SCOTT: ENTELONYCHIA OF THE SANTA CRUZ BEDS. 
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facet is much smaller than in the latter and does not cover the whole of 
the distal end, massive rugosities projecting beyond it on the external 
and plantar sides. 
The navicular is very large, especially in transverse breadth, projecting 
internally much beyond the astragalar surface, which is rather small and 
quite deeply concave. On the fibular side, the navicular articulates with 
both calcaneum and cuboid by distinct facets. Of the cuneiforms only 
the ectocuneiform is known. This I have not seen, but, if Ameghino’s 
figure (’94*, 256, fig. 5) is correct, it is a relatively large bone, with nearly 
square dorsal face; it not only covers the head of mt. Ill, but overlaps it 
on each side and articulates by narrow facets with mt. II and IV, a feature 
not found in any other known mammal. The cuboid differs much from 
the short, nearly square bone of Adinotherium and Nesodon; it is much 
higher proximo-distally and the calcaneal facet is oblique, sloping steeply 
downward and outward. On the tibial side are two quite large facets, 
the proximal one for the navicular and the distal one for the ectocunei- 
form. Most of the distal end is taken up by the facet for the head of mt. 
IV and, making an obtuse angle with this, is another very large surface 
for mt. V, which, however, is more lateral than distal. 
Like the metacarpus, the metatarsus consists of five members. These 
show no interlocking or overlapping, but are so arranged that their prox- 
imal ends describe a regular, concave curve, which rises much higher on 
the fibular side, while distally the bones diverge like the sticks of a fan. 
Mt. II, III and IV have a narrow, projecting facet on each side of the 
head, which is largest between mt. IV and V, and the prominence of 
these facets makes wide interspaces between the metatarsals. The shafts 
are grotesquely short, mt. Ill being but little more than one-third as long 
as the corresponding metacarpal. So far as can be determined from the 
imperfect material, this pes is isodactyl, mt. II, III and IV being of nearly 
the same length and thickness, though III is a little more slender than the 
others. The fifth metatarsal is strikingly different in being much broader 
and heavier and in having a massive and rugose prominence, which is 
given off from the fibular side of the proximal end, much as in the Santa 
Cruz Gravigrada. Its facet for the cuboid is very concave and this meta- 
tarsal encircles the cuboid much as me. V does the unciform. 
The phalanges of the pes are entirely unknown. 
All the articulations, from the femur to the metatarsals, make it prob- 
