On a New Species of Scymnognathus (S. tigriceps). 27 



or sub-order Gorgonopsia for Gorgonops and a number of other allied 

 forms now known. 



Gorgonops torvus is met with in the Endothiocloii zone, and with it 

 is a larger allied form, Scymnognathus whaitsi. In the Pareiasaurus 

 zone a small Gorgonopsian has been found by the Kev. J. H. Whaits, 

 and named Scylacognathus parvus. And it is thus interesting to 

 note that while almost all the carnivores of the Pareiasaurus zone 

 are Therocephalians, when we come to the Endothiodon zone 

 Gorgonopsians are nearly as frequent as Therocephalians, and when 

 we get up 2,500 feet higher Therocephalians appear to be absent, or 

 at least much rarer than Gorgonopsians. 



As has been shown in the paper describing Sci/lacops, the 

 Gorgonopsians are probably the ancestors of both Anomodonts and 

 Cynodonts, and being thus on the direct mammalian line all new 

 facts concerning their morphology are extremely important. 



SKULL. 



The skull is nearly perfect, though slightly crushed. It agrees 

 closely with Scymnognathtis wlmitsi, though more powerful. From 

 the snout to the back of the squamosal measures 310 mm., and the 

 width across the zygomatic arches is 180 mm. The depth of the 

 snout from the nasal to the mentum is 175 mm. The interorbital 

 width is 80 mm., and the interternporal 93 mm. 



There is nothing of special note about the premaxilla or septomaxilla 

 except that the latter is very large, and partly divides the anterior 

 nares into upper and lower passages by a inwardly directed process 

 or turbinal. There is also the usual outer foramen between the 

 septomaxilla and the maxilla. 



The maxilla is very similar to that in Scymnognathus whaitsi. It 

 has a long posterior process which strengthens the suborbital arch 

 and extends to opposite the middle of the base of the postorbital arch. 



The teeth are remarkable. The dental formula is i 5, c 1, m 4 

 for the upper jaw. The incisors are all large except the last. They 

 occupy a space of 50 mm. Then follows a diastema of 23 mm. in 

 front of the canine, the antero-posterior diameter of which is 21 mm. 

 Behind the canine is a diastema of 20 mm., and this is followed by 

 i molars which occupy a space of 30 mm. The first three molars 

 are larger than the 4th. All are simple pointed teeth, and we 

 fail to observe any serrations. All the incisors and the canines have 

 their points worn down, and this must have been done during the 

 life of the animal. Further, this wearing could only have taken 

 place when the jaws were widely opened, and whatever was the 



