374 MEMOIRS OF THE CARNEGIE MUSEUM. 
obliquity to the ectocuneiform articulation, and, as in Titanotheriwm, the cuboid 
articulates with the fibular portion of the head. The shaft of Mt. III in Macro- 
therium is broad transversely, and not round as in Moropus. 
MEASUREMENTS OF THIRD METATARSAL.7 
No. 2193 Y.M. No. 1706a No. 1701 No. 9077 A.M. 
(M. elatus, type), (M. elatus), (M. petersoni), (M. matthew), 
mm. mm. mm. mm. 
Lengths steed siessts ors le Bas Oe COR OE CE Re - 156 122 122 
Antero-posterior diameter of head............... 54 53 40 47 
Transverse diameter of head...................-. 45 48 48 43 
Transverse diameter of distal end................ .. 45 39 48 
Antero-posterior diameter of distal end........... ta 54 38 48 
Metatarsal IV (Fig. 106)—The head of Mt. IV is square in outline. Proxi- 
mally there is a large, nearly plane facet for the cuboid. The fibular and plantar 
faces are considerably expanded due to heavy rugosities and protuberances. On the 
tibial face are two facets for Mt. III, which are 
conspicuous because situated on these projec- 
tions, so that, when the metatarsals are placed 
in position, the lateral faces of the shafts are 
entirely separated (see Plate LX XII). The 
shaft is less cylindrical than in Mt. III. This 
is chiefly due to a heavy and rugose ridge which 
extends from the head throughout the entire ~ 
: Jength of the shaft on the fibulo-plantar angle. 
Se My = The distal end of the bone points slightly in 
Fic. 106. Mt. IV of right foot of M.elatus the tibial direction, due to the curvature of 
(No. 17064). x3. 1, fibular view; 2, dorsal the shaft (see Fig. 105, 2). The trochlea has 
views 5 mbialwew. a greater obliquity than in Mt. III; otherwise 
there is very little difference in the details of the two metatarsals here compared. 
Mt. IV in Macrotherium is conspicuously the longest, while in Moropus it is 
very little, if any, longer than Mt. III. In Macrotherium the facet for the cuboid 
is more concave due to the raised fibular and plantar borders; the outline of the 
articular surface is more nearly square; while the distal trochlea has about the 
same degree of obliquity as in the American form. 
In Nestoritherium Mt. IV is fully as heavy as Mt. III, but considerably shorter, 
as previously stated. The facet for the cuboid is somewhat more oblique than 
in Moropus, which is entirely due to the more elevated tibio-plantar angle of the 
7% Italicized numbers represent estimated measurements. 
