58 



Theriodontia — Galesam-idce. 



Reptilia, for, as in the carnivorous mammals, the incisors are 

 separated from the molars by well-developed canines, and the 



Table-case, 

 No. 17. 



iEluro- 

 saurus. 



Teeth of 

 Therio- 

 dontia. 



Fig. 77. — Anterior and right lateral aspects of a lumbar vertebra of Tapinocephalus 

 Athtrstonei (Owen); from the Karoo Beds, South Africa. About ^ nat. size. 



canines of the lower jaw cross those of the upper in front. In 

 many of the p^ener-a the npper canines are long and trenchant, and 

 the incisors large and close together (Lycosaurus, ^lurosaurus, 

 etc.), the molars, as a rule, being smaller than the incisors. In 

 most reptiles, living and extinct, the teeth that are worn away by 

 use, or otherwise lost, are replaced by others that are constantly 



Kic. 78. — Left lateral aspect of skull of Galesaurus planiceps (Owen), from the Karoo 

 beds (Triassic), South Africa (^ nat. size), a, an upper cheek-tooth, and 6, an incisive 

 tooth. 



forming in the jaws ; biTt there is no evidence of preceding teeth, 

 like the milk-teeth in mammal.s, nor of successional teeth, in the 

 jaws of the Theriodonts. From this negative evidence Sir Richard 

 Owen assumes them to have been " Monophyodont " reptiles, 

 having but one set of teeth, which were permanent, during life. 

 He has described eleven genera, varying in the size and form of 



