THE TRIASSIC PERIOD. 



221 



also are long and pointed, very much compressed, and having 

 their lateral margins finely serrated, thus presenting a singular 



Fig. 154. Triassic Anomodont Reptiles. A, Skull of Dicynodon Jacerttcefls, showing, 

 one of the great maxillary tusks; B, Skull of Oudenodon Bainii, showing the toothless, 

 beak-like jaws. From the Triis of South Africa. (After Owen.) 



resemblance to the teeth of the extinct " Sabre-toothed Tiger" 

 (Machairodus). The bone of the upper arm (humerus) further 

 shows some remarkable resemblances to the same bone in the 

 Carnivorous Mammals. As has been previously noticed, Pro- 

 fessor Owen is of opinion that some of the Reptilian remains 

 of the Permian deposits will also be found to belong to this 

 group of the " Theriodonts." 



Lastly, we find in the Triassic rocks the remains of Reptiles 

 belonging to the great Mesozoic order of the Deinosaufia. 

 This order attains its maximum at a later period, and will be 

 spoken of when the Jurassic and Cretaceous deposits come to 

 be considered. The chief interest of the Triassic Reptiles of 

 this group nrises from the fact that they are known by their 

 footprints as well as by their bones ; and a question has arisen 

 whether the supposed footprints of birds which occur in the 

 Trias have not really been produced by Deinosaurs. This 

 leads us, therefore, to speak at the same time as to the evi- 

 dence which we have of the existence of the class of Birds 

 during the Triassic period. No actual bones of any bird have 

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