Charles R. Essick ial 
stripped off, the ponto-bulbar body can be seen making its appearance 
on the ventro-lateral surface of the pons near the emerging root bundles 
of the trigeminal nerve and extending backward passing between the 
roots of the acoustic and facial nerves. Continuing backward ventral 
to the restiform body the main mass passes dorsal to the emerging glosso- 
pharyngeal roots, finally, assuming the dorsal position shown in Figs. 1 
and 2. So that the ponto-bulbar body is superficial throughout its extent 
and its development usually throws the surface into a more or less well- 
marked fold which can be traced from its beginning on the ventro- 
lateral surface of the pons to its ending at the lateral wall of the fourth 
ventricle. As soon as these caudally directed fibers leave the pons it 
becomes evident that they are accompanied by a cellular mass which is 
itself distinct from the neighboring structures. This nuclear mass fused 
with the pons between the facial and acoustic nerves gains the dorsal 
surface of the medulla by passing around the restiform body caudal to 
the dorsal cochlear nucleus. 
Out of fifty brain specimens which were examined macroscopically, it 
was found that nearly all showed clearly the ponto-bulbar body through- 
out its entire extent. About half showed a prominent ridge from its 
beginning on the pons to its ending at the lateral wall of the fourth 
ventricle. In all the brains examined, the ponto-bulbar body was 
visible macroscopically in some part of its course. The reason it is not 
seen throughout its whole extent in all of the specimens is not due to 
its absence, but to its retraction beneath the surface of the hind-brain. 
At the point of its emergence on the pons its position, size, and shape 
vary considerably in different brains. The ponto-bulbar body appears 
first as small bundles of fibers which turn away from the tranverse pons 
fibers proper somewhere median to the trigeminal nerve. Gradually 
these bundles converge to form a more or less compact ridge which curves 
backward just behind the fifth nerve and runs caudally almost at right 
angles to the other pons fibers, to pass between the facial and acoustic 
nerves. ‘The eminence thus formed is generally single as far front as the 
fifth nerve and measures from 3-6 mm. in width; the extent to which it is 
raised above the pons surface varies from a sheet-like layer of fibers to a 
corded ridge. The manner in which the ponto-bulbar body sweeps out 
of the pons resembles somewhat the converging roots of the cauda equina ; 
one specimen showed a distinct claw-like arrangement of fiber bundles. 
At times the fibers go to form two separate ridges which unite just 
cephalad to the facial nerve. The region from which these fibers turn 
