental eyes, 272, 296;
otocyst, 273
Polype à pannache, 496
Polypide, 468, 469, 474, 488, 523;
retraction and protrusion, 498 f.
Polypide-bud, 468, 472, 487, 496, 499, 501, 510;
connected with reproduction, 507
_Polypostia_, _19_;
penes, 27
Polystomatidae, _53_, 55, _73_
Polystomatinae, _73_
_Polystomum_, 55, 57;
life-history, 58, 59
Polyzoa, 465 f., 475;
external characters, 465 f., 479 f.;
anatomy, 468 f., 469;
brown bodies, 471 f., 472;
history, 474 f.;
classification, 475 f., 515, 517 f.;
occurrence, 477 f.;
avicularia and vibracula, 482;
enemies, 486;
Entoprocta, 487;
fresh water, 492 f.;
reproduction, 501, 506;
development, 509;
affinities, 461, 509, 510;
metamorphosis, 512;
budding, 514;
distribution, 493, 504, 519;
palaeontology, 520;
terminology, 523;
determination of British genera, 505, 521, 525
_Pomatoceros_, habitat, 300, _340_ {554}
_Pompholyx_, 201, 203, _225_
_Pontobdella_, 393, 401, 404, 406
_Pontodora_, _314_
_Pontodrilus_, 366, 370, _383_
_Pontoscolex_, 350, 366, _387_ f.;
chaeta, 351
Pore, in Polyzoa, 471, 482, 522, 524;
median, 484, 524;
dorsal, 348
_Porella_, 516, _518_, 522, 527, 529
_Porina_, _518_, 527, 529
_Potamilla_, _338_
Praeoral lobe (= Prostomium), 245, 439
Predaceous worms, 304
Priapuloidea, _412_, 446;
anatomy, 430;
classification, 432;
habits, 433
_Priapulus_, 430, 431, _432_;
anatomy, 430 f.
_Pristina_, _377_
_Proales_, 204, _224_, 226, 227
Proboscidae, _49_;
occurrence, 44
Proboscis, of Nemertinea, 100, 101 f., 103 f.;
of Hoplonemertea, 104, 110;
opening by mouth, 117, 119;
severance of, 116;
of Acanthocephala, 174 f.;
of Rotifers, 203;
of Kinorhyncha, 237;
of Echiuroidea, 434
Proboscis-pore of Nemertinea, 102, 103
Proboscis-sheath of Nemertinea, 103, 103 f.
_Procerodes_, _42_
Procerodidae, _42_
_Procerus_, host of _Gordius_, 172
_Procotylea_, 36, _42_
Proglottis, 5, 74, 75, 79, 85
_Promesostoma_, occurrence, 44;
British species, _49_
Proporidae, _49_
_Proporus venenosus_, _49_
Prorhynchidae, _49_
_Prorhynchus sphyrocephalus_, terrestrial habit, 44;
_P. stagnalis_, _49_
_Prosorhochmus claparedii_, _110_, 114, 117
Prostate-gland, of _Leptoplana_, 16;
of Polyclads, 30;
of _Planaria_, 39;
of Rhabdocoela, 47;
of Oligochaeta, 361
_Prostheceraeus_, _19_, 22;
spermatophores, 27
Prosthiostomatidae, _19_
_Prosthiostomum_, 17, 18, _19_, 24
Prostomial tentacles, 248, 262
Prostomium, 241;
of _Dinophilus_, 243;
of _Polygordius_, 244;
of Trochosphere, 245;
of _Nereis_, 248;
of Polychaeta, 259;
of Glyceridae, 320;
of Terebellidae, 327;
of Oligochaeta, 348
_Protodrilus_, 242, 244
Protonemertini, _112_
_Protula_, _341_;
genital organs, 273, 274;
eggs, 275
Prouho, on Polyzoa, 489, 507 f.
Provisional chaetae, 274
_Provortex_, British species, _50_
_Proxenetes_, 44;
British species, _49_
Pruvot, on Polychaeta, 261
_Psamathe_, 300, _308_
_Psammolyce_, _313_;
elytra, 294, 313
_Pseudalius_, 135, _142_, 163
_Pseudaxine_, _73_
Pseudoceridae, _19_, 20
_Pseudoceros_, _19_, 20
_Pseudocotyle_, 73
_Pseudorhynchus bifidus_, _49_
_Psygmobranchus_, _341_
Pterobranchia, 461
_Pterodina_, 200, 201, 203, 206, 211, 215, 216, _225_, 226, 230
Pterodinidae, 201, _225_
_Pteroessa_, _224_
_Pteronella_, _73_
_Pterostichus niger_, infested by _Gordius_, 170, 170, 172
_Pterosyllis_, ciliated lappets, 273 n.
