provisional chaetae,274Polychoerus,49;development of,44n.Polycirrus,330;habits of,285;P. aurantiacus, warning colours,294;phosphorescence,295;P. haematodes, coelomic corpuscles,253Polycladida (Polyclads),4f.,7;classification,16f.;development,28f.;British species,19,20,22Polycladus,42Polycotyle,73Polydora(=Leucodore),323;frontal ridge,260;head,261;special chaetae,267;withHeliopora,298;P. ciliata, borings,287Polydoridae,258,323Polygordius,242,244;development,245Polymnia,328Polymorphism, ofNereis,277Polymyarii,137,142Polynoe310;segments258;parapodium,265;jaws,270;anus,259;nephridium,254;habits,286;as ectoparasites or commensals,294,298,325;distribution,299,300;British species,299,310f.;P. squamata,309;elytron,310;P. clava, elytron,310;P. imbricata, elytron,311Polynoina (= Polynoids),309;head,262;chaetae,266,267;jaw,270;intestine,271; eggs,275;sexual dimorphism,276n.;tubes,285;colours,291,292;protective resemblance,294;phosphorescence,295,296;food,296;parasitic and commensal,297,325;elytra,275,294,295,299,309f.Polyodontes,313n.Polyophthalmus,332;segmental eyes,272,296;otocyst,273Polype à pannache,496Polypide,468,469,474,488,523;retraction and protrusion,498f.Polypide-bud,468,472,487,496,499,501,510;connected with reproduction,507Polypostia,19;penes,27Polystomatidae,53,55,73Polystomatinae,73Polystomum,55,57;life-history,58,59Polyzoa,465f.,475;external characters,465f.,479f.;anatomy,468f.,469;brown bodies,471f.,472;history,474f.;classification,475f.,515,517f.;occurrence,477f.;avicularia and vibracula,482;enemies,486;Entoprocta,487;fresh water,492f.;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,505,521,525Pomatoceros, habitat,300,340Pompholyx,201,203,225Pontobdella,393,401,404,406Pontodora,314Pontodrilus,366,370,383Pontoscolex,350,366,387f.;chaeta,351Pore, in Polyzoa,471,482,522,524;median,484,524;dorsal,348Porella,516,518,522,527,529Porina,518,527,529Potamilla,338Praeoral lobe (= Prostomium),245,439Predaceous worms,304Priapuloidea,412,446;anatomy,430;classification,432;habits,433Priapulus,430,431,432;anatomy,430f.Pristina,377Proales,204,224,226,227Proboscidae,49;occurrence,44Proboscis, of Nemertinea,100,101f.,103f.;of Hoplonemertea,104,110;opening by mouth,117,119;severance of,116;of Acanthocephala,174f.;of Rotifers,203;of Kinorhyncha,237;of Echiuroidea,434Proboscis-pore of Nemertinea,102,103Proboscis-sheath of Nemertinea,103,103f.Procerodes,42Procerodidae,42Procerus, host ofGordius,172Procotylea,36,42Proglottis,5,74,75,79,85Promesostoma, occurrence,44;British species,49Proporidae,49Proporus venenosus,49Prorhynchidae,49Prorhynchus sphyrocephalus, terrestrial habit,44;P. stagnalis,49Prosorhochmus claparedii,110,114,117Prostate-gland, ofLeptoplana,16;of Polyclads,30;ofPlanaria,39;of Rhabdocoela,47;of Oligochaeta,361Prostheceraeus,19,22;spermatophores,27Prosthiostomatidae,19Prosthiostomum,17,18,19,24Prostomial tentacles,248,262Prostomium,241;ofDinophilus,243;ofPolygordius,244;of Trochosphere,245;ofNereis,248;of Polychaeta,259;of Glyceridae,320;of Terebellidae,327;of Oligochaeta,348Protodrilus,242,244Protonemertini,112Protula,341;genital organs,273,274;eggs,275Prouho, on Polyzoa,489,507f.Provisional chaetae,274Provortex, British species,50Proxenetes,44;British species,49Pruvot, on Polychaeta,261Psamathe,300,308Psammolyce,313;elytra,294,313Pseudalius,135,142,163Pseudaxine,73Pseudoceridae,19,20Pseudoceros,19,20Pseudocotyle,73Pseudorhynchus bifidus,49Psygmobranchus,341Pterobranchia,461Pterodina,200,201,203,206,211,215,216,225,226,230Pterodinidae,201,225Pteroessa,224Pteronella,73Pterostichus