NO. 4 NERVOUS SYSTEM OF A CENTIPEDE — LORENZO 2$ 



cells (pi. 5, fig. i) which may be confused with neuroglial or peri- 

 lemmal elements. These cells adhere to the surface of the tracheoles 

 and may be observed at the site where certain nerves (e.g., N14 and 

 N17) emerge from the central neural mass. 



3. The nenropile. — The histology of the neuropile is more revealing 

 in the present study than is that of the cortex. The three neuromeres 

 of the brain of bipuncticeps are easily homologized with these entities 

 as they are exhibited in other arthropods by a study of the neuropile. 

 The limits and extent of the protocerebrum, deutocerebrum, and trito- 

 cerebrum are poorly outlined in gross dissections as they are extremely 

 reduced. Silver impregnations reveal, however, that the medullary 

 substance is arranged according to a definite pattern, and the apparent 

 radical departure of the geophil brain from the typical arthropod plan 

 is clarified. 



The protocerebrum is identifiable by the presence of the "frontal 

 lobes." These lobes are weak, lateral outbulgings of the neuropile 

 (pis. 3 and 4). The deutocerebrum is represented by the antennal 

 lobes situated anteriorly. These are two bilaterally symmetrical bodies 

 which are separated by an area of cortical cells located in the midline 

 for the major portion of their extent (pi. 2, fig. PI [AL]). Only a 

 microscopical study reveals this separation. The deutocerebrum is 

 ventral to the protocerebrum posteriorly and is continuous with the 

 tritocerebrum and the circumesophageal connectives. Fibers inter- 

 connect each of these neuromeres and distinct fiber tracts are traceable. 



In naming the fiber bundles in the brain of bipuncticeps we have 

 attempted to recognize homologies with the entities previously de- 

 scribed in other centipedes. Invention of a new terminology would 

 be confusing and tends to overlook the significance of biological af- 

 finity. The names employed are subject to correction if additional in- 

 formation makes this necessary. 



The fiber groups in the brain of bipuncticeps were carefully studied 

 with the intention of determining probable interconnections and spa- 

 tial interrelations before names were assigned. This appeared to be 

 the only logical approach to the problem. If it be assumed that the 

 supraesophageal ganglion of this centipede is homologous with that 

 of Thcreuopoda, whose tracts were studied by Fahlander, then some 

 order can be found in the neuropile of the geophil brain. 



The head of the scutigeromorph is roughly globose, resembling in 

 certain respects the head of an insect ; the head of bipuncticeps, how- 

 ever, is extremely compressed dorsoventrally. If one imagines the 

 ventral portion of the brain of the scutigeromorph to be shifted pos- 

 teriorly and the dorsal portion anteriorly, and the relocated structures 



