George L. Streeter 159 
In the summary of these nerves it should be emphasized that we have 
distinct points of difference between the vestibular and cochlear divisions 
of the acoustic complex, both as regards the ganglia and the nerve trunks 
themselves. The ganglia, belonging to the vestibular division, are spread 
along the trunk of the nerve; the ganglion of the cochlear division is 
situated at the extreme distal end of the nerve, and lies directly on the 
membranous labyrinth, being closely incorporated with it later in the 
cartilagenous capsule. The vestibular terminal branches develop as dis- 
erete and fairly long nerves; the cochlear terminal branches are short 
and freely anastomose. The main trunk of the cochlear division is 
characterized by the compactness of its fibers and their spiral arrange- 
ment; while in the vestibular division the fibers are less compactly 
bundled, showing a tendency to subdivision, and do not have the spiral 
character. 
N. Factatis AND Pars INTERMEDIUS. 
The facial nerve is so closely united in position with the acoustic 
ganglion that it was found advisable to include it in the reconstructions. 
For reason of simplicity it is not shown in Plates I and II, but its form 
and general position at two different stages is shown in the Text Figs. 
1 and 2. It can be seen how it is divided into ventral and dorsal (motor 
and sensory) roots, and the situation of the geniculate ganglion on the 
latter. 
Particular attention was given to the ganglion geniculatum and pars 
intermedius in order to bring their early morphology into accord with 
the conditions found in the adult. Though the “portio media inter 
communicantem faciei et nervum auditorium” was described by several 
writers over a century ago, and in the intervening time frequent reference 
and much speculation has been made concerning it; yet it has turned out 
that none of this was actually in advance of the original description until 
there appeared the paper of Sapolini, 83, who was the first to give a 
detailed report of its deep origin and terminal distribution. This inves- 
tigator succeeded in dissecting out the pars intermedius in adult human 
material throughout its whole course. He describes it as arising in the 
floor of the fourth ventricle, from where it ascends as a nerve band which 
runs along the median edge of the acoustic area. At the level of the 
inferior cerebellar peduncles it makes its exit through the side of the 
pons, between the seventh and eighth cranial nerves, and then passes 
through the geniculate ganglion, and is continued into the chorda tym- 
pani, which in turn joins the lingual branch of the fifth nerve and forms 
