X.] RODENTIA. i6i 



In the mandible, the symphysial portion is narrow, curving 

 upwards, and rounded laterally, with a single large alveolus 

 on each side. The coronoid process is never large, and is 

 oftenrudimentary or absent, in relation to the small develop- 

 ment of the temporal fossa and muscle ; while the portion 

 adjacent to the angle is greatly developed, showing marked 

 masseteric and pterygoid foss?e, and often with its lower 

 edge expanded laterally, or slightly incurved. The angle is 

 rounded in the Hares, but it is more often produced into a 

 long backward process, more or less pointed and upturned. 

 The condyle is considerably elevated, with a rounded 

 articular surface, usually longer from before backwards than 

 from side to side. 



The hyoid has a transversely extended basihyal and a 

 straight compressed rod-like thyrohyal, often ankylosed with 

 the basihyal. The anterior arch is long, but mostly liga- 

 mentous, the ossification being usually confined to the lower 

 part (cerato- and epi-hyals). In the Hares, the basihyal is 

 deep from above downwards, and compressed, keeled, or 

 pointed in front. 



M 



