INDEX 



5.5.5 



Myxosporida, 35. 

 Myzostoma, 141. 

 Myzostomida, 141. 



reous layer, of shells, 228. 

 1 haje, 318; N. tripudians, 318. 

 ition.sn. 



Narwhal, 374. 



Nasal bone, of fowl, 331. 



i eapsule, of lamprey, 273. 

 openings, of Cetacea, 373. 



Natica heros, 236. 



Natural barriers, 469. 



Natural selection, 460, 463, 485 ; objections 

 to theory of, 468; suggested by Darwin, 

 509; by Matthew, 509; by Wells, 509. 



Nauplius larva, 149. 



Nautiloids, 422, 424. 



Nautilus, pearly, 254 ; paper, 257. 



Nautilus pompilius, shell, 254. 



Nearctic region, 452. 

 lia geoffroyi, 160. 



\< 1 tocalyx, 70, 71. 



Necturus maculatus, 303. 



Nekton, 447,451. 



Nemathelminthes, 120. 



Nematocyst, 60, 62. 



Nematoda, 120, 451. 



Nemerteans, same as Nemertina, q.v. 



Nemertes neesii, 117. 



Nemertina, 116, 447, 451. 



Nemertini, same as Nemertina, q.v. 



Neo-Lamarckism, 460. 



Neo-tropical region, 454. 



Nephridia, 135; of Amphioxus, 269; of 

 Brachiopoda, 133; of Hirudinea, 144, 

 145; of Nemertina, 119. 



Neptune's cup, 56. 



Nereis dumerilii, 135, 136. 



Nervous system, of Mammalia, 358. 



Nests, of apes, 411 ; of birds, 335 ; of duck- 

 bill, 363; of fishes, 287,294; of orang- 

 utang, 410; of rodents, 386. 



Nettle cells, 60. 



Neural arch, 282. 



Neural spine, of frog's vertebra, 300; of 

 trout, 288. 



Neural tube, of Amphioxus, 268. 



Neural zygapophvsis, 292. 



Neuroptera, 210, 226, 227,424. 



Newt, 303. 



New World monkeys, 408, 409, 441. 



Nicothas, 155. 



Nidamental glands, 252. 



Nighthawks, 348. 



Nightingales, 355. 



Nine-banded armadillo, 372. 



Nine-eyes, 272. 



Nipple, 356. 



iluca miliaris, 43, 44. 

 turnal birds of prey, 348. 

 aria, 26. 



Non-poisonous serpents, 317. 



Non-precociou 536. 



North American flying squirrel, 388. 



North American sparrows, 355. 



Northern sea cow, 372. 



Nose-leaved bats. 397. 



\ feus, 127. 



Notholca, \2rj. 



Notochord, 259; of Balanoglossus, 261,262; 

 1 >t ( 'eph \ 260; ol lamprey, 273 ; 



of Rhabdopleura, 260; of Tunicata, 267. 



Nucleoplasm, definition of, 5. 



Nui leus, definition of, 5; role of, in germ- 

 cells, 478. 



Nudibranchia, 238. 



Number of animals, 6. 



Nummulites, 26. 



Nummulitic limestone, 27. 



Nutcrackers, 355. 



Nutria, 391. 



Nymph, of May fly, 198. 



Nymphon hispidium, 187. 



Oarfish, 296. 



Obelia, 63. 



Ocean, depths of, 444; light in, 446; pres- 

 sure in, 446; temperature of, 445. 



Oceania languida, 65. 



Ocelot, 404. 



Octocorallia, 77. 



Octopoda, 256. 



Octopus, 257, 258. 



Octopus punctatus, 258; 0. vulgaris, 258. 



Ocular plates, 97. 



Oi i/!i/ia, 75. 



Odd-toed Ungulata, 377. 



Odonata, 226, 227. 



Odontolca;, 429, 430. 



Odontophore, 231. 



Oil gland, of pigeon, 333. 



Old World monkeys, 408, 409, 435. 



Olfactory capsule, of frog, 300. 



Olfactory lobe, of frog, 301 ; of dogfish, 277 ; 

 of roach, 286. 



Olfactory organ, of Mammalia, 357. 



Olfactory pit, of Amphioxus, 269. 



Olfactory sac, of lamprey, 273. 



Oligochaeta, 139, 451. 



Oligolophus spinosus, 181. 



Omo-sternum, of frog, 301. 



Oncorhynchus tchawytcka, 291. 



Ontogeny, definition of, 513. 



Onychophora, 188. 



Ooecium, 130. 



Operculum, of Bryozoa, 129; of Dipnoi, 

 297 ; of fishes, 275 ; of Gastropoda, 232, 



