The palatine grooves are distinct for a short distance only. Just beyond the cheek teeth the palate narrows and becomes concave; beyond this it widens and flattens. The =posterior= or =nuchal surface= is extensive and somewhat pentagonal in outline in the adult. About its center is the eminence for the attachment of the ligamentum nuchæ. From this a median crest extends toward the foramen magnum, and laterally two lines (Lineæ nuchæ superiores) curve outward, marking the upper limit of the area which is roughened for muscular attachment. The surface above the lines is relatively smooth, and is covered only by the skin and the thin auricular muscles in the living animal. It is separated from the cranial roof by a thick border, which forms centrally the frontal eminence, and bears at its extremities the processus cornu—except in the polled breeds. The condyles are further apart, and the articular surfaces are more clearly divided into upper and lower parts than in the horse. [Illustration: FIG. 95.—CROSS-SECTION OF SKULL OF OX. SECTION PASSES THROUGH FIFTH CHEEK TOOTH. ] [Illustration: FIG. 96.—CROSS-SECTION OF SKULL OF OX. SECTION PASSES THROUGH SECOND CHEEK TOOTH. _a_, _b_, _c_, Superior, middle, inferior meatus; _b′_, communication between middle meatus and cavity of upper part of inferior turbinal; _c′_, communication between inferior meatus and lower part of inferior turbinal; _d_, cavity of superior turbinal; _e_, _f_, outer and inner walls of _d_; _g_, _h_, upper and lower cavities of inferior turbinal bone; _i_, basal lamella of inferior turbinal; _i′_, _i″_, upper and lower divisions of inferior turbinal bone; _k_, floor of nasal cavity; _m_, lacrimal sinus; _n_, maxillary sinus; _p_, palatine sinus; _q_, septum between maxillary and palatine sinuses; _r_, infraorbital canal; _s_, septum between palatine sinuses; _t_, common meatus; _u_, naso-lacrimal canal; _v_, floor of nasal cavity and roof of palatine sinus; _1_, septum nasi; _2_, posterior part of second cheek tooth; _3_, posterior part of fifth cheek tooth; _4_, hard palate. (After Ellenberger, in Leisering’s Atlas.) ]