338 MEMOIRS OF THE CARNEGIE MUSEUM. 
one superior and the other inferior (see Fig. 79, 2). The former is plane and 
suboval in outline, while the latter is divided by a rounded ridge, which is nearly 
vertical in position. The portion anterior to this ridge is a basin-shaped surface 
suboval in outline, and the portion back of the ridge is plane and triangular in 
outline. These features vary somewhat in different individuals. Immediately 
anterior to these articulating surfaces the bone is deeply excavated forming a 
large and irregularly shaped cavity when the scaphoid and lunar are placed in posi- 
tion. This cavity is rapidly contracted posteriorly at the point between the upper 
and lower facets for the lunar, described above, and continues to the palmar face 
of the seaphoid. On the ulnar face, back of the superior lunar facet, there is a 
heavy and rough ridge, but no articular 
facet for the lunar. The facets for the 
trapezium, trapezoid, and magnum take 
up the distal face of the seaphoid in an 
unusually unequal manner, the facet for 
the trapezoid occupying by far the greater 
portion of the three. The facet for the 
trapezium is convex fore-and-aft as well 
Fic. 79. Scaphoid of M. elatus (No. 1604). x3. a laterally and takes up the inferior face 
1, anterior view; 2, internal lateral view; 3, radial of a prominent tubercle, which is located 
Mcp 4, posterior view; 5, inferior view; 6, superior on the postero-radial angle and descends 
aes ~ toa considerable extent over the supero- 
lateral face of the trapezoid. The articular facet for the trapezoid is obliquely 
concave antero-posteriorly and somewhat saddle-shaped in its general form, due 
to the prominence of the arm, which, extending in the ulnar direction, articulates 
with the magnum; and also due to the low facet for the trapezium described above. 
The facet for the magnum is confined to the distal end and very slightly to the 
postero-ulnar angle of the heavy descending arm of the scaphoid (see Fig. 79, 1, 2 
and 4). This arm of the scaphoid has been referred to by Mr. Peterson as a 
possible remnant of the centrale, which was characteristic of the early Tertiary 
mammals.*! 
The greater portion of the fore foot and the lower portion of the radius and 
ulna of Nestoritheriwm are represented by plaster casts in the Carnegie Museum. 
The scaphoid as represented in these is unlike that of Macrotherium and Moropus 
elatus, in having a much smaller vertical diameter, and by the extremely small 
development of the descending arm on the ulnar angle. Furthermore the broad 
*! “Preliminary Notes on Some American Chalicotheres,’ American Naturalist, Vol. XLI, p. 747 (1907). 
