JOUKNAL, OF ENTOMOLOGY AND ZOOLOGY 197 



ganglia of Phalangium as described by Loman '05 seem to re- 

 semble the peripheral masses of Chelifer although they seem to 

 be more caudal in position. 



In addition to these cells and irregular masses about the 

 central system there are a number totally or partially surround- 

 ing the mandibular nerve some distance from the brain. 



There are scattered cells, apparently nerve cells, under the 

 hyi^odermis and some of these may be similar to the peripheral 

 plexus described in insects. Methylene blue used repeatedly 

 failed to demonstrate such a plexus however. 



Nerve Cells of the Centeai. Nekvous System. The nerve 

 cells are rather small, closely crowded together with large nuclei 

 and very little cytoplasm. The cells vary little in size and present 

 a uniform appearance in all parts of the central ganglia. Some 

 of the cells have two or more processes, but most cells are uni- 

 polar with the process directed out to the central mass of fibers. 

 Cells in small groups may in places send their fibers in together, 

 forming a distinct bundle. No demonstration of special granules 

 of tigroid substance was made altliough the usual methods for its 

 demonstration were used, but the large nuclei nearly always 

 showed six or eight distinct masses of chromatin. Sometimes 

 there was an indication of a larger body which may have been a 

 nucleolus. In some cells instead of rounded masses of chromatin 

 there were longer rod-like masses. 



The neuroglia cells were easily demonstrated. They bad 

 rather large nuclei and very little cytoplasm forming a mesh- 

 work of strands. In the meshes of this network the nerve cells 

 are arranged, much as Haller '12 has described and figured for 

 spiders. A delicate membrane of thin cells with prominent 

 nuclei surrounds the nervous system as shown in Haller 's 

 figures. 



Cell Aeeas. In the brain the nerve cells cover the central 

 fibrous mass on all sides. The cells are most numerous at the 

 cephalic and caudal ends and also laterally. In the mid-dorsal 

 region they are least abundant, forming in places hardly a double 

 row. The more cephalic ventral portions of the supra-esopha- 

 geal ganglion are indistinguishably fused with the subesopha- 



