65 
Measurements of Right Humerus of Edmontosaurus, Cat. No. 2289. 
Mm. 
Length 694 
Maximum transverse breadth at proximal end 167 
Distance from lower angulation of radial crest to posterior face of shaft 165 
Thickness of radial crest at its midlength and breadth 21 
Thickness of same at a short distance in from its lower angulation 36 
Antero-posterior diameter of shaft at one-third of the bone’s length from distal 
end 92 
Interno-external diameter at same level 70 
Maximum transverse breadth of distal end 116 
Antero-posterior diameter of inner condyle 114 
Antero-posterior diameter of outer condyle 104 
Ulna (U.). Figure 35. The ulna is the 
longest bone of the fore limb, the humerus 
being the next in length, with the radius slightly 
shorter than the humerus. The ulna exceeds 
the radius in length by about 95 mm. It is 
slender for its length, is heaviest in its upper 
half, and reaches its maximum size proximally. 
Distally it is only slightly enlarged. At its 
upper end its outline in cross-section is trian- 
gular. Here the olecranon process is well deve- 
loped rising to a considerable height above the 
articular surface for the humerus. Anteriorly 
toward the inner side above it is excavated 
for the proximal end of the radius, the exca- 
vation narrowing and lessening downward, and 
disappearing above the bone’s half-length. 
Below the olecranon process posteriorly there 
is a protrudent angulation which accentuates 
the general forward bend of the bone in its 
upper part. At midheight the shaft is oval in 
cross-section, with the greater diameter fore- 
and-aft, and one and a half times the lesser 
diameter. Distally the greatest diameter is 
nearly twice the maximum transverse breadth, 
and on the inner side toward the front there 
is a rugosely striated, depressed surface for the 
close application of the distal end of the radius. 
Throughout, the lower end of the ulna is deeply 
striated in a longitudinal direction for the inser- 
tion of muscles. 
Measurements of Left Ulna of Paratype of Edmontosaurus. 
Mm. 
Length 760 
Maximum transverse breadth of proximal end 128 
Maximum diameter of distal end 114 
Maximum diameter at midlength 80 
\ t t.- - Figure 35 . Left ulna and radius 
HadlUS \Ha.). ihe radius, Figure 35, is of paratype of Edmontosaurus; 
slender, nearly straight, and shorter than the v size; anterior view 
1 .,1 1 1 i. 1 j. '1 slightly from without. oZ, olecra- 
ulna, with a length equal to about 6 f times its non process; Ra, radius; U, ulna 
