172 THE SKULL. [chap. 



The mandible has a broad flat condyle (cd), a long 

 slender coronoid process (cf), a rounded angle, a rather 

 slender horizontal portion, contracted and with a sharp 

 upper edge in front of the molar teeth, and expanded 

 anteriorly for the lodgment of the incisors. 



The Ox agrees generally with the Sheep in its cranial 

 characters. The face is bent down on the basicranial axis 

 almost in the same manner. The occipital surface is flat, 

 and terminates above in a broad transverse ridge, which 

 extends between the horn cores. The parietals are ex- 

 tremely narrow above, and placed almost entirely behind 

 this ridge. They unite very early with the interparietal and 

 supraoccipital. The intercornual ridge of the frontals is 

 excavated by large air-cells, communicating with those of 

 the horn cores, and is especially developed when the horns 

 are large. Unlike the parietals, the frontals are of very 

 great extent, and have a broad and flattened upper surface. 



The tympanies are compressed and scarcely at all bullate. 

 They end anteriorly in long compressed styliform processes, 

 and become firmly ankylosed with the periotic and squa- 

 mosal. The under surface of the meatus auditorius has a 

 compressed ridge. The large tympanohyals are entirely em- 

 bedded in the tympanic, only the rough lower surface for 

 articulation with the stylohyal being exposed. 



The mandible and hyoid are like those of the Sheep, but 

 the basihyal is rather more developed, and has a rounded, 

 anterior, median projection. 



Many Ruminants (especially among the Cervida) have a 

 vacuity of varying extent on the side wall of the face, 

 between the frontal, lachrymal, maxillary and nasal bones, ' 

 leading in the macerated skull into the nasal chamber, but 



