RESTORATIONS OF SOME AMERICAN PERMOCARBON- 

 IFEROUS AMPHIBIANS AND REPTILES 



S. W. WILLISTON 



University of Chicago 



(with illustrations by the author) 

 The drawings illustrating the present paper were made in the 

 hopes thereby of learning more concerning the animals as living 

 organisms. Depending exclusively upon dried and petrified bones, 

 the paleontologist is apt to forget that his fossils were once parts 

 of living, active beings. Nearly all the restorations are based upon 

 practically complete skeletons preserved in the museums of the 

 University of Chicago or Yale University, technical descriptions 

 of which have been published in various places during the past few 

 years. Their living restorations, except that of Eryops, are here 

 attempted for the first time. I will not attempt to give any tech- 

 nical details of their structure here; my only desire is to place 

 before the general student of geology something of what I see, 

 after years of study of the fauna, in some of the animals that lived 

 in Texas and New Mexico during the closing times of the Pennsyl- 

 vanian and the early times of the Permian. 



The land vertebrate fauna of those times in America must have 

 been very rich. More than forty distinct genera of amphibians 

 and reptiles are represented in the collections of the University 

 of Chicago, and the remains of at least a dozen more are preserved 

 in the American Museum and at Yale University. It is the oldest 

 fauna of reptiles known in the world, and by far the most compre- 

 hensive of the older amphibians known. The animals of the South 

 African Karoo system are nearly all of later age. Upper Permian 

 as distinguished from Lower Permian and Carboniferous, and they 

 were, for the most part, more highly specialized and less primitive. 

 And the light these animals of the American Permocarboniferous 

 have thrown upon the evolution of the higher vertebrates is very 

 great, though there is very much more to learn. The primitive 



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