RESTORATION OF SEYMOURIA BAYLORENSIS BROILI, 

 AN AMERICAN COTYLOSAUR 



S. W. WILLISTON 



The University of Chicago 



Few Permian vertebrates are of greater interest than the one 

 herewith figured, as restored from a remarkably complete speci- 

 men discovered the past year by Mr. Paul C. Miller in the vicinity 

 of Seymour, Baylor County, Texas. The genus and species were 

 originally described by Dr. Broili in 1904 from two imperfect 

 skulls, the clavicular girdle, and a few of the anterior vertebrae 

 and ribs, found on West Coffee Creek, Texas, and preserved in the 

 museum at Munich. Nothing whatever has since been added 

 to our knowledge of the genus, and the appendicular skeleton has 

 remained quite unknown. Of the numerous genera of amphibia 

 and reptilia from the Texas beds not a few are yet but imperfectly 

 known, making it almost impossible to determine many of the 

 isolated limb bones and girdle bones so often found in those regions. 

 The past year I described various limb bones and vertebrae of a 

 small reptile discovered on West Coffee Creek under the name 

 Desmospondylus anomalus, suggesting its possible identity with 

 either Seymouria or Pantylus, especially Pantylus, which also is 

 known only from skulls, one of which is in the University of Chicago 

 collections. The two specimens upon which this genus was based 

 are of almost identical size, indicating that the specimens were 

 of adult animals. They prove, however, by comparison with the 

 later acquired specimen, to be congeneric, and of very immature 

 individuals, so immature that they present a number of embryonic 

 characters not seen in the adult specimens, for by the aid of the 

 articulated specimen others of Seymouria previously indetermi- 

 nable have been recognized among the material of the University 

 collections, all from the same region and horizon, the upper or 

 Clear Fork division. And these additional specimens have aided 

 materially in the production of the restoration because of their 



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