280 University Geological Survey of Kansas. 



see that this portion is entirely distinct from the supraoccipital, 

 and that the bone he calls parietal is included in the pterotic 

 and is not separated from it by suture. 



The epiotics are wedged in between the pterotics and supra- 

 occipital and form prominent inner processes of the skull. 

 They become narrow anteriorly and are provided with promi- 

 nent ridges along the superior borders, which end in slight 

 upward projections posteriorly which are thickened at the ex- 

 tremity. 



The supraoccipital forms a prominent crest and is projected 

 well backward and upward. In some of the specimens having 

 the posterior end preserved, I find that there are a number of 

 tooth-like projections which closely resemble a suture, but they 

 probably gave attachment to muscles alone. The bone is 

 moderately thick and is somewhat rounded along the superior 

 border. I think that I can detect the suture which separates 

 this bone from the granular portion mentioned above. The bone 

 is somewhat irregularly striated on the sides, and posteriorly it 

 descends almost to the basioccipital, forming a prominent narrow 

 ridge in the median line. 



The pterotics lie just external to the epiotics and back of the 

 parietals, and form prominent outer processes of the skull. The 

 bones are very robust, and have deep grooves along the external 

 borders, which articulate with the superior condyles of the hyo- 

 mandibulars. The posterior extremities are somewhat ex- 

 panded, and have small elliptical surfaces internally, which are 

 covered with coarse striae radiating from near the center. These 

 surfaces probably are connected with the post-temporal. The 

 sutures separating these bones from the parietals are often in- 

 distinct. 



The postfrontals form prominent processes just back of the 

 orbital cavities, and anteriorly they form the posterior sides of 

 the conspicuous notches which accommodate the posterior su- 

 praorbitals mentioned above. Posteriorly, by their union with 

 the pterotics and prootics, they give a small support to the hyo- 

 mandibulars, and are excavated along the sides for this purpose. 

 Internally they unite with the parietals. 



