600 LAND MAMMALS IN THE WESTERN HEMISPHERE 



transversely, so as to support the huge mass of viscera in the 

 semi-erect position which the animal, it is believed, frequently 

 assumed in feeding. Collar-bones were present. 



The fore limb was very much more slender than the hind, 

 but of nearly the same length. The humerus had a com- 

 paratively slender upper portion and extremely broad lower 

 end, due to the great development of the internal epicondyle 

 and supinator ridge ; there was no epicondylar foramen. The 

 radius evidently had the power of very free rotation upon the 

 humerus. The femur was short, flattened antero-posteriorly, 

 but excessively broad and heavy, and had no third trochanter. 

 The tibia and fibula were likewise short and very massive and 

 were extensively coossified at each end, leaving but a short 

 interspace open between the bones. The very peculiar feet 

 were so connected with the limb-bones, that the animal must 

 have walked upon the outer edge of the foot, somewhat as the 

 existing Ant-Bear {Myrmecophaga jubata) uses the fore foot. 

 The manus had four functional digits, the first being a mere 

 vestige ; the fifth, upon which the weight rested in walking, 

 had two very small phalanges and no claw, while the second, 

 third and fourth had long, sharp claws. The pes had but 

 three functional digits, for the first and second were reduced 

 to rudiments ; digit III had an enormous claw and of this digit 

 the metatarsal was short and very heavy and the first two 

 phalanges were fused together ; the two external digits, Nos. 

 IV and V, had no claws. The astragalus had a very peculiar 

 shape, made necessary by the application of the external border 

 of the foot to the ground and thus in both fore and hind feet 

 the great claws were turned inward and, in the case of the pes, 

 it must have been impossible to rest the sole upon the ground. 

 The heel-bone was enormous and club-shaped and formed the 

 hinder portion of the weight-carrying outer edge of the foot. 



Almost all who have studied the structure of this extraor- 

 dinary beast are agreed as to its habits. That it fed prin- 

 cipally, if not exclusively, upon leaves, is indicated by the 



