INDEX 



637 



Nerve, net, 140, 464, 472, 496, 498 



ring, 181, 182, 201 

 Nerves, 161, 319, 326, 333 



cell body of, 103 



peripheral, 238 

 Nervous activities, 243, 495 

 Nervous impulse, 103, 243 

 Nervous stimulus, 243 



Nervous system, 57, 104-106, 161, 217, 238, 283, 

 333, 471-473, 495-496, 500, 574, 575 



amphibia, 375 



arthropods, 310 



ascaris, 179 



bird, 408 



cephalopods, 229 



chordate, 313, 317 



crayfish, 259 



dorsal tubular, 313 



earthworm, 238-239 



fish, 358 



fly, 283 



frog, 375-376 



Helix pomatia, 224 



honeybee, 281 



insects, 282 



mammals, 427 



mussel, 217 



nemertines, 187 



planaria, 160-162 



reptiles, 388 



rotifers, 189 



shark, 347 



snail, 223 



spiders, 304 



squid, 226 



starfish, 200-201 



termite, 283 



types of, 472 



vertebrate, 333-334 



water beetle, 283 

 Nervous tissues, 103, 123 

 Nervures, 279 

 Nesting, 503 

 Nests, birds, 419 



California bush-tit, 421 



dove, 420 



robin, 421 



Texas night hawk, 419 

 Neural arch, 323 

 Neural groove, 361, 362, 418 

 Neural tube, 323, 362, 378 

 Neurilemma, 102 

 Neurocoel, 313 



{See also Neural tube) 

 Neuroglia, 463 

 Neuromotor center, 85 

 Neuromuscular cells, 133, 471 

 Neuromuscular mechanism, 138-139 

 Neurons, 243, 472 



motor, 244 



receptor, 244 

 Neuroptera, 295 

 Newts, 370-372 



Nictitating membrane, 375, 409, 427, 547 

 Nidicolae, 420 



Nidifugae, 420 

 Night blindness, 565 

 Nighthawk, beak, 412 



nest, 419 

 Nitrogen, 19, 486 

 Nitrogen cycle, 486, 487 

 Noctiluca, 81 

 Noctiluca scintillans, 80 

 Nomenclature, 59-60, 573, 676 

 NonmeduUated nerve fibers, 103 

 Nonmetals, 8 

 Nostrils, 370, 386, 390 

 Notochord (chorda), 124, 312, 316, 318-320, 322. 



323, 342, 378, 384, 466, 575 

 Nuclear membrane, 30, 48 

 Nuclear sap, 30 

 Nucleolus, 30 

 Nucleoplasm, 29, 30 

 Nucleus, 29, 30, 31, 32, 47, 48, 64, 79, 84, 86, 102, 



114, 115, 118-121, 127 

 Nudibranchs, 225 

 Nurse bees, 298 

 Nurse cells, 113, 164, 241 

 Nymphs, 284 



Garfish, 364 

 Obelia, 152 

 Obstetrical frog, 372 

 Oceanic distribution, 531 

 Ocelli, 277, 278, 282 

 Octopus, 221, 226, 227, 229 

 Oculina, 154 

 Odonata, 294 

 Oecium, 191 

 Oil, 448 



gland, 100, 324, 413, 467 



(See also Sebaceous glands) 

 Old age, 461 

 Olfactory bulb, 346, 430 

 Olfactory cells, 151 

 Olfactory lobes, 334, 343, 346, 347, 357, 374-377, 



387, 408, 427 

 Olfactory membrane, 336, 428 

 Olfactory organ, 226, 277, 282, 336, 359 

 Olfactory sac, 342, 347, 359 

 Olfactory tentacles, 222, 223 

 Olfactory tract, 346 

 Oligochaeta, 248 

 Oligochaets, 248-249 

 Omasum, 441 

 Ommatidium, 260, 261 

 Oniscus asellus, 267 

 Ontogeny, 118, 272 

 Onychophora, 273-274, 310, 311 

 Oocyst, 89 



Oocytes, 109, 111, 112, 668, 567 

 Oogenesis, 109, 111, 112, 475 

 Oogonium, 109, 111 



Ookinete, 89 ; 



Opalina, 83 

 Opalina ranarum, 84 

 Operculum, 224, 249, 350, 352, 357, 358 

 Ophiopluteus, 210 



