io AMERICAN PERMIAN VERTEBRATES 



otic notch never closed behind; no dorsal dermal ossifications; 

 a single pair of sacral ribs ; tail long; ribs with uncinate processes ; 

 parasphenoid large. 



Eryops grandis Marsh. 



Ophiacodon grandis Marsh, American Journal of Science, XV, 211, May 3, 

 1878. Rio Arriba County, New Mexico. 



? Eryops reticulatus Cope, American Naturalist, 1881; ibid., 34, 1884; 

 Trans. Amer. Phil. Soc, XVI. New Mexico. 



A second, larger species of apparently the same genus [Ophiacodon] is repre- 

 sented by portions of the jaws, and teeth, and various parts of the skeleton. 

 In this species the dentary bone is angular at its anterior extremity, and 

 triangular in section. Its external surface is rugose, as in the crocodiles. The 

 crowns of the teeth are striate at the base, and the latter is furrowed vertically. 

 The teeth are not so thickly set as in the smaller species, and the bases of the 

 crowns are somewhat transverse. 



MEASUREMENTS 



Space occupied by ten anterior lower teeth 140 mm. 



Depth of lower jaw at symphysis 1 29 



Antero-posterior extent of symphysis 25 



Depth of dentary bone below seventh tooth 30 



Width of dentary at this point 20 



The present species was about ten feet in length, and the largest reptile 

 yet found in this fauna. The remains are from New Mexico. 



Among the material studied by Marsh from the Baldwin bone- 

 bed there is a considerable portion of a skeleton, probably all of 

 one individual, of this species. The left mandible, with all its 

 teeth broken away, the type specimen, has been made much more 

 complete than when Marsh described it. In addition, there are 

 parts of another mandible, numerous intercentra, pleurocentra, 

 and neurocentra, the larger part of two scapulae, etc. Among the 

 later collections from the same bone-bed there are two more or 

 less complete skulls, two scapulae, a pelvis, portions of limb bones, 

 and numerous vertebrae. All these parts probably belong to the 



