34.4 MEMOIRS OF THE CARNEGIE MUSEUM. 
smoothly convex tubercle of the scaphoid, which overhangs the radial face of the 
trapezoid, a feature lacking in M. holland: (see Fig. 12, p. 232). On the antero- 
ulnar angle is a third facet, which is the smallest of the three. This facet is plane 
(see Fig. 84, 1, 3), sub-triangular in outline, and articulates with the trapezoid 
on the postero-radial face of a heavy process, which projects strongly in the postero- 
radial direction in the trapezoid, when it is in position in the carpus. ‘This is a 
second feature which does not appear in the trapezoid of M. hollandi (see Figs. 11 
and 12, p. 232). The inferior and radial views present rough and unevenly convex 
faces, sub-triangular in outline, and are well illustrated in Fig. 84, 2, 4. Antero- 
radially the trapezium terminates in a heavy tuberosity which is abruptly rounded. 
As indicated by the smooth surface of the radial face of the trapezoid and facets 
on the radial angle of the head of Me. II in the cast of Nestoritherium there was 
undoubtedly a trapezium present in the foot of the animal found at Pikermi. 
This bone apparently did not articulate with the scaphoid as in Moropus elatus, 
due to the lack of the well-developed ‘tubercle on the distal radial angle of the 
scaphoid as described above, a feature in which Nestoritherium and Macrotherium 
resemble M. hollandt. 
That the scaphoid of Nestoritherium was able to glide over the inner face of 
the trapezoid to reach the head of Me. II as suggested (cf. Zittel) is untenable, 
because (1) there are no facets indicated on the scaphoid in the cast to correspond 
with the small facets on the radial face of the head of Me. II; and (2) there would 
be too much displacement of the entire carpus to allow such extreme flexion. 
There is no trapezium present in the cast of the foot of Macrotherium, nor is 
there any apparent indication of articular facets for this element on the scaphoid 
or Me. II as in Moropus elatus and Nestoritherium. From the downward con- 
tinuation of the articulation of the scaphoid on the radial palmar angle it appears, 
however, that this element may possibly have been present in Macrotherium. 
Zittel (p. 310) states that the trapezium was reduced. 
MEASUREMENTS OF TRAPEZIUM. 
No. 1604 
(M. elatus), 
mm. 
Greatestatransy.erse: diame terspcarwcy errr eee eee gear 28 
Greatest antero-posterion diameters pee reece een eee 46 
Greatest vertical diameter 02 sac aie esa re es Ee ae 30 
The Trapezoid (Fig. 85).—The trapezoid of Moropus elatus is of large size, as 
in the European genera Macrotherium and Nestoritherium. Viewed from above 
or below the bone is triangular in. general outline (Fig. 85, 2, 3), while from other 
