INDEX. 



Needham's sac, 439. 



Nellia, 565. 



Nemathelniinthes, 273. 



Ni'inatobothrium, 240. 



Nematocyst, 39, 101,211 ; 

 in Mollusca, 412. 



Xematoda, 274. 



Nematogen, '_'42. 



Xematomorpha, 292. 



Nematoiiereis, 481. 



Nematophore, 126. 



Nematoxys, 284. 



Nemertea, 263. 



Nemertodrilus, 511. 



Xrmertnpsis. 271.' 



Nemopsis, 131. 



Neohelia, 195. 



Neomenia, 355. 



Neopelta, 94. 



Xeorhynchus, 296, 297. 



Xeosiphonia, 94. 



Xleottis, 485. 



Xq.helis, 518, 519, 523, 

 524. 526. 



Nephridia, 450 ; megane- 

 phric, 498 ; plectone- 

 pln-ic, 500; rectal, 502; 

 pi-pto-. 450. 



Nephridial coeloivi, 314. 



Nephridiopore, 314. 



Nephridium of Gastro- 

 poda, 376; Polyzoa, 

 553. 



Xephroselmis, 32. 



Nephtliya, 179. 



Nephthys, 459, 475, 

 480. ' 



Xcreidifoniiia, 475. 



Xereilepas, 479. 



Nereis, 465, 468, 471, 

 473, 479. 



Xnilla, 476. 



Nerinaea, 399. 



Xerine, 475, 483. 



Nerita, 361, 380, 395. 



Xeritina, 395. 



Xeritopsis, 395. 



Xcrve cells, 100. 



Nerves in Medusae, 114. 



Nethea, 94. 



Nenro podium, 460. 



Nicidion, 481. 



Xk-olea, 485. 



Nicomaclio. 488. 



Nidalia, 179. 



Nidamental "lands, 440. 



Kitzschia, 234. 



Noctilnca, 35, 37. 



Xodosaria, 14. 



Nonionina, 15. 



Xotamia, 565. 



Xotarchus, 357, 362, 



407. 



Notaulax, 491. 

 Noteus, 310. 

 Notholca, 310. 

 Notobranchaea, 374,408. 

 Notocirrus, 481. 

 Notocotyle, 240. 

 Notonuistus, 486. 

 Notommata, 300, 309. 

 Notophyllum, 479. 

 Xotopodimu, 460. 

 Notops, 309. 

 Notopygos, 462, 480. 

 Nototrochus, 194. 

 Notykus, 511 

 Xuliecularia, 13. 

 Nuclial cirrus, 481. 

 Xuclearia, 19. 

 Nucleus of operculurn, 



361. 

 Nucula, 328, 331, 336, 



337, 345. 

 Xnculidae, 341. 

 Nudibranchiata, 409. 

 Xullipore, 171. 

 Xummulites, 10, 15. 

 Nutrition of Sponge, 80. 

 Nyclna, 478. 

 Nyctotherus, 38, 48. 



Ohelaria, 134. 

 Obelia, 132. 134. 

 Oceanapia, 96. 

 Ocelli medusae, 116. 

 Ocnerodrilus, 510. 

 Octobothrium, '226, 235. 

 Octocanna, 134. 

 Octochaetus, 501, 502, 



505, 511. 

 Octomeralia, 166. 

 Octonenia, 134. 

 Octophellia, 188. 

 Octopoda, 321, 445. 

 Octopus, 433, 440, 446. 

 Octorchandra, 134. 

 Octorchidium, 134. 

 Octorchis, 134. 

 Oculina, 195. 

 Ocyroe, 208. 

 Odontobius. 291. 

 Odontocyathus. 194. 

 Odontophora, 291, 320. 

 Odontophore, 320, 369. 

 Odontosyllis, 476. 

 Odostomia, 377. 

 Oecistes, 308. 

 Oegopsida, 420, 438, 445. 

 Oerstedia, 271 ; pallida, 



268. 

 Ogmogaster, 240. 



2 R 



Oikomonas, 30. 



Oligocelis. 221. 



Oligoceras, 98. 



Oligochaeta, 493. 



Oligocladus, 223. 



Oligognatlius, 471. 



Oligonema, 17. 



Oligosilicina, 95. 



Oligosporea, 61. 



Oligotricha, 49. 



Olindias, 135. 



Oliva, 386, 397. 



Olivancillaria, 397. 



Olivella, 356, 361, 397. 



Olullanus, 235. 



Olynthus, 75, 89. 



Omalostomum, 219. 



Ominatostrephes, 444. 



Omphalopoina, 491. 



Omphalopomopsis, 491. 



Onchidiopsis, 377, 398. 



Onchidium, 368, 378, 

 385, 414, 416. 



Onchnesoma, 537, 539. 



Onchobothrium, 259. 



Oneliocotyle, 236. 



Oncholaimus, 291. 



Onchopora, 565. 



Onchoporella, 565. 



Onchosphere, 251. 



Onchotrochus, 194. 



Onuphis, 481. 



Onychocliaeta, 511. 



Onychodactylus, 46. 



Onychodronius, 49. 



Onychoteuthis, 421,445. 



Oocorys, 400. 



Ooecium, 550. 



Ootype, 226. 



Opalina, 40, 41, 48. 



Opalinopsis, 47. 



Opercularia, 51. 



Operculina, 15. 



Operculurn of Gastro- 

 poda, 357, 361 ; of 

 Polyzoa, 550. 



Ophelia, 467, 487. 



Opbioides, 132. 



Ophiodiscus, 187. 



Ophiodromus, 477. 



Ophrydium, 51. 



Opliryocystis, 69. 



Ophryodendron, 54. 



Ophryoglena, 47. 



Ophryoscolex, 49. 



Ophryotrocha, 481. 



Opisthobranohiata, 403 



Opisthobranchiate, 374. 



Opisthodon, 46. 



Opisthotrenia, 240. 



Opistomuin, 220. 



