NEW FOSSIL 11EI>T1LI;S. 871 



hidden by the postorbitals. There has been a little doubt as to 

 whether the pair of bones usually supposed (Seeley, Broom, etc.) 

 to be parietals are really the parietals, or whether the median 

 bone in which lies the pineal foramen, and usually called the 

 pi'eparietal (Seeley, Broom) or interparietal (J^ewton), may perhaps 

 be the true parietal. This latter view has recently received the 

 support of Jaekel. The median bone, called for convenience 

 preparietal, is met with in most Anomodonts. In some [Endo- 

 thiodon) it is very large; in others (Cistecephahts) it is quite 

 absent. The size of the paired bones depends to a considei'able 

 extent on the development of the preparietal. In Gistecephalus 

 there can hardly be any doubt that the large pair of bones behind 

 the frontals are the parietals. They have the same relations to 

 the squamosals, interparietal, frontals, and postorbitals as the 

 parietals have in most reptiles, and there can be, I think, no 

 reasonable doubt but that these bones are homologous with the 

 parietals of the mammals. When the preparietal appears and 

 the intertemporal region becomes narrowed the parietals are 

 much reduced in front, but posteriorly the relations to the 

 squamosals, interparietal, and postorbitals remain constant. In 

 Endothiodon the preparietal is so large that the parietal seems to 

 be completely separated from it by the frontal. In Dicynodon, 

 as exemplified by this skull, the parietals still meet the frontals. 

 What the preparietal is, is not clear. It certainly is not the 

 intei^parietal. I am inclined to look on it as a neomorph 

 developed in connection with the pineal eye. There is no trace 

 of it known in Dinocephalians, Dromasaurians, Pelycosaurs, 

 Therocephalians, or Cynodonts, though in some of these the 

 pineal eye was probably as large as even in Endothiodon. 



There is little of special note in the palate or occiput. 



The horizon from which the specimen was obtained is probably 

 about 300 feet above that of Beaufort West. 



Emydops minor, gen. et sp. n. (PL XCIII. fig. 20.) 



When Owen, in 1876, described the specimens of Gistecephalus 

 in the British Museum, he named one species Kistecejjhcdus 

 arctatus and referred two specimens to it. The type differs very 

 considei-ably from Gistecephalus onicrorhinus, the type species of 

 the genus, and Lydekker in his Catalogue places G. arctatus 

 doubtfully under Gistecephalus. On more than one occasion I 

 have also expressed the opinion that G. arctatus does not belong 

 to Gistecephalus. 



Recently, I discovered at Kuilspoort a small imperfect skull 

 which apparently belongs to the same genus as Owen's G. at'ctatus, 

 though a distinct species. Pretty certainly the genus is not 

 Gistecephalus, and the question arises, is it Oudenodon, or rather 

 Dicynodon ? The only specimens known are tuskless, and there 

 are apparently no molar teeth. In the imperfect state of the 

 s[>ecimens it is impossible to clearlv diflferentiate the genus from 



5b* 



