REPTILES 455 



gigantic size attained by some of these creatures, even in the 

 Trias, is shown by the footprints, some of which are 14 to 18 

 inches in length. Of the few American forms of which the bones 

 have been found, the best known is Anchisanrus from the Con- 

 necticut valley, and of the European genera, Zanclodon. 



The earliest Turtles are found in the Triassic of Europe, and 

 these first-known members of the order are as typically differen- 

 tiated as any of the later members. No doubt, the Turtles orig- 

 inated in the Permian, in some region as yet unknown, and 

 migrated to Europe in the Trias. The Theromorphs, which we 

 found beginning in the Permian, culminated in the Trias, espe- 

 cially in southern Africa. Of this group there are two Triassic 

 suborders, the Anomodontia and the Theriodontia. The former 

 have cutting jaws, like Turtles, and may or may not possess a pair 

 of great tusks in the upper jaw. Dicynodon, a genus of this sub- 

 order, has been found in southern Africa, India, and Scotland. 

 The Theriodonts present extraordinary approximations to the 

 mammals, and have left a great wealth of remains — some of 

 them very large — in the Karoo beds of South Africa, and less 

 abundantly in India. 



We thus observe a notable contrast between the Triassic reptiles 

 of Europe and North America, on the one hand, and those of south 

 Africa and India, on the other. In the northern continents the 

 fauna is much more diversified, and consists of Rhynchocephalia, 

 Crocodiles, Turtles, Ichthyosaurs, Plesiosaurs, a great variety of 

 Dinosaurs, and a few Theromorphs ; and associated with these 

 are many great Stegocephalous Amphibia. In south Africa the 

 reptilian fauna is almost^ entirely composed of an extraordinary 

 variety of Theromorphs, some of which were exceedingly curious 

 in appearance, and in size ranged from very large to very small 

 types. India was the meeting-ground of the northern and south- 

 ern faunas, and had representatives of both. 



The Trias has, as yet, yielded no Lizards, Snakes, or Pterosaurs, 

 all of which became very important at a later date. No birds are 

 known from this period, nor any reptiles which can be regarded 

 as the ancestors of birds. 



