178 THE SKULL. [chap. 



There is a small distinct interparietal. The frontal region 

 is broad and flat. The zygoma is tolerably strong, and 

 formed mainly of the malar, which extends backwards so as 

 to form the outer wall of the glenoid fossa, but it is supported 

 anteriorly by a strong process from the maxilla. The orbit 

 / is bounded posteriorly by well-marked postorbital processes 

 J which sometimes meet, the lower one from the malar, and 

 j the upper one from the parietal (a very unusual condition). 

 The lachrymal is small, and scarcely extends at all on to 

 the face, but sends outwards a strong antorbital process (as 

 in the Rhinoceros and Elephant). The face is short, and 

 compressed laterally. The nasal bones are wide posteriorly, 

 and anteriorly are either truncated, or more produced at 

 their outer than their inner margins. The premaxillae do 

 not send up processes to meet the frontals, as in all 

 Rodents. 



The palate is not produced posteriorly beyond the middle 

 of the last molar tooth. The palate bones are large. The 

 pterygoids very slender. There are well-marked pterygoid 

 fossae, and alisphenoid canals. The paroccipital processes 

 are long and slender. The glenoid fossa is wide transversely, 

 and with a considerable postglenoid process. The periotic 

 and tympanic are ankylosed together, but usually remain 

 distinct from the squamosal. The tympanic forms a 

 moderate-sized bulla, and a spout-like floor to the external 

 auditory meatus, between the glenoid and post-tympanic 

 processes of the squamosal. The periotic has a very slight 

 floccular depression, and sends backwards no distinct mas- 

 toid process. The pituitary fossa is very shallow, without 

 clinoid processes. The foramen rotundum and foramen 

 ovale are distinct perforations through the alisphenoid. The 

 optic foramen pierces the large orbitosphenoid near its 

 hinder margin. 



