EXPLANATION OF PLATE XLIIL 



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



Fig. 1. Basioccipital, parts of byomantlibular and preoporciilar, with the syraplectic and quadrate bones 

 in relation ; natural size. 



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



hyomaudibular are seen fragments of the superior brancbihyals. 



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



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



3. Superior aspect of the dentary bone. 



4. Sclerotic bone of s.ame. 



