JOURNAL, OF ENTOMOLOGY AND ZOOLOGY 19^ 



Haller '12, bomologizes areas in the spider and scorpion brain 

 to the mushroom bodies of other arthropods. These areas are 

 located in the dorso-lateral portions of the nervous system in 

 cephalic and caudal regions. These areas are marked by clusters 

 of small nerve cells and small clear areas in this region. In 

 Chelifer all the cells are about the same size ; there are, however, 

 little clear areas in the same general regions of pseudoscorpions. 

 There are two areas on each side of the brain dorsally just in 

 front of the great caudal dorsal mass of cells and just back of 

 the cephalic dorsal mass. These little areas are almost free 

 from cells and they seem to be the only indications of anything 

 like mushroom bodies. 



In some specimens the fibers are intensely stained and at 

 certain areas sucli as tlie region just under the large cephalic 

 mass of cells on either side of the brain, fibers extend down from 

 the cell areas of the brain. It is possible that some of these fibers 

 represent connections which correspond to the mushroom fibers. 



IMPORTANT CONCLUSIONS 



1. There are no important abdominal ganglia beyond the 

 fused mass of the central nervous system. 



2. The pedipalpal nerves are the largest. 



3. A small number of simple more or less straight tracheoles 

 penetrate the nervous system. 



4. There are few deeja-staining masses of fibers. 



5. The cells have very little cytoplasm. The nuclei are 

 usually i^rovided with six or more chromatin granules. 



6. The sense organs so far as determined are: a pair of 

 simple eyes and hollow setae provided with nerves from bipolar 

 nerve cells. 



7. The cells of the brain are largely unipolar, but other 

 forms are found. 



8. The neuroglia cells form a network of their fibers and 

 this network between nerve cells serves as a sort of sheath for 

 them. The fibrous part of the nervous system also has strands 

 from neuroglia cells and this forms a support for the nerve fibers 

 which run in various parts of the ganglia. 



