Annals of the Transvaal Museum 
127 
angular section with a vertical medial side. The distal end is slightly twisted 
to the medial side. 
Metacarpale V is different in the two hands, but the left has suffered from 
pressure and the right has completely escaped this misfortune (text-fig. 27). 
The proximal end has a triangular shape of the same type as that of meta- 
carpale IV, only narrower and higher. The upper angle, which lies on the 
extreme medial side of the upper surface, is very broadly rounded. The 
lateral corner is also very broadly rounded. The lower medial corner is sharp 
and narrow; between this corner and the upper one lies a concave surface. 
The proximal articulation surface is greatly convex, except the lower portion, 
which is concave. The upper corner passes further forward on the shaft than 
any other portion of the articulation surface. The distal end is convex. Later- 
ally it runs out into a knob-like point; medially it is broadly rounded. A 
section of the shaft is more or less triangular, with a nearly vertical medial 
side and a convex lower one. The longest dimension of the distal articulation 
surface stands from above downwards and inwards. This metacarpale does 
not possess collateral pits. 
Phalanges. The first phalanx of the first digit is a remarkable bone. Its 
distal end is twisted nearly 45 0 on its proximal end. The proximal articulation 
surface has a trapezoidal shape. Its lateral side, however, is convex and its 
medial side is concave above and convex below. The lower medial corner of 
the surface is tongue-shaped and projects far to the medial side. The whole 
surface is deeply convex; it is divided into two unequal portions by a slight 
ridge; the lateral portion is the larger, the medial portion only consisting of 
a narrow strip along its concave border and of the tongue-shaped lower corner. 
The lower border is slightly concave below the end of the ridge over the 
articulation surface. The distal end is pulley-shaped. The groove between 
the two portions stands obliquely from above downwards and inwards. Its 
lateral side projects further forwards than its medial side, but the medial 
portion of the articulation surface passes further backwards on the lower 
surface than the lateral portion. The lateral collateral pit is deeper than the 
medial one. 
Excepting the claws, the phalanges of the second and third fingers have 
all the same general shape. The contour of the proximal surface of all these 
phalanges is trapezoidal. The proximal articulation surface of II, 1 and III, 1 
is deeply hollow and not divided by a ridge. The upper posterior end of the 
phalanges does not project far backwards. The lateral side of their distal end 
projects further forwards than the medial side. The distal end of II, 1 is 
twisted to the lateral side, that of III, 1 slightly so. There is a slight con- 
cavity behind the anterior articulation surface on the upper surface of the 
bone. The lateral collateral pit is deeper than the medial one. 
As in the foot there is no pit behind the articulation surface on the upper 
surface of all the penultimate phalanges of the hand. The proximal articula- 
tion surface of both penultimate phalanges of the second and third fingers is 
divided into two portions by a ridge. The lateral portion is broader than the 
medial one. The penultimate phalanx of the second finger differs from that of 
the third, except in size, through the upper portion of the medial border of 
the proximal surface being concave in the former and straight in the latter. 
A further difference is, that in the penultimate phalanx of the second finger 
the lateral side of the distal articulation surface passes slightly further down- 
wards than the medial side, whereas in the penultimate phalanx of the third 
finger this is just the reverse. Both phalanges have a broad and thick upper 
posterior process. The distal articulation surface of both phalanges passes 
9—2 
