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 
dificult 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 fibrille. 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 
determined. 
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 system 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. 
