VAGUS NERVE OF THE TURTLE 303 
specimen both right and left spinal roots contained afferent 
ganglion cells. According to Weigner (’01) the accessory nerve 
of man also contains afferent ganglion cells. 
The vagus arises by one large and two or three smaller rootlets 
from the posterior part of the lateral surface of the medulla. 
These soon unite to form a single fascicle somewhat larger than 
that formed by the union of the rootlets of the accessory. The 
two fascicles, the accessory and vagus, then run together into the 
jugular foramen, fuse into a single trunk, and entirely lose their 
individuality some distance above the cervical ganglion of the 
vagus. 
The vagus and accessory nerves pass through the jugular 
foramen as a single nerve trunk, which is joined shortly after 
it leaves the cranium by the hypoglossal nerve (fig. 1). By 
careful dissecting the hypoglossal nerve may be separated from 
the common vagoaccessory trunk and is then seen to pass be- 
hind the vagus toward the pharyngeal wall. 
The position of the more cephalad of the two gangha of the 
vagus, which we shall call the ganglion cervicale vagi, differs con- 
siderably in different specimens. In three of our specimens 
the position and connections of this ganglion were found as 
shown diagrammatically in figure 1. In these three specimens 
the vagus divides just above the ganglion into two branches. 
One of these branches runs by the ganglion without forming 
connections with it and continues into the thoracoabdominal 
cavity without giving off any branches in the neck. This 
branch, which we shall call the ramus thoracoabdominalis, is the 
continuation of the vagus nerve and is directly homologous 
with the vagus nerve in the lower part of the neck of mammals. 
The other branch which is distributed entirely to structures in 
the neck we have called the ramus cervicalis. It divides into 
two branches: one of which the nervus laryngopharyngeus 
is distributed to the pharynx and larynx; the other the nervus 
esophageus runs with the thoracoabdominal ramus for some dis- 
tance and is then distributed to the upper end of the esophagus. 
The spinal part of the accessory is given off as a small branch 
in the neighborhood of the cervical ganglion. ‘There is also a 
