124 Journal of Entomology and Zoology 



the nerve band. These fibers are for the most part unbranched 

 except at the inner ends where most seem to be slightly forked just 

 at the inner limit of the nerve band. There may be small branches 

 to a limited degree along the sides of the nerve fibers, but it is very 

 difficult to be sure that this is the case. Certain cells which may be 

 multipolar did not seem true nerve cells. The terminal ends of the 

 nerve cells on the inner side of the nerve band seems to be the chief, 

 if not the only region of interrelation of the nerve cells. I did not 

 find them quite so long or so numerous as Meyer, 1906. There are 

 diagonal fibers, especially in the mid-ventral line of older and larger 

 specimens. There are also a few fibers near the cell-body layer of 

 the nerve strands, which are perpendicular to the other fibers. Very 

 few bipolar cells were found except in the outer zone of nuclei, but 

 there were a few. 



The nerve fibers were not found to contain fibrilla?. Possibly 

 each cell has but one fibril. Although the nerve processes differ 

 in diameter none of them seem made of smaller elements. Often 

 several processes from several cells run almost in a single bundle. 



The cell-body just about the nucleus was often difficult to make 

 out, although in some cases it retained its epithelial character at the 

 outer end. No clear indications of tigroid substance could be 

 cietermined. 



The two deeper nerves In each arm are not so well marked as 

 the superficial. They are much simpler in structure and not so 

 clearly nervous structures although a few fibers are shown. At the 

 margins of the nerve ring and the other surface nerve bands, there 

 seems to be some connection between the superficial and deep sys- 

 tems, by direct junction in part and by individual fibers in small num- 

 ber passing from the outer to the inner nerve bands. 



Most of the cells of the superficial central svstem seem to be nerve 

 cells, the nuclei of the external zone seem to belong to unipolar or 

 bipolar cells, but a few of these may not be. Between the fibers 

 there is a granular mass which does not clearly show cells, yet there 

 are some cells in it, some dimly shown larger ones and some marked 

 smaller ones which have many fine branches. These smaller cells 

 especially seem like neuroglia cells of other forms. 



