HOLLAND AND PETERSON: OSTEOLOGY OF THE CHALICOTHEROIDEA. 349 
ally near the dorsal margin of the facet (Fig. 87, 1). The inferior face of the unci- 
form is occupied by the large facet for Me. IV, which is subovate in outline. The 
dorsal portion of this facet occupies a lower position and is slightly convex from 
side to side, while farther back it rises gently and again descends near the palmar 
face so as to form on this portion of the facet a saddle-shaped surface. There is 
no facet for Me. V on the unciform. 
The unciform of Nestoritheriwm, though broad, has not the great development 
on the dorso-ulnar angle which obtains in Moropus. Furthermore, there is no true 
palmar process as in the latter genus, the bone being more heavily built in this 
region. The facet for the cuneiform descends lower down on the dorsal face than 
in Moropus and ascends more gradually to the radial palmar angle. There is no 
indication of a facet for Me. V. 
There is no unciform present in the cast of the manus of Macrotherium. In 
Titanothervum the unciform differs most prominently from that in Moropus elatus 
by having a large facet for Mc. V, a proportionally larger palmar tubercle and 
the dorso-radial angle less produced. 
MEASUREMENTS OF UNCIFORM. 
No. 1604 No. 1700 
(M. elatus), (M. petersoni), 
mm. mm. 
Greatestaransverseaiameterseioae eee ences an. 5) 55 
Greatest antero-posterior diameter..................-.0005- 81 38 
Greatest vertical diameter.................-...00+e+eseees 57 41 
The Metacarpals. 
Metacarpal II (Fig. 88)—The second metacarpal is the heaviest and the 
shortest of the series. The proximal end has a great transverse expansion due to 
the heavy tuberosities on the radial and ulnar angles. The proximal end carries 
six facets. The first is for the trapezium and is located on the radial angle immedi- 
ately back of the tuberosity on the dorso-radial angle, which is mentioned above 
and the tuberosity well illustrated in Fig. 88, 2. Directly proximal is a large 
facet for the trapezoid, which is separated from the facet for the magnum by a 
prominent ridge, so that the latter facet is located rather on the ulnar angle. Di- 
rectly in front of this oblique facet is a second facet for the magnum, which in 
No. 1604 occupies the proximal face of the heavy tuberosity on the dorso-ulnar 
angle of the head (see Fig. 88). On the posterior face of this tuberosity is a large 
plane facet which is sub-quadrate in outline and articulates with a corresponding 
facet on the dorso-radial angle of Me. III. Immediately back of the facet last 
