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 an tero- 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 is 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. 



