of Nematoda,130;of Gordiidae,166,169;of Chaetognatha,187;of Rotifers, etc.,209,233,237;of Archiannelida,243;of Polychaeta,249,269;of Oligochaeta,358;of Hirudinea,396;of Gephyrea,414;ofPhoronis,454;of Polyzoa,468,469,487Digitibranchus,353Diglena,212,217,224,226Digonopora,16Dimorphism, inPolystomum,59;sexual, of Trematodes,70;of Orthonectida,95;ofDinophilus,243;of Polychaeta,276,279f.;of Gephyrea,438Dinocharididae,225Dinocharis,225Dinophilus,242;D. taeniatus,242;D. gyrociliatus, sexual dimorphism,243Dinops,223Diopatra, gill,318Diphyllinae,91Diplax,225Diplectanum,73Diplobothrium,73Diplocardia,385Diplodiscus,73;D.(Amphistomum)subclavatum, life-history,71Diplogaster,154Diplois,225Diplostomum,73Diplozoon,55,60,73;life-history,60,61;reproductive organs,60Diporochaeta,381Diporpa,60,61Diporula,528Dipylidium,81,91;life-history,83,88,89;specific characters,90Disc, in Rotifers,200,202f.,202Discharge, of genital cells;Nemertinea,116;Archiannelida,244;Polychaeta,256,274,275Discobdella,226Discocelis,19,23Discodrilidae,350,376,392,395Discopus,201,222,226,227Dispharagus,147,149,163Dispinthera,225Distemma,212,224,226Distomatidae,73Distomum advena(=D. migrans), life-history,71;D. appendiculatum, life-history,71;D. ascidia, life-history,71;D. atriventre, life-history,71;D. brachysomum, life-history,71;D. buskii,63;D. caudatum, life-history,71;D. clavigerum, life-history,72;D. conjunctum,63;D. crassum,63;D. cygnoides, life-history,72;D. cylindraceum,72;D. dimorphum,72;D. echinatum,63;life-history,72;D. echiuri,444;D. endolobum, life-history,72;D. excavatum,63;D. ferox,63;D. globiporum, life-history,72;D. hians,63;D. hepaticum(liver-fluke),3,63,67f.,72;D. heterophyes,63;D. hystrix, life-history,72;D. japonicum(=D. spathulatum),63;D. lanceolatum,63;D. luteum, excretory system of,62;D. macrostomum, life-history,64,65,72;D. magnum,68;D. militare, life-history,72;D. nodulosum, life-history,72;D. oculi-humani(=D. ophthalmobium),63;D. ovocaudatum, life-history,72;D. pulmonale,63,70;D. rathouisi,63,70;D. retusum, life-history,72;D. ringeri(=D. pulmonale),63;D. signatum, life-history,72;D. sinense,70;D. spathulatum,63;D. squamula, life-history,72;D. trigonocephalum, life-history,72;D. westermanni(=D. pulmonale),63Distyla,225Dithyridium,91Ditrupa,301Diurella,225,226Dochmius,133,135,142,160,163;D. cernua,143;D. duodenalis,143,163;D. stenocephala,143;D. trigonocephala,143Dodecaceria,287,326,327Dog, parasites of,80f.,90,125,140,142,143,145Dolichoplana,37,42Domestic animals, Trematodes of,67,68,70,72;Cestodes of,81,89;Nematodes of,139f.,163;Acanthocephala of,184Domopora,531,532Dorsal ciliated organ,247,254,256Dorsal pores,348Dorylaimus,131,157,160Dracunculus,131,135,147Drepanidotaenia,91;D. anatina, life-history,84,85;D. gracilis,D. infundibuliformis,D. setigera, life-history,84Drepanophorus, excretory system,108;British species,110Drilophagidae,224Drilophagus,204,210,212,224,227Dugès, on Planarians,6,10;on Oligochaeta,368Dujardin, on Rotifers,198;on Gastrotricha,231;on Kinorhyncha,236Duplicature,499,500Duthiersia,91Dwarf males, ofMyzostoma,344;of Gephyrea,438Ear-cockle,155Earthworms,347,365;senses,354;food,359;effect on the soil,368;distribution,369f.;classification,380f.;British,390—see also OligochaetaEbrard, on