PLATE 1 



EXPLANATION OF FIGURES 



1 Dorsum of skull of Diplocaulus magnicornis Cope. Infraorbital canal at 

 point of arrow. X 2. 



2 Ventral surface of the mandible. The operculo-mandibular canal at the 

 point of the arrow. X 5. 



3 Oblique view of one ramus of the mandible to show the entire course of the 

 operculo-mandibular canal. Nearly natural size. 



40 



