The =cranial cavity= is shorter and its long axis is more oblique than in the horse, but it is relatively high and wide. The anterior fossa lies at a much higher level than the rest of the floor. The olfactory fossæ are smaller, and the sella turcica is much deeper than in the horse. A deep groove leads from the petrous temporal forward over the foramen ovale to the foramen rotundum. Behind the sella there is often a distinct prominence (Dorsum sellæ). The internal sagittal crest is prominent anteriorly, but absent further back. A faintly marked elevation takes the place of the tentorium osseum. The small petrous temporal bone projects into the cavity laterally. The ridges and digital impressions are very pronounced. The parieto-temporal canal is formed entirely in the temporal bone, and opens at the apex of the petrous, where it is joined by the condyloid canal. The foramen lacerum is divided into two parts (For. lacerum anterius et posterius). The =nasal cavity= is incompletely divided by the septum, which does not reach the floor posteriorly. The floor is relatively long, and is more concave from side to side than in the horse. In the dry skull it has a large oval opening into the palatine sinus, which is closed during life by mucous membrane. The middle meatus is divided behind into upper and lower branches by the great ethmoturbinal. The posterior nares are narrow and oblique. [Illustration: FIG. 97.—SKULL OF OX, DORSAL VIEW. The outer plate of bone has been removed to show the sinuses. _a_, Frontal sinus; _a′_, cranial plate of frontal bone; _a″_, anterior part of frontal sinus, which is separated from remainder by a septum (_b_); _c_, _c′_, communications between frontal sinus and nasal cavity; _d_, supraorbital foramen; _e_, supraorbital canal; _f_, cavity of superior turbinal bone, and _g_, its opening into the nasal cavity; _h_, lacrimal sinus, _i_, its communication with the maxillary sinus; _k_, maxillary sinus; _l_, orbit; _1_, frontal bone; _1′_, processus cornu; _2_, nasal bone; _3_, premaxilla (nasal process); _4_, maxilla; _5_, lacrimal bone; _6_, malar bone; _7_, dotted line indicating course of naso-lacrimal duct. (After Ellenberger, in Leisering’s Atlas.) ]