SOUTH AFRICAN THEROCEPHALIAN REPTILES. 349 



teeth. In many skulls when no molars are found we suspect 

 that they may have been lost, l)ut here this can hardly be the 

 case. Both maxilla? are well preserved and the dentary as well, 

 yet in none of the three bones is there any trace of molars. 

 Further, the alveolar margin is narrow and sharp, and would be 

 much too slender for the accommodation of molars large enough 

 to be serviceable to an animal of the size. 



The lacrimaJ is fairly large, and forms a considerable part of 

 the facial surface, which is veiy smootli. 



The prefrontal forms the ajiterior and upper quarter of the 

 orbital margin. It meets the frontal, nasal, maxilla, and 

 lacrimal bones. 



The frontals are relatively small, and the two form most of the 



Text-figure 5. 



Upper surface of skull of Alopecojysis atavus liroom. 



slio-htly conca,ve interorbital surface. In front each has a short 

 articulation with the nas;dand a much longer oblique articulation 

 with the prefrontal, and as the prefrontal nearly extends back- 

 w^ards to the postorbital, the frontal only forms a very small part 

 of the orbital margin. Posteriorly the frontal has a long articu- 

 lation with the postorbital, and a short interdigitating suture 

 with the parietal mainly liidden by tiie postorbital. 

 There is no postfrontal. 



The postorbital is a peculiarly twisted bone. Its inner end 

 lies against the narrow parietal crest, and from this, passing 



