862 DR. R. BROOM ON 



published in 1910*. Within the last few months Mr. Whaits 

 has fortunately discovered a good skull of Gorgonops which shows 

 that it has quite a lai-ge temporal opening, very similar to that 

 in the present genus. 



In general appearance Scymnognathvs differs from the more 

 typical Therocephalians mainly in having the intertemporal region 

 about as wide as the interorbital. The snout is long, the orbits 

 small, the temporal region fairly wide, and the squamosals more 

 powerfully developed than in most Therocephalians. 



The total length of the skull is, in the type, 305 mm. In a 

 second but much crushed specimen the length is probably about 

 325 mm. From the front of the snout to the front of the orbit 

 the measurement in the type is 165 mm., and the length of the 

 orbit about 40 mm. The interorbital width in the type is 70 mm. : 

 in another very imperfect specimen it measvires 78 mm., and in a 

 third about 76 mm. The narrowest part of the parietal region 

 measures in one of the larger specimens 78 mm. 



The parietal foramen is situated well back and is 6 mm. in 

 diameter. 



Though the limits of many of the bones cannot clearly be made 

 out, much of the cranial structure can be seen. The bones of the 

 snout seem to agree with those of the better known Thero- 

 cephalians, though the septomaxillary is relatively larger. The 

 jugal is unusually well developed and the postorbital is very large. 

 The postfrontal also seems to be much larger than in any other 

 type hitherto examined. The squamosal is more massive than in 

 most Therocephalians, and the quadrate is relatively small and 

 largely hidden by the squamosal. The occipital condyle is single. 



The lower jaw is fairly similar to that previously described 

 and figured in Lycosuchus and Aloposaurus. The front of the 

 dentary is vei-y deep and has a well-marked mental process. 

 Posteriorly the dentary has a shoi't coronoid process and for a 

 considerable distance lies above the angular. The surangular is 

 much smaller than in other known Therocephalians. 



There a.re five upper incisors, one large canine and three or four 

 molars. The incisors are long pointed teeth, oval in section, and 

 apparently without serrations. The space occupied by the five 

 incisors in three specimens is 37 mm., 39 mm., and 40 mm. The 

 space between the last incisor and the canine in four specimens is 

 18 mm., 22 mm., 25 mm., and 26 mm. The length of the canine 

 in seven specimens is 16 mm., 18 mm., 20 mm., 20 mm., 20 mm., 

 20 mm., and 21 mm. Behind the canine is a diastema varying from 

 7 mm. to 16 mm., followed by either three or four molars. The 

 number of molars apparently depends on age. When three molars 

 are present the distance occupied by them is 20 or 21 mm. : when 

 four are present they occupy 25 mm. to 29 mm. 



The dental formula is, i. t, c. - m. „ — . . 

 ' 4 ' 1 3 or 4 



* " Observations on some specimens of South African Fossil Reptiles preserved in 

 the British Museum." Tr. Roy. Soc. S. Afr. vol. ii. pt. 1, 1910, p. 20. 



