PROSOTHERIUM GARZONI 69 
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 
bonesare 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 telatively low and flat. This. troch- je) es cesicaneum, 
lear surface is far from being symmetrical, astraewus anc cubow 
the inner ridge being much flatter and lower ““'S' 
than the outer. The head of the astragulus 
is rounded, on a long neck, and directed 
obliquely inward. The fibular facet for 
i the fibula is crescent-shaped and vertical 
Fig. 38. Astragulusfrom except that the small 
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 calecaneum. 
The metatarsals are moderately long 
and rather heavy, not quite as long Fig.39. Right foot—natural 
and slender as those of Pachyrukhos. ioe 
The phalanges are also shorter and slightly heavier than 
those of Pachyrukhos. We found four proximal and four of 
