194 Annah of the South African Muteum. 



The nostrils are large, close together, almost terminal, and 

 look upwards and forwards. 



The bones of the skull surface are similar to those of Scal<>/><'- 

 saurus. The frontal forms part of the orbital border. The parietal 

 crest is ridged, but the parietal region is fairly broad ; the temporal 

 openings are short. There is no postfrontal and no preparietal ; 

 but a pineal foramen is present. The postorbital arch was possibly 

 incomplete. 



The basicranial region is essentially similar to that of Xcalopo- 

 saurus. The occipital condyle is single. The large jugular foramen 

 looks almost entirely downwards. The basisphenoidal tubera 

 lying in front of the fenestrae ovales are stronger than in the 

 specimen figured by Dr. Broom. The two carotid foramina lie 

 one on either side of the posterior end of a short basisphenoid 

 keel. Anterior to this the pterygoids are separated by a V<T\- 

 long interpterygoid vacuity. The suborbital vacuity is present 

 as in the Therocephalia and is bounded by the transpalatine, 

 pterygoid, and palatine. 



A fracture across the interpterygoid vacuity shows a small 

 bone lying in the median line about 5 mm. above the level of the 

 basisphenoid keel. In cross-section it is seen to have a roundly- 

 keeled ventral surface and a shallowly concave broadened upper 

 surface. This bone is not seen as a separate bone in a section 

 taken a little further back, across the basisphenoid keel ; but the 

 upper surface of the basisphenoid is similarly grooved. On the 

 ventral surface of the latter bone there is a narrow groove on 

 either side of the median keel. 



Anterior to the interpterygoid vacuity the palate is slightly 

 vaulted and rises slightly anteriorly. The structure seems to be 

 similar to that of Scylacosaurus except that the distance between 

 the posterior nares and the transverse process of the pterygoid 

 is much shorter. The palatine occupies its usual position, forming 

 part of the posterior border of the internal narial opening and of 

 the anterior and inner borders of the suborbital vacuity, and 

 articulating with the pterygoid and prevomer medially. Its 

 inner portion has a longitudinal canal, covered both dorsal I y 

 and ventrally with a very thin layer of bone. I cannot be certain 

 of a median suture between the pterygoids. That between the 

 prevomers is very definite in the posterior half of the bones, which 

 reach very far back, but between them and the interpterygoid 

 vacuity it is not definite. On the other hand, the presence of 



