RELATIONSHIPS. 4 l 
neural spines of the after dorsals in Barosaurus, and position of the capitular facet 
on the dorsal vertebra, which rises more rapidly in Diplodocus. The other marked 
distinctions are those of proportions, for while the dorsal series of vertebrae as a whole 
approximate in length in the two animals, that of Barosaurus being only slightly the 
longer, the cervicals in the latter are vastly greater and the caudals markedly less. The 
relatively lower height of the spines of the after vertebrse is correlated with the more 
abbreviated tail. The weight of the hind limbs is more like that of Brontosaurus than 
of Diplodocus camegiei. Of their length and the character of the fore limbs we have 
no data. The obliquity of the centrum faces of the posterior cervicals and first dorsal 
of Barosaurus seems to imply a different carriage of neck, probably giraffe-like as in 
the Tendaguru "Brachiosaurus" as restored by Matthew. If so, it would perhaps also 
imply elongated fore limbs like those of Brachiosaurus. 
Comparison with Brontosaurus. — With Brontosaurus, the general mechanical 
resemblances also hold; this applies to the character of the neural spines, but the huge 
proportions of the cervicals in Barosaurus are a distinction, as is also the more Diplodo- 
cw-like character of the caudals. 
Comparison with Brachiosaurus. — Compared with the American Brachiosaurus 
of Riggs 8 and the smaller related form, Haplocanthosaurus Hatcher, 9 I find no points 
of resemblance in any known element. The following characters are given by Riggs 
for the family Brachiosauridse, especially Brachiosaurus itself: (i) Humerus as long 
as femur. In Barosaurus the humerus is unknown. (2) Neural spines of vertebrae 
simple. In Brachiosaurus' those of more than half of the dorsal series are deeply 
bifid. (3) In Brachiosaurus the zygapophyses reach extreme reduction and the 
hyposphene-hypantrum articulation reaches extreme development. In Barosaurus the 
zygapophyses are well developed and also the latter articulation, but there is nothing 
extreme about it. (4) Riggs also emphasizes the low, broad structure of the vertebral 
pedicels. This perhaps may also be said of Barosaurus to a certain extent. (5) The 
dorsal pleurocceles in Brachiosaurus are much longer than high, the length being between 
two and two and a half times the height, whereas in Barosaurus they are as high as or 
higher than long. (6) The laminae are not so pronounced in Brachiosaurus as in 
Barosaurus, and the neural spines of the dorsal vertebra? and probably of the sacrum 
are relatively lower in Brachiosaurus. 
Altogether, I see no indication of relationship with the Brachiosaurida?. 
Comparison with "Brachiosaurus" of Tendaguru. — The description of the Tenda- 
guru species, "Brachiosaurus'" brancai, which we possess is unfortunately very meagre. 10 
The figured cervical (Fig. 1), which is spoken of as lying in the "second quarter," 
that is, between the sixth and ninth, is quite similar to those of Barosaurus in many 
details, the principal distinction being the overhanging prezygapophyses which increase 
the over-all length markedly beyond that of a Barosaurus cervical, the centrum of which 
8 E. S. Riggs, Brachiosaurus altithorax, the largest known Dinosaur. Amer. Jour. Sci., 4th ser., Vol. 
IS, 1903. pp. 299-306, 7 figs. 
9 J. B. Hatcher, Osteology of Haplocanthosaurus. Mem. Carnegie Mus., Vol. 2, 1903, pp. 1-72, 6 pis., 
28 figs. 
10 W. Janensch, Uebersicht ueber der Wirbeltierfauna der Tendaguru-Schichten. Archiv f. Biontol- 
ogie, Berlin, III. Bd., 1. Heft, 1. Teil, 1914, pp. 82-83, 86-98, Figs. 1-6. 
