South African Fossil Reptiles and Amphibia. 191 



Such a bone in the Gorgonopsia is said by Watson to be a fused 

 pair of prevomers and has been described by Broom as a true 

 unpaired vomer. A section across the median bar just in front 

 of the 'transverse bar" shows the upper surface of this bone 

 with a median ridge, bounded on each side by a broad shallowly 

 concave depression and a lateral rounded ridge. Lying to one 

 side of the median ridge is a narrow spike of bone which was 

 doubtless a vertical median septum before crushing. It may be 

 that in this skull we have a fused pair of prevomers and that the 

 thin median bone seen above it in section which passes back to 

 articulate with the pterygoids is the vomer. This latter may, 

 however, be the mesethmoid. 



Then the nature of the dentition is peculiar in that no molars 

 are present. It might be supposed that all the teeth had been 

 lost during life ; but both skulls show the same features, and 

 there are not even remnants of the alveoli still preserved, nor of 

 roots when seen in section. 



A portion of the lower jaw was found crushed on to the back 

 of the type skull. It is part of the right dentary. Near the 

 anterior end is a canine tooth, oval in cross-section. Just in front 

 of this is seen in cross-section a much smaller tooth, occupying the 

 position of an incisor. The outer surface of the anterior part of 

 the dentary is rugose. The dentary is long and slender. Behind 

 the canine the upper edge is regularly concave right back to the 

 coronoid process, so that when the jaw is placed in position in the 

 skull there is a wide gap between the upper and lower jaws behind 

 the canines. Posteriorly the upper border of the dentary narrows. 

 There is no distinct mentum, the dentary being thus more remi- 

 niscent of the Therocephalia or the Cynodontia than of the 

 Gorgonopsia. 



The lower jaw is more fully preserved in the co-type. The 

 symphysis is long and loose. The front of the jaw is prow-shaped 

 and there is no distinct mentum. Each dentary carries one large 

 canine, and, fairly closely in front of it, one incisor.* The dentary 

 is large and long, but not very deep, and has a very large coronoid 

 process. The bone forms almost as large, a portion of the lower 

 jaw as in Cynognathus, and certainly a greater portion than in a 

 Gorgonopsian such as Scymnognathus. The splenial is a small 



* In a specimen consisting of the front halves of both dentaries from Kruger's 

 Kraal, Graaff-Eeinet, 3 incisors occur in front of the canine. This specimen 

 probably belongs to the species under discussion. 



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