86 Annals of the South African Museum. 



of the plate. It has a prominent median ridge in its lower half, 

 which barely passes over to the bone below. 



The most recent accounts of the basicranial region of the 

 Gorgonopsia have been given by Watson, who describes skulls of 

 Arctops willistoni and Scymnognathus whaitsi, discussing their 

 relations with Dimctrodon on the one hand and Diademodon on the 

 other. In Gorgonognathus the basioccipital condyle is rounded and 

 swollen below, and hollowed above for the reception of the foramen 

 magnum. The paroccipital process is short and powerful, forming 

 the lower border of the post-temporal fossa. It is considerably 

 in advance of the tabulare, and shallow when viewed from be- 

 hind, so that the post-temporal fossa looks almost wholly down- 

 wards. The exoccipitals are like those figured by Watson, and form 

 the lateral borders of the foramen magnum. The foramen jugulare 

 is at the bottom of the skull in front of the exoccipital, bounded by 

 that bone, the paroccipital, and the basioccipital, and looks wholly 

 downwards. 



The whole occiput is concave and the squamosals fairly wide. 

 The interparietal is narrow and the tabulare large as in Scymnog- 

 nathus. The interparietal carries a well-marked median ridge, 

 which dies out below on the supraoccipital. The tabulare forms the 

 outer upper border of the post-tempoi'al fossa, and covers part of 

 the back of the inner ramus of the squamosal. 



Thus this form, occurring as it does in the Cisteceplialus zone, 

 seems to occupy rather an anomalous position. In the width of the 

 parietal region, the shortness of the temporal fossae, the shape 

 of the basioccipital condyle, and the stoutness of the paroccipital 

 it agrees with Arctops. But in the reduction in height of everything 

 below the foramen magnum, the downward aspect of the post- 

 temporal fossae, the position of the foramen jugulare, and the size 

 of the squamosal, interparietal and tabulare it agrees with Scymnog- 

 nathus, indicating possibly an advance on that form. 



The palatal view of the premaxilla shows a somewhat pitted 

 flat plate anteriorly, which forms part of the inner border of the 

 large internal narial openings, and articulates behind with the 

 " vomer." 



This vomer is comparatively broad anteriorly and narrows behind. 

 It has ventrally a median keel and two lateral keels, with slight 

 intermediate grooves. Although the median suture separating the 

 two premaxillae can be well seen, there is no suture running down 

 the middle of this bone, and it is undoubtedly a single bone. For 

 some time Dr. Broom has considered that this median bone is a 