niger, infested byGordius,170,170,172Pterosyllis, ciliated lappets,273n.Pyriform organ,509,511Quatrefages, on Gephyrea,411,445Rabbit, parasites of,141,145Ragworm,322Railliet, on Cestodes,91Rami, in Rotifers,210Rasping plate, of Eunicidae,270Rattulidae,210,225Rattulus,212,225,226Ratzel, on Earthworms,350Red Cat,316Regeneration 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,471,488Repetition of parts,249Replacement of species,300Reproduction (and Reproductive organs), ofLeptoplana,14f.;of Polyclads,26,30;of Triclads,31,38,39;of Rhabdocoelida,45,47f.;ofTemnocephala,54;of Polystomatidae,57f.;ofDiplozoon,60;of Digenea,65;ofCalliobothrium,75;ofSchistocephalus,86;of Mesozoa,93f.;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,243f.;of Polychaeta,253,254,256,269,273;ofMyzostoma,343;of Oligochaeta,360;of Leeches,401;of Gephyrea,418,431,437;ofPhoronis,457;of Polyzoa,471,490,501,506—see also Ovary and Asexual reproductionReptiles, parasites of,163Respiration, inNereis,252;in Chaetopoda,272;in Gephyrea,416Retepora,479,515,518,527Rhabdites (rods), ofLeptoplana,11,12;in Polyclads,29;in Triclads,37;absent in parasitic Rhabdocoela,45;inTemnocephala,53,54Rhabditiformae,137Rhabditis,154,160;R. nigrovenosa,140,155Rhabdocoelida,4,7,36,42f.;occurrence and habits,43;parasitic forms,44;reproduction,47;classification,49;British species,43,44,49Rhabdogaster,158Rhabdonema nigrovenosum,134,136,140,151,160,161Rhabdopleura,461f.Rhinodrilus,348Rhinopidae,220n.,224Rhinops,224;male of,223n.Rhizopoda, as food for Polychaeta,296Rhizota,220n.Rhombogen (form of Dicyemid),93Rhopalonaria,521n.Rhopalophorus,73Rhopalura giardii, occurrence and structure,94,95;R. intoshii,94Rhynchelmis,365,376Rhynchobdellae,396f.,405Rhynchodemidae,35,42Rhynchodemus,34,35,42Rhynchopora,531Rhynchozoon,529n.,531Riches, on British Nemertinea,110;onMalacobdella,119Rietsch, on Gephyrea,443Rockworm,319Rods—see RhabditesRohde, on muscles of Nematoda,128f.Rootlet, in Polyzoa,485,517Rosa, on Oligochaeta,364,380,385,390Rosette-plates,471,522Rotifer,201,202,210,216,222,226,227Rotifera,197f.;distribution,200;parasitic,204;digestive organs,209;renal organs,213;nervous system and sense organs,215;reproduction and development,216;classification,220;habits226;preservation,228;affinities,229Rousselet, on Rotifers,198,216,228Sabella,299,337; parapodium,265;habitat,286;tube,287;tube-building,288;colour,293,294;S. saxicava, habits of,287Sabellaria,341;body,259;cirri,265.;tube,287,290;S. alveolata,259,300;S. spinulosa, paleae,267,300Sabellidae,258,336;
provisional chaetae,274
Polychoerus,49;
development of,44n.
Polycirrus,330;
habits of,285;
P. aurantiacus, warning colours,294;
phosphorescence,295;
P. haematodes, coelomic corpuscles,253
Polycladida (Polyclads),4f.,7;
classification,16f.;
development,28f.;
British species,19,20,22
Polycladus,42
Polycotyle,73
Polydora(=Leucodore),323;
frontal ridge,260;
head,261;
special chaetae,267;
withHeliopora,298;
P. ciliata, borings,287
Polydoridae,258,323
Polygordius,242,244;
development,245
Polymnia,328
Polymorphism, ofNereis,277
Polymyarii,137,142
Polynoe310;
segments258;
parapodium,265;
jaws,270;
anus,259;
nephridium,254;
habits,286;
as ectoparasites or commensals,294,298,325;
distribution,299,300;
British species,299,310f.;
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,276n.;
tubes,285;
colours,291,292;
protective resemblance,294;
phosphorescence,295,296;
food,296;
parasitic and commensal,297,325;
elytra,275,294,295,299,309f.