Pyriform organ, 509, 511

Quatrefages, on Gephyrea, 411, 445

Rabbit, parasites of, 141, 145
Ragworm, 322
Railliet, on Cestodes, 91
Rami, in Rotifers, 210
Rasping plate, of Eunicidae, 270
Rattulidae, 210, _225_
_Rattulus_, 212, _225_, 226
Ratzel, on Earthworms, 350
Red Cat, 316
Regeneration of lost parts, in Polyclads, 26;
in Triclads, 40;
in Cestodes, 77;
in Nemertinea, 115;
in Polychaeta, 278, 282;
in Oligochaeta, 348, 379;
in Polyzoa, 471, 488
Repetition of parts, 249
Replacement of species, 300
Reproduction (and Reproductive organs), of _Leptoplana_, 14 f.;
of Polyclads, 26, 30;
of Triclads, 31, 38, 39;
of Rhabdocoelida, 45, 47 f.;
of _Temnocephala_, 54;
of Polystomatidae, 57 f.;
of _Diplozoon_, 60;
of Digenea, 65;
of _Calliobothrium_, 75;
of _Schistocephalus_, 86;
of Mesozoa, 93 f.;
of Nemertinea, 102, 103, 104, 109;
of Nematoda, 134;
of Nematomorpha, 166, 169;
of Acanthocephala, 178;
of Chaetognatha, 188;
of Rotifera, etc., 216, 234, 238;
of Archiannelida, 243 f.;
of Polychaeta, 253, 254, 256, 269, 273;
of _Myzostoma_, 343;
of Oligochaeta, 360;
of Leeches, 401;
of Gephyrea, 418, 431, 437;
of _Phoronis_, 457;
of Polyzoa, 471, 490, 501, 506—see also Ovary and Asexual reproduction
Reptiles, parasites of, 163
Respiration, in _Nereis_, 252;
in Chaetopoda, 272;
in Gephyrea, 416
_Retepora_, 479, 515, _518_, 527
Rhabdites (rods), of _Leptoplana_, 11, 12;
in Polyclads, 29;
in Triclads, 37; {555}
absent in parasitic Rhabdocoela, 45;
in _Temnocephala_, 53, 54
Rhabditiformae, _137_
_Rhabditis_, _154_, 160;
_R. nigrovenosa_, 140, _155_
Rhabdocoelida, 4, _7_, 36, 42 f.;
occurrence and habits, 43;
parasitic forms, 44;
reproduction, 47;
classification, _49_;
British species, 43, 44, 49
_Rhabdogaster_, 158
_Rhabdonema nigrovenosum_, 134, 136, _140_, 151, 160, 161
_Rhabdopleura_, 461 f.
_Rhinodrilus_, 348
Rhinopidae, _220_ n., _224_
_Rhinops_, _224_;
male of, 223 n.
Rhizopoda, as food for Polychaeta, 296
Rhizota, _220_ n.
Rhombogen (form of Dicyemid), 93
_Rhopalonaria_, 521 n.
_Rhopalophorus_, _73_
_Rhopalura giardii_, occurrence and structure, 94, 95;
_R. intoshii_, 94
_Rhynchelmis_, 365, _376_
Rhynchobdellae, 396 f., _405_
Rhynchodemidae, 35, _42_
_Rhynchodemus_, 34, 35, _42_
_Rhynchopora_, 531
_Rhynchozoon_, 529 n., 531
Riches, on British Nemertinea, 110;
on _Malacobdella_, 119
Rietsch, on Gephyrea, 443
Rockworm, 319
Rods—see Rhabdites
Rohde, on muscles of Nematoda, 128 f.
