e are two condylar foramina
instead of one, through each of which, a moiety of XII. passes.

Section 128. The eighth nerve (auditory) is purely sensory, the nerve
of the special sense of hearing; it runs into the periotic bone, and
breaks up on the labyrinth. The seventh nerve (facial) is almost
entirely motor; it passes through the periotic anterior to VIII., and
emerges by the stylo-mastoid foramen (s.m.f.) behind the bulla, to run
outside the great jaw muscle across the cheek immediately under the
skin (Figure 1).

Section 129. The ninth (glossopharyngeal) nerve is chiefly sensory;
it is the special nerve of taste, and is distributed to the tongue. The
tenth nerve (vagus) arises by a number of roots, and passes out of the
skull, together with IX and XI, by the foramen lacerum -posterium-
[posterius] (f.l.p.). It is a conspicuous white nerve, and runs down the
neck by the side of the common carotid artery. It sends a superior
laryngeal branch (Xa) to the larynx. The left vagus passes ventral to
the aortic arch, and sends a branch (l.x.b.) under this along the
trachea to the larynx-- the recurrent laryngeal nerve. The
corresponding nerve on the right (r.x.b.) loops under the subclavian
artery. The main vagus, after this branching, passes behind the heart
to the oesophagus and along it to the stomach. XI., the spinal
accessory, supplies certain of the neck nerves. XII., the hypoglossal,
runs out of the skull by the condylar foramen (c.f.), is motor, crosses
the roots of XI., X., and IX., passes ventral to the carotid, and breaks
up among the muscles of the tongue and neck.

Section 130. Of the functions of the several parts of the brain there is
still very considerable doubt. With disease or willful destruction of
the cerebral tissue the personal initiative is affected-- the animal
becomes more distinctly a mechanism; the cerebellum is probably
concerned in the coordination of muscular movements; and the
medulla is a centre for the higher and more complicated respiratory
reflexes, yawning, coughing, and so on. The great majority of reflex
actions centre, however, in the spinal cord, and do not affect the
brain.

Section 131. A cross section of the spinal cord is shown in Figure 6,
Sheet 8. It is a cylinder, almost bisected by a dorsal (d.f.) and a
ventral (v.f.) fissure. Through its centre runs a central canal (c.c.),
continuous with the brain ventricles, and lined by ciliated epithelium.
The spinal cord co