54 
outward to join the prefrontals, their junction being indicated by a short, 
raised, flaring border of the prefrontal. On the left side above the orbit 
a longitudinal excavated recess runs underneath the base of the crest and 
terminates anteriorly at the forward border of the orbit. 
The alisphenoid of the right side is missing, but on the left side it turns 
outward from its participation in the brain case beneath the parietal and 
frontal, with its outer extremity received in the usual pit on the inner side 
of the postorbital. 
The maxillary and attached jugal have been crushed forward out of 
their normal positions (Plate XI), but, except for the loss of parts of the 
anterior and posterior ends, are in a fair state of preservation. They are 
relatively heavier than in Lambeosaurus, but, as in the other crested forms, 
the restricted distance between the anterior end of the jugal articulation 
and the entrance to the infraorbital foramen is very short. 
The precise number of rows of teeth carried by the maxillary cannot 
be determined, but it is in excess of forty. 
The occipital condyle when viewed from the back may be described 
as subreniform with a broad, slightly convex articular condyle that looks 
strongly downward in relation to the longitudinal axis of the skull. The 
basioccipital bounds the foramen magnum below, and on either side 
articulates by oblique sutural surfaces with the exoccipitals. The latter 
bones contribute extensively to the condyle by sending backward two high 
posteriorly directed processes whose posterior extremities slightly overhang 
the occipital condyle. These condylar processes are wide apart, slightly 
divergent, and form together a deep valley leading up to the entrance of 
the foramen magnum. The articulation of the basioccipital with the 
basisphenoid has become coalesced and their sutural union can no longer 
be observed. The condyle has a greatest transverse diameter of about 
60 mm., a vertical diameter at the centre of 26 mm., and at the sides 
55 mm. 
The exoccipitals bound the foramen magnum laterally and above, 
and contribute largely to the formation of the occipital condyle. In 
completion of the occipital condyle they extend freely backward where 
their articular posterior ends overhang the condylar portion of the basioc- 
cipital. Though no median suture can be detected between the exoccipitals 
above the foramen magnum, a low vertical ridge appears to represent the 
line of their coalescence. The exoccipitals extend outward and slightly 
backward from the centre, developing greatly expanded, pick-shaped para- 
occipital processes. Their distal expansion is especially produced as long 
tapering processes that terminate far below the squamosal processes 
against which they abut. 
The suture between the exoccipitals and the supraoccipital cannot be 
detected, but a broad area lying between the upward expansion of the 
paraoccipital processes, having a vertical, median ridge with flattened 
surface that widens from below upwards, is regarded as the supraoccipital 
contribution to the occiput. The surface of this part of the occipital 
region is inclined slightly forward. In Edmontosaurus the median portion 
of the coalesced exoccipitals is directed strongly backward as a broad 
overhanging roof, in striking contrast with the slight overhang in this genus. 
It is certain that in Edmontosaurus the supraoccipital was excluded from 
