RUM1NAXTIA THE SKULL. 101 



The squamosal and petrosal bones are united into a tingle temporal bone. 

 The temporo-maxillary articulation, zygomatic process, temporal conduit, the 

 auditory bulla, and styloid process, are large. The zygomatic process does 

 not articulate with the frontal bone. The foramen lacerum basis cranii is 

 considerably occluded by the prominence of the auditory bulla. The external 

 auditory meatus is small, and directed slightly downwards. Immediately 

 behind the sella turcica is a slight and rough eminence, very prominent in 

 some classes, the posterior clinoid process. 



The sphenoid has large and thin pterygoid processes, a deep sella turcica, and 

 a prominent olivary process. The pterygoid foramen is absent ; the foramen 

 lacerum basis cranii small, its place being largely occupied by the auditory 

 bulla, but there is a large foramen ovale, for the passage of the inferior maxil- 

 lary nerve and the spheno-spinal artery. The foramen lacerum orbitale, 

 foramen patheticum, and foramen rotundum are represented by an anterior 

 common foramen. 



The ethmoid and its cells are well developed. It has a large volute, pro- 

 longed forwards, forming a kind of third turbinal bone, called the olfactory 

 cave (antre olfactif). 



The nasal bones are short'er, narrower, and not so firmly articulated as those 

 of the horse. The posterior extremity is sunk in a groove in the anterior 

 border of the frontal bone ; the anterior extremity presents two points with a 

 notch between them, the central pair joining to form one ; therefore the nasal 

 peak is trifid ; in the smaller ruminants it is usually double. 



The superior maxilla is shorter but broader, the maxillary spine being repre- 

 sented by a rough protuberance, not continuous with the zygoma. The infra- 

 orbital foramen is opposite the first molar tooth. The maxillary sinus is large, 

 and is prolonged between the two plates of the palatine bone. There is no 

 alveolus anteriorly for a canine tooth. This bone does not assist in forming 

 the palatine foramen. 



The premaxilla is broad ; its inferior surface is flat and destitute of alveolar 

 cavities. There is no incisive foramen, but very large incisive openings. The 

 premaxillse are rarely united by suture. 



The lachrymal bone is large, forming at the bottom of the orbit a large 

 lachrymal protuberance continuous with the maxillary sinus. The wall of 

 this protuberance is thin and fragile. The lachrymal tubercle is absent. 



The malar bone is well developed. Posteriorly it is bifid ; the superior 

 branch meets the orbital process of the frontal bone, and the posterior joins 

 the zygomatic process of the temporal bone, behind the orbital fossa. 



The palatine bones are large, the part entering into the formation of the 

 bony palate being broad. The palatine crest is thin and elevated, being formed 

 by the union of the posterior borders of the palatine, pterygoid, and pterygoid 

 process of the sphenoid bones. The posterior nares are very narrow, and 

 situated behind, not between, the superior maxillae. 



The pterygoid bones are large, and usually close an opening which is left 

 between the sphenoid and palatine bones. 



The superior turbinal is small, while the inferior one is largely developed. 



The vomer is very large, resting on the anterior half of the maxillary suture. 



The inferior maxilla is longer but less massive than in the horse ; the neck 

 is more constricted, and the symphysis seldom becomes completely ossified. 



