IN THE GENUS SQUALUS. 
159 
ance of clumsiness, when compared to the magnificent cir- 
cular sweep of those of the Shark, 
I have therefore selected the ear of the Squalos borealis, 
as containing the best specimen of the auditory canals, not 
only because of the elegance, superior size, and tangibility, 
of the parts, — but likewise for the similarity of the mem- 
branous tubes to those of the human subject, in respect to 
form and position, — of which they form the finest illustra- 
tion that is found in the animal kingdom. 
The auditory nerve of the Squalus is large and very 
tough, when compared to that of the human subject, and 
composed of numerous fasciculi which divide in the mea- 
tus internus, into four, sometimes five, tolerably large 
branches. A branch leaves the anterior and inferior parts 
of the meatus, by a small foramen in the cartilaginous sub- 
stance of the cranium, and gives off numerous branches 
that ramify in a large duct which leads from the coronal 
surface of the head to the orbit. 
The nerve then passes outwards, and is distributed on the 
sides of the head. 
In the superior part of the meatus, there is a small fossa 
containing two foramina, the one rather superior and ante- 
rior to the other. 
The superior and anterior branch enters the anterior- 
superior foramen, and, proceeding upwards in a small ca- 
nal, contained in the cranium, runs upwards and forwards, 
and a little outwards, until it arrives in the cavity of the 
horizontal canal destined for the reception of the ampulla. 
It then divides into two branches, which stretch outwards 
and upwards, and perforate the membranous ampulla near 
the centre, on the inside of which the filaments are distri- 
buted, chiefly on the inferior parts of the cavity. 
As soon as the nerve divides, it sends numerous small 
