IN THE GENUS SQUALUS. 
157 
degree of inflammation must ensue before any of these glo- 
bules can pass. 
In a preparation now before me, where the subject had 
been killed by repeated blows on the head, the vessels lead- 
ing to the canals were quite turgid, and of a red colour. 
The space between the membranous fibres and the canals 
is filled with a clear fluid, similar in appearance to water, 
but of a saltish bitter taste, and is a continuance of the 
surrounding fluid of the vestibule ; and from this circum- 
stance, the vibrations can be more rapidly communicated 
throughout the labyrinth than without this provision.* 
The membranous canals are filled with a transparent 
fluid, which has no direct communication with that con- 
tained in the interspaces surrounding the tubes, for, when 
a section is made of the cartilaginous canals, the fluid in 
the interspaces oozes quickly out, while the membranous 
canals continue full and distended. Close to and upon the 
extremity of the great sac is the base of a large oblong 
substance, smooth outwardly, but full of reticulated elastic 
membranous substance. 
We noticed above, that a ridge or process ran, on the 
floor of the vestibule, the whole length of that cavity, and 
likewise a corresponding process in the superior part, which 
caused a partial longitudinal division of the vestibule, and 
formed, as it were, beds for the lodgement of two bodies. 
In the anterior division is the great sac, containing the sa- 
bulous body ; and close to it, on the posterior side of the 
process, is the body of this oblong reticulated membranous 
substance, with its extremity resting on the great sac as on 
a cushion. This substance, contracting gradually, makes a 
* The liquor in the vestibule and cartilaginous canals of the Thorn- 
back, measured about two drachms of a transparent fluid, the taste of 
which was similar to salt water, but not quite so strong. 
