26 



tup: morphology of the. skull 



It is impossible to pass from the discussion of the skull of the Pehjcosauria without 

 speaking of its relations to cei-tain of the more primitive reptiles of the African region ; 

 it has been shown in the first part of this paper that there can be no relation as pre- 

 viously supposed between the more specialized African which are ancestral to the 

 Promammalia and the Pelycosauria but there is a group of very primitive forms 

 which show a very decided resemblance to the Pelycosaurs. 



In the prosecution of his valuable work on the Permian reptiles of South Africa 

 Broom has divided the original group Theriodontia into two groups, the Therocephalia 

 and Theriodontia ( : 03). These groups are characterized as follows : 



THEROCEPHALIA. 



" Medium sized I'eptiles, with temporal region supported by a single lateral arch. 

 Post frontals usually absent (present in Scylacosaurus), postorbitals and squamosals 



f 



Fig. 7a. Cross section through the skull of P. fer- 

 gusi after Broom. 



Fig. 7. The palate of J'roterosuchui fergusi, Broom after 



Broom. 



Fiu. 8. The palatal region of Scylacosaurus 

 sclaleri, Broom after Broom. 



