ON ANOMODONT REPTILES FROM SOUTH AFRICA. 647 



PAPERS. 



35. On some new Genera and Species o£ Anomodont Reptiles 

 from the Karroo Beds of South Africa. By R. Beoom, 

 F.R.S., C.M.Z.S. 



[Received April 6, 1921 : Eead May 24, 1921.] 



(Text-figures 28-45.) 

 INDEX. 



The genus Dicynodon was estabHshedby Owen in 1845 for the 

 remarkable South African fossil reptiles discovered by Bain and 

 referred to by him as Eidentals. As the result of the labours of 

 Owen, supplemented by that of later workers, nearly every detail 

 in the structure of the skeleton of Dicynodon is now as fully known 

 as that of the Dog. It was a primitive reptile with a skeleton built 

 essentially on the same plan as that of the mammal, but with 

 certain remarkable specializations of the skull, especially in the 

 complete loss of incisor teeth, the presence of a lai'ge permanently 

 growing canine in the male, and in the fact of the front of the 

 upper and lower jaws having formed a horny beak as in the 

 tortoise or bird. 



While there remains little to add to our knowledge of the 

 skeleton, there is still much to be done ere we have anything 

 like a satisfactory knowledge of the large number of species 

 which must be referred to the genus. 



Dicynodon first occurs in South Africa at the base of the 

 Pareiascmi:us zone, which may be regarded as Middle Permian 

 in age, and it extends through all the zones to the top of the 

 Permian, and forms which are very closely allied, if not indeed 

 referable to Dicynodon, are met with to the top of the Trias. A 

 form closely allied to Dicynodon occurs in the Dwina of Russia, 

 and Placerias of the Trias of North America is, if not Dicynodon 

 also, at least very closely allied. 



Oudenodon, originally described as a distinct genus difiering 

 from Dicynodon in the absence of the tusk, we now know to be 

 the female. So long as all the known species of Oudenodon 

 differed from the known species of Dicynodon in other characters 

 besides the absence of the tusk, it was felt wiser to keep Oudenodon 



Proc. Zool. Soc— 1921, No. XLIY. 44 



