PLATE XVII. 



Yi". 1. ? Monoclonius dawsoni, Lambe, side view of? nasal horn core ; one-half the natural size. 



Fig. 2. Sectional outlines of the same at " a " and " b ". 



Fi". 3. Monoclonius canadensis, Lambe, right orbital horn core, obliquely from behind ; one-halfe 

 natural size. Page 63. o, orbit. 



Fig. 4. The same, sectional outline at "a". 



Fi". 5. Palceoscincus asper, Lambe, side view of tooth ; four times natural size. Page 54. 



