REVISION OF THE PELYCOSAURIA OF NORTH AMERICA. 



INTRODUCTION. 



The vertebrate fauna of tlie Permian beds of North America was made 

 known as early as 1877-78, and quickly attracted the attention of Professor 

 Cope, who, with his wonderful acumen, saw the importance of the fauna 

 lying so close to the beginnings of the reptilian line. From the first 

 discovery of Permian reptiles until his death he retained his interest in the 

 group, some of his latest papers having to do with the orders Cotylosauria 

 and Chelydosauria. Much of the material in the collections of Professor 

 Cope is in a very fragmentary condition, and none of it was carefully 

 prepared while in his possession. He contented himself with the descrip- 

 tion of new forms without detailed study or complete morphological discus- 

 sion, and yet he based upon this material many of his most brilliant 

 generalizations ; and it is more surprising that he should have seen so 

 much and built so well than that he described some genera and species 

 that will not stand and drew some conclusions that have proven incorrect. 



From the discovery of Permian vertebrates in Texas until his death, 

 Cope sent parties into the field at irregular intervals, and the material 

 collected by them is now preserved in the American Museum of Natural 

 History in New York. These collections contain the types from Texas 

 described by Cope. A small collection made in Vermilion county, Illinois, 

 by Mr. William Gurley, and now in the Walker Museum of the University 

 of Chicago, contains the types from Illinois described by Cope. Another 

 small collection obtained from New Mexico by Professor Marsh is preserved 

 in the Museum of Yale University. The author made two collections 

 in Texas for the University of Chicago in 1895 and 1903 ; these are 

 preserved in the Walker Museum and contain the specimens upon which 

 was based the work of the late Doctor Baur and the author. In 1901 

 Dr. Ferdinand Broili, of Munich University, visited the Texas region, 

 accompanied by Mr. Charles Sternberg, and carried home many fine speci- 

 mens ; this, with a collection purchased by the Munich University a few 

 years before from the veteran collector, Mr. Charles Sternberg, constitutes 



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