Rootlet, in Polyzoa, 485, 517
Rosa, on Oligochaeta, 364, 380, 385, 390
Rosette-plates, 471, 522
_Rotifer_, 201, 202, 210, 216, _222_, 226, 227
Rotifera, 197 f.;
distribution, 200;
parasitic, 204;
digestive organs, 209;
renal organs, 213;
nervous system and sense organs, 215;
reproduction and development, 216;
classification, 220;
habits 226;
preservation, 228;
affinities, 229
Rousselet, on Rotifers, 198, 216, 228

_Sabella_, 299, _337_; parapodium, 265;
habitat, 286;
tube, 287;
tube-building, 288;
colour, 293, 294;
_S. saxicava_, habits of, 287
_Sabellaria_, _341_;
body, 259;
cirri, 265.;
tube, 287, 290;
_S. alveolata_, 259, 300;
_S. spinulosa_, paleae, 267, 300
Sabellidae, _258_, _336_;
head, 261;
chaetae, 266, 267;
regeneration, 283;
from fresh water, 284;
colour, 292
Sabelliformia, _258_, _306_, 336;
chlorocruorin in, 252; body, 259;
head, 260, 261;
uncini, 266, 267;
nephridia, 269, 306;
genital organs, 273;
development of gills, 275;
gland shields, 287
_Saccobdella_, _226_
_Sacconereis_, 275, 276, 280
_Saccosoma_, 434, 440, _442_
_Sagitella_, _321_
_Sagitta_, _186_, 186, 191, 534;
anatomy, 186 f., 188;
development, 189;
habits, 190;
species, 191, 193;
American species, 534
Salensky, on development of Nemertinea, 99;
of Rotifers, 218
_Salinella_, 93, 96
Salivary glands, in Polyclads, 10, 24;
in Leeches, 396
_Salmacina_, 273, _341_;
brood-pouch, 276;
fission, 281
_Salpina_, 200, _225_
Salpinidae, _225_
Sandmason, 328
_Saxicava_, _Eulalia_ in borings of, 314
Scales, of Gastrotricha, 233
_Scalibregma_, _334_
Scalibregmidae, _258_, _334_
Scapha, 259, 330
_Scaridium_, 201, 207, _225_
_Schistocephalus_, 75, _91_;
reproductive organs, 86;
larva, 84;
life-history, 78, 85
_Schizocerca_, _225_
Schizogamy, in Syllidae, 278, 279, 281
Schizonemertea, _109_;
characters, 111;
development, 113;
transverse section, 103
_Schizoporella_, _518_, 527, 528, 529, 530, 531;
zooecium and avicularia, 482;
_Leptoplana_ on, 22
_Schizotheca_, 482, _518_, 529
Schmarda, on Oligochaeta, 366, 387
Schmidt, on Rhabdocoels, 6
Schneider, on life-history of certain _Mesostoma_, 48;
on classification of Nematoda, 129;
on oesophageal glands, 131;
on Strongylidae, 142
Schultze, on Polyclads, 13, 26;
on Nemertinea, 108, 109
_Schultzia_, _50_
Schulze, F. E., _Stichostemma_ found by, 118;
_Trichoplax_ found by, 96
Scirtopoda, 200, 201, 203, 206, 207, _223_
_Sclerocheilus_, _334_
_Sclerostomum_, 163
Scoleciformia, 258, _305_, _331_ f.;
vascular system, 252;
buccal region, 269;
food of, 296
_Scolecolepis_, 299, _322_
Scolex, 5, 74, 75 f., 89;
_S. polymorphus_, 77;
of _Taenia solium_, 79
_Scolithus_, 302
_Scoloplos_, 299, _321_;
parapodium, 265;
habitat, 286
_Scruparia_, 527
_Scrupocellaria_, 517, _518_, 519, 526;
vibracula, 477, 485, 517;
phosphorescence, 478;
larva, 511
Scutum, 525 {556}
Seals, parasites of, 142, 183
Sea-mat, 466, 477
Sea-mouse, 312
Secondary orifice, 522, 524
Sedentaria, 285
Segment, 241;
of _Nereis_, 246, 247
_Seison_, _226_
Seisonaceae, 204, 216, 220 n., _225_, 227
Seisonidae, _226_
_Selenaria_, _518_;
vibracula, 487
Selenka, on Sipunculids, 424 n., 447
Self-fertilisation, in certain _Mesostoma_, 48;
in Trematodes, 52, 58;
in Cestodes, 86
Semper, on excretory system of Nemertinea, 108;
on _Geonemertes palaensis_, 101 n., 117;
on mimicry in Polychaeta, 294
Sense-organs, of _Leptoplana_, 13;
of Polyclads, 26;
of Triclads, 36;
of Trematodes, 56, 86;
of Cestodes, 86;
of Nemertinea, 106;
of Nematoda, 128;
of _Gordius_, 166;
of Acanthocephala, 178;
of Chaetognatha, 188;
of Rotifera, etc., 215, 233, 234;
of Polychaeta, 255, 272;
of Oligochaeta, 354;
of Leeches, 395;
of Gephyrea, 417;
of _Phoronis_, 457
Septum, of Archiannelida, 244;
of _Nereis_, 249, 251;
of Polychaeta, 269;
of Chlorhaemidae, 334;
of Oligochaeta, 355;
of Gephyrea, 440
_Serpula_, 300, _339_, 340;
fossil, 301;
tubes, 290, 301;
commensal with Polynoid, 298;
colour, 292
Serpulidae, _258_, _339_;
nerve cords, 255;
gills, 261;
operculum, 261;
cirri, 265;
thoracic membrane, 266;
uncinus, 267;
fission, 281;
tube, 290;
colour, 292, 293;
from great depth, 300;
fossil, 301
Serpulite chalk, 301
Seta, of vibraculum, 484, 485, 486, 517, 524
_Setosella_, 530
Sharks, Trematodes of, 62, 72;
Cestodes of, 78
Sheep, parasites of, 67, 81, 82, 83
Sheldon, Miss, on Nemertinea, 99 f.
