Annals of the Transvaal Museum 
114 
and 2 mm. breadth is situated on the medial surface, at a short distance below 
the oval depression. The hinder surface of the bone is narrow and rounded. 
The edge between the hinder surface and the medial surface is rounded in its 
upper two-thirds. At the upper end of its lower third it forms a short, sharp 
and low ridge, the lower end of which lies 10 cm. above the distal articulation 
surface. From this ridge two diverging ridges run towards the distal end. 
The posterior one is low, broad and rounded at its upper end ; at its lower end 
it is a high and broad ridge, the edge of which, however, is broken off. As the 
medial-posterior side of the distal end is weathered, one cannot be sure whether 
this ridge reached the border of the articulation surface ; there are indications 
that it did not. The anterior ridge is also low, broad and rounded at its upper 
end, but its lower end is high and narrow, this being the result of the medial 
and anterior surfaces meeting at an acute angle. This ridge runs right down 
to the antero-medial corner of the distal end. The medial surface between 
the two ridges is concave. The posterior and anterior surfaces of the distal 
end are narrow and slightly convex in horizontal section. In a vertical direction 
they are concave, especially the anterior surface. The lateral surface of the 
distal end is narrow and very convex in horizontal section ; 
it is slightly concave from above downwards. The distal 
articulation surface (text-fig. 19) has somewhat the shape 
of an oval. Its long axis makes an angle of slightly more 
than 45 0 with the sagittal line. Its anterior end lies 
medially and its posterior end laterally. The articulation 
surface is covered with irregularities but is generally flattish. 
It slopes from the antero-medial end downwards to the 
postero-lateral end. The difference in height of the two 
corners is about 16 mm. The postero-medial border is 
weathered, but was probably an evenly convex line from 
the antero-medial end to the postero-lateral end. The 
border of the postero-lateral end is broadly rounded, that 
of the antero-medial end bluntly pointed. There is a short, 
straight anterior border running from the antero-medial 
end outwards till past the middle of the distal end. The 
front border is connected by another straight border with 
the postero-lateral end. The distance from the antero-medial corner to the 
postero-lateral corner is 6-2 cm. The breadth of the distal end as preserved 
is 3*3 cm. The diaphysis is bent and concave medially. At a distance of 
20 cm. from the proximal end the breadth of the shaft (transverse dimension) 
is 2-5 cm. and the thickness 2-6 cm. 
Foot. 
The foot is represented by some well-preserved fragments. 
Metatarsale I is represented by two pieces, one of which is the proximal 
end of the right bone (text-fig. 20). Its breadth is 5 cm. and its thickness 
2*4 cm. The length of the piece is 5-5 cm. There is a narrow ridge in front 
which passes into the rounded anterior surface of the shaft before reaching 
the end of the piece. A broad ridge runs downwards from the middle of the 
lateral border of the proximal articulation surface; it reaches the anterior 
border of the shaft at the fractured end. Posteriorly the bone has a broad 
rough edge. Further downwards this edge is smooth and passes into the 
rounded posterior surface of the shaft. There is a slight angle between the 
rough and the smooth surface. The medial surface bends to the lateral side 
near the posterior border. The proximal surface is hollow in the middle; 
Text-fig. 19. Dro- 
micosaurus gra- 
cilis. Rightfibula. 
Outline of distal 
end seen from 
below. Anterior 
border above. 
Medial side to 
the right, -x 
