South African Fossil Reptiles and Amphibia. 



213 



The specific identity is doubtful, as the dentition is not well dis- 

 played, but the form is from the middle or top of the lower half 

 of the Tapinocephalus zone. The pro-otic has similar features 

 to that of Alopecognathus minor except that the anterior processes 

 are more vertical and longer. 



Pr 



FIG. 59. Irregular longitudinal section of Therocephalian No. 

 4332. 



A fracture has shown the posterior ramus of the pterygoid, a 

 thin arched plate of bone which posteriorly forms the outer border 

 of the fossa which opens into the brain-cavity laterally through 

 the pituitary fossa. 



Articulating with the outer face of this plate and rising directly 

 upwards from it is a fairly broad thin slightly curved lamina of 

 bone which articulates above with the parietal. The posterior 

 limit of this bone, which must be the epipterygoid, is not seen ; 

 but the plate appears to have extended sufficiently far back to 

 have covered the pituitary completely from side view. 



There is a fairly large elongate interpterygoid vacuity. A 

 median section shows a thin median vertical plate of bone lying 

 some distance above this which plate may be an anterior pro- 

 longation of the basisphenoid or a parasphenoid. Above this is 

 a median bone whose cross-section is an inverted V ; and in contact 

 with the dorsal ridged surface of this is a hollow cylinder of bone 

 which may be open at the top below the roofing bones of the skull 



