366 MEMOIRS OF THE CARNEGIE MUSEUM. 
MEASUREMENTS OF ASTRAGALUS. 
No. 1706a No. 1701 No. 1424 
(M. elatus), (M. petersoni), (M. hollandi), 
mm. mm. mm. 
Greatestiverticalidiameter see ne eee ener RS eM 90 68 64 
Transverse Giameter. )ossh5 bee ne eae ee Ot ee 96 76 83 
The Calcaneum (Fig. 99).—As in other members of this group the tuberosity 
of the caleaneum is quite long and very heavy, while the lower end is extremely 
truncated. The plantar face of the tuberosity is rugose and very broad trans- 
versely, quite like that in the rhinoceroses, with gradually sloping lateral sides, 
giving a pear-shaped outline to the cross-section. There is no tendinal groove on 
the proximal end of the tuber, the extensor muscle of the foot being attached in 
the same manner as in other Perissodactyla. The lesser process of the distal end 
is developed to nearly the same extent as in Titanotherium, and less than in Macro- 
thervum. In some individuals there is a decided facet for the tibia on the upper 
border of the facet for the astragalus; there is also sometimes a minute facet for 
the fibula on the fibular side of the greater process, and a small irregularly shaped 
facet below the sustentaculum near the distal angle, which articulates with a 
corresponding facet on the posterior face of the as- 
tragalus near the distal angle. Distally the lesser 
process extends downwards even with the distal end 
of the astragalus, so that the navicular facet of the 
latter bone and the cuboidal facet of the caleaneum 
are on nearly a horizontal line when the two bones 
are in position, while in Macrotherium and Titano- 
thertum the lower end of the astragalus extends 
more or less below the caleaneum. The articular 
facets for the astragalus are large and interlocking. 
The surface for the interosseous ligament is promi- 
: nent and forms a considerable sinus between the 
Fic. 99. Os calcaneum of right foot facets when the caleaneum and astragalus are placed 
Cee eee ae FOC SS aan position. The facet for the cuboid is nearly 
superior view; 2, lateral view. 
plane and pear-shaped in its general outline. 
The remains of the caleaneum of Nestoritherium show strong resemblances 
to the same bone in the American genus. Unfortunately the tuber of the cal- 
caneum in the specimen from Pikermi before us is not entirely complete, but what 
remains indicates that the plantar face is broader than the dorsal, that as in Moro- 