Polyodontes,313n.
Polyophthalmus,332;
segmental eyes,272,296;
otocyst,273
Polype à pannache,496
Polypide,468,469,474,488,523;
retraction and protrusion,498f.
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,465f.,475;
external characters,465f.,479f.;
anatomy,468f.,469;
brown bodies,471f.,472;
history,474f.;
classification,475f.,515,517f.;
occurrence,477f.;
avicularia and vibracula,482;
enemies,486;
Entoprocta,487;
fresh water,492f.;
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
Pompholyx,201,203,225
Pontobdella,393,401,404,406
Pontodora,314
Pontodrilus,366,370,383
Pontoscolex,350,366,387f.;
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,430f.
Pristina,377
Proales,204,224,226,227
Proboscidae,49;
occurrence,44
Proboscis, of Nemertinea,100,101f.,103f.;
of Hoplonemertea,104,110;
opening by mouth,117,119;
severance of,116;
of Acanthocephala,174f.;
of Rotifers,203;
of Kinorhyncha,237;
of Echiuroidea,434
Proboscis-pore of Nemertinea,102,103
Proboscis-sheath of Nemertinea,103,103f.
Procerodes,42
Procerodidae,42
Procerus, host ofGordius,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, ofLeptoplana,16;
of Polyclads,30;
ofPlanaria,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;
ofDinophilus,243;
ofPolygordius,244;
of Trochosphere,245;
ofNereis,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,489,507f.
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 byGordius,170,170,172
Pterosyllis, ciliated lappets,273n.
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), ofLeptoplana,14f.;
of Polyclads,26,30;
of Triclads,31,38,39;
of Rhabdocoelida,45,47f.;
ofTemnocephala,54;
of Polystomatidae,57f.;
ofDiplozoon,60;
of Digenea,65;
ofCalliobothrium,75;
ofSchistocephalus,86;
of Mesozoa,93f.;
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,243f.;
of Polychaeta,253,254,256,269,273;
ofMyzostoma,343;
of Oligochaeta,360;
of Leeches,401;
of Gephyrea,418,431,437;
ofPhoronis,457;
of Polyzoa,471,490,501,506—see also Ovary and Asexual reproduction
Reptiles, parasites of,163
Respiration, inNereis,252;
in Chaetopoda,272;
in Gephyrea,416
Retepora,479,515,518,527
Rhabdites (rods), ofLeptoplana,11,12;
in Polyclads,29;
in Triclads,37;
absent in parasitic Rhabdocoela,45;
inTemnocephala,53,54
Rhabditiformae,137
Rhabditis,154,160;
R. nigrovenosa,140,155
Rhabdocoelida,4,7,36,42f.;
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,461f.
Rhinodrilus,348
Rhinopidae,220n.,224
Rhinops,224;
male of,223n.
Rhizopoda, as food for Polychaeta,296
Rhizota,220n.
Rhombogen (form of Dicyemid),93
Rhopalonaria,521n.
Rhopalophorus,73
Rhopalura giardii, occurrence and structure,94,95;
R. intoshii,94
Rhynchelmis,365,376
Rhynchobdellae,396f.,405
Rhynchodemidae,35,42
Rhynchodemus,34,35,42
Rhynchopora,531
Rhynchozoon,529n.,531
Riches, on British Nemertinea,110;
onMalacobdella,119
Rietsch, on Gephyrea,443
Rockworm,319
Rods—see Rhabdites
Rohde, on muscles of Nematoda,128f.
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,197f.;
distribution,200;
parasitic,204;
digestive organs,209;
renal organs,213;
nervous system and sense organs,215;
reproduction and development,216;
classification,220;
habits226;
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;