EQUIDE 389 
chiefly in consequence of the immense size of the face as compared 
with the hinder or true cranial portion. The basal line of the 
cranium from the lower border of the foramen magnum to the 
incisor border of the palate is very nearly straight. The orbit, of 
nearly circular form, though small in proportion to the size of the 
whole skull, is distinctly marked, being completely surrounded by a 
strong ring of bone with prominent edges. Behind it, and freely 
communicating with it beneath the osseous bridge (the postorbital 
Fic. 163.—Side view of skull of Horse, with the bone removed so as to expose the whole of 
the teeth. Px, Premaxilla; Jf, maxilla; Na, nasal; Ma, malar or jugal; L, lachrymal; Fr, 
frontal; Sq, squamosal; Pa, parietal; oc, occipital condyle; pp, paroccipital process; i1, i2, 
and i8, the three incisors ; c, the canine; pml, the situation of the rudimentary first premolar, 
which has been lost in the lower, but is present in the upper jaw; pm?, pm3, and pm4, the 
three fully developed premolars ; m1, m2, and m8, the three true molars. 
process of the frontal) forming the boundary between them, is the 
small temporal fossa occupying the whole of the side of the cranium 
proper, and in front is the great flattened expanse of the “ cheek,” 
formed chiefly by the maxilla, giving support to the long row of 
cheek-teeth, and having a prominent ridge running forward from 
below the orbit for the attachment of the masseter muscle. The 
lachrymal occupies a considerable space on the flat surface of the 
cheek in front of the orbit, and below it the jugal or malar does 
the same. The latter sends a horizontal or slightly ascending 
process backwards below the orbit to join the under surface of the 
zygomatic process of the squamosal, which is remarkably large, and, 
instead of ending as usual behind the orbit, runs forwards to join 
the greatly developed postorbital process of the frontal, and even 
