160 
ON THE ORGAN OF HEARING 
filaments to the inferior parts of the ampulla, which pene- 
trate the membranous expansion, and form on the inside a 
delicate nervous process, in the direction of the circular 
part of the lower half of the ampulla, so as to join the two 
branches, independent of the central inosculating fasciculus. 
These inosculating or uniting processes have a beautiful 
flocculent appearance, somewhat tinged with the cerulean 
hue of the surrounding cartilage. 
In a preparation of the thornback now before me, the 
nerve divides and penetrates the membranous ampulla, in 
a similar manner to the above, near the centre, each branch 
forming a small mamillary process on the inside of the 
cavity. These processes send each a delicate branch, that 
forms a nervous fasciculus, extending across the centre of 
the ampulla, and uniting with its fellow on the opposite 
side. By this provision, the slightest vibratory motion of 
the surrounding fluids or liquor contained in the tube will 
affect this nervous circle. 
A large bundle of delicate filaments enters the other fora- 
men in the meatus of the squalus, which leads to the cavity 
occupied by the spherical sac, where it divides suddenly 
into twenty or thirty slender branches, the greater number 
of which proceed upwards, and almost completely cover the 
inner, anterior, and posterior parts of the sac. 
It may be remarked, that each branch as it divides 
unites with the branch next to it on either side, which also 
in its turn divides and unites in the same manner, and so 
on, alternately dividing and uniting during their course 
upwards, until the whole of the fasciculi are intimately 
connected, and form a beautiful plexus of nervous fila- 
ments that nearly covers the sac. 
This plexus gives off numerous filaments, some of which 
perforate the sides of the membranous spherical sac, and 
unite with others that enter by the bottom of the cavity, 
