610 



INDEX. 



Oractis, 189. 

 Oral vacuole, 33. 

 Orbiculina, 13. 

 Orbitoides, 15. 

 Orbitolites, 13. 

 Orbulina, 11, 14. 

 Orbuliuella, 19. 

 Orcadella, 17. 

 Orchistoma, 134. 

 Organ pipe coral, 178. 

 Organidus, 178. 

 Oria, 491. 

 Orifice, 550. 

 Ormer, 394. 

 Orpiella, 416. 

 Orthoceras, 444. 

 Orthoconcha, 326. 

 Orthodon, 46. 

 Orthonectidae. 240. 

 Orthospora, 60. 

 Oscarella, 95. 

 Osculum, 72. 

 Osphradium, 320 ; of 



Gastropoda, 366; 



Laniellibranch, 333. 

 Os sepiae, 417. 

 Ostrea, 330, 346. 

 Ostreidae, 328, 338, 341. 



342, 344. 

 Othonia, 491. 

 Otina, 415. 

 Otoconia, 367. 

 Otocyst, 214. 

 Otocysts of Medusae, 



115; of Polychaeta, 



463. 



Otolith, 367. 

 Otomesostomum, 219. 

 Otoplana, 221. 

 Otoporpa, 113. 

 Ototyphlonernertes, 271. 

 Ovicell, 550. 



Oviposition of Gastro- 

 poda, 380: of Oligo- 



cliaeta, 506. 

 Ovula, 400. 

 Ovum, 70. 

 Owenia, 207, 484. 

 Oxea, 82. 

 Oxydromus, 477. 

 Oxyhexact, 92. 

 Oxyrrhis, 31. 

 Oxysoma, 284. 

 Oxytricha, 49. 

 Oxyuris, 275, 279, 284. 

 Oyster, 346. 

 Ozobrancbus, 526 



Pachastrella, 94. 

 Pacbychalina, 96. 

 Pachydrilus, 509. 



Pacbymatisma, 94. 

 Pacbypsaniniia, 196. 

 Hachyseris, 196. 

 Paedophykx, 476. 

 Paleae, 460. 

 Palepbyra, 167. 

 Pali, 193. 

 Pallial bay, 326 ; cavity, 



319. 



Pallium, 319. 

 Palmicellaria, 566. 

 Palmyra, 478. 

 PaloLa, 481. 

 Palpacles, 139, 151. 

 Pal} of Polychaeta, 459. 

 Palpon, 138, 139. 

 Paludicella, 556, 567. 

 Paludina, 363, 376, 380, 



381, 383, 395, 399. 

 Paludomus, 399. 

 Palytboa, 189. 

 Panartus, 23. 

 Pandaea, 131. 

 Pandora, 349. 

 Pandorina, 32. 

 Panthalis, 478. 

 Paper-nautilus, 446. 

 Papyrula, 94 

 Paractidae, 188. 

 Paractiuia, 187. 

 Paractis. 187. 

 Paractius, 480. 

 Paradrilus, 511. 

 Paragastric canal, 201. 

 Paragorgia. 182. 

 Paralcyoniuin. 179. 

 Paramenia, 355. 

 Paramaecium, 40, 47. 

 Paramoeba, 29. 

 Paramuricea, 182. 

 Paramylum, 28. 

 Paranepbtbya, 179. 

 Parantipatbes, 190. 

 Paranthus, 187. 

 Parapedal commissure, 



409. 



Paraphellia, 187. 

 Parapodium, 357, 458. 

 Paraseison, 310. 

 Parasmilia, 195. 

 Parasitic Gastropoda, 



386,402; Lamellibran- 



cbiata, 345 : Mollusca, 



323. 



Parazoantlms, 189. 

 Parenchyma, 209, 211. 

 Parenchymalia, 92. 

 Parenchytraeus, 509. 

 Parendrilus, 511. 

 Parieto- vaginal muscles, 



550. 



Parisis, 182. 

 Parmacella, 416. 

 Parmopborus, 361, 395. 

 Parmula, 96. 

 Paroral cilia, 49. 

 Partbenogenesis, 70. 

 Partbenogonidium, 32. 

 Pasythea, 564. 

 Patella, 360, 362, 367, 



369,371.372,374,376, 



380, 385, 394. 

 Patellina, 14. 

 Patera, 167. 

 Pavonaria, 181. 

 Pavoniiia, 13. 

 Peacbia, 188. 

 Pearl oyster, 327, 346. 

 Pearly-nautilus = 



Nautilus. 



Pebrin-disease, 64, 68. 

 Pectantbis, 135. 

 Pectantbus asteroides, 



109. 

 Pecten, 331, 332, 333, 



334, 341, 342, 347. 

 Pectinaria, 462, 486. 

 Pectinatella, 568. 

 Pectinia, 195. 

 Pectinibranchiata, 395. 

 Pectinidae, 328. 

 Pectis, 135. 

 Pectunculus, 333, 345. 

 Pectyllis, 135. 

 Pedal ganglion, 31 P ; 



gland, 357. 

 Pedalion, 302, 310. 

 Pedetes, 309. 

 Pedicellina, 572. 

 Pedipes, 415. 

 Prduin, 347. 

 Pegantha, 136. 

 Pegasia, 136. 

 Pelagia, 167. 

 Pelagobia, 479. 

 Pelagonemertes, 266,270, 



271. 



Pelecypoda, 324. 

 Peiodera, 290. 

 Pelodrilus, 504, 508. 

 Pelodytes, 277, 280. 

 Pelogenia, 478. 

 Pelomyxa, 11. 

 Peloscolex, 508. 

 Pelosina, 13. 

 Pelta, 404, 405, 406. 

 Pemmatodiscus, 208. 

 Pen, 425. 



Penis, 215 ; of Gastro- 

 poda, 378. 

 Pennaria 130. 

 IVinmtula, 181. 



