INDEX 



631 



Nemathelminthes, 412 



Xematocyst, 300, 311, 317 



Xephridiopore, 341 



Nephridium, 146, 340, 406, 421, 

 424, 600 



Nephrostome, 98, 145 (Fig. 46), 

 146 (Fig. 47), 340, 424, 601 



NEREIS : occurrence and gene- 

 ral characters, 350 ; parapods 

 and setae, 350-352 ; sense- 

 organs, 353 ; trochosphere 

 larva, 354 ; practical direc- 

 tions, 359 



Nerve-cells, 167, 303, 318, 343 



Nerve-collar, 342 



Nerve-cord, ventral, 342, 379 



Nerve-fibres, 167 



Nerve-foramina, 495 ; and see 

 Skull and Vertebral column 



Nerve-ganglia, 162, 163, 164, 

 167, 342, 379, 408, 592 



Nerve-plexus : brachial, 161, 

 532 ; coeliac, 533 ; sciatic or 

 lumbosacral, 162, 532 



Nerve-roots, 163, 425, 461, 532 



Nerves : afferent and efferent, 

 166, 175 ; cerebral, 163, 461, 

 532, 592 ; of lateral line, 463 ; 

 motor and sensory, 162, 169 ; 

 phrenic, 532 ; sciatic, 62, 162, 

 532 spinal, 160, 425, 461, 



532 sympathetic, 162, 461, 



533 vaso-motor, 174 ; visce- 

 ral, 380 



Nervous impulse, 62, 154 



Nervous system : Frog, 155 ; 

 Hydra, 303 ; Obelia, 318 ; 

 Earthworm, 342 ; Cravfish, 

 379 ; Mussel, 408 ; Lancelet, 

 424 ; Dogfish, 459 ; Rabbit, 

 528 ; development of, in 

 Vertebrates, 588 



Neural arch, spine, and canal, 

 see Vertebra 



Neural cord and plate, see 

 Medullary cord 



Neural crest, 592 



Neural plate and process, 440 



Neuraxis, 167 



Neurenteric canal, see Canal 



Neurocoale, 459 ; and see Canal, 

 central of spinal cord, and 

 Ventricles of brain 



Neuroglia, 169 



Neurolemma, 167 



Neurone, 167 



Neuropod, 351 



Newt, 218 



Nictitating membrane, 5, 486 



Nodes of nerve-fibre, 167 



Nose, see Olfactory organ 



Nostrils, 4, 17, 180, 432, 464, 487, 



534 

 Notochord, 203, 419, 441, 580, 



604 



Notopod, 351 

 Nuclear division, 560 ; indirect 



and direct, 563 

 Nuclear membrane,~559 ; spindle, 



560 

 Nucleolus, 109 ; and see under 



Nucleus 



Nucleoplasm, 599 

 Nucleus, 106 et seq., 129, 231, 



243, 254, 265, 269, 280, 286, 



559, 507. 569 



Nucleus, conjugation-, 268 ; seg- 

 mentation-, 572 



Nutrition, 67 ; and see under 

 various types 



O 



OBELIA : occurrence and general 

 characters, 309 ; microscopic 

 structure, 311 ; structure of 

 medusa, 314 ; nervous system, 

 318 ; lithocysts, 315 ; repro- 

 duction and development, 320 ; 

 alternation of generations, 

 321 ; practical directions, 325 



Occipital condyle, see Skull 



Ocellus, see Eye-spot 



Odontoblasts, 415 



Odontoid process, 499 



(Esophageal glands, see Calcifer- 

 ous glands 



(Esophagus, see Gullet 



Olecranon, 49, 502 