Hirudinea,393Echeneibothrium,91Echinella,73Echinobothrium,74,75,85,91Echinococcus,80,83Echinocotyle,91Echinoderes,236f.,236Echinorhynchidae,182Echinorhynchus acus,175,179;E. angustatus,174,183;E. clavula,183;E. haeruca,176;E. linstowi,183;E. lutzii,183;E. moniliformis,183;E. proteus,174,180,181,182,182Echinosiphon,424,429Echiuroidea,241n.,412,434,446;anatomy,434f.;classification,440;development,439;parasites,444;habits,442Echiurus,336,411,435,440,441;development,439Eckstein, on Rotifers,198Eclipidrilus,380Economic uses, of Polychaeta,296,297Ectocyst,469,470,523;of Phylactolaemata,496f.,503Ectoderm, of Mesozoa,93,95Ectoparasitic Trematodes,4,52,53Ectoprocta,475,518;structure,469;lophophore,476;reproduction,506f.;larva,509,510,511;compared with Entoprocta,488Effects, of parasites on their hosts,56,68,69,80,94,162Eggs, ofLeptoplana,10,16;of Polyclads,28;of Triclads,33,40;of Rhabdocoels,47,48;of Termatodes,52;of ectoparasitic Trematodes,54,58,60,61;of endoparasitic Trematodes,63,69;of Cestodes,87;of Orthonectidae,95;of Nemertinea,116;of Nematoda,135,162;ofGordius,171;of Acanthocephala,179;of Chaetognatha,189;of Rotifera,200,216f.;of Gastrotricha,234;ofNereis,256;of Polychaeta,274,275;of Phyllodocids,314;ofScoloplos,321;ofMyzostoma,343;of Polyzoa,506,507Ehrenberg, on Turbellaria,3,6;on Rotifers,198,220n.,228;on Gastrotricha,231;on Polyzoa (Bryozoa),475Eichhorn, on Rotifers,197Eisen, on Oligochaeta,380,390Eisig, on Capitellidae,373;onBonellia,443Electra,481,518,523,530;larva,509,510;variation,516Elytra, of Polynoids,265,292,294,298,299,309,310,311;phosphorescent,295,296;as brood-pouch,275;of Aphroditidae,266;arrangement of,309;of Sigalionina,313Enantia,16n.,19Enantiidae,19Enchelidium,157Enchytraeidae,359,360,361,366,367,370,375Enchytraeus, host ofGordius,173Encotylabe,73;eggs ofE. pagelli,58Endocyst,471Endoderm, of Mesozoa,93,95Endoparasitic Trematodes,4,52,62Enopla,109Enoplidae,157Enoplus,157,160Entalophora,518,532Enteroploea,224Enterostoma,46;British species,50Entoprocta,475,479,487f.,518;lophophore,476;reproduction,506;larva,509,510Eosphora,216,218,224Ephemera, host ofGordius,172,173Ephesia,321Epibdella,55,73Epidermis, ofLeptoplana,11,12;of Polyclads,20,25,29;of Trematodes,56;of Cestodes,85;of Nemertinea,102;of Nematoda,125;of Acanthocephala,175;ofNereis,249;of Oligochaeta,349;of Leeches,396;of Gephyrea,414;ofPhoronis,454—see also HypodermisEpigamous, phase, ofNereis,277n.;worms,281Epistome, inPhoronis,453,455;in Phylactolaemata,476,476,499;in larva ofLoxosoma,509Epistomia,518,526Epithetosoma,444,445,449Epithetosomatoidea,412,444Epitokous, phase, ofNereis,277n.Eretmia,225,226Eriographidae,258,338Erpocotyle,73Errantia,258,285Eschara,516Escharina,518Escharoides,527Euchlanididae,225Euchlanis,225,226Eucratea,518,525,527,528Eudrilidae,359,360,380,385,403f.Eudrilus,354,385,403f.Euichthydina,235Eulalia viridis,314;pigment,292;colour,293;eggs,314n.Eumenia,334Eunice,318,319;nephridium,254;eye,255;head,262;parapodium,264;gill,265;chaetae,266,267;jaws,270;substance of tube,290;commensal,298;E. tibiana,290Eunicidae,258,318;palps,260;tentacles,262;
of Nematoda,130;
of Gordiidae,166,169;
of Chaetognatha,187;
of Rotifers, etc.,209,233,237;
of Archiannelida,243;
of Polychaeta,249,269;
of Oligochaeta,358;
