2 8 THE SAUROPOD DINOSAUR BAROSAURUS MARSH. 
Measurements of Caudal XVII 
Barosaurus Diplodocus 
lentus carnegiei Ratios 
mm. mm. 
Length over all 355 345* 103 
Height over all 350 530* 0.66 
Width across diapophyses ? 200* 
Centrum, length 270 277* 0.97 
" anterior face, height 187 204* O.92 
" " " width 220 200* 1. 10 
" posterior face, height 180 204* 0.88 
" " " width 210 195* 1.08 
" " " circumference ca. 670* 
" mid length, width 130 
Pleuroccele, length 170 
Neural canal, height 27 
" " width 30 
Average ratios: Barosaurus lentus and Diplodocus camegiei O.95 
* Peterson's measurements. 
Caudal XIX. — This is a very well preserved bone, characterized by a total absence 
of diapophyses, which in Diplodocus longus cease at the twenty-second caudal, and by 
the reduction in depth of the pleurocceles. The bone is both proportionately and actually 
longer than the four preceding vertebKe, but the neural arch has been crushed down- 
ward so that the normal height of the spine has been somewhat reduced. Possibly this 
as well as the peculiar appearance of the postzygapophyses is due in part to antemortem 
causes. Both zygapophyses overhang the vertebral centrum. Of the latter, the anterior 
face is somewhat concave, which is also true, although in less degree, of the posterior 
one. The ventral groove is likewise increasing in depth. The chevron facets are well 
developed and coequal. 
Measurements of Caudal XIX 
Barosaurus Diplodocus 
lentus carnegiei Ratios 
mm. mm. 
Length over all 355 360* 0.99 
Height over all , 290 490* 0.59 
Width across diapophyses 145* 
Centrum, length 285 278* 1.02 
" anterior face, height 170 210* 0.81 
" " " width 215 193* I-I2 
posterior face, height 155 195* 0.79 
" " " width 200 190* 1.05 
" " circumference 650* 
mid length, width 126 
Average ratios : Barosaurus lentus and Diplodocus carnegiei 0.91 
* Peterson's measurements. 
Caudal XX. — This bone has been badly crushed, so that the anterior part is tele- 
scoped back upon the posterior, thus reducing very considerably the original length of 
the bone. There is little or no trace of pleurocceles nor is the hollow beneath the bone 
as pronounced as in XIX. The neural spine is lighter and the summit is distinctly 
smaller, which may indicate an original position still further back in the caudal series. 
But few dimensions have value owing to the distortion of the bone. 
