308 



MAMMALIA. 



flattened, triangular teeth, with a conspicuous cingulum on the inner side. 

 The premolars and molars may be described as intermediate in height 

 between the brachyodont and hypsodont types. The upper and lower 

 premolars are simpler than the molars, which when worn are quite 

 rhinocerotic in type. The last lower molar is distinctly only bilobate. 



TV 



FIG. 177. 



Homalodontotherium segovice ; right manus, upper aspect (A) and third digit 

 of the same in side view (B), two-ninths nat. size. Santa Cruz Formation 

 (Lower Tertiary); Patagonia, en. , cuneiform; lu., lunar; m. magnum; 

 me., metacarpal; p, pisiform; sc., scaphoid; td., trapezoid; (m., trapezium; 

 un., unciform. i v, numbers of digits ; 1 3, numbers of phalanges. 

 (After Ameghino.) 



The centra of the vertebrae exhibit flattened or slightly concave ends. 

 The transverse process of the axis is perforated by the vertebrarterial 

 canal ; the odontoid process is peg-shaped. The humerus is short and 

 stout, with an enormous deltoid crest, which suggests the power of burrow- 

 ing or digging. The radius and ulna are complete and separate, and there 

 is a deep fossa in the humerus for the olecranon. The two rows of carpal 