of Hirudinea,396;
of Gephyrea,414;
ofPhoronis,454;
of Polyzoa,468,469,487
Digitibranchus,353
Diglena,212,217,224,226
Digonopora,16
Dimorphism, inPolystomum,59;
sexual, of Trematodes,70;
of Orthonectida,95;
ofDinophilus,243;
of Polychaeta,276,279f.;
of Gephyrea,438
Dinocharididae,225
Dinocharis,225
Dinophilus,242;
D. taeniatus,242;
D. gyrociliatus, sexual dimorphism,243
Dinops,223
Diopatra, gill,318
Diphyllinae,91
Diplax,225
Diplectanum,73
Diplobothrium,73
Diplocardia,385
Diplodiscus,73;
D.(Amphistomum)subclavatum, life-history,71
Diplogaster,154
Diplois,225
Diplostomum,73
Diplozoon,55,60,73;
life-history,60,61;
reproductive organs,60
Diporochaeta,381
Diporpa,60,61
Diporula,528
Dipylidium,81,91;
life-history,83,88,89;
specific characters,90
Disc, in Rotifers,200,202f.,202
Discharge, of genital cells;
Nemertinea,116;
Archiannelida,244;
Polychaeta,256,274,275
Discobdella,226
Discocelis,19,23
Discodrilidae,350,376,392,395
Discopus,201,222,226,227
Dispharagus,147,149,163
Dispinthera,225
Distemma,212,224,226
Distomatidae,73
Distomum advena(=D. migrans), life-history,71;
D. appendiculatum, life-history,71;
D. ascidia, life-history,71;
D. atriventre, life-history,71;
D. brachysomum, life-history,71;
D. buskii,63;
D. caudatum, life-history,71;
D. clavigerum, life-history,72;
D. conjunctum,63;
D. crassum,63;
D. cygnoides, life-history,72;
D. cylindraceum,72;
D. dimorphum,72;
D. echinatum,63;
life-history,72;
D. echiuri,444;
D. endolobum, life-history,72;
D. excavatum,63;
D. ferox,63;
D. globiporum, life-history,72;
D. hians,63;
D. hepaticum(liver-fluke),3,63,67f.,72;
D. heterophyes,63;
D. hystrix, life-history,72;
D. japonicum(=D. spathulatum),63;
D. lanceolatum,63;
D. luteum, excretory system of,62;
D. macrostomum, life-history,64,65,72;
D. magnum,68;
D. militare, life-history,72;
D. nodulosum, life-history,72;
D. oculi-humani(=D. ophthalmobium),63;
D. ovocaudatum, life-history,72;
D. pulmonale,63,70;
D. rathouisi,63,70;
D. retusum, life-history,72;
D. ringeri(=D. pulmonale),63;
D. signatum, life-history,72;
D. sinense,70;D. spathulatum,63;
D. squamula, life-history,72;
D. trigonocephalum, life-history,72;
D. westermanni(=D. pulmonale),63
Distyla,225
Dithyridium,91
Ditrupa,301
Diurella,225,226
Dochmius,133,135,142,160,163;
D. cernua,143;
D. duodenalis,143,163;
D. stenocephala,143;
D. trigonocephala,143
Dodecaceria,287,326,327
Dog, parasites of,80f.,90,125,140,142,143,145
Dolichoplana,37,42
Domestic animals, Trematodes of,67,68,70,72;
Cestodes of,81,89;
Nematodes of,139f.,163;
Acanthocephala of,184
Domopora,531,532
Dorsal ciliated organ,247,254,256
Dorsal pores,348
Dorylaimus,131,157,160
Dracunculus,131,135,147
Drepanidotaenia,91;
D. anatina, life-history,84,85;
D. gracilis,D. infundibuliformis,D. setigera, life-history,84
Drepanophorus, excretory system,108;
British species,110
Drilophagidae,224
Drilophagus,204,210,212,224,227
Dugès, on Planarians,6,10;
on Oligochaeta,368
Dujardin, on Rotifers,198;
on Gastrotricha,231;
on Kinorhyncha,236
Duplicature,499,500
Duthiersia,91
Dwarf males, ofMyzostoma,344;
of Gephyrea,438
Ear-cockle,155
Earthworms,347,365;
senses,354;
food,359;
effect on the soil,368;
distribution,369f.;
classification,380f.;
British,390—see also Oligochaeta
Ebrard, on Hirudinea,393
