PROSOTHERIUM GARZONI 



69 



Fig 37 Calcaneumi 



straighter. It is further distinguished by the third trochan- 



ter being swung onto the back side of the bone. The tibia 



and fibula are separate throughout their en- 



tire length, in which this genus is in strong 



contrast to Pachyrukhos, where these two 



bones are fused, both distally and proximally. 

 The astragulus is also quite characteris- 



tic, the trochlear surface being entirely on 



the dorsal surface, and the condylar ridges 



being relatively low and flat. This troch- 



lear surface is far from being symmetrical, 



the inner ridge being much flatter and lower uralsize - 



than the outer. The head of the astragulus 

 is rounded, on a long neck, and directed 

 obliquely inward. The fibular facet for 

 the fibula is crescent-shaped and vertical 



Fig. 38. Astragulus from CXCCpt that the Small 

 below natural size. i r ., i 



proximal end of the cres- 

 cent flares out. The outline of the sus- 

 tentacular facet is that of an acute ovoid, 

 and is situated mostly on the neck of this 

 bone. The ectal facet is roughly rectan- 

 gular in outline, strongly concave, and is 

 separated from the sustentacular facet 

 by a deep groove. 



The calcaneum is of moderate size, has 

 a narrow fibular facet, a broad ectal facet, 

 and a moderately large sustentacular 

 one. The facet for the cuboid is slightly 

 concave, and occupies the whole of the 

 distal and of the calcaneum. 



The metatarsals are moderately long 

 and rather heavy, not quite as long Fig. 39. Rightfoot natural 

 and slender as those of Pachyrukhos. 

 The phalanges are also shorter and slightly heavier than 

 those of Pachyrukhos. We found four proximal and four of 



