586 S. W. WILLISTON 



amphibians represented by limb bones and parts of skulls; and 

 certain large intercentra which agree well with those of Trimero- 

 rhachis. At least one of these amphibians has a wide dermal 

 armor of a new kind, probably belonging with one or the other 

 of the humeri from this deposit figured by me in my recent paper 

 on Cacops.^ Other limb bones and such parts of the carapace as 

 have been recovered I will figure as soon as opportunity permits. 



Among the reptile remains there are representatives of at least 

 seven genera, including three distinct species of Dimetrodon, one of 

 them the largest vertebrate hitherto recorded from the Permian 

 of Texas; numerous vertebrae and teeth of Diadectes; limb bones 

 which agree well with Case's figures of Clepsydrops natalis, and 

 with limb bones in the collection obtained elsewhere; femora and 

 humeri, as well as other limb bones of at least two distinct genera 

 which I cannot yet identify, some of which are, with scarcely a 

 doubt, new; vertebrae, parts of a humerus and femur which I 

 refer to Desmospondylus; and the gtrms, Araeoscelis herein described. 

 Rather interesting is the fact that, so far, no certain evidence is 

 forthcoming of the Pariotichidae, the curious acrodont Pantylus, 

 Poliosauridae, Eryopidae, or Cricotidae. A few vertebrae having 

 short spines with a pair of lateral tubercles suggest the probability 

 of Naosaurus, and it is possible that some of the girdles and limb 

 bones may be of this genus. Altogether I recognize in the deposit 

 evidences of fourteen or fifteen genera and seventeen species. 



Among the material recovered from this deposit is a temno- 

 spondylous coracoscapula, in which the three elements are separate. 

 The suture between the coracoid and scapula is quite as in the 

 pelycosaurian girdle, passing directly forward through the pre- 

 glenoid articular facet and above the supracoracoid foramen. 

 The metacoracoid is small, a mere vestige in fact. The evidence 

 furnished, not only by the temnospondyls but by the almost 

 identical structure of the coracoscapula of the contemporary reptiles, 

 is, it seems to me, conclusive that there is no such bone as the pro- 

 coracoid, that the coracoid of all modern reptiles is homologous 

 with the anterior element, the so-called procoracoid, and not with 

 the posterior one, which has disappeared, or remains as the merest 



I Bull. Geol. Soc. Amer., XXI (1910), 249, PI. XV, Figs. 4, 5. 