Echeneibothrium,91
Echinella,73
Echinobothrium,74,75,85,91
Echinococcus,80,83
Echinocotyle,91
Echinoderes,236f.,236
Echinorhynchidae,182
Echinorhynchus acus,175,179;
E. angustatus,174,183;
E. clavula,183;
E. haeruca,176;
E. linstowi,183;
E. lutzii,183;
E. moniliformis,183;
E. proteus,174,180,181,182,182
Echinosiphon,424,429
Echiuroidea,241n.,412,434,446;
anatomy,434f.;
classification,440;
development,439;
parasites,444;
habits,442
Echiurus,336,411,435,440,441;
development,439
Eckstein, on Rotifers,198
Eclipidrilus,380
Economic uses, of Polychaeta,296,297
Ectocyst,469,470,523;
of Phylactolaemata,496f.,503
Ectoderm, of Mesozoa,93,95
Ectoparasitic Trematodes,4,52,53
Ectoprocta,475,518;
structure,469;
lophophore,476;
reproduction,506f.;
larva,509,510,511;
compared with Entoprocta,488
Effects, of parasites on their hosts,56,68,69,80,94,162
Eggs, ofLeptoplana,10,16;
of Polyclads,28;
of Triclads,33,40;
of Rhabdocoels,47,48;
of Termatodes,52;
of ectoparasitic Trematodes,54,58,60,61;
of endoparasitic Trematodes,63,69;
of Cestodes,87;
of Orthonectidae,95;
of Nemertinea,116;
of Nematoda,135,162;
ofGordius,171;
of Acanthocephala,179;
of Chaetognatha,189;
of Rotifera,200,216f.;
of Gastrotricha,234;
ofNereis,256;
of Polychaeta,274,275;
of Phyllodocids,314;
ofScoloplos,321;
ofMyzostoma,343;
of Polyzoa,506,507
Ehrenberg, on Turbellaria,3,6;
on Rotifers,198,220n.,228;
on Gastrotricha,231;
on Polyzoa (Bryozoa),475
Eichhorn, on Rotifers,197
Eisen, on Oligochaeta,380,390
Eisig, on Capitellidae,373;
onBonellia,443
Electra,481,518,523,530;
larva,509,510;
variation,516
Elytra, of Polynoids,265,292,294,298,299,309,310,311;
phosphorescent,295,296;
as brood-pouch,275;
of Aphroditidae,266;
arrangement of,309;
of Sigalionina,313
Enantia,16n.,19
Enantiidae,19
Enchelidium,157
Enchytraeidae,359,360,361,366,367,370,375
Enchytraeus, host ofGordius,173
Encotylabe,73;
eggs ofE. pagelli,58
Endocyst,471
Endoderm, of Mesozoa,93,95
Endoparasitic Trematodes,4,52,62
Enopla,109
Enoplidae,157
Enoplus,157,160
Entalophora,518,532
Enteroploea,224
Enterostoma,46;
British species,50
Entoprocta,475,479,487f.,518;
lophophore,476;
reproduction,506;
larva,509,510
Eosphora,216,218,224
Ephemera, host ofGordius,172,173
Ephesia,321
Epibdella,55,73
Epidermis, ofLeptoplana,11,12;
of Polyclads,20,25,29;
of Trematodes,56;
of Cestodes,85;
of Nemertinea,102;
of Nematoda,125;
of Acanthocephala,175;
ofNereis,249;
of Oligochaeta,349;
of Leeches,396;
of Gephyrea,414;
ofPhoronis,454—see also Hypodermis
Epigamous, phase, ofNereis,277n.;
worms,281
Epistome, inPhoronis,453,455;
in Phylactolaemata,476,476,499;
in larva ofLoxosoma,509
Epistomia,518,526
Epithetosoma,444,445,449
Epithetosomatoidea,412,444
Epitokous, phase, ofNereis,277n.
Eretmia,225,226
Eriographidae,258,338
Erpocotyle,73
Errantia,258,285
Eschara,516
Escharina,518
Escharoides,527
Euchlanididae,225
Euchlanis,225,226
Eucratea,518,525,527,528
Eudrilidae,359,360,380,385,403f.
Eudrilus,354,385,403f.
Euichthydina,235
Eulalia viridis,314;
pigment,292;
colour,293;
eggs,314n.
Eumenia,334
Eunice,318,319;
nephridium,254;
eye,255;
head,262;
parapodium,264;
gill,265;
chaetae,266,267;
jaws,270;
substance of tube,290;
commensal,298;
E. tibiana,290
Eunicidae,258,318;
palps,260;
tentacles,262;