30 
Explanation of Plate II. 
Figure 1. Hypothetical form of frill of ancestral ceratopsian; superior 
aspect. 
Figure 2. Frill of Eoceratops canadensis L,a tribe; one-eighteenth natural size; 
viewed from above. 
Figure 3. Frill of Triceratops flabellatus Marsh; one-sixteenth natural size; 
viewed from above. After Marsh. 
