304 THE OSTEOLOGY OF ELOTHERIUM. 
project over the pyramidal. The lunar of Anthracotherium (see Kowalevsky, ’73, Taf. 
XI, Fig. 37) is like that of Hlotheriwm, but is narrower, especially its palmar face, and 
much thicker, and the distal beak is more nearly in the median line. In Hippopotamus 
the lunar is broad and rests almost equally upon the magnum and the unciform, as it 
does also in Sus. 
The pyramidal quite resembles the scaphoid in shape, but is much broader, not so 
thick antero-posteriorly, and generally of a more rugose and massive appearance. In 
view of the reduced lateral digits and the codssified radius and ulna, the relatively large 
size of the pyramidal is somewhat surprising. The proximal end is occupied by the 
ulnar facet, which is convex transversely and deeply concave antero-posteriorly. On the 
palmar side is a narrow, plane facet for the pisiform, which is very oblique in position. 
This facet is carried upon a compressed and slightly recurved, hook-like ridge, which 
runs for nearly the full vertical height of the bone, though not quite reaching to the 
distal end. On the radial side are two facets for the lunar, separated by a wide and deep 
suleus; the palmo-distal one is larger than the corresponding surface on the lunar, and 
its curvatures are, of course, in opposite directions to those of the latter, being concaye in 
the vertical, and conyex in the dorso-palmar diameter. The distal end of the pyramidal 
is taken up by a large, but shehtly concave facet for the unciform. 
In the material described by Kowalevsky the pyramidal of Hlotherium is not repre- 
sented, while that of Anthracotherium is so badly preserved and of such uncertain 
reference, that any comparison founded upon it would be valueless. The pyramidal 
of Hippopotamus is broad, square and heavy, as is also that of Sus, on a smaller scale. 
The pisiform is quite small and slender, though of considerable length ; it is strongly 
recurved toward the median side of the carpus, presenting the conyexity externally ; the 
distal end is thickened and club-shaped, though but little expanded in the vertical 
dimension. The pyramidal facet is nearly plane and oblique in position, broadest exter- 
nally and narrowing to a point on the radial side. The ulnar facet is very much smaller 
and somewhat concave; the two meet at almost a right angle. 
The pisiform of H. magnum (Kowalevsky, ’76, Taf. XX VI, Fig. 27) is not unlike 
that of H. ingens, but is of a more irregular shape, which looks as though it might be 
due to disease, that of Anthracotherium (XKowalevsky, ’73, Tat. XI, Fig. 58) is of quite 
similar shape, though much larger. In Sus the pisiform is of an entirely different shape 
from that of either of the extinct genera, being much deeper vertically, more compressed 
and plate-like, and less strongly recurved. That of Hippopotamus is more like that of 
the fossil forms. 
The trapezium is not associated with any of the specimens which I have seen, nor is 
any facet for it distinctly visible on either the scaphoid or the trapezoid. If present at 
