EXPLANATION OF PLATE XLIII. 



Porihcus thaumas, Cope, parts of one specimen from Butte Creek, Kansas. 



Fig. 1. Basioecipital, parts of hyoraandibular and preopercular, with the sympleotie and quadrate bones 

 in relation ; natural size. 



1 a. The same piece to the middle of the hyomaudibular bone, viewed from tbe inner side ; on tbe 



bycmandibular are seen fragments of the superior brancbibyals. 



2. Premaxillary and maxillary bones of the same ; tbe latter broken off near tbo middle. 



2 a. Inferior view of the same, displaying the bases of the teeth. 



3. Superior aspect of the dentary bono. 



4. Sclerotic bone of same. 



