348 MEMOIRS OF THE CARNEGIE MUSEUM. 
crowded over to the dorso-radial angle, and the anterior portion of the lunar facet 
in consequence occupies a larger part of the anterior region and is more proximal 
in position than in Moropus elatus or Nestoritherium. In Titanotherium the mag- 
num differs from these genera in having the superior face more nearly sub-equally 
divided between the scaphoid and lunar, in having the palmar portion of these 
facets more steeply elevated, and in having a more conspicuous palmar hook. 
MEASUREMENTS OF MaGnum. 
No.1604 No. 1700 No. 1424 No. 9078 A.M. 
(M. elatus), (M. petersoni), (M. hollandt), (M. matthewi), 
mm. mm. mm. mm. 
Greatest wransverse diametennn ene ee aoe: 43 30 30 43 
Greatest antero-posterior diameter................... 85 72 65 70 
Greatestaverscaludiame tenance necro are 62 36 45 57 
The Unciform (Fig. 87).—The unciform is of large size, and, as in Titano- 
therium, is more or less triangular in appearance, especially when seen from above 
or below. The transverse diameter of the unciform is the greatest of all the carpal 
bones, while the antero-posterior diameter is very nearly as great as that of the 
magnum. The dorsal surface is rugose, somewhat excavated, and there is developed 
on the radial angle a large tubercle which is compressed vertically, expanded 
transversely, and extends well in the radial direction when in position in the carpus 
(Fig. 87, 3). Radially the bone has two facets of equal size; the superior, which 
articulates with the magnum, is nearly plane and 
sub-quadrate in outline; the inferior is concave an- 
tero-posteriorly, slightly convex supero-inferiorly, 
and articulates with Me. III (Fig. 87,4). Anterior 
and posterior to these facets this figure plainly indi- 
cates rugose excavations and two heavy processes; 
the larger is the dorsal tubercle described above, and 
the smaller is the palmar process. The superior face 
Fie. 87. Unciform of left manus of of the unciform is divided into two subequal articu- 
M. elatus (No.1604). 4. 1, proximal, 
2, distal, 3, dorsal, 4, posterior, views. 
lations by a prominent ridge which extends nearly 
in a straight line fore-and-aft. The facet for the 
lunar on the radial side of the ridge is concave laterally near the radial face, but 
rises suddenly in the palmo-ulnar direction, so that this region of the facet is 
convex both transversely and antero-posteriorly, and the general outline of the 
whole surface is diamond-shaped. The facet for the cuneiform is subtriangular 
in outline and convex antero-posteriorly and slightly concave transversely, especi- 
