1877.] 235 
[Cope. 
chambers communicate with the cavity of the body by a large foramen 
on each side, which is below the base of the diapophysis. In the cer- 
vical vertebra it is very elongate, and extends between the bases of the 
parapophysis and diapophysis. In the dorsal centra there are but two 
chambers, which are separated by a longitudinal median septum. 
The neural arches are codssified with the centrum throughout the col- 
umn. They are extraordinarily elevated, and their antero-posterior diam- 
eter is small. The zygapophyses are at its summit, and have extensive 
articulating surfaces. The anterior pair are divided by a deep median 
fissure, while the posterior are united, and support as a pendant from their 
inferior median line a hyposphen, a structure more fully described under 
the head of the genus Amphicoelias, where it is equally developed. When 
the vertebre are in relation, the base of the hyposphen enters the fissure 
between the anterior zygapophyses, and maintains them in position. This 
structure is obsolete in the lumbar vertebre. 
The diapophyses rise from the neural arch to a considerable length up- 
wards and outwards, in the anterior dorsals. They become shorter pos- 
teriorly, but in none of the vertebre anterior to the sacrum do they issue 
from the centrum. In the caudal vertebre they are short and robust, and 
issue from the superior part of the centrum, They do not continue far on 
the tail. Those of the dorsal vertebre are light and concave below. They 
are supported by thin osseous buttresses, the most important of which are 
the two inferior ones. The anterior of these is much the most prominent, 
and bears the capitular articular facet for the rib. Jn no case is this sur- 
face seen on the centrum, but it descends somewhat in the posterior verte- 
bree, but not as low as the level of the neural canal. 
The neural spines are rather short, and are set transversely to the axis 
of the animal. The superior portion is expanded transversely, and in an 
anterior dorsal vertebra, is widely emarginate above, so as to appear double. 
The neural spines of the caudal vertebre are compressed and elevated, 
though thickened at the apex. The zygapophyses are situated low down, 
and are directed very obliquely. The chevron bones of the caudal verte- 
bre have short limbs which are not united at the base, and a Jong common 
median spine. : 
The sacrum is short and consists of only four vertebral centra, thoroughly 
coéssified. The anterior articular extremity is convex ; that of the poste- 
rior extremity slightly concave. Its transverse processes are, like those of 
the other vertebra, much elevated, although they spring from the centra. 
The external face of their bases is not prominent, and the spaces between 
their projecting portions are deeply excavated. The centra are like those 
of the caudal vertebre, composed of dense bone. The extremities of the 
adjacent transverse processes are united, thus enclosing large foramina. 
The scapula is relatively of large size. It is rather elongate, and the 
superior extremity is expanded. There is a very large mesoscapular pro- 
cess, which is wanting in Cetiosaurus, according to Phillip’s figures. It 
appears to resemble the scapula in Dystropheus.* The two proximal faces, 
+See Report of Lt. Wheeler, Vol. IV, pl. LX XXIII, p. 31. 