Shell-gland, of _Leptoplana_, 8, 9, 14, 16;
of Polyclads, 28;
of Trematodes, 59;
of Cestodes, 86
Shield, cuticular, of Polychaeta, 259;
of _Sternaspis_, 335;
glandular—see Gland shields.
Shipley, on _Bipalium_, 37;
on Nemathelminthes, 123 f.;
on Chaetognatha, 186 f., 534;
on _Gephyrea_, 411 f.;
on _Phoronis_, 450 f.
_Sialis lutaria_, host of _Gordius_, 171, 172;
host of Acanthocephala, 185
Side organs, of Carinellidae, 107
Siebold, von, on Tape-worms, 76
_Sigalion_, _313_
Silliman, on Nemertinea, 101, 109, 118
Silurian, Polychaeta, 301
Sinus, in Polyzoa, 482, 484, 525
Siphon, of Capitelliformia, 272, 305;
of Gephyrea, 436
_Siphonogaster_, 353, 368
_Siphonostoma_, _334_;
commensal, 298
Sipunculoidea, _412_, 420, 446;
species, 426
_Sipunculus_, _425_;
history, 411;
species, 426;
anatomy, 412 f., 413, 415;
development, 419, 419;
food, 422;
habits, 426
Size, of Cestodes, 5;
of Polyclads, 20;
of Land Planarians, 33;
of Cestodes, 75;
of Nemertinea, 100
_Slavina_, _377_
Sluiter, on Gephyrea, 429, 447
Smitt, on Polyzoa, 516
_Smittia_, _518_, 527, 529;
zooecium and avicularium, 482
Snakes, parasites of, 142
Solenopharyngidae, _50_
_Solenopharynx_, _50_
Solenophorinae, _91_
_Solenophorus_, _91_
_Sorocelis_, _42_
_Spadella_, _186_, 189, 192;
anatomy, 186 f.;
eggs, 189;
habits, 190;
species, 192, 194;
American species, 534
Spallanzani, on Oligochaeta, 348
_Sparganophilus_, 366, _386_;
anatomy, 355.
_Spatangus_, as host, 298
Spencer, on Land-Planarians, 34;
on earthworms, 349, 380
Spengel, on Gephyrea, 440
Spermatheca, of _Dinophilus_, 243;
of Oligochaeta, 362, 363, 364
Spermatophores, 27, 402
Spermiducal gland, 361
Sphaerodoridae, _320_
_Sphaerodorum_, _321_
_Sphaerosyllis_, _308_
_Sphaerularia_, _150_, 153, 160, 161
_Sphyranura_, _73_;
setae in, 56
Spine, of Polyzoa, 481, 523 f., 524
_Spinther_, _318_
_Spio_, _322_
Spionidae, _258_, _321_;
larva, 274, 275
Spioniformia, _258_, _304_, 321;
peristomial cirri, 263;
gill, 265;
chaetae, 266, 267;
eyes, 272;
food, 296
Spirographin, 290
_Spirographis_, _338_;
substance of tube, 290
_Spiroptera_, _147_, 163;
_S. reticulata_, 149;
_S. obtusa_, 161;
_S. alata_, 163
_Spirorbis_, _340_, 341;
operculum, 261, 341;
genital organs, 273, 274;
brood-pouch, 261, 276;
fossil, 301; shell, 341
_Spirosperma_, _378_;
chaeta, 350
_Spirulaea_, 301
Sporocysts, 92; {557}
of _Distomum macrostomum_, 64, 65;
of _D. hepaticum_, 67;
hosts of, 71
Staggers, induced by _Coenurus_, 82
Statoblast, 493, 499, 501 f., 506;
sessile, 502;
germination, 501, 503, 514;
resemblance to ephippian ova, 493
Steenstrup, on Tape-worms, 76
_Steganoporella_, 530
Stelechopoda, 344
_Stelechopus_, _342_
_Stenostoma_, 44, _49_;
asexual reproduction, 44
_Stephanoceros_, 202, 205, 210, 213, 220, _221_
_Stephanops_, _225_
_Stercutus_, _376_
Sternaspidae, _258_, _335_;
nephridia of, 305
_Sternaspis_, _335_, 411, 445;
anatomy, 335, 336;
shape, 259;
shield, 259;
head, 264;
chaetae, 265;
gills, 268;
intestine, 271;
compared with Gephyrea, 336, 447, 449
_Sthenelais_, 299, 300, 309, _313_
_Stichostemma eilhardii_, 118
_Stilesia_, _91_;
generic characters, 90;
_S. centripunctata_, 91;
_S. globipunctata_, 91
Stock, asexual, of _Autolytus_, 279;
of _Myrianida_, 281
Stolc, on Oligochaeta, 360
Stolon, 480, 488, 518, 525
Stolonata, 518 n.
