Index 



731 



Nerve tracts, intracentral, 359 

 Nervous system, cholinesterase ac- 

 tivity of, 546, 547 

 development of, 346-401 

 in amphibian limb regenera- 

 tion, 685 

 Neural antigens, 370 

 Neural arches, segmental arrange- 

 ment of, 372 

 Neural axis and primitive streak, 



307 

 Neural crest, 370, 371 

 dermis and, 500, 501 

 induction of, 254—255 

 morphogenesis of, 372 

 oral ectoderm and, 455 

 skin pigment cells and, 502, 



503, 513 

 visceral arch and, 455 

 Neural epithelium, defects in, 379 

 diversity within, 380 

 precursor cells in, 379 

 Neural plate. 370, 371, 374, 387 

 folding of, 370, 379 

 localization of, 307, 308 

 Neural tube, 359, 370 

 Neuroblasts, 348, 379, 381, 382 



cytoplasm of, 350 

 Neurofibrils, 376 

 Neurogenesis, 346-401 



nutrient requirements in, 388 

 nutritional deficiencies in, 366, 

 372, 388 

 "Neuromas," 350 

 Neuromuscular activity and cho- 

 linesterase development, 546, 

 547 

 Neuron growth, 389 



biochemistry of, 365-366 

 factors controlling, 365 

 Neuronal connections, precise pat- 

 terns of, 387 

 Neurons, 350-370, 381-383, 385 

 cathodal site of, 356 

 commissural, 377, 380 

 intracentral, 363 

 "overloaded," 365 

 pools of, 392 

 size of, 365 

 size classes of, 365 

 specificity of, 347 

 Neuropil, 347, 352, 360 



density of, 370 

 Neurosecretions, 347 

 Neurosecretory cells, brain hor- 

 mone of, 640 

 of insects, 637 

 Neurotropism, 356-358 

 Neurula, heterotropic grafts of, 

 378 

 inductive capacity of mesoderm 



in, 250-252 

 organization of, 247-250, 252- 

 254 

 Neurulation, 370-371 



Node of Ranvier, 361, 367, 368 



Noradrenaline, 590-591 



Nose, 362 



cartilage formation of, 424 

 nerve fiber origin of, 424 

 organogenesis of, 423^24 

 prospective areas of, 415, 416 

 sensory epithelium of, 424 



Notochord, 309, 371, 373 



abnormalities in amphibian 

 metamorphosis, 707, 708 



Nucleic acids, in induction, 569 



Nucleus, 364, 365, 367, 376 

 development and, 129-147 

 differentiation of, 146 

 enlargement of, 365 

 transplantation of, 146 



Observation vs. interference, 26- 

 31 

 limitations to interpretation 

 from, 26-28 

 Boveri on, 32 

 Odontoblasts and dentin forma- 

 tion, 494, 496 

 "One-center effect," 354 

 Ontogenesis, enzymes in, 543-548 



differentiation and, 545-548 

 Ontogeny of immunological prop- 

 erties, 556-573 

 Oocyte, growth of, 177-180 



nucleoprotein absorption of, 



179-180 

 nurse cells of, 179-180 

 source yolk constituents of, 177- 

 179 

 Optic centers, 380 

 Optic chiasma, 360 

 Optic nerve, 362 

 aberrant, 383 

 fibers of, 383, 385 

 deflection of, 360 

 Organ, supernumerary, 381 

 Organ fields in insects, 340, 341 

 Organ growth, self-regulation of, 



113 

 Organ-forming area, 309 

 Organization, colloidal state of, 

 41 

 fibrous pattern of, 59-60 

 of gastrula, 238-243 

 of insect egg, 337 

 molecular level of, 27 

 new approach to, 30 

 problem of, 29, 30 

 segmental, 378 

 Organizer, 243-247, 279-282 

 extent of, 246 



field properties of, 279-281 

 in regeneration, 668 

 regional differences of, 245-247, 

 250-252 

 Organogenesis of blood vessels, 

 450-452 

 of ear, 415-423 



Organogenesis of entodermal de- 

 rivatives, 453-458 



of eye, 402-414 



of heart, 440-450 



of limb and girdle, 429-439 



of nervous system, 346-401 



of nose, 423-424 



of skin and derivatives, 499-519 



of teeth, 492-498 



of urinogenital system, 462-491 

 Orientation, 359 



fibrillar, 354 



mechanism of, 351-356 



of nerve, 351, 353 

 Otocyst, determination of, 258 



induction of, 308 

 Oviduct, origin of, 469 

 Oxygen in development, 522-528 



Pancreas. See Liver-pancreas. 

 Pangenesis, early theories of, 2 

 Parasympathetic neurons, 382 

 Parathyroid glands, 611-614 

 bone development and, 613 

 chief cell origin in, 611 

 fetal regulation of calcium 



level and, 612 

 indices of functional activity 

 of, 611,612 

 Parthenogenesis (artificial), 201, 

 202, 203 

 activation of, 202-203 

 chromosome numbers in, 201 

 of non-nucleated egg frag- 

 ments, 201 

 origin of cleavage amphiaster 



in, 201 

 sex and, 202 

 Parthenogenetic merogony, 217, 



218 

 Pathway structures, 362 

 Pathway systems, 354, 356, 359, 



360 

 Pathways, nerve, 356, 358, 360, 

 361 

 preneural, 361-362 

 specificity of, 361 

 Patterns, nerve, 359 

 structural, 354 

 Pectoral girdle, chondrogenesis of, 

 434 

 limb disc removal on, 434 

 localization of parts of, 434, 



435 

 mosaic character of, 434, 435 

 Pelvic girdle, 435-436 

 Perikaryon, 346, 347, 349 

 Peripheral innervation, density of, 



367 

 Pharynx, 362 

 Phase-specific changes, 388 

 Phenocopies of hereditary abnor- 

 malities, 702-703, 706 

 Phenocritical periods in terato- 

 genesis, 702 



