484 LAND MAMMALS IN THE WESTERN HEMISPHERE 



tional, indicating an extraordinary mobility of the toes, and the 

 hoofs had been transformed into large, bluntly pointed claws, 

 somewhat like those of the fchalicotheres, those aberrant 

 perissodactyls (see p. 354), but not so large or so sharp. In 

 the pes, the ankle-bone had hardly any groove for the tibia, 

 and its lower end was hemispherical, as in the fCondylarthra 

 and the clawed mammals generally. The toes were quite 

 grotesquely short in comparison with those of the fore foot, 

 and, as in the latter, the fifth was the heaviest of the series. 

 The hind foot was apparently plantigrade, the heel-bone and 

 the entire sole being applied to the ground in walking, while 

 the fore foot was probably digitigrade, the wrist being raised 

 and the metacarpals vertical. The weight was carried upon 

 the metacarpals and one or more pads under the phalanges, 

 as in the digitigrade carnivores, such as dogs and cats. In 

 describing the fchalicotheres, it was pointed out that it was 

 uncertain whether each foot had a single large pad, or whether 

 there was a separate one under the phalanges of each digit, 

 and a larger one, the ''ball of the foot," under the metacarpals 

 collectively. The same doubt applies to the manus of the 

 fhomalodotheres. 



This is the third instance to be cited of the acquisition of 

 claws by a hoofed mammal and, as in the other two cases, the 

 fchalicotheres and fagriochcerids (p. 383), we are con- 

 fronted by the seemingly incompatible association of teeth 

 which could have masticated only soft vegetable tissues with 

 feet like those of a beast of prey. As in the other two groups, 

 the problem as to the habits and mode of life of the fhomalodo- 

 theres is an unsolved one, chiefly because no mammal now 

 living is at all like these extraordinary creatures and one can 

 therefore form but vague conjectures as to the use of such feet 

 to herbivorous animals. Possibly they subsisted largely 

 upon roots and tubers and used the great claws for digging up 

 food, the principal employment that bears now make of their 

 claws. This remarkable transformation of hoofs into claws 



