472 



SUBJECTS INDEX 



Ophryotrooha, 277, 278, 280, 313, 



316. 

 OrthonectidsB, 206. 



relationships of, 215. 

 Orthoptera, sexual cells of, 12. 

 Oscarella, 20, 22, 28, U. 

 Otomesostoma, 177. 

 Oxysotna, 236. 



Paractinies, 93. 



Parenchymula, 22, 41. 



Peachia, 94. 



Pelagia, 105, 118, 122. 



Pelagidas, 120. 



Pennaria, 47. 



Pennatula, 83, 87. 



Pentacttra, 458, 459. 



PeromedusaB, 123. 



Person, 1. 



Phalangidee, sexual cells of, 12. 



Phascolosoma, 357, 36±. 



Phialidium, 49. 



Pboronis, relationships of, to 



Sipunculidae, 365. 

 Phyllochsetopterus, 274. 

 Phyllophorus, larva of, 419. 

 Physalia, 59, 62, 74, 75. 

 PhysonecteB, 59, 75. 

 Physophora, 64. 

 Physophoridse, 59, 60, 67. 

 Pietocystis dythiridium, 195. 



variabilis, 195. 

 Pileolaria, 279, 300. 

 Pilidium, 217. 



auriculatum, 220. 



brachiatura, 220. 



gyrans, 220. 



recurvatum, 220. 

 Placina, 14. 

 Plakinidae, 22, 28. 

 Planaria angulata, 169. 



polychroa, 169. 

 Planula, 14. 

 Platyhelminthes, 159- 

 Plerocerci (Taeniadse), 195. 

 Plerocercoids (TseniadaB), 195. 

 Pleurobrachia. 138. 

 Pleurochaeta, 291. 

 Pluteus, 422, 4U. 

 Pneumatophoridae, 59, 62. 

 Polar globules, 3. 



ingression, see Ingression, 

 polar. 

 Pole, animal, 3. 



vegetative, 3. 

 Polia. 228. 



Polychssta, 262. 

 Polycladida, 160. 173, 174. 

 Polygordius, 263, 267, 268, 2S7, 



290, 292, 295. 

 Polylophus, 34. 

 Polynoe, 262. 

 Polyopsis, 93. 

 Polyphyidfe, 71, 72. 

 Polypodium, 49. 

 Polystomidae, 188, 190. 

 Polystomum, 188. 

 Polytrochffi, 271, 273. 

 Pomatoceros, 3, 263. 

 Porifera, 13, 28, 32. 

 Porpita, 59, 65. 

 PorpitidfiB, 65. 

 Praya, 71. 



Primary germ-layers, 5. 

 Primitive mesoderm cells, 10. 



mouth, see Blastopore. 

 Prorhynchus, 173. 

 Prostoma, see Blastula. 

 Prostomial discs (Pilidium), 221, 

 Prostomum lineare, 173, 175. 



Steenstrupii, 173, 174. 

 Protaxonia, 9. 

 Protodrilus, 287. 

 Protohydra, 49. 

 Protozoa, 11. 

 Protula, 302. 

 Pseudoceridse, 160. 

 Pseudoccele, 11. 

 Pseudogastrula, 17. 

 Psolinus, 419. 

 Psygmobranchus, 263, 275, 279, 



284, 291, 297, 299, 300. 

 Pteraster, brooding in, 436. 



Easpailia, 24. 

 Ratariae, 65. 

 Rathkea (Fig. 13), 40. 

 Redia (Distomidas), 183. 

 Reniera, 24, 27. 

 Renilla, 76, 83, 88. 

 Rhabditis, 238. 



aceti, 235. 



nigrovenosa, 234, 242. 



stercoralis, 242. 

 Rhabdocoela, 159. 

 Rbabdocoelidffi, 159, 173, 174. 

 Rbabdonema, 242. 

 Rhizocrinus, 453. 

 Rhizophysa, 59. 75. 

 Rhizostoma, 120. 

 Rhizostomse, 124. 

 Rhizoxenia, 82. 

 Rhopalonema, 57. 



