MAMMALIAN FOSSILS FROM DEVIL'S GULCH 187 



The mandible of Eubelodon morrilli constitutes a striking char- 

 acter. It is massive, straight, and of great length, with low 

 ascending rami. In life the tusks projected scarcely more than a 

 foot and a half beyond the jaw and lip. There are no inferior 

 tusks. The symphysial prolongation is 15^2 inches 393 mm.) 

 and is not decurved. The mandible is massive up to the sym- 

 physis, where it begins to contract somewhat, then tapers rapidly 

 to the tip. Two grooves, one to the right, and one to the left, 

 parallel the lingual groove, noticeably reducing the bulk of the 

 symphysial portion. Perhaps this is but prophetic that the sym- 

 physial portion is destined to become vestigial as in Elephas. 



In Eubelodon morrilli, the end of the long, straight, massive 

 tapering mandible comes well towards the tip of the tusks, thus 

 making an interesting, if not grotesque, facial portion to the 

 skull. It is an unmastodon-like mastodon. The teeth are reduced 

 to one in each jaw, and they measure about 3^/2 inches (89 mm.) 

 by 8 inches (203 mm.). These teeth have four deeply worn 

 ridges, showing inner and outer trefoiled cones, and a small fifth 

 ridge or heel. Alveolar impressions in the maxillae show where a 

 preceding tooth has been crowded out by a horizontal successor. 

 The ascending rami are low, being at most but 3 inches (77 mm.) 

 above the grinding surface of the molars. They are capped by 

 nearly circular condyles of low convexity, and unlike Elephas are 

 without necks. Contrast with this Elephas imperator, in which 

 the ascending rami are about n inches (280 mm.) above the 

 grinding surface, and that of Elephas indicus, which are about 

 9 inches (230 mm.). 



The coronoids are on a level with the condyles, and, though 

 somewhat compressed, are thick and strong compared with any 

 fossil or living elephant. The sigmoid notch is very shallow. The 

 inferior mandibular border, which is very broad and round at the 

 molars, narrows and swings by an easy curve into the ascending 

 ramus. 



The tusks of Eubelodon morrilli are relatively large, but short, 

 distinctly wedge-shaped at the tips, and without enamel bands. 

 Starting at the skull, where the maxillae are just I foot (305 mm.) 

 across from outside to outside, the tusks diverge until they are 3 



