340 



INDEX AND GLOSSARY 



Nervous system, peripheral, 106 

 phylogeny of. See Nervous sys- 

 tem, evolution of. 

 physiology of, 96 

 segmental. See Segmentation 



and Segmental apparatus, 

 subdivision of, 106, 115-123 

 sympathetic, 53, 65, 76, 89, 93, 

 106, 107, 125, 126, 147, 148, 

 150,211,224-233,234,241, 

 242, 255, 259 

 peripheral autonomous part, 



225, 227 

 synaptic, 53 

 vertebrate, 29, 106 

 Neural canal. See Canal, neural, 

 groove (medullary groove), the 

 trough-like form assumed by the 

 Neural plate during its in- 

 \ -agination to form the Neural 

 tube. 



plate, a thickened plate of Ecto- 

 derm in early vertebrate em- 

 bryos from which the Neural 

 tube develops. 



tube, the embryonic central ner- 

 vous system when in the form 

 of an epithelial tube, 106, 116, 

 126, 160, 181 

 Neurasthenia, 103 

 Neuraxis, the central nervous sys- 

 tem; and also applied to the 

 Axon. 



Neuraxon. See Axon. 

 Neurenteric canal, in the embryo, a 

 communication between the 

 raudal end of the Neural tube and 

 tin' digestive tract. 

 Neurilemma, the outer sheath of a 



peripheral nerve-fiber, 40, Hi 

 Neurite. See Axon. 

 Neuroblast, an immature nerve cell, 



:;'.. 45 



Neurocyte. See Neuron. 

 Neurofibrils, delicate protoplasmic 

 fibrils within the cytoplasm of the 

 Neuron, 40, 46, 47| 102 

 Neuroglia (glia), a supporting fabric 

 of cells and horny fibers pervad- 

 ing the central nervous system, 38, 

 101. 190, 20.-,, 206,269 

 Neurogram, 295 



Xeuromasts. See Organs, lateral 

 line. 



Neuromere, one of the segments of 



the embryonic Neural tube. 

 Neuron (neurocyte), a nerve cell; 

 cf. Cell, 38, 40, 41, 42, 49, 56, 96, 

 190, 268, 269, 270, 274 

 afferent, 42 

 bipolar, 44, 45 

 correlation, 133, 134, 158 

 efferent, 42 



fatigue of, 96, 101, 102 

 of first, second, etc., order, 42 

 multiform, See Neuron, poly- 

 morphic, 

 polarization of. See Polarity of 



the Neuron. 



polymorphic, 268, 269, 274 

 postganglionic, an efferent sym- 

 pathetic neuron which is ex- 

 cited by a preganglionic Neuron, 

 94, 126, 146, 147, 229, 231, 235, 

 238, 239. 244 



preganglionic, an efferent sympa- 

 thetic neuron whose cell body 

 lies in the central nervous sys- 

 tem, 93, 126, 146-14S, i;,(), 229. 

 231, 234, 235, 23S, 239, 241, 244 

 pyramidal, of cerebral cortex, 42, 



44, 269, 270, 274, 290 

 retraction of, 103 

 type I, 43, 44, 190 

 type II, 43, 44, 190, 268, 269 

 unipolar, 45 

 Neurone. See Neuron. 

 Neuropil (molecular substance, dot- 

 ted substance), an entanglement 

 of unmyelinated fibers containing 

 many synapses, 65 

 Neuropore, in the embryonic brain 

 an opening between the anterior 

 end of the neural Canal and the 

 exterior, 116 

 Nicotin, 231 



N id ul us. See Nucleus (2). 

 Nidus, a depression on the ventral 

 surface of the cerebellum; also 

 used as a synonym for Nucleus 

 (2), ins 

 NlSSL, F., 42, 46, 55,274 



bodies of, granules of, substance 

 of. See Substance, chromo- 

 philic. 



Nociceptor, a sense organ or Recep- 

 tor which responds to injurious 

 influences. 



