THE REPTILES OF THE KARROO FORMATION 249 



Contemporaneously with these large animals, there 

 were many small forms both herbivorous and carnivo- 

 rous. The herbivores belong to a group of reptiles 

 called Anomodonts, which form a much more important 

 element in the later faunas. Dicynodon, which is the best 

 known type, is represented in these later beds by a large 

 number of species, and continued almost unchanged from 

 this early period to near the close of the Karroo epoch. 

 Some species are not much larger than a rat, others pro- 

 bably stood three feet high. The larger sorts were heavily- 

 built animals which in general appearance must have 

 looked like small hippotami. The head, however, was 

 remarkable for having a large horny beak like that of a 

 tortoise, with the addition of two large tusks in the 

 upper jaw. With the exception of the peculiar appear- 

 ance of the head, the animal must have been singularly 

 mammal-like in build. Each foot had five toes, with the 

 same number of joints as in mammals, and provided 

 with large flat claws. Oudenodon was a closely allied 

 form which differed mainly in having no tusks. 



The carnivorous reptiles were even more mammal-like 

 than the Anomodonts. One form, in fact, only known by 

 the limb bones, was actually described as a mammal, and 

 for some years believed by everyone to be so. They be- 

 long to a reptilian order called Therocephalia, the skull 

 of which has a marked superficial resemblance to that 

 of mammals. The teeth are divided into incisors, 

 canines and molars, but frequently there are more than 

 one pair of eye-teeth in each jaw and the temporal arch is 

 formed on quite the mammalian pattern. The skull, 

 however, differs from the mammalian in having the 



