SKULLS OF CYNODONT llEPTILES. 



915 



postorbital arch. In the drawing given the lower margin is 

 entirely hypothetical. The posterior or zygomatic portion of the 

 bone is very short. 



Text-fis. 180. 



Upper view of skull of Sesamodon hroivni, restored from t-lie type. From the specimen 

 the whole of the frontals, parietals, and most of the occiput have weathered away, 

 so that these parts are unknown. As, however, the prefrontals, postorbitals, and 

 the margins of the orbits and temyioral foss<« are preserved, the only points 

 that are left in doubt are the position of the frontO'parietal suturCj whether 

 there is a parietal forameuj and the nature of the condyles. 



The squamosal is sufficiently well preserved to show its main 

 features, and it is seen to be unlike that of any other Cynodont. 

 As in Bauria it is much smaller than in the higher types. It 

 articulates, as in other forms, with the parietal, but on passing 

 outwards it has not, as in Bauria^ a posterior ridge. The zygomatic 

 portion is much shorter than in Bauria or any other known type, 

 but it is relatively fairty deep. 



What appears to be the quadrate is a small flattened bone which 

 I have shown in the figure, but the parts are crushed and some- 

 what displaced, and it is impossible to speak with certainty of the 

 condition. 



