37 
This fragmentary specimen, as I have determined by comparison, 
pertains to the genus Lambeosaurus, and consists of the greater part 
of the parietals, complete frontals, postorbital, and part of the alisphenoid, 
the latter of the right side. It displays for the first time in the sub-family 
Lambeosaurinae, the strong-grooved sutural surfaces (See Figure 8 A, Nas ) 
for the anchorage of the nasals, which in these crested forms have assumed 
such fantastic and unusual proportions. The great vertical depth of this 
contact is most striking. Viewed from above it is a straight, transverse 
suture that is in line with the prefrontal-postorbital suture. The fronto- 
parietal suture, as shown in Figure 8, runs inward and slightly backward 
from their lateral borders and at the centre sends forward a loop that 
separates the frontals on the median line for one-half their total length, 
much as in Troodon ( Stegoceras ) validus. The forward extent of this loop 
on the ventral side, however, is much abbreviated. 
>Yas' 
Figure 8. Brain case of Lambeosaurus sp. No. 8502, Geol. Surv., Can. A, Oblique superior 
view; B, Inferior view; C , lateral view, alsp., alisphenoid; fr, frontals; nas, nasal suture; pa, 
parietal; po, postorbitals. One-half natural size. 
The ventral view (Figure 8 B) of this cranial fragment shows the very 
short, broad cerebral expansion of the brain, a peculiarity of the crested 
hadrosaurs that is strikingly different from the elongated compressed 
cerebrum of Edmontosaurus or Thespesius annectens as figured by Marsh. 
