EXPLANATION OF PLATE XVL 



View (if crania, (if Piithonomorpha, from above, oiu-Iuilf natural size. 



Fig. 1. CUdaities lortor ; 6, preraaxillarj' boue, from below. 



2. I'lutecnrpiis mndijci, frontal and parietal bones. 



3. rUiicmrpiis coriipliwiii, frontal bone only. 



Figs. 4-5. Pluteearjius curliroslris : 4, frontal and parietal bones, from above; 5 premaxillary and adja- 

 cent part of right maxillary bones, from left side and below. 



