154 BRODE. [VOLE ADV. 
and come to lie among the circular muscle fibres. At the point 
where the nerve enters the muscle layers a branch is given off 
which passes to the ventral side of the body, while the main 
trunk passes dorsally. The nerves pursue a straight course 
around the body, and no branches have been noticed from any 
of the nerves in the body region. 
The first nerve from the ganglion (/.7z.1) passes around the 
body near the middle of the segment. It is the second largest 
of the four, and apparently innervates the muscles and other 
organs of the viscera. The second nerve (/.z.?) passes through 
the setae bundles, and is the largest nerve of the group. It 
innervates the greater band of sense organs found on the poste- 
rior part of the segment. The third and fourth nerves (/.7.3, 
/.n.4) are smaller than the first and are nearly equal in size. The 
third passes into the dissepiment, and very probably innervates 
the muscles of its walls. The fourth lies in the following seg- 
ment, and supplies the sense organs in the lesser band which 
encircles the body close to the anterior end of the segment. 
This arrangement of nerves I have traced forward through all 
the segments up to the first. 
The nerves from the dorsal ganglion are four in number, 
and, like those from the following ganglia, are placed three 
in the first segment and one in the next following or second 
segment. This latter, fourth nerve, has a course correspond- 
ing to that of the following nerves, while the three anterior 
nerves have a varied course. The first nerve (z.1) is large and 
leaves the ganglion dorsally and laterally at a point near where 
the commissure begins its downward course. It grows out a 
short distance as a single nerve, and later breaks up into three 
branches. The first runs almost straight forward, while the 
second bends below the first and follows the anterior wall of 
the proboscis, approaching the corresponding branch from the 
other nerve of the pair at the median line. The third branch 
passes forward and downward, and extends to the epidermis. 
Each of these branches subdivides into smaller branches near 
the body wall. The second and third nerves (z.?, 2.3) arise 
close together a short distance below the first. The second 
soon divides into two rami and these pass to the ventral and 
