THE ANATOMY OF TBE OX. 43 



Sella turcica is deep, and the bony projection separating it from 

 the basilar process is very prominent. The three suprasphenoidal 

 canals blend to form a single wide one. There are no notches 

 in the superior border for the passage of the internal carotid and 

 spheno-spinous arteries. There is no pterygoid foramen, and 

 likewise there is no foramen lacerum basis cranii, its place being 

 occupied by the large auditory bulla ; but there is a large fora- 

 men ovale through which passes the inferior maxillary nerve. 

 The foramen lacerum orbitale and the foramen rotundum are not 

 separated by a plate of bone. In the sheep the osseous promi- 

 nence which bounds the pituitary fossa behind forms a lamina 

 which curves forward, and is prolonged at its extremities into 

 two points, the posterior clinoid processes. 



The Temporal Bone. — In the ox, the sheep, and the goat 

 the petrous and squamous portions of the temporal bone are 

 always united. The zygoma is slender in ruminants. The 

 summit of the zygomatic process only articulates with the malar 

 bone. In the ox the condyle of the zygomatic process is very 

 wide and large and convex. The mastoid process is hirge. The 

 styloid processes are short and wide and greatly curved inwards, 

 and broader than in the case of the horse. The parieto-temporal 

 canal is very large, and it is entirely excavated in the temporal 

 bone. Its superior or internal extremity opens above the petrous 

 portion in an excavation, which represents the lateral cavity of 

 the parietal protuberance in the horse. At its inferior extremity 

 it always shows several orifices. The mastoid crest is united 

 with the upper root of the zygomatic process, and it is prolonged 

 below to the mastoid protuberance, which is very large. The 

 external auditory meatus is small, and directed slightly down- 

 wards. The tympanic bulla exists in ruminants, but it is not 

 markedly developed. In the case of the sheep and goat the 

 mastoid process is scarcely distinct from the crest, and the mas- 

 toid portion of the bone is only at a late period united with the 

 petrous portion. 



The superior maxilla is shorter but broader than that of the 

 horse, the maxillary spine consisting of, or rather being repre- 

 sented by, a rough protuberance, which is not continuous with 

 the zygoma. In fact, in the ox, sheep, and goat the maxillary 

 spine does not directly join the zygomatic crest. A curved line, 

 whose concavity is directed posteriorly, effects the union between 



