172 J. B. Johnston 
which the three lateral subdivide and are soon lost. They are pro- 
bably general cutaneous. The mesial branch turns eephalad and 
continues mesially until it crowds into the angle between the ventral 
cartilage and the ventral muscle. Here (497) it divides into minute 
strands which pieree the ventral muscle and gain the dermis. A 
group of the ventral neuromasts lie here and some of the strands 
are traced to them. I suppose that the neuromasts cephalad from 
this point to 340 are innervated by these branches, but apparently 
the strands destined for individual organs run for a long distance 
separately and they are too fine to be traced. 
The glossopharyngeus arises by two roots containing general 
cutaneous, visceral sensory (fase. com.), and visceral motor compo- 
nents. Its ganglion receives in addition a neuromast component from 
the VII—X anastomosis. These components are distributed to the 
first gill sae and to the first branchial arch by means of pharyngeal 
(pretrematie?) twigs, a ramus visceralis to special sense organs, mo- 
tor rami, and a cutaneous ramus to pit organs and the general skin. 
The entire eourse of the nerve is shown in a schematie cross section 
in Fig. 18. 
Nervus vagus. Returning to 445 where the roots 7b, 4, 5, 6, 
7, $ and 9 form a single trunk, a few ganglion cells are seen on 
its mesial surface, perhaps in connection with the communis fibers 
which are thought to be in root 7. A strong connective tissue mem- 
brane separates this trunk from that formed by root /a plus the 
VII—X anastomosis (N. lineae lateralis. All the neuromast com- 
ponent of the vagus trunk comes by way of root 75, none from the 
VII—X anastomosis (Fig. 12). The trunk goes caudad, becomes 
more compact and rounded, is flattened as it passes beneath the 
first ventral spinal nerve at 474, is again rounded, passes beneath 
the second motor nerve at 486, becomes pear-shaped in section on 
account of large ganglion cells in its lower part. At 495 a little 
bundle of ten or twelve fibers separates from the ventral side of 
the ganglionated trunk and continues at first parallel with the trunk. 
At 515 this small branch bends down along the inner face of the 
body muscle and is lost about half way to the gill slit. 'This branch 
resembles in every way certain branches further caudad which are 
known to be at least in part somatie motor for the lateral body 
museles.. But no somatie motor eomponent is present in this part 
of the vagus trunk and it seems probable that this branch is destineil 
for the pit organs above the second gill slit. c 
