57 
VERTEBRAE. 
There are available for present description one cervical and three 
dorsal vertebrae belonging to the 1916 skeleton, Cat. No. 2289. In both 
skeletons the greater part of the tail is missing, in the type from behind 
the sixth caudal, in the paratype from behind the fifth, but in each the 
remainder of the vertebral column is apparently present. Until the 
enclosing matrix is removed the vertebral column as a whole cannot be 
described in detail, but the four vertebrae of the paratype so far taken 
from the rock supply with accuracy the characteristics of the majority of 
the presacral vertebrae, and indicate the changes in form and proportion 
that took place in passing back from the head. 
There was a general increase in size in the presacral vertebrae in passing 
back in the series. 
The cervicals, and the anterior dorsals at least, were strongly opistho- 
ccelous. Neural spines were absent, or feebly developed in the majority 
of the cervicals until apparently late in the series. In the dorsals they were 
short anteriorly in the series but gained slightly in length posteriorly. 
The transverse processes in the anterior dorsals were long and stout, and 
pointed upward with an inclination outward and forward. In the posterior 
dorsals they were almost horizontal, and less robust. The cervical and 
dorsal ribs with the exception of the last dorsal, or possibly the last two or 
three, were double headed. 
Figure 30. Cervical vertebra of paratype of Edmontosaurus, 
Cap No. 2289; | natural size. A, left lateral view; B, pos- 
terior view, nc, neural canal; ns, neural spine; p, parapopyhsis; 
R, rib; tp, transverse process; z, prezygapophysis; z', postzyga- 
pophysis. 
Cervical Vertebra. This 
vertebra (Figure 30) from 
the paratype of Edmonto- 
saurus is apparently from 
near the middle of the 
cervical series. The cen- 
trum is deeply cupped 
behind, and the anterior 
end is correspondingly 
convex. It narrows to the 
front, and has a length 
considerably in excess of 
the posterior height and 
breadth which latter are 
about equal. The ventral surface is narrow and flat, and angulated laterally 
where it passes into the excavated sides of the centrum. The anterior face is 
bounded posteriorly by a definite protruding girdle against which the 
narrow rim of the concave posterior end of the preceding centrum fitted. 
The neural arch is lower than broad enclosing a large neural canal. The 
transverse process is short and stout and is directed obliquely upward and 
outward horizontally in line with the neural canal; it terminates distally 
in a facet for the attachment of the tubercle of the rib, and gives off super- 
iorly a short prezygapophysis. Laterally a short parapophysis with a 
narrow vertical diameter provides for the attachment of the head of the 
rib considerably below the level of the floor of the neural canal. The 
posterior zygapophyses are long, robust, and curve backward far beyond 
the posterior end of the .centrum. The articulating surfaces of the post- 
and prezygapophyses facing downward and upward respectively, are 
