IN THE GENUS SQUALUS. 16S 
as formerly mentioned, in which it is surrounded by the 
elastic semi-cartilaginous substance. 
After being united to the plexus by means of the nervus 
communicans, it proceeds outwards enveloped in the sub- 
stance, and, keeping rather behind and below the fossa, en- 
ters a large canal in the substance of the cranium. The 
nerve, enlarged now to nearly three times its original size, 
appears, when viewed from without, as if it sent a branch 
to form the plexus, and another to the cranium, instead of 
its being only an auxiUary, enlarged by means of the union 
of filaments from other nerves. This nerve, after leaving 
the cranium, is distributed on the neck, and parts adjacent. 
The sabulous nerve, as it proceeds, gives off several slen- 
der branches, and afterwards another large branch, that di- 
vides into two branches, and each of these again into others, 
more minute, which also unite with the communicating 
nerve. It then divides into six, eight, sometimes ten^ long 
slender branches, which run outwards, and dip into the 
fossa, where they form the horn-like process of the sabulous 
body. 
The above is the distribution of the branches on the an- 
terior side of the nerve. On the posterior side, the sabu- 
lous nerve gives off six, sometimes seven, long slender 
branches, one or two of which pass through, and are distri- 
buted in, the upper parts of the vestibule, but the most of 
them supply the superior and posterior parts of the great 
sac ; and we may infer, from these circumstances, that the 
sac itself, as formerly mentioned, is susceptible of the vibra- 
tions of the hquor amplectens. 
In a preparation now before me, one of these slender 
branches runs to, and is distributed on, the membrane 
stretched over the foramen rotund um ; so that the reciprocal 
vibrations of that membrane with those of the membrana 
vestibuli, are thus instantaneously transmitted to the sabu- 
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