DISSOROPHUS COPE 



S. W. WILLISTON 

 The University of Chicago 



The material herein described and figured was collected by the 

 writer from the upper or Clear Fork Division of the Texas Red-beds 

 on Coffee Creek, in August, 1909. It comprises a nearly complete 

 skull, but little distorted, the two scapulae with attached cleithra, 

 neither complete, but the two supplementing each other nearly per- 

 fectly; the two complete clavicles attached to the incomplete inter- 

 clavicle; the two humeri, one complete save for the capitellar angle, 

 the other with the distal part quite complete and the proximal portion 

 missing; two attached proximal carpals, several vertebrae and frag- 

 ments of ribs, the nearly complete carapace, a broken and somewhat 

 distorted pelvis, a femur, and fragments of epipodial bones. 



For the most part, the surface of the skull is unimpaired, showing 

 deep, almost circular pits, with narrow, reticulating ridges between 

 them. The pittings seem to be most pronounced in the upper pos- 

 terior part. There are no indications of mucous grooves, and I am 

 convinced that, were they originally present, evidences of them would 

 be apparent. Nor, as in the case of the skulls of Cacops, can I 

 distinguish the sutures. 



The skull is very broad posteriorly, with a rounded, obtuse muzzle. 

 The orbits are situated about midway in its length; they are rather 

 small, nearly circular in outline, and broadly separated. The table 

 of the cranium, back of the orbits, is rather broader than long, a 

 little wider anteriorly, with a broad emargination behind; it is nearly 

 plane, with its margins elevated. The parietal foramen is situated a 

 little back of a line drawn through the posterior margin of the orbits. 

 Just back of each orbit there is a distinct depression, as in Cacops, 

 apparently for the lodgment of some gland. In the middle part behind 

 there is, on each side, a prominent, nearly hemispherical elevation, 

 deeply impressed with large pits; they correspond to the prominent 

 rugosities of the Cacops skull, but are much more rounded and less 



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