Charles R. Essick 127 
surface of the pons between the facial and acoustic nerves. The nuclear 
mass which lies adjacent to the fibers can be traced serially back into the 
caudal tip of the process, but it will be noticed in these two sections that 
the nuclear mass is directly continuous with that scattered throughout 
the pons. Fig. 4 shows the nervus intermedius passing through the 
ponto-bulbar body on its way to join the facial nerve in the same man- 
ner as the glosso-pharyngeal nerve does farther caudally. 
We may say its middle division begins at the point where the ponto- 
bulbar body leaves the pons between the facial and acoustic nerves. It 
les ventral to the restiform body and all the fibers in our sections, as in 
Fig. 5, are cut across transversely—that is they are running caudo- 
cephalically. Here again it will be noted that the fibers are arranged 
along the surface. Throughout the length of the ventral portion numer- 
ous small strands of obliquely cut fibers are found scattered in the 
nuclear mass. By carefully following the sections serially it becomes 
evident that these small bundles are passing between the restiform body 
and the ponto-bulbar body. These nerve fibers leave the restiform body 
and travel obliquely out across the nucleus in a caudal direction and 
finally take their position on the surface of the nucleus, thereby swelling 
the number of fibers. As we pass back and forth in serial sections, a 
variability in the number of fibers cut transversely, calls attention to the 
fact that there are not only fibers arising in the nucleus itself and running 
along the edge, but that there are also fibers which are passing into other 
structures. These obliquely cut fiber bundles can be seen in Figs. 5 and 6, 
between the superficial fringe of transversely cut fibers and the restiform 
body. The exchange of fibers between the ponto-bulbar body and the 
restiform body takes place even in the regions where the nucleus has 
fused with the pontine nuclei and although the obliquely cut fibers with 
the same directions persist, the cross fibers from the pons and the trape- 
zoid body make it impossible to trace bundles from the ponto-bulbar body 
to their junction with the restiform body. The ponto-bulbar body is 
separated from the restiform body by the trapezoid body as soon as the 
level of the ventral cochlear nucleus is reached. The separation is partial 
in Figs. 5 and 6, and complete in Figs. 3 and 4, where the trapezoid body 
can be traced to the superior olive. Attention might be called to Fig. 7, 
where the coarse fibers of the most cephalic of the glosso-pharyngeal nerve 
roots may be followed from the fasciculus solitarius through the descend- 
ing spinal root of the fifth nerve and the restiform body and out through 
the most ventral part of the ponto-bulbar body. Fig. 7 also shows the 
dorsal cochlear nucleus in its relation to the ponto-bulbar body which, a 
