MORPHOLOGY OF BAROSAURUS LENTUS 
Because of the paucity of material representing the other two species, and the 
fact that they do not surely belong to. the genus Barosaurus, the type of Barosanrus lentus 
will be the principal subject for discussion. 
Axial Skeleton 
skull 
The skull was unrepresented by a single fragment, nor are any of the anterior 
cervicals present; the presumption is, therefore, that the entire head and neck, except 
for the posterior portion, was swept away, possibly after entombment, as the cervical 
vertebrae which are preserved lay near the outcrop (see Fig. 2). 
CERVICAL VERTEBRAE 
The four posterior cervicals are present. They are the estimated twelfth to 
fifteenth, the comparison being made with the mounted specimen of Diplodocus carnegiei 
at the Carnegie Museum at Pittsburgh. These cervicals resemble those of Diplodocus 
more than of any other genus in their general proportions and great length and also in 
the arrangement of the buttresses and lamina?. The lateral depressions, or pleurocceles, 
of the centra, while generally fully as deep as in Diplodocus, are not relatively so 
extensive in their antero-posterior dimension. The sequence of the vertebra? has been 
determined in part by the circumference of the posterior articular face of the centrum, 
which increases as follows : Cervical XII, 800 mm. ; XIII, 840 mm. ; XIV, 870 mm. ; 
XV, 970 mm. ; anterior face of dorsal I, 970 mm. 
Cervical XII (Vertebra S) (PL II, Fig. 1). — This great bone has the longest 
centrum of any which are present, measuring no less than 930 mm. The vertebra is 
well preserved, although it has probably been subjected to a slight lateral crushing. It 
is, however, distorted the least of any of the cervicals present, with the exception of 
the fragmentary fourteenth. 
The anterior face of the centrum is hemispherical, though somewhat laterally 
crushed. The surface of the bone, however, is removed, so that the interior cancellous 
tissue is exposed. The cancelli are very coarse. Ventrally, the centrum is characterized 
by a longitudinal groove enclosed by lateral carinas which anteriorly pass into the 
capitular articulation for the rib. There is also a slight longitudinal lamina discernible 
for about one fourth the length of the centrum. The capitular facet is rather massive, 
and well braced antero-posteriorly. 
The right lateral aspect of the bone bears a deep cavity or pleuroccele, the anterior 
limitation of which commences about the level of the diapophysis. This pleuroccele 
extends backward for a distance of about 240 mm., but is crossed by an oblique lamina 
of bone (pleurocentral lamina) running from above downward and backward. This 
lamina bifurcates at its anterior third and is in the line of the compression thrust from 
the prezygapophyses. The height of the pleuroccele is about 60 mm., and its greatest 
depth, at the anterior end, about 50 mm. 
