FACE

The =maxilla= is extensive. Its external surface forms a longitudinal

groove, which is continued upon the premaxilla in front and the facial

parts of the lacrimal and malar behind. The infraorbital

foramen—sometimes double—is large and is situated above the third or

fourth cheek tooth. The alveolus for the canine tooth produces a ridge

at the anterior end which is very pronounced in the boar. The facial

crest extends forward from the root of the zygomatic process and fades

out behind the infraorbital foramen; in some specimens it is prominent

and thin-edged, in others it is rounded and projects little. The

zygomatic process is short but stout and buttress-like; it is overlapped

externally by the malar. The maxillary tuberosity forms in the young

subject a long bulla, which occupies most of the pterygo-palatine fossa

and contains the developing permanent molars; after the eruption of the

teeth the tuberosity flattens and joins the vertical part of the palate

bone. The palatine process is very long and is marked in its anterior

part by transverse ridges corresponding with those of the mucous

membrane of the palate. The anterior palatine foramen is near the

junction with the palate bone; from it the palatine groove can be traced

distinctly along the entire length of the process. The alveolar border

presents a large alveolus for the canine tooth at its anterior end;

behind this are seven alveoli for the cheek teeth, which increase in

size from first to last. The maxillary foramen and infraorbital canal

are very large. The maxillary sinus is small.

The body of the =premaxilla= is narrow and prismatic. It presents three

alveoli for the incisor teeth, which are separated by short intervals

and diminish in size from before backward. As in the ox, a narrow space

separates the right and left bones and takes the place of the foramen

incisivum. The palatine process is long and narrow. The nasal process is

very extensive and is somewhat rhomboid in outline. Its upper border

forms a very long suture with the nasal bone, and the lower articulates

to about the same extent with the maxilla. The palatine fissure is

relatively wide.

The horizontal part of the =palate bone= forms a fourth to a fifth of

the length of the palate; its palatine surface is triangular, the apex

being anterior; its nasal surface is deeply grooved and smooth. A

pterygoid process (processus pyramidalis of man) projects backward and

downward, and its thick rounded end is received between the pterygoid

process of the sphenoid and the pterygoid bone. The perpendicular part

is largely overlapped externally by the maxilla and concurs in forming

part of the palatine canal. Superiorly the two plates separate and

inclose an air-cavity which opens into an ethmoidal meatus. The inner

plate curves inward and unites with the vomer and ethmoid to form a

horizontal plate (Lamina transversalis), which divides the posterior

part of the nasal cavity into an upper olfactory part and a lower

respiratory part.

The =pterygoid bone= is nearly vertical in direction, and is narrow in

its middle, wide at each end. The external surface is free below and

forms the inner wall of the pterygoid fossa. The lower end is notched

and forms a distinct hamulus.

The =nasal bone= is very long and its width is almost uniform, except at

the anterior end, which is pointed and reaches almost as far forward as

the premaxilla. The facial surface is flattened from side to side. In

profile it is nearly straight in some subjects, variably concave in

others. The external border is free to a small extent in front only;

otherwise it is firmly connected with the premaxilla and maxilla. In the

adult the frontal sinus extends into the posterior part of the bone.

The =lacrimal bone= is very sharply bent. Its facial surface presents a

deep depression, surmounted by a ridge or tubercle. On or close to the

orbital margin are two lacrimal foramina which lead to the lacrimal

canals. The orbital surface presents a fossa in which the inferior

oblique muscle of the eyeball arises, and its lower part bears a crest,

which is crossed obliquely by a vascular furrow. The upper border

articulates with the frontal only. The bone concurs in the formation of

the maxillary sinus.

The =malar bone= is strongly compressed from side to side. Its facial

surface is small and presents a fossa which is continuous with the

depressions of the maxilla and lacrimal. The orbital surface is still

smaller and is smooth and deeply grooved. The zygomatic process is very

extensive, especially in the vertical direction. Its external surface is

convex and free, and bears a rough eminence in its middle. Its internal

surface is concave; it is overlapped in front by the maxilla, and in the

remainder of its extent is free and smooth. The upper border is thick

and rounded in front, where it forms the lower part of the orbital

margin; behind this it forms an extensive notch which receives the

zygomatic process of the temporal. (It might be regarded as dividing

into frontal and temporal branches.) The lower border is convex and

becomes thinner behind.

The =turbinal bones= resemble those of the ox. The superior turbinal is,

however, relatively longer, less fragile, and more firmly attached to

the nasal bone. There is no middle turbinal.

The =vomer= is very long. The anterior extremity reaches to the body of

the premaxilla or very close to it. The lower border is received into a

groove formed by the nasal crest of the maxillæ and palate bones and in

front by the palatine processes of the premaxillæ. The posterior border

is concave, thin, and sharp.

The =os rostri= (or prenasal bone) is situated in the snout between the

nostrils. It has the form of a short three-sided prism. The upper

surface is convex and is notched at each end. The lateral surfaces are

concave, smooth, and converge below, forming a grooved lower border. The

posterior surface is triangular, notched centrally, and rough laterally.

The anterior surface is deeply pitted and is surrounded by an irregular

sharp border.

The =mandible= is very strong, and differs very much from that of the

horse or ox. The body narrows decidedly in front; the lingual surface is

deeply concave; the mental surface is strongly convex, slopes downward

and backward, and forms a distinct prominence at the point of divergence

of the rami. Above this prominence is a pair of foramina. The alveolar

border presents six alveoli for the incisor teeth, and a little further

back two large cavities for the canine teeth. There are two pairs of

mental foramina of considerable size and a variable number of smaller

ones. The rami diverge more than in the horse or ox, and the upper part

is somewhat incurved. The horizontal part is very thick and strong. Its

outer surface is strongly convex from above downward. The inner surface

is prominent over the roots of the molar teeth and overhangs the concave

lower part. The alveolar border is thin in front and widens behind; it

does not follow the axis of the ramus, but runs nearly straight and

produces the marked overhang noted above. There are seven alveoli for

the lower cheek teeth, which increase in size from before backward. The

first is small, not always present in the adult, and is separated by

short spaces from the second and the canine alveolus. The vertical part

is relatively wide above. The condyle is convex in both directions, wide

in front, narrow and declivitous behind. The very small and thin-edged

coronoid process is not quite so high as the condyle, from which it is

separated by a very wide notch. The mandibular foramen is large. The two

halves of the bone unite soon after birth in the improved breeds.

The body of the =hyoid bone= is broad from before backward, short

transversely, and bears on its ventral aspect a very short pointed

lingual process. The thyroid cornua are wide and curved, concave and

grooved dorsally; their ends are attached to the thyroid cartilage of

the larynx by rather long bars of cartilage. The small cornua are short,

wide, and flattened dorso-ventrally; they are attached to short bars

which project from the junction of the body and thyroid cornua. The

middle cornu is a little longer than the small cornu, but is relatively

slender; it is largely cartilaginous in the young subject and does not

ossify at either end. The great cornu is a very slender rod, slightly

enlarged at either end; the upper extremity is attached to the hyoid

process of the temporal by a rather long and wide bar of cartilage.

[Illustration: