20 THE SAUROPOD DINOSAUR BAROSAURUS MARSH. 
zygapophyses are preserved, although the right one is displaced. They still show the 
hyposphene articulation, but the entire structure is small and weak compared with that 
of dorsal V. 
Lateral aspect (left). — The centrum has been crushed out to a greater than normal 
length, measuring about 300 mm. The pleuroccele is well developed, but rather high 
on the centrum. There is a faint indication of the capitular rib facet on Lhe left pre- 
zygapophysis. It is more decided on the right, where a distinct limitation may be seen. 
The inference is that the rib head was light, the tubercular being the chief articulation — 
this last, however, can not be verified, as the diapophyses which bore the tubercular 
facets are missing. 
The various lateral laminae are well developed, the anterior oblique and diapophy- 
sial laminae being the dominant ones, as they overlie the posterior oblique. The last 
has its origin on the forward end of the centrum and runs directly upward and 
backward to the postzygapophysis. Where it crosses the pedicel, it divides and aids in 
reinforcing the diapophysis. 
The posterior aspect is so remarkably distorted that a description of it would have 
but little value. 
Measurements of Dorsal VII* 
Barosaurus 
lentus 
mm. 
Length over all 290 
Height over all 800 
Centrum, length 270! 
anterior face, height 245 
posterior face, height 280 
" width 240f 
Height to prezygapophyses 480 
Height to postzygapophyses 530 
* Dorsal VII of Diplodocus carnegiei is a plaster restoration, hence measurements are not given, 
f Altered by crushing. 
Dorsal IX (Vertebra N) (PI. IV, Figs. 4-6). — This vertebra, as usual, lacks the 
diapophyses, otherwise it is fairly perfect, although somewhat obliquely crushed. It 
differs from that just described in having somewhat heavier prezygapophyses, with a 
distinct capitular rib facet on their outer aspect at the level of the zygapophysial facet. 
There is the same peculiar asymmetry on the forward face of the spine as in dorsal VII, 
but reversed. The vertebra is crushed in the reverse way also, which may heighten 
the apparent asymmetry but can not entirely account for it. The neural spine is very 
tall, forming 370 mm. of the height of the entire vertebra. Laterally, the latter 
broadens materially, due to the development of the diapophysial laminae, although the 
entire outline is not preserved as shown in the figure (PI. IV, Fig. 5). 
The anterior face of the centrum is rather flat, but the posterior one is deeply 
concave, due, however, in large part to crushing. 
Lateral aspect, right (PI. IV, Fig. 5).— The pleuroccele is large and high, and is 
situated well forward, so that the oblique lamina which bounds it forms the upper 
hinder margin and is very heavy. The zygapophyses are strong and well buttressed 
and the hypantra are still well developed, though closely approximated. Laminse, much 
as in Diplodocus carnegiei, arise high up under the diapophyses. 
