74 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
the lateral surface of the medulla a few sections anterior to the fora- 
men. Its fibers enter the brain at a sharp upward angle. The coarser 
fibers of the posterior root remain together and may be traced as they 
pass mesad in a broad upward curve to become spread out in the midst 
of a group of cells lying a little dorsal and lateral to the fasciculus 
solitarius. The more lightly medullated components of this root 
could be found making continuous connection with the fasciculus 
solitarius, into which they abruptly turn. The other two roots enter 
the brain along the same line as the posterior one. The smaller 
one could not be followed, but the larger could be traced to the 
fasciculus solitarius. It also contained several coarse fibers, which 
take the same direction as those of like character in the posterior 
root. The three roots remain separate until they enter the jugular 
ganglion. 
The ganglion jugulare, or root ariaiion of the vagus (Plates 2, 3, 
figs. 4, 5, 6, gn. ra. X), Plates 3, 7, figs. 7, 22, gn. X), lies closely 
crowded into the angle formed between the otic capsule and the 
basioccipital where the jugular foramen opens. This foramen appears 
in the same transverse section as the first. occipital foramen of XII 
(Plate 7, fig. 20). The ganglion which is larger than that of IX or 
VII, is triangular in transverse sections of the head (Fig. 22, gn. X). 
This form is the result of the pressure of surrounding structures, the | 
ganglion being crowded against the otic capsule by the spinalis colli 
muscle (Plate 7, fig. 22, sp. coll.). The form of the ganglion as a 
whole is notable, owing to the fact that the ganglion cells are so | 
grouped on the mesial side of the fiber bundle that in dissections | 
(Plate 3, fig. 7) the ganglion appears to lie free along the root 
bundles for a short distance. 
The fibers entering the ganglion as separate roots emerge on its | 
distal side as one bundle, the coarse motor fibers, about sixteen in 
number, being grouped in its dorsal portion. This bundle (X) passes | 
caudad parallel with IX and XII (Plates 2 and 3). On its way it 
shows the small ramus connecting it with IX (Plates 2 and 3, figs. 
4, 7, comn. IX-X). Posterior to the ganglion of IX, the trunk of 
the vagus divides into a superior laryngeal ramus and a visceral ramus 
(usc. X.). The superior laryngeal ramus soon joins the pharyngeal 
ramus of IX to form the pharyngo-laryngeal ramus of [IX + X (Plate 
2, fig. 4, phx-lar.). This then combines with the trunk of XII (fig. 7)! 
to reach the ventral side of the pharynx. (ef. fig. K). 
(a) Ramus laryngeus superior (lar. su.). This division of the vagus 
includes all the coarse fibers of the main trunk and about one hall 
