320 THE OSTEOLOGY OF ELOTHERIUM. 



X. Restoration of Elotherium (Plate XYII). 



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 exj>anded 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 jn'ocesses for muscular attachment. The trunk is short, but 

 heavy ; the anterior thoracic spines are very 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, 

 thousdi the individual vertebras are p'reatlv elongated. The limbs are Ions; and rather 

 slender, and the fore and bind legs are of nearly equal height ; the humerus and femur 

 are almost tlie 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 prominent 

 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, didacty] feet are in curious contrast to the huge head and short, massive trunk, 

 and form a combination which would hardly have been expected. 



Prof. Marsh has published, with a very brief explanatory text, a restoration of 

 Elotherium ('94, PL IX) 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- 

 |» hi ion to the length of the limbs. (2) The neck is more slender and the spines of the 

 cervical vertebrae, notably those of the sixth ami seventh, are much less developed. (3) 

 The trunk is decidedly longer and twenty thoraeo-lumbar vertebras are figured. No 

 reason is assigned for this departure from the well-nigh universal formula of the artio- 

 daetyls, which is nineteen, and we are therefore ignorant of the evidence by which it is 

 supported. (4) The spines of the thoracic vertebrae are much more slender and decrease 

 more gradually in length posteriorly, so that there is no such decided hump at the 



