THE SKULL 



159 



Ti'iiipordl crest 

 Cvroniiid process 



Frontal hone 



Orbit 



Supraorbital 

 foramen 



Inr bone 

 lacrimal bons 



since the basal lamella of the ventral turbinate bone curves ventro-medially, joins 

 the palatine bone, and is separated only by a narrow hiatus from the nasal plate of 

 the palatine process of the maxilla. The anterior palatine foramen is at the trans- 

 verse palatine suture. The anterior end of the palatine process tapers to a point. 

 The maxillary sinus resembles that of the ox, but is relatively small. 



The premaxilla has a narrow and pointed body. The palatine process is ex- 

 tremely narrow in front and is grooved laterally. The palatine fissure is long and 

 narrows to a very acute angle behind. 



The palatine bone resembles that of the ox, but there is no air-cavity in its 

 horizontal part. The spheno- 

 palatine foramen is large and Occipital bone Parietal hone 

 oval. 



The pterygoid bone is 

 very broad above and narrow 

 below, where it ends in a sharp- 

 pointed hamulus. 



The nasal bone tapers to 



a point at its anterior end, 



which is not notched. 



The facial part of the 



lacrimal bone has an elongated 



quadrilateral outline; in front 



of the orbit it forms, with the 



adjacent part of the malar, the 



external lacrimal fossa (Fossa 



lacrimalis externa) which 



lodges a cutaneous cul-de-sac 



known as the infraorbital or 



lacrimal pouch. The bone here 



may be more or less cribriform. 



The lacrimal bulla is relatively 



small, is usually cribriform, 



and has a pointed posterior 



end; the maxillary sinus ex- 

 tends into it. The orbital 



margin forms a distinct promi- 

 nence, and behind the latter is 



the fossa for the lacrimal sac. 

 The facial part of the 



malar bone is extensive and . 



quadrilateral. Its upper part concurs in the formation of the external lacrimal 



fossa- this area is limited below by a curved crest which continues backward on 



the zygomatic process. The latter divides into two branches, as m the ox. 



The turbinates and the vomer resemble those of the ox. , , , . 



The mandible differs from that of the ox chiefly in that the ventral border of 



the ramus, from the body to the angle, is only slightly curved. 



On account chiefly of the limited extent of the frontal sinuses, the cranial 



cavity corresponds to the external form of the cranium more closely than is the case 



in the ox. It is ovoid, and is much longer relatively, but has a much shorter dorso- 



ventral diameter than that of the ox. The parietal bone forms a distmct ridge on 



the lateral wall between the cerebral and cerebellar compartments, but, on the other 



hand, the petrous temporal projects very little into the cavity _,,:,ik. 



The nasal cavity resembles that of the ox, but is relatively narrow (especially 



anteriorly), and there is no large hiatus in the nasal plate of the maxilla. 



Facial tuberosity 

 Maxilla 



Nasal hone 



Nasal process of pre- 

 maxilla 



Palatine process of pre- 

 maxilla 

 Palatine fissure 



Body of premaxilla 



Incisor teeth 



Fig. 162. — Skull of Sheep; Dorsal View. 



