Myology, Comparative, 23. 

 Myomeres, 336,433 ; of Am- 



phioxus, 438. 



Myomorphi, v. Mus, Lepus. 

 Myopsidae, 465. 

 Myriapoda, 514-519. 

 Mytilacea, 490. 

 Myxamoeba, 908. 

 Myxastrum, 916. 

 Myxine, 437. 

 Myxodictyum, 916. 

 Myxosporidia, 863. 

 Myzostomidae, 575, 609. 



N. 



Nacre, 109. 



Narcomedusae, 749 ; deve- 

 lopment, 752 ; 776. 

 Nassellaria, 883. 

 Natantia=Heteropoda, 482. 

 Nauplius, 172, 304, 305, 538. 

 Nautiloidea, 464. 

 Nebela, 898 n, 905. 

 Nectocalyces, 771. 

 Needham's sac, 463. 

 Nematobothrium, 654. 

 Nematocysts, 241, 330-332. 

 Nematoda, 676-688. 

 Nematogen, 815. 

 Nematophores, 758. 

 Nemertea, 635-641. 

 Neocrinoidea, 576. 

 Neomeniae, 469. 

 Nephridium of Helix, no, 



112; Anodonta, 133, 134; 



of Unio, 292 ; Lumbricus, 



204 ; Hirudo, 222, 223. 

 Nephrostomata, Anodonta, 



134 ; Vertebrata, 355. 

 Nereis, eye, 599. 

 Nerve-eminences of Pisces, 



410; of Cyclostomi, 433. 

 Nerve sacs of Ganoidei, 410. 

 Nervi transversi s. respira- 



torii, 149. 

 Nervures, 156. 

 Nervus recurrens, 139, 143. 

 Nettle-bulbs, nettle-whips, 



783. 

 Neural arch, 339 ; of Pisces, 



414 ; of Cyclostomi, 434. 

 Neural gland, Ascidia, 103, 



105 ; of Urochorda, 442. 

 Neural pore of Amphioxus, 



438 ; of Urochorda, 442. 

 Neurapophyses, 340. 

 Neurochord, xvi, 212, 598. 

 Neuroptera, 510. 

 Nictitating membrane, 74, 



346, 363 ; of Pisces, 419. 

 Noctihtca, 852. 

 Non-deciduate placenta, 367. 



INDEX. 



Non-palliata, 483. 



Non-ruminantia, 368. 



Notochord, 334, 337 ; of 

 Pisces, 414; of Cyclosto- 

 mi, 434 ; of Urochorda, 

 442 ; so-called, of Entero- 

 pneusta, 590, 592. 



Nototrochae, 606. 



Nuchal gland of Crustacea, 



533- 



'Nuclearia, 916. 

 Nucleus, xxi, xxii ; of Shell, 



107 ; of Salpa, 444 ; pul- 



posus, 59. 



' Nucleus de reliquat,' 859. 

 Nucula, gills, 488. 

 Nummulinidae, 895. 

 Nyctotherus, cytopyge, 833. 



O. 



Obtected, v. Pupa. 



Ocellatae, 247. 



Ocellus, 150, 501, 502. 



Octactiniae, v. Alcyonaria. 



Octopoda, 465. 



Ocular canal, 96. 



Odonata, 509. 



Odontoid process, Amphibia, 

 397- 



Odontolcae, 380. 



Odontophore, 115, 452. 



Odontotormae, 381. 



Oegopsidae, 465. 



Oesophagus, Sauropsidan, 

 48. 



Olfactory organ, Teleostei, 

 86. 



Oligochaeta, 610 ; v. Lum- 

 bricus. 



Oligosilicina, 810. 



Omentum, 3. 



Ommastrephes, 465. 



Ommateum, 492. 



Ommatidium, 492. 



Omostegite, 162. 



Omphalo-mesenteric duct, 

 358. 



Onchidium, eyes of, 45 1, 477 ; 

 tentacles, 120. 



Onychophora = Protrache- 

 ata. 



Ooecium, 237, 



Oosperm, xxv. 



Ootype of Trematoda, 647. 



Opalina, 75, 836. 



Opercular gill, 422. 



Operculum of Mollusca, 455 ; 

 of Anisopleura, 473 ; of 

 Serpula, 595 ; of Pisces, 

 414 ; of Teleostei, 93 ; 

 Flustra, 234. 



302 



93 1 



Ophidia, 391 ; v. also Tropi- 



donotus, Python. 

 Ophiurida, 569. 

 Ophiuroidea, 567-570. 

 Ophryocystis, 862. 

 Opisthobranchia, 483. 

 Opisthocoelous,vertebra,34O. 

 Optic chiasma, 345. 

 Orbitolites, 886 n, 892 n. 

 Orbulina, 892 n. 

 Oreocephalus cristatus, 39 1 . 

 Organ of Bojanus, 133. 

 Ornithodelphia = Proto- 



theria. 



Ornithopoda, 392. 

 Ornithorhynchidae, 370. 

 Ornithosauria, 392. 

 Ornithoscelida, 392. 

 Orthonectida, 813. 

 Orthoptera, 510; v. Peri- 



planeta. 



Orycteropus, placenta, 367. 

 Os acetabuli, 65. 

 Os centrale, v. Carpus. 

 Oscarella, brood-buds, 805. 

 Osculum, 249, 793, 803. 

 Osphradium, Helix, 122 ; 



Anodonta, 136 ; Mollusca, 



451- 

 Ossicles of stomach, Astacus, 



187 ; of Asterias, 190, 191, 



193- 



Ostracoda, 539. 



Ostrea, figures, etc., 288-291. 



Otocyst, Helix, 122 ; Ano- 

 donta, 137 ; 452, 599, 615, 

 669, 672, 701, 749, 761. 



Otolith, 347, v. Otocyst. 



Otoporpae, 750. 



Oviducts, Teleostei, 89 ; Ver- 

 tebrate, 356. 



Ovoid gland of Echinoidea, 



559- 



Ovo-testis, 113, 117. 

 Ovum, xxiii. 



P. 



Paedogenesis of Amphibia, 

 408 ; of Pisces, 429 ; of 

 Insecta, 507, 514. 



Palae angulares, 568. 



Palaeo-crinoidea, 576. 



Palaeo-echinoidea, 561. 



Palaeonemertea, 641. 



Palaeostoma, 556. 



Palapteryx, 380. 



Pallial line, 125, 485. 



Palliata, 483. 



Pallium, 128. 



Palpocil, 806. 



Palpus, 140. 



Pancreas, Teleostei, 87 ; 



