THE AGE OF REPTILES 



49 



the United States more than fifty genera and twice that many 

 species of amphibians and reptiles have been made known in 

 recent years, and doubtless as many more will be discovered in the 

 future. From other parts of the world the history of reptiles of 

 the Lower Permian is yet scanty, two or three forms from South 

 America, as many more from Africa, and a half-dozen or so from 

 Europe are all; and of these very few are known at all well. 



We classify all the known forms of reptiles from the Lower 

 Permian under three or four orders, 

 the Cotylosauria, Theromorpha or 

 Pelycosauria, Proganosauria, and 

 possibly the Protorosauria, but the 

 classification is yet provisional, 

 representing merely the present 

 stage of our knowedge. The Pro- 

 ganosauria and Protorosauria, 

 including distinctively aquatic 

 reptiles, will be more fully 

 described in the following pages. 

 To give even a brief description of 

 the more terrestrial reptiles of this, 

 the earliest known reptilian fauna, 

 would be beyond our purpose; the 

 accompanying life restorations by 

 the author of some of the more 

 typical and better known forms, 

 based upon nearly perfect skele- 

 tons, will suffice. 



From the reptiles and amphib- 

 ians of the Lower Permian of Texas and New Mexico to the 

 ichthyosaurs of the Middle Triassic of California there is a 

 complete gap in the records of the land life of North America. 

 We do not know what became of all the remarkable animals 

 of the Permian. There are few traces of their descendants else- 

 where known, unless it be in South Africa. From the Middle 

 and Upper Permian of South Africa and Russia, a marvelous rep- 

 tilian fauna has been made known in recent years. More than a 



Fig. 26. — Captorhinus, a cotylosaur 

 reptile from Texas, about one-fourth 

 natural size. 