_Stomatopora_, _518_, 532
Stork, parasites of, 63, 163
Strobila, 75, 76
Strobilation, 76
Strodtmann, on Chaetognatha, 191
Stromatoporoids, 520
Strongylidae, 131, _142_
_Strongylus_, 129, _142_, 143, 160, 163;
_S. filaria_, 132;
_S. tetracanthus_, 163
Stuhlmann, on Polyzoa, 493
_Stuhlmannia_, 359, _386_
_Stylaria_, 348, _377_
Stylets of Nemertine proboscis, 104, 110
_Stylochoplana_, 18, _19_, 20
_Stylochus_, _19_;
development, 28
_Stylostomum_, _19_, 22
Sub-cuticle, 125, 175
Submalleate, 210, 211
_Succinea putris_, infested by larvae of _Distomum macrostomum_, 64, 66
Sucker, of _Leptoplana_, 8, 16 n.;
of Triclads, 35, 36;
of _Temnocephala_, 53, 54;
of Monogenea, 53, 56, 57, 60;
of Digenea, 62, 64, 65, 69;
of Cestodes, 75, 79;
of _Dinophilus_, 243;
of _Chaetopterus_, 324;
of _Myzostoma_, 342;
of larva of Polyzoa, 509, 511
Summer-eggs, of _Mesostoma_, 48;
of Rotifera, 216
_Sutroa_, 376, _380_
Swim-bladder, of Syllidae, 272
Swimming, of _Leptoplana_, 9, 10;
of Polyclads, 23;
of Rotifers, etc., 206, 235
Syllidae, 258, _306_;
palps, 260;
tentacles, 262;
head, 262;
parapodium, 264;
jaw, 270, 271;
alimentary tract, 271;
swim-bladder, 272;
asexual reproduction, 278 f., 279;
regeneration, 278, 283;
colours, 293;
phosphorescence, 296;
ancestral, 303
_Syllis_, 274, _307_;
development, 278;
_S. armillaris_, 307;
_S. ramosa_, 282;
_S. vivipara_, 276
_Synapta_, bearing Rotifers, 222, 227
_Synchaeta_, 200, 204 f., _224_, 226
Synchaetidae, _223_, _224_
_Syncoelidium_, 33, _42_
Syncytium, 125
_Syngamus trachealis_, 130, _142_, 144, 161, 163, 164
_Syrinx_, 411

_Taenia_, 74, 78, 79, _91_;
life-histories of species of, 83;
table of species, 89;
_T._ (_Cysticercus_) _acanthotrias_, 80;
_T. coenurus_, 81, 82;
life-history, 83;
specific characters, 90;
_T. crassicollis_, life-history, 78, 83;
specific characters, 89;
_T. echinococcus_, 80;
life-history, 83;
specific characters, 90;
_T. krabbei_, 81;
_T. marginata_, 81;
life-history, 83;
specific characters, 90;
_T._ (_Hymenolepis_) _murina_, 70, 80 n., 89;
life-history, 80, 83;
specific characters, 91;
_T. perfoliata_, 163;
_T. saginata_ (= _T. mediocanellata_), 78, 79;
life-history, 83;
specific characters, 89;
_T. serialis_, 82;
life-history, 83;
specific characters, 90;
_T. serrata_, 81;
life-history, 83, 87, 89;
specific characters, 90;
_T. solium_, 79;
life-history, 79, 83;
specific characters, 89
Taeniasis, 82
Taeniidae, _91_
Tail, of _Arenicola_, 333;
of _Nereis_, 246, 248;
regeneration of, 283
_Tanypus_, host of _Gordius_, 172
Tape-worms, 5, 74
_Taphrocampa_, 200, 204, _224_
Tardigrada, affinities, 344
_Telmatodrilus_, _378_
_Temnocephala_, 4, 53, 54, _73_
Temnocephalidae, _53_, _73_;
habits and structure, 53 f.;
affinities, 54
Tennent, on land-leeches, 408
Tentacles, in Polyclads, 15, 26;
in Triclads, 30, 36;
in _Vorticeros_, 45, 46;
in Trematodes, 53;
(peristomial), of Spionidae, 322;
(prostomial), 255, 260, 262 f.;
of _Nereis_, 248;
of _Polycirrus_, 294, 295;
