South African Fossil Reptiles and Amphibia. 183 



keel formed by the junction of the ridges from the tubera, and 

 having its lower border considerably below the level of the basi- 

 occipital condyle. This condition is also seen in the primitive 

 Gorgonopsian Arctops and in the Therocephalian Scymnosaurus 

 watsoni. The basisphenoid keel passes forward almost to the 

 lateral process of the pterygoid, lessening in height anteriorly and 

 being clasped anteriorly and superiorly by the vertical pterygoid 

 plates. 



On the median line these pterygoid plates pass back almost to 

 the level of the back of the basisphenoid keel. They are at first 

 vertical, then turn outwards and finally downwards, so that in 

 section they have the appearance of a curved arch. The outer 

 ramus passes back presumably to the quadrate. 



In front of the basisphenoid keel there is a narrow, somewhat 

 elongate pterygoid vacuity, at the sides of the back of which the 

 powerful pterygoid flanges pass out to meet the transpalatine. 

 The transpalatine is comparatively small. 



There is a fair-sized suborbital vacuity. The inner posterior 

 border is formed by the pterygoid, which passes forward with the 

 same relation to the palatine as in Scymnosaurus watsoni. I am 

 not able to distinguish a median vomer. The pterygoid has a small 

 ridge bearing a few teeth. 



The front of the palate is not displayed, but it is probably 

 typically Therocephalian in structure. Its chief feature is its great 

 length compared with the breadth ; in fact, the whole palatal 

 aspect is long and narrow. 



The lower jaw is practically complete. The symphysis is loose 

 and low, the front of the jaw rapidly retreating. There is a large 

 and wide coronoid process to the dentary. The angular is large 

 and passes well forward to below the middle of the orbit. The 

 splenial plays no part in the symphysis. 



The following are some of the chief measurements of the type 

 specimen : 



Greatest length . . .... 240 mm. 



Greatest width .. (about) 110 ,, 



Snout to front of orbit .. .. .. ..Ill ,, 



Interorbital width . . . . . . . . . . 30.5 ,, 



Intertemporal width .. .. .. .. 11.5 



Length of temporal opening . . . . 58 



Type. Skull and lower jaw (S.A.M. Cat. No. 3415). 



Locality. Klipbank, Beaufort West Division, Cape Province. 



Horizon.- Lower Beaufort Beds (Tapinocephahis zone.) 



