482 THE STRUCTURE AND RELATIONSHIPS OF ANCODUS. 
sulcus for the tendons of the anterior tibial muscles (tibialm anticus, flexor longus 
li!Lmun) is remarkably deep, and its entrance is narrowed by a projectmn from 
tlm posterior side. TbJ shaft is shaped almost exactly as m a nearly 
straight posterior border, but having a considerable lateral curvature Ihe dista 
eud likewise is very similar to that of the last-named genus, except that the internal 
malleolus is much shorter, thinner, and less pointed. The external cotyle for the 
astragalus is considerably wider than the internal, but its articular surface is more 
extensively invaded by the large sulcus, which, just as in Oreodon, crosses the 
intercondylar ridge ; this ridge forms a somewhat more prominent anterior tongue 
than in the latter. There is a well-defined distal facet for the fibula in addition to 
the lateral one on the distal end of the shaft, the fibula extending considerably be- 
neath the tibia. In Oreodon this also occurs, but the displacement is less, and con- 
sccjuently the facet in the distal face of the tibia is less developed. 
Of the fibula only the distal end is preserved in any of the specimens, but it 
is plain that no coalescence between the two leg-bones occurred at any point, and 
that the shaft of the fibula, though slender and reduced, was, in all probability, 
complete and uninterrupted. The distal end is narrow and transversely compressed, 
but considerably expanded antero-posteriorly, much more than the depth of the 
calcaneal facet. This facet is somewhat saddle-shaped, concave transversely and 
convex from before backward; it is broadest about the middle of its course, narrow- 
ing toward the ends. A strong shelf projects inward from the mesial side of the 
fibula, which extends underneath the tibia and bears a facet on its proximal side 
which articulates with the surface already described on the distal face of that bon'e. 
The mesial side of this fibular projection bears a large facet for the astragalus. 
Kowalevsky’s figure (PI. XXXV, fig. 3) shows that in Diplopus the distal end of 
the fibula is much like that of Ancodus brachyrhynckus, but the calcaneal and 
astr.agular facets are larger and of a somewhat different shape. 
The pes (PL XXIII, fig. 4; PI. XXIV, fig. 9) is, in some species at least, much 
larger than the manus in every dimension, and especially in vertical height. The 
tarsus is, on the whole, very much like that of the oreodonts, but with some 
characteristic features of its own. 
Ihe astragalus is relatively much higher and narrower than that of Oreodon. 
1 he proximal trochlea is more symmetrical than in the European species of Anco- 
dus, owing to the lesser height of the external condyle, and the median groove is 
broader. The distal trochlea is proportionately much higher than in Oreodon, and 
separated from the proximal one by a wider interval; the navicular facet is much 
narrower and the cuboidal wider. The calcaneal facets of the astragalus are very 
characteristic, and differ in a marked way from those found in the European species 
of Ancodus, as well as from those of Oreodon. The articular surface for the sus- 
tentaculum of the calcaneum ,s divisible into two facets, the outer one of which is 
thrTnmT^^ y convex proximo-distally and plane transversely, and presents toward 
TheS ; 1 to the entire sustentacular surfL in Oreodon. 
The internal, or mesial, sustentacular facet is of the same proximo-distal length as 