of _Polygordius_, 244;
of Terebellids, use of, 289;
nerves to, 254
Tentacle-sheath, in Polyzoa, 470 {558}
Tentacular cirri = Peristomial cirri, _q.v._
Tentacular filaments, 304;
of Cirratulids, 326, 327
_Terebella_, _328_;
otocyst, 273;
fossil, 301;
_T. conchilega_, tube, 286, 287, 288;
building of tube, 289, 290;
gill, 329;
_T. nebulosa_, colour, 292;
as host, 311;
gill, 329
Terebellidae, _258_, _327_;
shape, 259;
tentacles, 263;
gill, 265;
chaetae, 266, 267;
gizzard, 271;
tube, 286;
use of tentacles, 289;
colour, 293;
phosphorescence, 296;
food of, 296;
tube containing Polynoid, 298
_Terebellides_, 299, _330_;
gill, 329
Terebelliformia, _258_, _325_;
definition, 304;
genital organs, 273;
gland shields, 287;
nephridia, 269;
nuchal organs, 273;
uncini, 266, 267;
vascular system, 252
_Terebripora_, 478
Terricola, 30, _42_
Tertiary, Polyzoa, 521
Tessin, on Rotifers, 198, 218
Testes, of _Leptoplana_, 14, 15;
of _Planaria lactea_, 38, 39;
of Acoela and Alloeocoela, 47;
of _Temnocephala_, 54;
of _Polystomum_, 57;
of Cestodes, 75, 76, 86—see also Reproductive organs
_Tetragonurus_, _389_
_Tetraonchus_, _73_
Tetraphyllidae, _91_
Tetrarhynchidae, _91_
_Tetrarhynchus_, 75, 76 n., 85, _91_
_Tetrastemma_, British species, 110;
land forms, 101, 115, 118;
fresh-water forms, 101, 118;
excretory system, 108, 109;
habits, 114;
hermaphrodite species, 109;
viviparous species, 117
_Thalamoporella_, 530
_Thalassema_, 411, 435 f., _441_, 443;
development, 439;
habits, 443
_Thelepus_, 299, _329_
_Theodisca_, _321_
Thompson, J. V., on term Polyzoa, 475
Thoracic membrane, 266, 305
Thorax, of Polychaeta, 259, 306, 337
_Thysanosoma_, _91_;
generic characters, 90;
_T. fimbriata_, life-history, 83;
specific characters, 90;
_T. giardii_, specific characters, 90
_Thysanozoon_, 13, 18, _19_, 20
Tomopteridae, 258, 291, _315_
_Tomopteris_, _315_;
colour, 294;
light-producing organ, 296;
prostomium, 259;
_T. rolasi_, 315
Tooth, in Polyzoa, 482, 522
Tortoise, _Temnocephala_ associated with, 53
Torus uncinigerus, 268
Tracks, fossil, 302
_Travisia_, _332_
_Travisiopsis_, _321_
Trematoda, 4, 51 f.;
life-histories, 71;
classification, 73
Trembley, on Turbellaria, 6;
on Polyzoa, 496, 497
Trepostomata, 520
_Triaenophorus_ (= _Tricuspidaria_), _91_;
excretory system, 84
_Triarthra_, 201, 203, 206, 211, _224_, 225, 226
Triarthridae, 200, 201, 202, 206, 207, _224_, 226
Trias, Serpulid in, 301
_Trichina_, 131, 135, _144_, 161;
_T. spiralis_, 146, 163
Trichinosis, 82, 146, 147
_Trichocephalus_, 131, 135, 136, _144_, 160, 163;
species of, 145;
_T. dispar_, 145
_Trichochaeta_, chaeta, 351
_Trichoderma_, _159_
_Trichoplax_, 93, 95
_Trichosoma_, _144_, 163;
species of, 145
Trichotrachelidae, _144_
Tricladida, _7_, 30 f.;
habits, 35 f.;
sexual reproduction, 38;
asexual reproduction, 40;
classification, 42;
British species, 31, 32, 34, 42
_Tricoma cincta_, _157_
_Tricuspidaria_, _91_
_Trigaster_, 359, _384_
_Trigonoporus_, _19_, 27
_Trinephrus_, 357, _382_ f.
