M.
Length ·178
Width of proximal surfaces (transverse) ·032
Width of proximal surfaces (antero-posterior) ·019
Transverse diameter of shaft ·022
Antero-posterior diameter of distal articulation ·018
Transverse diameter of distal articulation ·018
_The _tarsus_._--The _astragalus_ (Plate IX., Fig. 5) has the
condyles asymmetrical and divided by a deep groove; the head is
narrow, with the neck elongate. The face for the cuboid is small, and
confined to the external border.
The _calcaneum_ (Plate IX., Fig. 4) is long and compressed, with its
upper and lower margins straight and nearly parallel; its tuberosity
is large. The face for the cuboid is small.
The _navicular_ (Plate IX., Fig. 6) is proportionately longer and
narrower than it is in the modern horse. The internal and middle
cuneiforms were probably separate.
_Metatarsals_ (Plate IX., Fig. 7).--Three in number. Are very much
shorter proportionately than in the modern horse. In shape they
are compressed and arched forward. The distal ends are flattened
vertically, arched forward, and deeply grooved in the middle.
The _phalanges_ (Plate IX., Fig. 7) are very short, rather stout, and
very smooth and convex above.
The ungual phalanges are very thin and crescent shaped.
_Measurements._