(f) 
(g) 
THE HEAD AND NECK. 249 
inserted on the medial portion of the eyeball around the 
optic nerve. It consists of four distinct parts. 
The Harderian gland (gl. Harderiana) is a large compact 
gland lying in the anterior portion of the orbit. It is com- 
posed of two portions, one of which is greyish red, the other 
white. The duct opens on the inner surface of che third 
eyelid... © 
The lacrimal gland (gl. lacrimalis) is a much smaller, also 
darker, structure lying close to the skull in the temporal 
angle of the orbit. It communicates by several fine ducts 
with the inner surface of the upper eyelid. 
The infraorbital gland (gl. 
infraorbitalis) is a diffuse white 
or yellowish gland lying in the 
anteroventral angle of the orbit 
immediately medial to the zygo- 
matic arch. The gland is one 
of the salivary series, its duct 
passing downward and opening 
through the mucous membrane 
of the cheek into the cavity of 
the mouth. 
To examine the structure 
of the eye, the muscles of 
the eyeball should be divid- 
ed at their insertions, and 
the whole structure re- 
moved. The second cra- 
nial or optic nerve (n. 

Diagram of the parts of the eye in 
C.a., anterior chamber; c.c., 
ch., chorioidea; co., cornea; C.p., 
c.r., ciliary portion of the 
retina; c.v., vitreous body; d.h., Harderian duct; 
d.l.; position of the lacrimal ducts; d.n., nasola- 
Fic. 80. 
vertical section: 
ciliary body; 
posterior chamber; 
crimal duct; i., iris; 1., lens; n.o., optic nerve; 
o.r., optic portion of the retina; p.i., lower 
eyelid; p.s., upper eyelid; p.t., third eyelid; 
r.b., retractor oculi; r.i., rectus inferior; r.s., 
rectus superior; sc., sclera; Z., Suspensory 
zonular fibres of the lens. 
opticus) is divided; also the ophthalmic artery, a small branch 
of the internal carotid which accompanies the nerve outward from 
the optic foramen to the eyeball. 
The eye may be divided by a circular incision into medial 
being again divided vertically. 
under water. 
(a) 
and lateral hemispheres, the lateral hemisphere, containing the lens, 
The parts should: %e examined 
The chief structures (Fig. 80) comprise: 
The fibrous tunic (tunica fibrosa oculi), the strong peri- 
pheral coat enclosing the whole structure. It is divisible 
into a medial portion, the sclera, or sclerotic coat, a thick 
