256 O. C. Marsh—American Jurassic Dinosaurs. 
The dorsal vertebree have their centra rather longer, and 
more or less compressed. The neural arch is especially ele- 
vated. The neural canal is much higher than wide. The head 
of the rib fits into a pit on the side of the neural arch. Figures 
3 and 4, Plate VII, represent a posterior dorsal, with character- 
istic features. The ribs are massive, and strengthened by 
their form, which is T shaped in transverse section. 
he sacral vertebree are codssified, but their exact number in 
the present genus has not yet been fully determined. 
The caudal vertebre offer the greatest diversity, both in size 
and form. e anterior caudals are the largest in the whole 
vertebral series, and highly modified to support a portion of 
the massive dermal armour. The articular faces of their cen- 
r 
tebre have no distinct faces for chevrons. The transverse 
processes are expanded vertically, and their extremities curve 
urther back, the same general characters are re- 
tained, but the centra are more deeply cupped, and the spmes 
less massive. Figures 5 and 6, Plate VII, show a caudal ver- 
tebra from this region. The chevrons here have their articular 
euds separate, and rest upon two vertebra. In the median 
caudals, the spine has greatly diminished in height, and the faces 
for chevrons are placed on prominent tubercles on the postero- 
inferior surface. The lower margin of the front articular face 
is sharp, and the chevrons do not meet it. In the more dis 
caudals (figures 7 and 8), the neural spine and zygapophyses are 
reduced to mere remnants, but the chevron facets remain distinct. 
These vertebrz, as well as those further back, have their centra 
much compressed. The caudal vertebra are remarkably unl- 
form in length throughout most of the series. 
Tse Fore Limes. 
he humerus (figure 2) is short and massive. It has a dis- 
tinct head, and a strong radial crest. The shaft is constricted 
medially, and is without any medullary cavity. The ulna (figure 
3) is also massive, and has a very large olecranal process. 
