344 University Geological Survey of Kansas. 



of the jaw. Both the external and internal sides of the bone 

 are covered with coarse longitudinal striae, the intensity of 

 which varies in different individuals. 



Maxilla : Length of tooth band 118 . mm. 



Height at posterior extremity '34.0 " 



Premaxilla : Length 81.0 " 



Greatest height 37.5 " 



The dentary has a tooth band above, covered with teeth very 

 similar to those on the parts described above. It is nearly flat 

 in front, but soon becomes directed downward internally, giv-, 

 ing it a somewhat beveled appearance, which may be due to 

 compression, although it seems to occur in all of the specimens 

 examined. The band is broadest near the center and is over- 

 hanging externally and in front. The symphysis is composed 

 of two parts : an upper facet, which is directed inward and 

 comes in contact with a corresponding facet on the opposite 

 side ; and a lower one, which is directed forward and enters but 

 little, if any, into the articulation of the two jaws. At the sym- 

 physis the bones are shallow, but they soon broaden and be- 

 come very deep at the coronoid process. There are very coarse 

 ridges and grooves on both the external and internal sides. 

 The articular extends well forward on the external side, and is 

 united with the emargination in the dentary by an indistinct 

 suture. The cotylus is supported principally by a thick shelf of 

 bone extending inward from the main portion of the bone. It 

 presents a small concave facet which looks slightly forward, 

 back of which the angle is slightly recurved, and has been de- 

 scribed by Professor Cope 101 as resembling a boot with the toe 

 inverted. 



Length of mandible from cotylus 204 mm. 



Depth at coronoid process (estimated) 65 " 



Depth at symphysis 17 " 



Length of tooth band (estimated) 155 " 



The bone originally described as a premaxilla 102 may be a 

 pterygoid, as it cannot be a vomer or palatine from the descrip- 

 tion of these parts, as given by Professor Cope. It is slightly 

 curved longitudinally and has a broad tooth band on one sur- 



101. Proc. Am. Phil. Soc. 1878, pp. 179, 180. 



102. 1. c, p. 195. 



