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THE AMEBIC AN NATURALIST [Vol. XLVHI 



tologists and even Case was very reticent in his sugges- 

 tion that they were much farther apart than was usually 

 thought. Following the generally conceived idea of Nao- 

 saurus a composite mount was prepared in the American 

 Museum of Natural History in New York in which the 

 skull and limb bones of a Dimetrodon were associated 

 with the vertebral column of a Naosaurus. This restora- 

 tion was published by Dr. Osborn in the Bulletin of the 

 American Museum and a model of the creature in the 

 flesh was prepared under his direction by Mr. Chas. 

 Knight. Case in his "Bevision of the Pelycosauria of 

 North America" republished this restoration by Osborn 

 but at the same time published an alternative restoration 

 in which the skull described as Edaphosaurus was asso- 

 ciated with the vertebral column of Naosaurus and the 

 two genera were united under the former name, as it had 

 priority. 



The composite restoration prepared at the American 

 Museum has gained wide circulation in the text books but 

 later discoveries have shown that it was unfortunate. In 

 the summer of 1911 Dr. F . v. Huene, of Tubingen, while 

 a guest of the joint expedition from the universities of 

 Chicago and Michigan to the Permo-Carboniferous beds 

 of New Mexico, discovered the remains of a skeleton of 

 Edaphosaurus in which both the skull and a portion of 

 the vertebral column were preserved. As the vertebrae 

 bore the typical cross-pieces of the genus Naosaurus the 

 identity of the two genera was established but new evi- 

 dence was speedily coming; Case in the summer of 1912 

 discovered in the Permo-Carboniferous beds of Archer 

 County, Texas, the nearly perfect vertebral column of an 

 Edaphosaurus (Naosaurus) cruciger Cope with the limb 

 bones, and a crushed skull, identical with the skull origin- 

 ally described as Edaphosaurus. 



From this skeleton, now preserved in the museum of 

 the University of Michigan, the author has prepared the 

 restoration shown in Fig. 1. The only conjectural parts 

 are the size of the feet and the length of the tail ; the re- 



