118 MEMOIRS OF THE CARNEGIE MUSEUM 
Pyramidal. —In Dinohyus the posterior ascending tubercle of the facet for the 
ulna is more prominent than in Archxotheriwm, which results in a greater concavity 
antero-posteriorly in the former. he facet for the ulna extends down on the bone in 
an unusual manner and hence it is proportionally greater than in Archeotheriwm, Hip- 
popotamus, or Sus. The pisiform facet is more oblique than in the Oligocene form. 
Below this facet is a large and deeply excavated sulcus which extends parallel to 
the sharp ridge on which is located the above mentioned facet. The radial face has 
two facets for the lunar; the supero-anterior one is plane, subtriangular in outline, 
and inclined obliquely upward and outward; the postero-inferior facet is convex 
antero-posteriorly and concave supero-inferiorly and separated from the ulnar facet 
by a sharp ridge, while in Archeotheriwm the two facets are separated by a sulcus of 
considerable diameter. The distal articular facet is similar to that of the Princeton 
specimen in every respect. 
MEASUREMENTS. 
ty oe transverse Me vosteriorly.. 
I 
i i vertical os anteriorly...... 
a LG us ECS FAGDOSLOLION lVatcves sates totus tede stent: 
Pisiform. — There is no pisiform present with the type of Dinohyus. In another 
specimen (No. 2136, Carn. Mus. Cat. Vert. Foss.) the pisiform was found nearly in posi- 
tion and is here described in connection with the type specimen. ‘There are only slight 
differences in the shape of the pisiform of Dinohyus and that of the older American 
types. The facet for the ulna extends slightly further back and is surrounded by a 
much heavier border so that the proximal face of the shaft has a deep excavation 
while in Archxotheriwm it is more evenly rounded. The facet for the pyramidal is 
larger than that for the ulna. From the attachment of the carpus the bone is 
strongly recurved backward and radially asin Archwxotheriwm and the free end is 
enlarged into a thick knob. The bone, though comparatively small, is relatively of 
slightly larger size than that of the Oligocene genus. 
The pisiform of Hntelodon, as Scott (87, p. 804) has pointed out, is very different 
in its outline, though not altogether unlike that of the American forms. Scott 
suggests that the irregular shape of the pisiform which Kowalevsky (88, Pl. XXVI, 
fig. 27) figures ‘““might be due to disease.’ It would, however, seem from the illus- 
tration that the facets also differ in having an irregular convexity while in the 
American forms they are obliquely concave. The pisiform of Anthracotherium is 
considerably larger and somewhat different in form, having a more decided shaft, a 
less club-shaped free end, and apparently differently shaped articular facets for the 
