ON THE SKULL OF CAR^fIV0E0U3 UINOCaPHALIAN REPTILES. 661 



34. On the Strncturc of thn Skull in Uie Carnivorous 

 Dinocoplialian Reptiles. Bj^ 11. Buoom, JVI.D., F.R.S., 

 C.M.Z.8. 



[Received May 7, 1923 : Read June 12, 1923.] 

 (Text-figures 1-17.) 



Index. 



Piiga 



Scapaiiodon duplessisi Broom 663 



Dinoplioneus itigens, gen. et sp. nov 666 



Dinartamus vanderhyli, g:en. et sp. nov 669 



Tftpinocophdlia, new Suborder of Dinoceplialia 671 



Titanosucliia, new Suborder of Dinoceplialia G71 



Jhirnetia mirabilis, gen. et sp. nov 671 



]5arnetiamorplia, now Suborder of Thoriodontia 673 



Classification of tbe Tberapsida 674 



Addendum 675 



Miu\>\\h\e o{ Tita7iosucJms cloetei iJroom 676 



Mnohkis struheni, gen. et sp. nov 683 



Though our knowledge of the structure of the Anomodoutia 

 and of the various suborders of the Theriodontia is fairlj com- 

 plete, the more primitive groups^the Dromasauria and the 

 Dinocephalia — are still very imperfectly known. Of the Dino- 

 ceplialia we know a good deal of both the skull and skeleton of 

 the Tapinocephaloid group, but of the TitanosuchusA\kQ forms 

 we know very little of either the skull or skeleton. The present 

 .short paper will add something to our knowledge of these latter 

 types. 



The chief reason why so little is known of the giant Dino- 

 cephalians while the Anomodonts and Theriodonts are so well 

 known, is that the Dinocephalians in South Africa are in older 

 beds, where they cannot be easily picked out from a loose shale, 

 but are usually in masses of extremely hard limestone. If 

 unweathered out it is only with great difiiculty that the bone 

 can be distinguished from the matrix ; and when weathered 

 usually much is hopelessly gone and probably much still in the 

 very hard .stone. Hence it happens that only a verj^ few skulls 

 are in any museums, and, so far as I know, only two mounted 

 skeletons. 



The first Dinocephalian remains from South Afi'ica were 

 collected by Dr. W. G, Atherstone in 1872 and described by 

 Owen in 1876. The front end of a snout of a large form was 

 named Tapinocephalus atherstonei. Some vertebrse and other 

 remains were referred to this species, but theie is some doub|t 



Proc. Zool. Soc— 1923, No. XLIY. 44 



