ey) 
i) 
S 
THE OSTEOLOGY OF ELOTHERIUM. 
X. Restoration or Erornertum (Plate XVII). 
The skeleton of this genus has a remarkable and even grotesque appearance. As in 
so many of the White River genera, the skull is disproportionately large, and the 
immense, dependant projections from the jugals, together with the knob-like protuberances 
on the mandible, produce a highly characteristic effect. The long, straight face, the 
prominent and completely enclosed orbits, the short cranium, the high sagittal crest, and 
the enormously expanded zygomatic arches give a certain suggestion of likeness to the 
skull of Hippopotamus. The neck is-short, nearly straight and very massive, with 
prominently developed processes for muscular attachment. The trunk is short, but 
heavy ; the anterior thoracic spines are yery high and heavy, while those of the posterior 
region are short and quite slender. In consequence of the sudden shortening of the 
thoracic spines, a conspicuous hump is formed at the shoulders. The thorax is of 
moderate capacity and the loins are short. The tail appears to be of no great length, 
though the individual vertebrae are greatly elongated. The limbs are long and rather 
slender, and the fore and hind legs are of nearly equal height ; the humerus and femur 
are almost the same in length, as are also the radius and tibia, while the pes is somewhat 
longer than the manus. The scapula is very large, especially in the vertical dimension, 
which considerably exceeds the length of the humerus, and has a short but promment 
acromion; the pelvis, on the other hand, is rather small, the ilium having a long and 
slender peduncle, and only a moderate anterior expansion. The elongate limbs and 
slender, didactyl feet are in curious contrast to the huge head and short, massive trunk, 
and form a combination which would hardly haye been expected. 
Prof. Marsh has published, with a very brief explanatory text, a restoration of 
Elotherium (94, Pl. 1X) which differs in several details from the skeleton here figured. 
It is difficult to tell from the data furnished exactly how much of this restoration is con- 
jectural, or to determine how far the discrepancies to be mentioned are the result of the 
association of parts of many different individuals in a single figure, and how far they are 
due to actual specific characters. On comparing the two figures, one is struck by the 
following differences: (1) In Marsh’s restoration the skull is somewhat smaller in pro- 
portion to the length of the limbs. (2) The neck is more slender and the spines of the 
cervical yertebree, notably those of the sixth and seventh, are much less developed. (3) 
The trunk is decidedly longer and twenty thoraco-lumbar vertebre are figured. No 
reason is assigned for this departure from the well-nigh universal formula of the artio- 
dactyls, which is nineteen, and we are therefore ignorant of the evidence by which it is 
supported. (4) The spines of the thoracic vertebree are much more slender and decrease 
‘more gradually in length posteriorly, so that there is no such decided hump at the 
