The bone of this region, around which all the others come to be grouped, is, as in man, the superior maxillary. The relations of this maxillary with the neighbouring bones is not exactly the same in all animals; for example, in the ox, sheep, and horse, in which the bones of the nose are wide in their upper part, and in which the lachrymal bone, which is very highly developed, encroaches on the face, the superior maxillary does not meet the frontal bone; it is separated from it by the above-named bones. It unites with it, on the other hand, in the dog and the cat. In the bear, it is separated from the bones of the nose by a small tongue of bone which springs from the anterior border of the frontal--a process which we have noticed in connection with this latter. [Illustration: FIG. 62.--THE SKULL OF THE OX: LEFT LATERAL ASPECT. 1, Occipital condyle; 2, jugular process; 3, parietal bone; 4, frontal bone; 5, osseous process, which serves to support the horn (horn-core); 6, orbital cavity; 7, external auditory canal, in front of which is found the zygomatic process; 8, temporal fossa; 9, superior maxillary bone; 10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior orifice of the cavity of the nasal fossæ; 13, malar bone; 14, lachrymal bone; 15, inferior maxillary bone; 16, condyle of the inferior maxillary bone; 17, incisor teeth; 18, molar teeth.] In the pig, ox, sheep, and horse, the external surface is traversed, to a greater or less extent, by a crest which is situated on the prolongation of the inferior border of the malar bone. This crest, which is straight in the horse, but curved with its convexity upwards in the ox and the sheep, is known as _the maxillary spine_ or _the malar tuberosity_: it gives attachment to the masseter muscle, and, in the horse, is distinctly visible under the skin. It does not exist in the carnivora. On the same surface is situated the sub-orbital foramen.