470° APPENDIX, 
on a fresh specimen, if one is at hand. The changes in size and form 
of the pupil can be observed in the living cat by changing it from a 
light to a dark place and wve versa. 
Dissection. Examine the internal structures on a preparation. 
Then with fine scissors and forceps remove from the eye about one- 
fourth of the wall, in the form of a quadrant having one point at the 
optic nerve, the other at the centre of the cornea. The coats of the 
‘ eye can then be studied on the piece removed, while the other struc- 
tures will be visible within the eyeball. No special directions are 
necessary for observation of the structures described, unless it be the’ 
capsule of the lens and the zonula ciliaris. The capsule of the lens 
may be demonstrated by tearing a bit of it off with fine forceps. 
The zonula ciliaris is easily seen by divaricating the edges of the cut 
made in removing the quadrant, so as to stretch the fine fibres of 
which the zonula is formed. 
II. Tur Ear (p. 415). 
(The muscles of the external ear are of little practical importance, 
and will doubtless usually be omitted.) 
(1) The External Ear. Read the description of the external ear 
(p- 415), verifying it by examination and comparison of an ear still 
covered with integument, in the natural condition, and of a prepara- 
tion of the isolated cartilages of the ear (Fig. 168). The latter may 
be obtained by dissecting the skin and muscles from a fresh ear. 
(2) The scutiform cartilage (p. 418) should be observed in the 
natural position, and as isolated. 
(3) The muscles of the external ear (p. 418, and Fig. 169). 
Those connecting the external ear with other parts of the head have 
been studied in connection with the facial muscles. The remainder 
will be studied on an external ear removed according to the direc- 
tions given on page 435. 
Remove the integument from the convex surface of the auricle, 
sufficiently to expose the entire extent of the muscles. 
1. The rotator auris. Transect. 
2. The adductor auris superior (Fig. 169, 1). 
3. The adductor auris medius (2). 
4. The transversus auricule (Fig. 63, 7, p. 97). 
5. The auricularis externus (Fig. 169, 10). 
. The helicis (Fig. 169, 8). To expose this it will be necessary 
to remove the integument from along the cranial border of the inner 
surface of the auricle. 
7. The antitragicus (Fig. 169, 6). Remove the integument 
farther if necessary. 
8. The tragicus medialis (Fig. 169, 5, 8). 
g. The concheus externus (Fig. 169, 9). 
(4) Remove the tympanic bulla and petrous bone from the rest 
of the skull, by the use of bone-forceps and scalpel. Trim away all 
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