HOLOSAURUS ABRUPTUS MARSH 355 
former sloping obliquely forward, and for the fibula obliquely back- 
ward, the two making an angle of something more than go°. ‘These 
two faces are separated by a rounded notch. The distal edge is a 
wide curve, and articulates with the second and third metatarsals 
and the other two tarsals. The two smaller tarsals lie one above the 
other, behind the large one. The upper one is the smallest, and 
articulates with the fibula, the other two tarsals, and the fifth meta- 
tarsal. ‘The lower of the two smaller tarsals articulates with the other 
two tarsals, and with the fourth and fifth metatarsals. 
Metatarsals—The first metatarsal is a stout bone, broadly 
expanded and thickened proximally, with a large, flat surface for the 
tibial articulation. ‘This face slopes obliquely backward. ‘Toward 
the middle the bone is constricted, and the posterior margin is deeply 
concave, and is shorter than the more gently concave anterior margin. 
The distal end is slightly expanded and ends in a suboval, flat 
articular facet. 
The second metatarsal is more slender than the first. Its proximal 
end is expanded laterally, with the anterior edge thicker than the 
posterior. ‘The articular face is directed forward and upward. The 
anterior margin of the shaft is thick and only slightly concave, while 
the posterior margin is thinner and rather deeply concave in the 
center. ‘The distal end is slightly expanded, and has a subtriangular 
articular face. 
The third metatarsal is the longest of the five. Its somewhat 
expanded proximal end terminates in a suboval face for articulation 
with the largest tarsal bone. The anterior margin of the shaft is 
almost straight, while the posterior margin is deeply convex toward 
the distal end, which terminates in a backward sloping articular face. 
The two articular faces are subparallel. 
The fourth metatarsal is smaller and more slender than the three 
preceding. Its proximal articulation slopes forward somewhat, and 
is subparallel with the backward-sloping distal articular face. The 
bone is somewhat expanded at both ends, and the concavity of the 
forward margin, though slight, exceeds that of the nearly straight 
posterior margin. is 
The fifth metatarsal is a thin, flattened bone, much Ponca 
proximally. The proximal Border is edged on the forward and 
