SOUTH AFRICAN FOSSIL REPTILES 



143 



lection [See illustrations in December 

 Journal]. 



The study of these various faunas of 

 South x\frica shows the progressive evo- 

 lution from the verv earlv mammal-like 



reptiles that preyed on the huge, slow- 

 moving Pareiasaurus to the Cynodonts of 

 later beds, carnivorous animals which are 

 so like mammals that it is only with diffi- 

 culty that they can be distinguished. 



A complete skull of the Dicynodon leontops, about one-third natural size. This is the only known 

 large Dicynodon in which the tusks are perfectly preserved. Although in the specimen they are some- 

 what crushed together, there is no doubt that the lower jaw passed up between the tusks. The inner 

 sides have been ground down by the rubbing of the lower jaw against them. Both tusks are blunt and 

 would probably be of little service as weapons of offense 



