112 EXTINCT MONSTERS 
of carnivorous mammals ; for the incisors are separated from the 
molars by well-developed canines, and the canines of the lower 
jaw crossed those of the upper in front. In some of the members 
of this family the upper canine teeth are long and trenchant, and 
the incisors large and close together. Visitors to the Natural 
History Museum will find a most valuable set of specimens of the 
skulls, ete. (Gallery IV.). 
In most reptiles, living and extinct, the teeth that are worn 
away by use, or otherwise lost, are replaced by others that are 
constantly forming in the jaws; but in the case of Theriodonts 
there is no evidence of preceding teeth, like the milk-teeth in 
Fia. 31.—Right side-view of skull and mandible of a Theriodont (Alurosaurus 
felinus), 2 natural size, with two upper teeth, natural size (a, b), from the Triassic 
Karoo Formation of Beaufort West, Cape Colony. Behind the large orbit the 
back part of the skull is broken away. (After Owen.) 
mammals, nor of succeeding teeth, like the crocodile’s. Sir R. 
Owen therefore concluded that these creatures had but one set of 
teeth, which lasted through life. He has described eleven genera, 
varying in the size and form of the skull and teeth; they are all 
from South Africa, and are figured in his Catalogue of the Fossil 
Reptiles of South Africa. 
The work of describing and classifying Anomodont reptiles has 
