Professor R. Broom — The Skull of Tapinocephalus. 401 



probable shape being represented by the dotted lines. Fig. 2 

 represents the under side of the skull, and shows a most interesting 

 condition of the palate. Between the large internal nares are a pair 

 of prevomers, and behind and to the outer side of the nares a pair of 

 small palatines. The pterygoids are large, and in front meet the 

 prevomers. Externally they form large descending processes along 

 the inner sides of the mandibles. There are no teeth on the palate, 

 and there appears to be no transpalatine. 



Fig. 1. Profile of skull of TajAjwcephalus athcrstoni, Owen: Karroo formation, 

 S. Africa (greatly reduced). 



The occiput is very large and slopes upwards and backwards. In 

 general structure it appears to resemble that of Bicynodon, but it is 

 not well preserved in either specimen. The condyle is large and 

 rounded and the foramen magnum small. There is a very large 

 exoccipital which meets the descending squamosal and also the 

 quadrate. As in Bicynodon there appears to be an ossified tympanic. 

 As preserved the skull measures 500 mm. in length, but if uncrushed 

 would pi'obably be about 30 mm. more. 



Of skulls hitherto described the only one closely allied to that of 

 Tapinoceplialus is Belphmognathiis. Though Tapmoccphalus differs from 

 Belpliinognathus in having a very feeble dentition, there is little doubt 

 it should be placed in the same sub-order, Dinocephalia of Seeley. 



The Dinocephalians have relations with both the Therocephalians 

 and the Anomodonts. In the structure of the palate they come 

 nearest to the Therocephalians, but in most other respects the affinities 

 appear to be nearer Bicynodon and its allies. Most probably they are 

 an offshoot from an early Therocephalian closely related to that which 

 started another line of descent and gave rise to the Anomodonts. 



Though the locality of Seeley's specimen is unknown, there can be 

 little doubt it is from the Pareiasauriis zone of the Gouph. 



In examining Owen's type in the light of this new skull it becomes 



DECADE V. — VOL. VI. NO, IX, 26 



