60 
Measurements of Dorsal Vertebra {ffourth or fifth) of Paratype of Edmontosaurus. 
Mm. 
Maximum length 327 
Maximum height 352 
Length of centrum at midheight 151 
Anterior height of centrum, about 97 
Posterior height of same. . 93 
Posterior breadth of same 81 
Depth of concavity of posterior end of centrum 20 
Height of neural canal, about • 42 
Anterior height of neural spine measured along its slope 194 
Antero-posterior breadth of same at upper end 106 
Transverse thickness of same at midheight 10 
Length of transverse process measured from base of neural spine 128 
Posterior Dorsal Vertebra. The vertebra shown in Figure 32 is appar- 
ently the last of the dorsal series judging from the small size of the single- 
headed ribs which are preserved attached to the transverse processes. 
This vertebra belongs to the paratype of Edmontosaurus and gives the 
changes in form that have resulted in passing to the back of the series. 
It has much the appearance of an anterior caudal vertebra which it might 
readily be mistaken for but for the presence of ribs. In comparison with 
the anterior dorsals there is an increase in size, the centrum is of a different 
shape, the neural spine is upright instead of sloping backward, and the 
transverse processes have become almost horizontal. 
Figure 32. Posterior dorsal vertebra of paratype of Edmontosaurus; 
I natural size. A, left lateral aspect; B, posterior aspect. Lettering 
as in Figures 30 and 31. 
The centrum is about as broad as high, and is very short. The 
posterior end is moderately concave, the anterior one almost flat with a 
slight convexity. The sides are deeply concave in a fore-and-aft direction, 
and ventrally a longitudinally directed ridge connects the two ends. In 
