INDEX 



527 



Mussel, 89 



Mutation, 285, 287, 308-312, 315, 



329, 372, 381-384 

 Mycelium, 337 

 Myoneme, 44 

 Myosin, 21 

 Myotome, 110 

 Myriapoda, 91, 92 

 Myxedema, 197 



Nail, 15, 134 



Nares; See: Nostril 



National Academy of Sciences, 424 



Natural history, 2, 3, 349 



Natural selection, 285, 374-377, 381- 

 385, 438, 473-476; See: Selection 



Nature and nurture, 312-315, 444; 

 See: Environment 



Nautilus, 86 



Neanderthal man, 427, 435, 436, 439, 

 440 



Nectar, 334 



Necturus, 118 



Needham, 220 



Negro, 299, 300 



Nemathelminthes, 79, 80, Ml 



Nematocyst, 71, 76 



Nematode, 400, 401, 477; See: Nema- 

 thelminthes 



Neolithic culture, 442-445 



Nephridiopore. 102, 103, 183 



Nephridium, 102, 103, 183, 186, 194, 

 397 



Nephrostomy 102, 103, 183 



Nereis, 81, 82, 247 



Nerve, 11, 64, 108, 134, 135, 200-216, 

 319; cell, 62, 64, 199-217; cord, 

 101-105, 108, 145; fiber, 200, 211, 

 216; impulse, 206; net, 199, 208 



Nervous system, 65, 108, 168, 199- 

 217, 269, 344; See: Nerve 



Neural, arch, 139, 140; groove, 201, 

 268, 269; spine, 139, 149; tube, 

 145, 201, 202 



Neurenteric canal, 268 



Neurology, 198 « 



Neuromotor system, 55, 199 



Neuromuscular mechanism, 199 



Neuron, 11, 62, 64, 199-211 



Neuroptera, 94 



New stone age, 442 



Newt, 117, 118 



Nictitating membrane, 357 



Nitella, 28 



Nitrate, 33, 40, 41 



Nitrite, 41, 42 



Nitrogen, 22, 41, 42, 159, 226, 403, 

 404, 417 



Nitrogen-fixing bacteria, 41, 42, 404 



Nitrogenous waste, 181-185 



Non-disjunction, 310, 311 



Nosema, 416 



Nostril, 132, 147-149, 162, 165, 

 211 



Notochord, 110-112, 133, 135, 138, 

 139, 145, 268, 269 



Noyes, 180 



Nucleolus, 19, 20, 247 



Nucleus, 10-12, 18, 19, 20, 27, 35, 41, 

 200, 239, 241, 247, 280, 390, 469 



Nurture, 312-315, 423, 424 



Nutrition, 30-45, 460; See: Metabo- 

 lism 



Nutritional chain, 336; See: Web of 

 life 



Oak, 408 



Obelia, 72, 73, 234 



Obliterative coloration, 327 



Ocellus, 93, 330 



Octopus, 89 



Oil, 386, 388 



Old stone age, 438-442 



Olfactory, cells, 211; lobes, *47, 148, 



202-205; nerves, /46V pouches, 211; 



pit, 270 

 Oligocene epoch, 359, 362, 363, 430 

 Oligochaeta, 81, 477 

 Ontogeny, 366; See: Embryology 

 Oocyst, 340 

 Oocyte, 245-247 

 Oogenesis, 245-248, 305 

 Oogonium, 239, 243-245, 275 

 Ookinete, 340 



Operculum, 114, 115, 270, 271 

 Opossum, 127 

 Opsonin, 343 

 Optic, cup, 214; capsule, 142: lobe, 



146, 147, 203, 204; nerve, 146, 148, 



205, 214-216; vesicle, 2*4, 215 

 Oral arm, 74 



Orang-utan, 427, 428, 431 

 Orchid, 334 

 Order, 352, 353 

 Order of nature, 227, 388 

 Organ, 3, 65, 104; systems, 65, 104 



