526 Dr. A. A. Gray. On the Anatomical [June 1, 
The 
The 
window the aqueduct of the perilymph, d.p., is seen opening out of the labyrinth at 
the junction of the saccule and cochlea, and passing round in front of the cochlea, 
then disappearing behind the inner wall of the latter, and finally reappearing at its 
posterior border to dilate into the large perilymph recess, 7.p., which lies to the 
right of the cochlea in the plate. The oval surface at the lower and outer portion of 
the perilymph recess is the round window, /f7., and it will be noticed that it, in 
common with the other walls of the perilymph recess, is speckled with pigment. 
Pigment is also seen over the aqueduct of the perilymph and, more scantily, over the 
lower portion of the saccule and over the anterior wall of the cochlea, c. 
PLATE, 19S EiGs 92: 
Left Membranous Labyrinth of the Monitor, Varanus salvator, viewed from the 
inner aspect and a little below. x 8. The ampulla of the posterior canal, a.p., is 
to the left, and it will be noticed that the crista acustica is “complex,” that is, it has 
three crests, as is also the case in many birds. The aqueduct of the perilymph, d.p., 
is seen running backwards over the inner surface of the neck of the cochlea, and then 
dilating into the large perilymph recess, 7.p., the anterior wall of which is in contact 
with the posterior wall of the cochlea, ¢c. The cochlea is seen containing the oval 
cartilaginous framework and the otoliths, as described in the text. The little 
nipple-shaped termination to the cochlea is shown, and is similar to that found in 
most of the ratite birds. 
l., lagena. _ p., Superior angle of posterior canal. 
fv, fenestra rotunda. 0.s., otolith of saccule. 
g., inferior angle of posterior canal. s., Superior canal. 
a.p., ampulla of posterior canal. o0.u., otolith of utricle. 
PLATE 19, Fig. 3. 
Left Membranous Labyrinth of the Monitor, Varanus salvator, viewed from the 
inner aspect and slightly in front. x 8. Taken by reflected light. The oval 
opening, o.p., on the upper surface of the perilymph recess, 7.p., is shown. It is by 
means of this opening that the perilymph communicates with the cerebro-spinal 
fluid. The opening corresponds to the aqueduct of the perilymph of birds and 
mammals. The other parts have already been described in figs. 1 and 2. 
p., posterior canal. 
S., superior canal. 
o.s., otolith of saccule. 
a.p., arapulla of posterior canal. 
d.p., ductus perilymphaticus. 
c., cochlea. 
r.p., recessus perilymphaticus. 
0.p., opening on upper surface of perilymph recess. 
PLATE 19, Fic. 4. 
The Right Membranous Labyrinth of the Emu, Dromeus novee-hollandie. x 5ea. 
The organ is viewed from the outer aspect and in front, and is rotated clockwise 
to the extent of about 20°. The superior canal, s., is of the “drooping” type. 
There is no communication between the arches of the horizontal, /., and posterior 
canals, p. The cristee acustice in the ampulle are “simple.” The footplate of the 
columella has been left in position in the oval window, fo. The large egg-shaped 
