150 
ANATOMY OF THE HORSE. 
in after age of two, the above described super-occipital and sub- 
occipital portions ; in adult life it becomes one entire bone. 
TEMPORAL BONES. (oSSA TEMPORUM.) 
Situation, Lateral parts of the cranium. 
Conformation. They consist of four separate pieces, in pairs, 
each irregular in its form. One presents a vaulted ovoid plate, 
surmounted by a curved or hooked projection ; the other is a 
solid convex form, remarkable for its hardness and whiteness. 
Division. In man these pieces are united and are considered 
as the squamous and petrous portions of one bone : in the horse, 
although the same names are preserved, the portions are in reality 
distinct bones. 
THE SQUAMOUS PORTION. (PARS SQUAMOSA.) 
Presents two surfaces, an external and internal, and a cir¬ 
cumference. 
The External or Auricular Surface is convex, and has projecting 
forward from its middle in a curvilinear direction the zygomatic 
process; this unites with a similar projection coming from the 
malar bone, the two forming the zygomatic arch, against which 
abuts the frontal arch : superiorly, this process presents a broad 
concave surface contributing to the temporal fossa, and has a nar¬ 
row sharpened convexity projecting upwards and backwards from 
it called the zygomatic crest; inferiorly, running transversely 
to its root, is the glenoidal cavity, for the reception of the con¬ 
dyle of the inferior maxilla, bounded in front by a smooth trans¬ 
verse eminence denominated the articular from its being in¬ 
cluded within the temporo-maxillary articulation, and behind 
by the anterior mastoid process, which descends in the form of a 
cone, serves to strengthen and limit the motion of the articula¬ 
tion, and gives attachment to part of the levator humeri. Be¬ 
hind the root of the posterior articular process is mastoid 
foramen, for transmitting blood-vessels to and from the temporal 
fossa. Farther backward is the orifice of the temporal conduit, 
which gives passage to a vein. 
The Internal or Cerebral Surface is concave, to contain and 
support the posterior lobes of the cerebrum by which it is 
imprinted, and displays several arborescent grooves which 
mark the course of the posterior arterial ramifications of the 
dura mater. 
The Circumference, ovoid and elongated posteriorly, is denti- 