_Triophthalmus_, _224_
_Triphylus_, _224_
_Tristicochaeta_, 158
Tristomatidae, _53_, 55, _73_
Tristomatinae, _73_
_Tristomum_, _73_
_Triticella_, 478, _518_, 533
_Trocheta_, 393, _407_
Trochophore, 229
_Trochopus_, _73_
_Trochosphaera_, 200, 201, _221_, 229, 230
Trochosphaeridae, _221_
Trochosphere, of Archiannelida, 243, 245;
of Polychaeta, 274, 275, 510, 512;
of Echiuroidea, 439, 510;
of Polyzoa, 510
Trochus, in Rotifers, 202, 204
Trophi, of Rotifers, 209, 210
_Trophonia_, 299, _334_;
genital organs, 273;
head, 262;
intestine, 271
Trunk, of _Nereis_, 246;
of Polychaeta, 259;
of Gephyrea, 412 f.
Tube, of Rotifers, 205;
of Polychaeta, 287 f.; composition of, 290;
fossil, 301, 302;
of Chaetopterus, 323;
of _Clymene_, 287;
of _Dodecaceria_, 326;
of _Eunice tibiana_, 290;
of Eunicidae, 285, 290, 318;
of _Haplobranchus_, 339;
of _Hekaterobranchus_, 326;
of _Hyalinoecia_, 290, 319;
of Maldanidae, 332;
of _Myxicola_, 285, 338;
of _Nereis_, 316;
of _Nicomache_, 287;
of _Onuphis_, 287, 319;
of _Owenia_, 325;
of _Pectinaria_, 285, 288, 330;
of _Polydora_, 323; {559}
of Polynoids, 285;
of _Panthalis_, 313;
of _Sabella_, 287 f.;
of _Sabellaria_, 287;
of Sabellidae, 337;
of Serpulidae, 290, 339 f., 340;
of Terebellidae, 286, 287, 288, 289, 327 f.;
of Priapuloidea, 433;
of _Echiurus_, 444
Tube-forming glands, 304
Tube-making, of Polychaeta, 287 f.
Tubicolous Polychaeta, 285, 300, 304, 306
_Tubifex_, 351, 367, 369, _378_;
chaetae, 350
Tubificidae, 350, 361, 366, _378_
_Tubulipora_, _518_, 531, 532
Turbellaria, 3 f.
Turtles, parasites of, 142
_Tylenchus_, 131, _154_, 155, 157, 160, 163
_Tylosoma_, 422, 423, _426_, _430_, 447
Typhloscolecidae, _258_, 291, _321_;
nuchal organ, 273 n.
_Typhloscolex_, 321
_Typosyllis_, regeneration of head, 283 n.

