102 THE DESEADO FORMATION OF PATAGONIA 



SPECIMEN 3291 



Femur, greatest length 202 mm. 



Femur, diameter of head 26 mm. 



Femur, width across head and greater trochanter 62 mm. 



Femur, width of internal condyle 16 mm. 



Femur, width of external condyle 24 mm. 



The tibia is much flattened at the upper end and tapers 

 to nearly circular in section in the distal portion of the shaft. 

 It is fused proximally to the fibula, but free distally. 



Tibia, length 222 mm. 



Tibia, greatest width proximally 51 mm. 



Tibia, least diameter of the shaft 24 mm. 



Tibia, diameter of distal articular end 23 mm. 



The fibula is a very slender bone, with the distal end 

 swollen and heavy. As it rises from the carpus it is so 

 twisted that it unites with the upper end of the tibia almost 

 on the posterior surface. 



Fibula, diameter of the articular end 17 mm. 



Fibula, least diameter of the shaft 10 mm. 



The calcaneum is of moderate length, and very stout, 

 resembling that of Adinotherium, except that it is longer. 



Calcaneum, length 64 in in. 



Calcaneum, width 28 mm. 



Of the hind foot there is preserved only the distal por- 

 tions of two metatarsals, which are about the same size 

 and character as those of the front foot, and a phalanx of 

 the first row, also similar to the same one of the front foot. 



Figure 65 gives a restoration of the animal based on the 

 bones described in the foregoing pages. The animal in all 

 features turns out a typical toxodont, adapted, by the 

 cropping teeth, and the broad-faced premolars and molars, 

 for a grazing animal, but its advancement in adapting 

 itself to feeding on grass has not proceeded very far, as is 

 indicated by the shortness of the molars. The legs are 

 longer than in the other families of the toxodonts which 

 would signify that it had developed some speed, but the 

 feet have progressed toward the modification of the hoofs 



