EOCERATOPS CANADENSIS. 
9 
known. On its outer free border there is a convexity which is 
a backward continuation of the series of undulations of the free 
border of the squamosal. Also, behind the squamosal, the bar 
has a slight axial twist which would bring its upper surface into 
greater conformity with the general plane of the median portion 
of the neck frill. 
The form of the back and median portions of the frill and 
the size and shape of the fontanelles must for the present re- 
main conjectural. That the openings in the frill were long in 
a fore and aft direction is indicated by the squamosal and the 
portion of the parietal bar remaining. 
The frill opening on either side was not altogether within 
the parietal, as in all other known forms of the Ceratopsia in 
which fontanelles were present, but was bounded on the outer 
side, for the greater part of its length, by the squamosal and to a 
limited extent postero-laterally by the parietal bar. In the speci- 
men the beginning of the inward curve of the bar, with an in- 
creased breadth, is shown immediately in advance of the break 
and suggests an outline to the posterior border of the frill and 
the median portion between the fontanelles as indicated in Plate 
II, figure 2. The undulations of the outer border of the squa- 
mosal continued backward by the parietal bar suggests a sinuous 
posterior border to the frill and it is probable that the median 
parietal portion between the fontanelles was of considerable 
breadth as an offset to any weakness in the frill occasioned by 
the tenuity and shortness of the lateral bar beneath the squa- 
mosal. 
The lower jaw (Plate I) is represented in the type material 
by the dent ary, a robust bone whose maximum length is slightly 
over three times its depth at midlength. The height of the top 
of the coronoid process above the lower border is nearly equal 
to one-half the length of the bone. In comparison with the larger 
dentary of Chasmosaurus (Plate VIII) it is proportionately 
more robust. Apart from having lost the teeth, the specimen 
is in a good state of preservation displaying very distinctly 
the surfaces for the articulation of the predentary, the splenial, 
the angular, and the surangular. There were about twenty-five 
alveoli for the teeth. 
