4 2 
THE SAUROPOD DINOSAUR BAROSAURUS MARSH. 
may actually have been longer. The "Brachiosaurus" bone in question naturally most 
nearly resembles cervical XII, that is, the anterior one of Barosaurus which is pre- 
served, and doubtless had we the identical element, the resemblance would be yet 
closer. From cervical XII it differs in the relatively slenderer centrum and longer 
pleuroccele, but the other differences, except the overhanging prezygapophyses, are 
largely those of detail, as the main laminse and other structural features are not unlike. 
Conclusions. — Unless the German author, Janensch, actually made a comparison of 
the dorsals of the Tendaguru genus with those of the American Brachiosaurus and 
found sufficient agreement, I see no reason for including the African form in this 
genus merely on the ground of the elongated fore limbs, as we have no reason to know 
that Brachiosaurus had huge cervical vertebrae. Certainly those of the related Haplo- 
canthosaurus were not, but on the contrary were relatively short. The unpaired neural 
spine is characteristic of the Brachiosauridae, but not of Brontosaurus, Morosaurus, 
Diplodocus, Barosaurus, nor so far as I know of the African genus. Whether Baro- 
saurus possessed an elongated fore limb we do not know, but there is certainly no 
evidence against it. Hence from the evidence before me, the huge cervicals of the 
African form, which resemble so much those of Barosaurus rather than the known 
cervicals of the Brachiosauridae, specifically Haplocanthosaurus . seem to show that the 
comparison lies with Barosaurus rather than with Brachiosaurus, especially as there 
is no present evidence to the contrary. Further evidence from Berlin, if such were 
available, might serve, in the light of the present study of Barosaurus, to clarify the 
relationships. 
The comparison with other Sauropoda may be expressed in tabular form as 
follows : 
Cervicals 
Anterior dorsal 
spines 
Tail 
Fore limbs 
Barosaurus 
Huge 
Paired 
Moderately short 
Unknown 
Great size inferred 
Brachiosaurus 
Unknown 
Unpaired 
Unknown, except 
two anterior 
vertebrae 
As long as hind 
limbs 
Haplocanthosaurus 
(Least specialized) 
Short 
Unpaired, short 
and simple 
throughout 
column 
Very short 
Unknown 
Brontosaurus 
Moderate 
Moderate 
Huge 
Paired 
Very long 
Smaller than hind 
Diplodocus 
Paired 
Very long 
Smaller than hind 
Tendaguru genus 
Unknown 11 
Very short 
As long as hind 
limbs 
11 One dorsal only was in part prepared for study in 1914. This has an unpaired spine, but as its 
position in the series is unknown, no significance can be attached to the character of the spine, since the 
spines are unpaired in the posterior dorsals of all Sauropoda. 
