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E X P L A N A T I O N OF THE TABLES.
P A briftle .pailed from the fcala of the cochlea into the veftible, and from
the veftible into the anterior end of the fuperior femicircular canal Q^
R' The pofterior femicircular canal cut open.
S Tlie common canal formed by the joining of the femicircular canals Q_
and R going into the veftible.
T The under end of the pofterior femicircular canal going into the veftÌÌilc.
U A briftle, the two ends of M^hich are introduced into the external inferior
horizontal fcmicircular canal,
V A briftle put into a paftage, which is open in the ikeleton at its inner
end, and which is fituated about a quarter of an inch farther out than the
hole for the feventh pair, then p^es under the fuperior perpendicular
fcmicircular canal, and terminates by a blind end, within the os petrofum.
W A briftle put into the beginning of the canal for the portio dura.
X A briftle put into a hole in the central pillar, or modiolus of the cochlea,
through which a principal branch of the portio mollis enters.
YZ Principal holes, through which branches of the portio mollis pafs to
the veftible.
a The hole for thè aqueduil from the cochlea defcribed by Cotunnius.
Ù The hole faid by Cotunnius to tranfmit an aqueduft from the veftible.
FIG. II. In this figure the bottom of the meatus auditorius internus, or
canal for the feventh pair of nerves, is reprefented, as it appears when magnified
to about fix diameters.
W X Y Z By thefe letters the fame parts are pointed out as in Fig. I.
c c Reprefents a cribriform plate through which the other nerves of the
cochlea pafs.
cle Shew cribriform parts through which the other nerves to the veftible
pafs, and from it to the femicircular canals.
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E X P L A N A T I O N OF THE TABLES. Ï57
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FIG. III. Reprefents the os petrofum difleded, fo as to fliew the cochlea
and femicircular canals with the paflages for the nerves, viewed from the
fore and outer fide of the head.
A The fella turcica.
B The pofterior chnoid proccfs.
C The anterior clinoid procefs.
D The round hole in the fphenoid bone for the paflage of the fécond
branch of the fifth pair.
E The oval hole for the paflage of the third branch of the fifth pair.
F The hole for the largeft artery of the dura mater.
G The future which divides the temporal bone H, from the fphenoid.
I The inner end of the os petrofum.
K The canal for the internal carotid artery.
L A hole cut to ftiew the beginning of the canal for the carotid artery.
MN The outer, or ofleous end of the Euftachian tube laid open.
O A briftle paflfed into the firft turn of the pofterior fcala of the cochlea,
which is cut open, and from it into the foramen rotundum. The diameter
of the modiolus is feen here.
PQUVWX Point out the fame parts as in the Figures I. and 11. X Shews
the fécond turn of the cochlea and its apex laid open. The ofTeous part
of the modiolus terminates in the fécond turn of the cochlea.
s The cavity of the tympanum cut open.
t A probe put from the cavity of the tympanum into the foramen ovale.
V. A probe put from the cavity of the tympanum into the foramen rotundum.
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R r T A B L E