CRANIUM 



169 



upper part of the medial wall of the latter. The supraorbital process is short and 

 blunt-pomted, and is not connected with the zygomatic arch. The gap in the or- 

 bital margin is closed by the orbital ligament in the fresh state. The orbital part 

 IS extensive and forms the greater part of the medial wall of the orbit. Its upper 

 part IS perforated by the orbital orifice of the supraorbital canal, in front of which 

 IS the distinct fovea trochlearis. The ethmoidal foramen is situated in the ventral 

 part near the junction with the orbital wing of the sphenoid. The temporal part 

 IS very narrow and is separated from the orbital plate by a ridge which joins the 



Parietal bone 

 Temporal fossa 



Squamous lempornl 

 bone 



External acoustic 

 meatus 



Zygomatic process 

 of temporal bone 

 Supraorbital pro- 

 cess 

 Frontal bone 



Supraorbital fora- 

 men 

 Zygomatic process 

 of malar hone 

 Lacrimal bone 



Infraorbital foramen 



A'asal process of premaiilla 



Nasal bone 



Canine tooth 



Palatine fissure 

 Body uf premaxilla 



Nuchal crest 

 Temporal crest 

 Parietal crest 



Lacrirnal foramen 

 Preorbital fossa 



Fig. 179.— Skttll of Pig; Dorsal View. 



pterygoid crest below. The interior of the bone is excavated by the frontal sinus in 

 practically its entire extent in the adult. In the young subject the cavity is con- 

 fined to the anterior part and the rest of the bone is thick. 



The temporal bone has a general resemblance to that of the ox. The zygo- 

 matic process is short and stout and is bent at a right angle. The dorsal border of 

 the process is thin; traced from before backward it curves sharply upward and 

 forms a high prominence in front of the external acoustic meatus; beyond this 

 it drops rather abruptly and is then continued upward to the nuchal crest. The 

 anterior part of the ventral border joins the zygomatic process of the malar, which 



