_1_, Sulcus transversus; _2_, longitudinal fissure; _3_,
antero-internal frontal gyrus; _4_, olfactory bulb; _5_, marginal or
sagittal pole of hemisphere; _6_, lateral fissure (of Sylvius); _7_,
hemisphere of cerebellum; _8_, vermis of same; _9_, accessory nerve;
_10_, dorsal root of first cervical nerve. (Ellenberger-Baum, Anat.
d. Haustiere.)
]
The =pons= is smaller, both transversely and longitudinally, than that
of the horse. It is strongly convex and has a distinct central
depression.
The =cerebellum= is smaller and more angular in form than in the horse.
The vermis is large and has a distinct depression on its anterior face
for the posterior corpora quadrigemina. The hemispheres are relatively
small and are not clearly divided into tabulations. The anterior
peduncles are very short.
The =cerebral peduncles= are short. A small eminence in the locus
perforatus posticus is caused by the presence of the interpeduncular
ganglion. The =internal geniculate body= is prominent. The =pineal body=
is long and fusiform, and is often pigmented in spots. The third
ventricle forms two considerable recesses in relation to the pineal
body: one (R. pinealis) extends up into the body; the other (R.
suprapinealis) is a long tubular prolongation in front of it.
The =optic tracts= cross the cerebral peduncles almost at a right angle.
The =pituitary body= is situated in a deep fossa and is surrounded by a
plexus of vessels.
The =cerebral hemispheres= are shorter, higher, and relatively wider
than in the horse. The frontal poles are small, the occipital large.
Viewed from the side, the dorsal surface is strongly convex. The highest
point of the dorso-medial border is a little in front of its middle and
forms a marked prominence termed the =sagittal= or =marginal pole=
(Polus sagittalis s. prominentia marginalis dorsalis). Anterior to this
the border drops abruptly, being cut into by the deep transverse
fissure. The arachnoid on the basal and anterior parts of the
hemispheres is usually pigmented. The =corpus callosum= extends through
a little more than a third of the length of the hemisphere. The pattern
of the =fissures= and =gyri= of the pallium is somewhat simpler than in
the horse.
[Illustration: