Cope,] «>^ [May 7, 



in Eryops and Cricoius, gives tlie following result : The glenoid cavity is 

 an excavation in two coossified elements, of which the inferior and posterior 

 is probably coracoid. The latter is then much smaller than in Beptilia and 

 BatracMa anura, but resembles that of the salamanders. The scapular 

 arch proper resembles that of the JJrodela. The pelvis is intermediate 

 between that of the anurous and urodelous BatracMa. There is no obtura- 

 tor foramen, and the common symphysis is deep. The humerus closely 

 resembles that of the Pelycosauria, differing chiefly in the non-enclosure 

 of the supracondylar foramen ; and as in that sub-order, some genera 

 possess condyles and some do not. 



Prof. Owen proposed the order Oanocephala chiefly for Archegosaurus, 

 but he included in it also the genera Deriderpeton and Pelion (Paleontol- 

 ogy, p. 182-3). This division has not been generally adopted, the genera 

 mentioned being usually placed in the Labyrintliodontia. Of the eleven 

 characters given by Prof. Owen in evidence of the existence of this order, 

 one only does not belong also to the Labyriniliodontia ; this is the absence 

 of occipital condyles. On this account I thought that the group should be 

 retained, but not as an order. Besides this group and the Labyrintlio- 

 dontia, there Avere the types called MiGrosaitria by Dawson, some of 

 which have simple enamel, all agreeing in general characters, and differ- 

 ing from other Batrachia. I therefore combined the three groups into 

 one order, the Stegocephali. (Proceedings, Academy, Philada., 1868, p. 

 209.) This order was most distinctly characterized in the Report of the 

 Geological Survey of Ohio, Paleontology, ii, p. 354, 1875. 



Von Meyer has given us enough of the cliaracters of Archegosaurus 

 to enable me to refer the forms of the Texan Permian to the same order. 

 Prof Owen, in his discussion of the afiinities of that genus (1. c, p. 170), 

 remarks, that the vertebrae and numerous very short ribs, with the "indi- 

 cations of stunted swimming limbs, impressed me with the conviction of the 

 near alliance of the Archegosaurus with the Proteus and other perenni- 

 branchiate reptiles." As it is now well known that perennibranchiate 

 batrachians belong to three different orders of the class {Trachystomata, 

 Proteida and Urodela), the above expressions lose point, and especially as 

 the characters mentioned as indicative of affinity are of the most subordi- 

 nate importance, or as in the structure of the vertebrae, are totally distinct 

 from what is found in those orders. When we read later (p. 173), that the 

 fact that the superior "ossifications of the skull have started from centres 

 more numerous than those of the true vertebral system, gives the charac- 

 ter of the present extinct order of Batrachia ; " we find that Prof Owen 

 has quite failed to perceive either the definitions or affinities of his new 

 order. He commits an error in describing a distinct pubic bone ; an ele- 

 ment which Von Meyer states (Paleontographica, vi, 179, 1858) that he 

 had not discovered. Von Mej^er describes the coossified inferior elements 

 of the pelvis as ischia. My numerous Texan specimens show that each of 

 these bones includes both ])ubis and ischhim. 



In now defining the G anocepihala anew, T confine myself to characters 



