On some Gorgonopsian Skulls. 517 



mers on to the central part of the palate and, at the same time, 

 the retrogression of the pterygoids from the posterior border of the 

 internal nares. There does not seem to be clear evidence of this 

 change in the Gorgonopsia; but the occurrence of the prevomers as 

 an essential part of the Therocephalian palate behind the plane of 

 the internal nares is a significant fact bearing on the question of 

 the origin of the Cynodonts. It is desirable that more should be 

 known of the details of the Therocephalian palate; the later forms 

 like Akidnognaihm and Moschorhinus are at one with earlier genera 

 such as Ictidosuchus, Alopecognathus and Scylacosaurus in having the 

 prevomers passing back between the palatines to articulate with the 

 pterygoids. 



