ASMODEUS OSBORNI 139 
upper end, while on the posterior face, there is a large 
interosseus crest, which starts just below and external to 
the spine, and extends in a sigmoid curve three-fourths of 
the length of the shaft, ending on the internal border 
Distally the tibia is flattened antero-posteriorly, and the 
internal margin extends as a wide process down to the 
level of the navicular face of the astragulus. The articular 
facet for the astragulus is a rectangular depression, being 
about half as wide in the antero-posterior direction as in 
the transverse. This facet is only slightly concave and the 
inner and outer portions are not separated by an inter- 
trochlear ridge. The fibula has not been found, but the 
tibia shows no indication of its having been fused to it. 
Ameghino has figured the astragulus as very low, with 
the trochlea flattened, the internal condyle being wider 
and flatter, while the external condyle is narrower and 
somewhat raised. The trochlea is peculiar in that its 
proximal margin 1s deeply notched by a depression in which 
there is a large perforation. The neck is prolonged and 
carries a large convex head articulating with the navicular 
only. The measurements given are, length 116 mm., 
width 75 mm. 
Gaudry figures a calcaneum, showing a long narrow 
tuber, and the facet for the fibula as a wide shelf which 
projects strongly on the external side. The size as given 
by Ameghino is 240 mm. long, by 120 mm. wide. 
I have two associated ungual phalanges, one of which 
corresponds to that figured by Ameghino as the third. 
It is high, laterally compressed, has a very rugose surface 
on either side, and a deep cleft in the end. This is 68 mm. 
long. The second ungual is very asymetrical, also laterally 
compressed, and with the point curved inward. I take it 
to be the fifth. The tibia, the tarsus, and the phalanges 
strongly suggest that this animal walked on the side of its 
foot. 
