478 THE STRUCTURE AND RELATIONSHIPS OF ANCODUS. 
to anything like the same extent. (3) The posterior hook is very much smaller. 
While these differences are very marked, the resemblances are even more important. 
In the carpus of both genera a displacement of the magnum toward the radial side 
and a tendency of the lunar to rest entirely upon the unciform are obvious, but 
this displacement has been carried farther in the oreodonts than in Ancodus. In 
A. (vnericanus i\\e shifting of the magnum has proceeded farther than in A. brachy- 
rhyuchns, and the contact with the lunar is more entirely lateral. The distal beak 
of the lunar is more prononnced, and the resemblance to the lunar of Oreodon more 
complete. In the European species of Ancodus the magnum has an even less dis- 
tinctly marked head than in the American, and the relation of the proximal facets 
is reversed, that for the lunar being larger than that for the scaphoid. The palmar 
hook is broader and more massive. Kowalevsky calls attention to the perissodactyl 
character of this bone. (See Monographie der Gattung Anthracotherium ; Palrn- 
ontographica, XXII, pp. .303-4, Taf. XI, fig. 39-42.) 
The unciform is the largest bone in the carpus, though not greatly exceeding 
the lunar in bulk. Its roughened dorsal face is considerably higher vertically than 
that of the magnum, and the palmar hook is broad, massive, depressed, and decurved, 
but not elongate. The proximal surface is unequally divided betwmen the facets for 
the lunar and unciform, the latter being considerably the wider of the two. Tlie 
lunar facet is somewhat oblique in position, broader in front and narrowing behind, 
somewhat concave transversely and strongly convex antero-posteriorly. The facet 
for the cuneiform has similar curves, but narrows toward the ulnar side. On the 
radial side is the large, infero-lateral hxcet for the projection arising from me. Ill, and 
above and behind this a surface for the extension from the ulnar side of the mag- 
num. The distal surface displays a large and nearly plane facet for me. IV, and a 
narrow, concave one for me. V ; the latter is almost as much lateral as distal, and is 
continued back the full depth of the palmar hook. The unciform of the European 
species of Ancodus much the same as in the American, but is broader in propor- 
tion to its height; its ulnar border is less abruptly truncated, and is drawn out into 
a sharp angle. The lunar facet is also somewhat wider, the displacement of the 
magnum toward the radial side having hardly advanced so far. The unciform of 
Oreodon is somewhat higher in relation to its width, and the posterior hook is de- 
cidedly more compressed and slender. The lunar facet is muol, more distinctly 
divided into anterior convexity and posterior conenvity, while the cuneiform facet 
.s rounded .nnd convex in both directions. The highest point of the bone is not, as 
“ f.T r j’-'' ."‘‘S' two fscets, but by the sninmit of tlie 
arched surface for the cuneiform. 
dactv'l r'T" ’’ P- of it Ponta- 
Sv Ime Lm ? "’‘"'''/“f. *>0 called welWeveloped, and tliongh it can 
hardly I a,e been of much functional importance, it is relatively larger than in any 
V;: e S i'a" ' boon dem„™tr!rd. 
along t e med arrj i I; “f tocond, measured 
g median line, it has an enlarged, rugose head bearing a narrow facet for 
