The astragulus is a very characteristic bone. The trochlea is asymetrical, the external condyle rising higher than the internal, and the median groove being wide and shallow. On the nearly vertical outer face of the astragulus, there is a semicircular band-like facet for the fibula. The trochlea extends well around the top of the bone, allowing a wide movement of the foot. The neck of the astragulus is long and wide, carrying a broad flattened head, with its convex facet for the navicular, covering the entire end. On the plantar side are the most marked features. The ectal facet is in two planes, the anterior portion being bent down to nearly right angles with the posterior, which seems to be characteristic of this _Diadiaphorus_ series. The sustentacular facet also is characteristic, being gently rounded and extending clear to the navicular facet on the head, in _Diadiaphorus_ becoming actually confluent with the navicular facet. Just at the edge of this sustentacular facet is a tiny surface where the astragulus rubs on the cuboid, the only case, as far as I am aware, where this occurs in any _Litopterna_. [Illustration: Fig. 11. Left astragulus plantar side: _a_, ectal facet—½ natural size; _b_, sustentacular facet; _c_, facet for cuboid.] The calcaneum is long and slender, the tuber being but slightly enlarged, its sustentacular facet being a broad oval surface, while the ectal facet is in two planes to correspond to that on the astragulus. The facet for the cuboid is at the distal end, but is unusually oblique, its inner margin sloping up almost to the sustentacular facet. It is this slope which brings the cuboid in contact with the astragulus. The navicular is broad and low, with a prominent hook behind. On its upper face there is only the broad facet for the astragulus head; on the lower face are three facets, externally, a large, more or less triangular area, for the ectocuneiform; medianly a smaller similar facet for the mesocuneiform; and on the internal side, sloping up onto the internal face, a small facet for the reduced endocuneiform. On the external face of this bone there is a tiny beveled facet for the cuboid. The endocuneiform is a large scale-like ossicle articulating on the lateral internal face of the navicular, and overlapping markedly the inner surface of Metatarsus II. The mesocuneiform is considerably reduced in size, carrying a broad flat facet on the upper surface for the navicular, and a shallow saddle-like one below for Mt. II, which is entirely carried by this bone. The ectocuneiform is considerably larger than the mesocuneiform, resting above on the navicular, and carrying below the whole of Mt. III. On its inner side are two facets which rub against the upper end of Mt. II.