472 



SUBJECTS INDEX 



Ophryotrocha, 277, 278, 280, 313, 



316. 

 Orthouectidae, 206. 



relationships of, 215. 

 Ortboptera, sexual cells of, 12. 

 Oscarella, 20, 22, 28, 34. 

 Otoraesostoma, 177. 

 Oxysoma, 236. 



Paractinise, 93. 



Parenchyrnula, 22, 41. 



Peachia, 94. 



Pelagia, 105, 118, 122. 



PelagidfB, 120. 



Pennaria, 47. 



Pennatula, 83, 87. 



Pentacta?a, 458, 459. 



Peromedusae, 123. 



Person, 1. 



Phalangidfe, sexual cells of, 12. 



Phascolosoma, 357, 361. 



Phialidium, 49. 



Pboronis, relationships of, to 



Sipunculidse, 365. 

 Phyllochsetopterus, 271. 

 Phyllophorus. larva of, 419. 

 Physali«, 59, 62, 74, 75. 

 Physonectse, 59, 75. 

 Physophora, 64. 

 Physophorida?, 59, 60. 67. 

 Pietocystis dythiridium, 195. 



variabilis, 195. 

 Pileolaria, 279, 300. 

 Pilidium, 217. 



auriculatum, 220. 



brachiatum, 220. 



gyrans, 220. 



recurvatum, 220. 

 Placina, 14. 

 Plakinidae, 22, 28. 

 Planaria angulata, 169. 



polychroa, 169. 

 Planula, 14. 

 Platyhelmintbes, 159. 

 Plerocerci (Tteniadae), 195. 

 Plerocprcoids (Tseuiadse), 195. 

 Pleurobrachia. 138. 

 Pleurocbffit«, 291. 

 Pluteus, 422, 424. 

 Pneumatopboridae, 59, 62. 

 Polar globules, 3. 



ingression, see Ingression, 

 polar. 

 Pole, animal, 3. 



vegetative, 3. 

 Polia, 228. 



Polycbssta, 262. 

 Polycladida, 160, 173. 174. 

 Polygordius, 263, 267, 268, 2S7, 



290, 292, 295. 

 Polylophus, 34. 

 Polynoe, 262. 

 Polyopsis, 93. 

 Polypbyidse, 71, 72. 

 Polypodium, 49. 

 Polystomid», 188, 190. 

 Polvstomum, 188. 

 Polytrocbae, 271, 273. 

 Piimatocei-os, 3, 263. 

 Porifera, 13, 28, 32. 

 Porpita, 59, 65. 

 Porpitidee, 65. 

 Praya, 71. 



Primary germ-layers, 5. 

 Primitive mesoderm cells, 10. 



mouth, see Blastopore. 

 Prorhyncbus, 173. 

 Prostoma, see Blastula. 

 Prostoiuial discs (Pilidium), 221. 

 Prostomum lineai'e, 173, 175. 



Steenstrupii, 173, 174. 

 Protaxonia, 9. 

 Protodrilus, 287. 

 Protobydra, 49. 

 Protozoa, 11, 

 Prot'ila, 302. 

 PseudoceridiB, 160. 

 Pseudocoele, 11. 

 Pseudogastrula, 17. 

 Psolinus, 419. 

 Psygmobranchus, 263, 275, 279, 



284, 291, 297, 299, 300. 

 Pteraster, brooding in, 436. 



Raspailia, 24. 

 Ratarise, 65. 

 Rathkea (Fig. 13), 40. 

 Redia (Distomidss), 183. 

 Reniera, 24, 27. 

 Renilla, 76, 83, 88. 

 Rhabditis, 238. 



aeeti, 235. 



nigroveuosa, 234, 242. 



stercoralis, 242. 

 Rhabdoccela, 159. 

 RbabdoeoelidBB, 159, 173, 174. 

 Rhabdonema, 242. 

 Rhizocrinus, 453. 

 Rhizophysa, 59. 75. 

 Rhizostoma, 120. 

 Rhizostorase, 124. 

 Rhizoxenia, 82. 

 Rhopalonema, 57. 



