58 



NEW KEPTILES AND STEGOCEPHALIANS FROM 



of the opisthotic and the openings look as much backward as upward; the posterior face 

 of the skull is very similar, except for the depressed parieto-squamosal bar; the post- 

 temporal opening is small, and the opisthotics extend out to the squamosal and are 



Fig. 23. 

 Paleorhinus, after Lees. Lettering as usual. 



A. Lateral view of skull. B. Upper view of skull. 

 Mystriosuchus, after McGregor. 



D. Upper view of skull. E. Lower view of skull. 



C. Lower view of skull. 

 F. Lateral view of skull. 



overlapped by it. In the specimen of M. planirostris, described by McGregor, the small 

 element on the outer side of the distal end of the opisthotic is apparently calcified car- 

 tilage; in Promystriosuchus the fragment in this position is true bone; the opisthotic 

 process stands a little higher above the condyle in Promystriosuchus. On the lower 



