INDEX 



579 



64; of Hydra, 266; localization of 



functions in, 115, 117; of locust, 



353, 358, 359; peripheral, 63, 115; 



of vertebrates, 106. 

 Nervous tissue, 107, 140, 148. 

 Neural crest, 416, 429. 

 Neural fold, 410, 411, 412, 429. 

 Neural groove, 410. 

 Neural transmission, 317. 

 Neural tube, 399, 410, 412, 429. 

 Neurenteric canal, of frog, 411. 

 Neuroid transmission, 316. 

 Neuromotor system, in Protozoa, 182, 



183, 194, 315. 

 Neuromuscular junction, 108, 127. 

 Neurone, 107, 148, 149; adjuster, 110, 



122, 299, 317, 318; motor or 



efferent, 108, 299; sensory or 



afferent, 108. 

 Neuroptera, 374. 

 NoctUuca, 175. 

 Non-striated muscle, 140. 

 Notochord, 11, 429; of Amphioxus, 



398; of frog, 409, 412. 

 Nuclear membrane, 135. 

 Nucleolus, 135. 

 Nucleoplasm, 135. 

 Nucleus, 132, 134, 135, 136. 

 Nummulites, 165. 

 Nutrition, 76; holophj'tie, 170; holo- 



zoic, 170; saprophytic, 171. 



Ohelia, 274, 275, 277. 



Ocellus, 312, 348, 361, 362. 



Odonata, 374, 378. 



Olfactory lobes, 65, 120, 416. 



Oligochaeta, 310, 311. 



Ontogeny, 506. 



Onychophora, 241, 339. 



Oogenesis, 228, 229; significance of, 



230. 

 Opalina, 189. 

 Operculum, 45, 415. 

 Ophiuroidea, 241. 

 Opossum, 434. 

 Optic chiasma, 65, 120. 

 Optic ganglion, of locust, 358. 

 Optic lobes, 65, 416; functions, 119. 



Optic vesicle, 413. 



Oral-aboral differentiation, 244. 



Oral appendages, of crayfish, 323; of 



locust, 346; see also Mouth parts. 

 Organic Evolution, 3, 6, 489, 494; 



evidence for, 497; fact, course and 



cause of, 494; genetics in relation 



to, 485; theories of causes, 539; see 



also Evolution. 

 Organismal Theorj-, 133, 194, 217. 

 Organization, of animal body, 243; 



internal, 288, 330, 352; types of 



internal, 244, 245; see also Body 



plan. 

 Organs, 149. 

 Organ-systems, 149; of vertebrates, 



50. 

 Origin of hfe, 489. 



Origin of species by Natural Selec- 

 tion, 546. 

 Ornithorhyncus anaiinus, 29, 433. 

 Orthogenetic theory of causes of 



evolution, 561. 

 Orthoptera, 344, 373, 377. 

 Ostia, of locust, 356; of crayfish, 331. 

 Ostracoda, 336. 

 Ovarj-, of birds, 426; of earthworm, 



2%; of frog, 47, 52, 54, 400, 401; 



of Hydra, 270; of locust, 358. 

 Oviduct, of birds, 426; of earthworm, 



283, 296; of frog, 54, 400; of 



locust, 358. 

 Ovipositors, of locust, 347, 369. 

 Ovisac, 55, 401. 

 Ovo\aviparous development, 421, 



423. 

 Ovulation, in frog, 400. 

 Ovum, 223, 229, 231; of frog, 54, 400, 



401, 402. 

 Oxytricha, 190. 



Psedogenesis, 220. 

 Pagurus, 335. 

 PaleontologA-, 3, 5, 6, 507. 

 Palingenetic stage, 503. 

 Palps, 312, 346. 

 Pancreas, 47, 51, 83, 101, 416. 

 Pancreatic duct, 47. 



