INDEX. 



485 



Median fusion and antero-posterior degeneration, 



277 



nerve, 43 



Merochord, 328, 330 

 Merostomes, 337 

 Mesencephalon, 18, 19, 65 

 Mesencoele, 66 

 Mesocephalon, 15 

 Mesoderm, 12, 22, 426 

 lateral plates of, 231 

 sources of, 230 

 Metacephalon, 19 



Metameres, formation of, in limulus, 225 

 Metamerism, 49 

 Metencephalon, 67 



Middle cord or lemmatochord, 12, 43, 323 

 of insects, 324 

 of limulus, 334 

 of scorpion, 328 

 summary or comparison, 335 

 Monstrosities, 274 

 Mouth, 25, 26, 253, 406 



closure of, 18, 31, 249, 251 



Nauplin, 408 

 Naupula, 406, 408 

 Navel, cephalic, 238, 253, 255, 4*4 

 Neostoma, 26, 238 

 Nerves of branchiencephalon, 10: 

 branchio-thoracic, 105 

 cardiac, 200 

 circumoral, 42 

 cutaneous, 105 

 enteric, 103 

 gustatory, 84 

 hsemo-neural, 102 

 hypo-branchial, 105, 107 

 lateral line, 97 

 longitudinal abdominal, 104 

 median, 42 

 of metencephalon, 98 

 neural, 94 

 olfactory, 162 

 parietal eye, 134 

 peripheral, 44, 94 

 arrangement of, 46 

 differentiation of, 45 

 of rostrum, 43 

 Vagal, 107 

 Nerve ends, in 

 roots, 76 



haemal, 77, 8 1 

 neural, 81 



Nervous system, framework of, 43 

 specialization of, 44; 

 summary of, 209 

 Neural arches, 307, 322 

 sinus, 328 

 surface, 44 



surfaces, orientation of, 27, 221 

 Neuritemma, 325 

 Neuroblast, 52 

 Neuro-ccelia, summary of, 92 

 Neuroglia, 93, 325, 331 

 Neuromeres, 49 



branchial, cell clusters of, 73 



specialization of, 44 

 cephalic, 80 



cell clusters of, 80 

 components of, 94 



. 2 53> 



Neuropile, cardiac, 204 



centres, 79 



Neuropore, anterior, 130 

 Neurostoma, 18, 26, 31, 249, 

 Notochord, 323 



termination of, 65 



Occipital ring, 316 

 Ocelli, larval, 125, 128 

 Olfactory ganglia, 170 



lobes, 55, 160, 164, 171 



of limulus, 164 

 organ, 127, 160, 162 

 of apus, 167 

 of branchipus, 166 

 of limulus, 1 60 

 of phyllopods, 165 

 nerves, 162 

 placodes, 162, 168 

 Optic ganglia, 13, 62 

 Oral arches, 16, 4, 2 55 



development of, in frog, 257 



C1 1 rfj} Pf* ^ /\ 



Orientation'of neural and haemal surfaces, 27, 2 

 Ostracoderms, 337, 34*, 34& 



auditory organs, 356 



cephalic appendages of, 350 



cutaneous sense organs of, 356 



eyes of, 355 



historical review, 342 



muscle markings in, 346 



olfactory organs of, 356 



skeleton of, 351 



subdivisions of body, 349 



trend of development in, 341 



exosketeton of, 352 



Parietal eye, 13, 125 

 ganglion, 142 

 nerve, 134 



roots, 134 



Peribranchial chamber, 428 

 Phoroinda, 446, 447 

 Polyzoa, 440 

 Primitive cumulus, 224 



streak, 22, 246 

 Procephalon, 12 

 Procephalic lobes, 13, 3 s 

 Prosencephalon, 54 

 Psamosteidae, 366 

 Pteraspida, 364, 366 

 Pterobranchia, 439 

 Respiration, 191 

 Rhabdospleura, 440 

 Rostrum, 14, 29 

 nerves to, 43 



Saccus vasculosus, 18 

 Segmental sense organs, 17 

 Sense buds, cell division of, 51 



primitive, 50 



organs, 13, no 



auditory, 120 



branchial warts, 115 



general cutaneous, no 



lateral line, 121 



primary, 38 



slime buds, 17, n6 



special cutaneous, in 



summary of, 209 



