28 Annals of the Soutli African Museum. 



cause of the blunting of the incisors the same was the cause of the 

 wearing down of the canines. Probably Scymnognathus tigriceps 

 preyed mainly on the contemporaneous Pareiasuchus p6ringueyi and 

 the prehensile teeth became ground down by friction against the 

 mud- and sand-crusted bony dermal plates during the struggles of 

 the powerful Pareiasaurian with its enemy. The fact that the 

 incisors and canines of the lower jaw are similarly ground down 

 renders this theory very probable. 



The sutures of the lachrymal and prefrontal are not very clear, but 

 both bones are evidently fairly large. The jugal forms a very deep 

 suborbital bar, and on passing back clasps the zygomatic portion of 

 the squamosal. 



The bones of the top of the skull resemble those of the more per- 

 fectly preserved Gorgonopsian Scylacops capensis. The preparietal 

 is in front of the pineal foramen, and the postf rental is very well 

 developed. The postorbitals and parietals are large, the former 

 forming the upper borders of the temporal fossae. 



The squamosal is very large, and remarkable chiefly by having the 

 zygomatic portion clasped by an outer and inner plate of the jugal. 



The interparietal is well developed and deep. It differs from that 

 of Scylacops in having a very prominent median ridge. At the sides 

 it meets the squamosal, and there is evidently no tabulare or other 

 bone at the side of the occiput as in some Therapsidans. In many 

 mammals there is a bone appearing on the lateral part of the 

 occiput, which is apparently rightly identified as an opisthotic. 

 What is possibly the same bone appears on the occiput of Cyno- 

 donts, and in the recent paper by one of us on the Cynodont skull it 

 was referred to as the opisthotic. Whether it is in the Cynodont an 

 opisthotic may be regarded as not yet proven, but that there is a 

 distinct element here is beyond question. In Dinocephalians there 

 is pretty certainly an element on the occiput which is neither squa- 

 mosal, parietal, or interparietal. In Anomodonts, Therocephalians, 

 and Gorgonopsians there does not appear to be usually at least any 

 extra element, but in Lystrosaurus there is a small lateral bone which 

 is evidently quite distinct from the parietal or squamosal. 



The palate is well preserved and very interesting. The basi- 

 sphenoid is somewhat Anomodont in character. It passes down 

 considerably below the level of the basioccipital, and forms a 

 deep median ridge which in front meets the median ridge formed 

 by the two pterygoids. Above, the basisphenoid forms a median 

 septum which passes upwards and forwards to near the front of the 

 orbital region. 



