PLATE XVIII. 



Fig. 1. Monoclonius canadensis, liamhe, right mandibular ramus, external view ; one-half the natural 

 size. Page 65. 



Fig. 2. The same, internal view. 



Fig. 3. Monoclonius canadensis, maxillary tooth, external view ; natural size. (Provisionally associated 

 with M. canadensis.) Page 66. 



Fig. 4. Internal view of the same. 



Fig. 5. Tooth from lower jaw, (provisionally associated with M. canadensis), internal view ; natural size. 



Fig. 6. The same, lateral view showing the two roots. 



Fig. 7. The same, external view. 



e, coronoid process ; a, alveolar groove ; 6, symphyseal surface ; c, mandibular groove ; f, facet 

 for predentai-y bone. 



