1917] The Ottawa Naturalist 121 



of bone. This posterior area of the frontal is much depressed in its 

 outer breadth but rises convexly inward to the mid-line. The suture 

 between the pair is conspicuously zigzagged. 



The supratemporal fossa is small, narrowly oval, and about twice 

 as long as wide, and passes downward into the lateral temporal fossa. 

 The two openings are close together posteriorly but toward the front 

 they diverge from each other. They are bounded by the frontal, post- 

 frontal, squamosal, and parietal, each of the four elements participat- 

 ing to an almost equal extent. 



The squamosal runs forward beneath the postfrontal to a point in 

 line with the anterior end of the supratemporal fossa. Intero-posteri- 

 orly it meets the parietal in a short jagged suture. Postero-inferiorly 

 it is deeply cupped to receive the upper end of the quadrate, and sends 

 downward a slender process which is applied to the paroccipital 

 (exoccipital) alar extension in the usual way. 



The occipital condyle is tripartite, the two exoccipitals and the 

 Dasioccipital entering into its formation to an equal extent, with the 

 bases of the exoccipital pair forming the upturned ends of the curved, 

 U-shaped condylar surface. 



The exoccipital in assisting in the formation of the condyle, 

 bounds the foramen magnum laterally. A paroccipital process of large 

 size supports the pendent extension of the squamosal from behind and 

 passes freely downward beyond it. 



The parietal bounds the supratemporal fossa on its inner side, 

 and intero-anteriorly along the greater part of its sutural junction with 

 the frontal. Postero-laterally it unites with the squamosal. Within 

 the supratemporal fossate area the pair rise to each other at the median 

 line together forming a narrow longitudinal ridge separating the 

 openings. 



The maxilla appears externally in contact principally with the 

 premaxilla and the jugal. Superiorly it passes for a short distance 

 between the jugal and the lowermost portion of the downward extension 

 of the lachrymal. 



The dentary supports a high and robust coronoid process, and is 

 in contact posteriorly with the surangular to the extent usual in the 

 Trachodontidae. Its anterior edentulous portion is strongly decurved. 



The teeth are of the general trachodont type, with the well known 

 mode of vertical succession and replacement. They are best preserved 

 in the right dentary where the inner enamelled surface is seen to be 

 long and narrow, with a high median keel and raised margins. In this 

 dentary the second tooth from the front has marginal papulations near 

 the tip resembling the dental border sculpture of the small Belly River 

 trachodont described from a maxilla under the name Trachodon 

 altidens by the writer in 1902* The larger teeth toward the centre 



*Contr. to Can. Palaeont., vol. Ill (quarto), p. 76, pi. IV, figs. 2, 3 and 4. 



