114 The Ottawa Naturalist [Dec. 



each side of the posterior end of the postfrontal fontanelle and 

 between it and the supratemporal fossa a small part of it re- 

 mains, shewing its sutural contact with the postfrontal. Where 

 the upper median portion of the parietal has been broken there 

 is a short transverse bar across the midline, which appears to 

 mark the posterior limit below of the postfrontal fontanelle. 

 Behind this bar is a small, shallow, oblong depression. The 

 very large excavations beneath the postfrontals, the supra- 

 temporal fossae, debouch widely backward with a smooth, lower 

 surface, or floor, formed of the parietal and the squamosal. 

 Although mainly beneath the postfrontal, this fossa extends 

 laterally at its exit beneath the squamosal on the outer side, 

 and the anterior end of the parietal inwardly, these three bones 

 together composing the roof of the excavation at its mouth 

 where they come to a sharp, overhanging, free edge, which 

 slopes upward from about the middle of the back part of the 

 squamosal, obliquely forward and inward and then descends 

 backward, apparently without interruption, if the specimen 

 were perfect, as the lateral edge of the median portion of the 

 parietal. The smooth floor of the supratemporal fossa extends 

 backward bevond its main opening toward the anterior end of 

 the parietal fontanelle and inward beneath the median portion 

 of the parietal, which it undercuts, leaving a free, overhanging 

 edge, and at a higher level enters a subsidiary fossa, which is 

 directed obliquelv inward and backward and terminates next 

 to the midline of the skull, where it is separated only by a thin 

 bony partition from the corresponding excavation on the other 

 side. These subsidiary fossa?, one on each side of the midline, 

 beneath the parietal, are behind the transverse bar already 

 mentioned, 



The parietal crest evidently rose behind at a rather steep 

 angle during the life of the animal. In the specimen now de- 

 scribed the crest has been crushed and bent downward, with the 

 result that the parietal has been broken across behind the post- 

 frontal fontanelle and pulled back, leaving the gap in the upper 

 surface, as seen in the two photographic reproductions of the 

 skull accompanying this paper. 



The bone forming the margin of the postfrontal fontanelle 

 comes to a thin rounded edge and within the fontanelle near 

 its anterior end is another transverse bar not so stout as, but 

 longer than, the one behind. 



The lachrymal foramen is seen between the maxilla and 

 the nasal in advance of the back end of the former bone. It 

 has been reduced in vertical diameter by the downward pressure 

 to which the skull has been subjected. 



