PLATE XX. 



Fig. 1. Monoclonius belli, Lambe, parietal element of posterior crest, superior view ; one-third the 

 natural size. Page 66. 



Fig. 2. The same, inferior view. 



Fig. 3. Monoclonixis daivsoni, Lambe, rostral bone, side view ; one-half the natural size. (Provisionally 

 associated with 3f. dawsoni). Page 63. 



Fig. 4. Outline of section of same at "c." 



Fig. 5. Horn core with an asymmetrical base. Not specifically determined. 



Fig. 6. Sectional outlines of same at "a " and " b." 



g, groove for premaxilia 