Udekem, D', on Oligochaeta, 365
_Udonella_, _73_;
_U. caligorum_, 55;
_U. pollachii_, eggs of, 58
Udonellinae, _73_
_Umbonula_, 531
_Uncinaria_, 143
Uncinate, 210, 211
Uncini, of Polychaeta, 266, 267, 304, 305
Uncus, 210
_Urnatella_, 490, 493, _518_
_Urobenus_, _388_
_Uteriporus_, _42_
Uterus, of _Leptoplana_, 8, 14;
of _Planaria_, 38, 39;
of Triclads, 40;
of Rhabdocoela, 48;
of _Temnocephala_, 54;
of _Polystomum_, 57, 59;
of Diplozoon, 60;
of _Didymozoon_, 71;
of _Calliobothrium_, 75;
of _Taenia_, 79;
of _Schistocephalus_, 86;
in Bothriidae, 87;
of Rotifers, 216

Vagina, of _Leptoplana_, 16;
in ectoparasitic Trematodes, 57 f.;
in Cestodes, 86, 87
Vaillant, on Hirudinea, 392, 405
_Valencinia_, _113_;
_V. lineformis_, _112_
_Valkeria_, 533
Vallentin, on Rotifers, 198
_Vallisnia_, _73_
_Vanadis_, _315_
Varme, 297
Vasa deferentia, of _Leptoplana_, 14, 15;
of _Planaria_, 38, 39;
of Acoela and Alloeocoela, 47;
of _Diplozoon_, 60;
of _Schistocephalus_, 86
Vasa efferentia, of _Leptoplana_, 14, 15;
of Triclads, 38
Vascular System, of Nemertinea, 106, 107;
of Archiannelida, 244;
of _Nereis_, 251 f.;
of Polychaeta, 251 f.;
of Cryptocephala, 252;
of Scoleciformia, 252;
of Terebelliformia, 252;
absence of, in certain Polychaeta, 253;
of Oligochaeta, 355;
of Leeches, 396;
of Gephyrea, 415, 436, 447;
of _Phoronis_, 455
_Vaucheria_, Rotifers in, 227
Vejdovsky, on Rhabdocoels, 46;
on _Gordius_, 164, 166;
on Oligochaeta, 365, 369, 374, 400
Vermes, 347
_Vermiculus_, _378_
Vermiformia, 461
Verrill, on Chaetognatha, 534
Vertebrates, parasites of, 163, 174, 179, 183
Verworn, on statoblasts, 501
Vesicula seminalis, of _Planaria_, 39
_Vesicularia_, 481, _518_, 533
Vesicularina, _518_, 523
Vestibule, 488, 490;
of larva, 509
Vibracular zooecium, 485, 486, 517, 524
Vibraculum, 477, 484, 485, 517, 524;
movements, 487;
function, 486
Vicarious avicularia, 482
_Victorella_, 492, 501, 505, _518_, 533
Villot, on life-history of _Gordius_, 172
_Vinella_, 521 n.
Virgate, 210
Visceral nervous system, of _Nereis_, 255
Vitellarium = Yolk-gland, _q.v._
Vitello-intestinal canal, in Polystomatidae, 57
Viviparous, Nemertinea, 109, 117;
Rotifers, 200, 216 f.;
Polychaeta, 256, 276
_Volvox_, Rotifers in, 227
Vortex, 44;
British species, _50_;
body-cavity, 43
Vorticellids, on Polychaeta, 299
_Vorticeros_, British species, 45, 46, _50_
Vorticidae, _50_
Vuillemin (misprinted in text), on Nematodes in deserts, 156

Walford, on Polyzoa, 521
Ward, on _Nectonema_, 168;
on _Sipunculus_, 417
Warning colours, in Polychaeta, 294, 314
Waters, on Polyzoa, 517
Wheeler, on Myzostomaria, 344
Whelk, shell occupied by _Nereis_, 298
White Cat, 317
Whitman, on Dicyemidae, 94;
on Hirudinea, 395 f., 402, 405 f.
Willemoes-Suhm, von, on _Tetrastemma agricola_, 101, 115, 117, 118
Willey, on affinities of Nemertinea, 120 n.;
on Oligochaeta, 382
Wings, of _Chaetopterus_, 295, 324
Winter-eggs, of _Mesostoma_, 48;
of Rotifers, 217;
compared with statoblasts, 493
Woodworth, on yolk-glands, 38 n.
Wreath, in Rotifers, 200
Wright, on _Phoronis_, 450, 456

Yellow-cells, in _Leptoplana_, 13 {560}
Yolk-gland, in _Planaria_, 38, 39;
in Rhabdocoelida, 47;
in _Temnocephala_, 54;
in Polystomatidae, 57;
in _Calliobothrium_, 75;
in _Schistocephalus_, 86;
in Rotifers, 199, 216
Yoruba Worm, 368, _387_
Youatt, on _Coenurus_, 82
_Yungia_, _19_, 25

Zebra, parasites of, 140
Zelinka, on Rotifers, 198, 215 n., 218, 219, 227, 229;
on Gastrotricha, 232
Zooecium, 466, 469, 474, 488, 523;
of Phylactolaemata, 495;
loss of zooecia, 481, (= calyces), 488;
primary, 506;
alterations with age, 522
Zone of budding, 279, 283
Zooid, sexual and asexual, 278 f.
Zoophytes, 465, 474

END OF VOL. II

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