INDEX 



553 



Placostegus, colour, 292 ; from deep sea, 

 300 



Placunetta, 73 



Plagiochaeta, 358, SSI, 3S4 



I'laijiostoma, 46 ; British species, 50 



Plagiostomatidae, 50 



I'luitaria, 30, 31 f., 39 ; British species, Jf.2 



Planarians, 3,' 7 ; Diaophilus, compared 

 with, 242, 243 



Planariidae, J$ 



Planctoplana, 19 



Plankton, Rotifers in, 225 



I'luaocera, 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 



Pledanocotyle, 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, 228, 

 226, 227 



Phanatella, 493, 494, 499, 503-505, 518, 

 519 ; protrusion of polypides, 499 ; 

 statoblasts, 499, 502, 503; larva, 512 



Podal membrane, of Spionidae, 322 



Podaxonia, 461 



Polyarthm, 201, 224, 226 



Polybostrichus, 280 



Pofycelis, 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 ; geni- 

 tal duct, 254, 269 ; genital cells, 256, 

 273 f. ; hermaphrodite, 273 ; regenera- 

 tion, 278, 282 ; habits, 285 ; carnivor- 

 ous, 304 ; distribution, 299 ; from fresh 

 water, 284 ; from deep sea, 300 ; pelagic, 

 291, 314 ; boring, 287 ; tubes, 287 ; pig- 

 ments, 291 ; colours, 291 f. ; warning 

 colours, 294 ; protective devices and 

 mimicrv, 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, 275, 300 ; 

 provisional chaetae, 274 



Polychoerus, 49 ', development of, 44 n. 



Polycirrus, 330 ; habits of, 285 ; P. auranti- 

 acus, warning colours, 294 ; phosphor- 

 escence, 295 ; P. haematodes, coelomic 

 corpuscles, 253 



Polycladida (Polyclads), 4 f., 7 ; classifica- 

 tion, 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 Heliqpora, 298 ; P. ciliata, 

 borings, 287 



Polydoridae, 258, 323 



Polygordius, 242, 244 ; development, 245 



Polymnia, 328 



Polymorphism, of Nereis, 277 



Polymyarii, 137, 142 



Polynoe 310 ; segment*, 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 ; phosphor- 

 escence, 295, 296 ; food, 296 ; parasitic 

 and commensal, 297, 325 ; elytra, 275, 

 294, 295, 299, 309 f. 



Polyodontes, 313 n. 



Polyophthcdmus, 332 ; segmental eyes, 

 272, 296 ; otocyst, 273 



Polype a pannache, 496 



Polypide, 468, 469, 474, 488, 523 ; retrac- 

 tion aud 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 



Polystcmmm, 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 vibra- 

 cula, 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 



