Annals of the Transvaal Museum 
113 
Fibula. 
Of the fibulae only the right bone has been found and this is in excellent 
condition. It has a length of 34*5 cm. v. Huene has already pointed out 
that one can readily ascertain whether the fibula belongs to the left or to the 
right side. The lateral side of the proximal end is convex. The thin and low 
portion of the proximal end is anterior, the thick portion posterior. 
In the following description the bone is so placed that the inner border 
of the posterior portion of the proximal articulation surface is directed straight 
backwards (PI. XV, figs. 1 — 3). The proximal articulation surface is convex 
from side to side and its anterior portion is bent inwards 
(text-fig. 18). The whole surface is covered with irregular 
grooves and ridges. The anterior portion of the proximal 
end of the bone is strongly directed inwards; it is really 
a high, thin, anterior process. Its most anterior point lies 
far below the articulation surface. The lateral surface of 
the posterior portion of the proximal end is evenly convex. 
That of the anterior portion is slightly concave. Between 
these two portions the lateral surface is strongly convex. 
The posterior portion of the medial surface is flat; its 
anterior portion is slightly concave. There is a broad low 
boss slightly below the middle of the inner surface of the 
proximal end. From the posterior corner of the proximal 
end a broad ridge passes downwards and inwards for a short 
distance; it narrows down quickly and ends opposite the 
middle of the broad boss on the inner surface. The greatest 
breadth of the proximal end is 7-7 cm. Its greatest thickness 
is 2-8 cm. The thickness of the bone over the broad boss is 
3 cm. The shaft narrows down rapidly immediately below the head. At a dis- 
tance of 9 cm. from the proximal end the, breadth of the bone has diminished to 
3*5 cm. and the thickness to 2-1 cm. At a distance of 15 cm. from the proximal 
end the breadth of the bone is reduced to 3 cm., but the thickness has in- 
creased and is at this spot 3 cm. The greatest horizontal dimension of the 
shaft at this distance from the proximal end is 3*4 cm. This is due to a broad, 
high ridge on the lateral surface of the bone. This ridge starts very gradually 
at a distance of about 9-5 cm. from the proximal end on the anterior border 
of the lateral side of the bone. It ends at about 19 cm. from the proximal 
end. The distal end of the ridge is situated in the middle of the lateral surface 
of the shaft. The posterior side of the ridge is slightly concave at its upper 
end, but at its lower end it passes gradually into the posterior surface of the 
bone. The anterior side of the ridge is slightly concave. The anterior edge of 
the bone passes down as a low ridge along the medial side of this concave 
surface. There is a large oval depression on the anterior surface of the bone, 
medial to the low ridge just mentioned and looking slightly inwards. The 
medial side of this depression is slightly elevated above the medial surface. 
The upper and lower ends of the depression lie at a distance of 12 cm. and 
15 cm. respectively from the proximal end. Slightly below the oval depression 
the low ridge subsides into the general surface of the bone. At a short distance 
from the depression the anterior edge again assumes a ridgy appearance. 
This ridge, however, is not a continuation of the preceding ridge, for the lower 
end of the latter lies higher than and lateral to the upper end of the former. 
This ridge runs downwards for a short distance and then also subsides into 
the general surface of the bone. A foramen nutritivum of about 6 mm. length 
micosauvus gra- 
cilis. Right 
fibula. Outline 
of proximal end 
seen from above. 
Medial side to 
the left, x A. 
