268 
PROFESSOR H. G. SEELEY ON THE STRUCTURE, ORGANIZATION, 
of the bone towarcis what may be the exteriial side is 6‘7 centims., and towards the 
other side about 5 centims. This articular surface is smooth, flattened, slightly 
convex in transverse width, and about 2'5 centims. thick in the middle, becoming 
narrower towards each side. 
The distal articular surface is 7‘3 centims. wide, and more than 3 centims. thick. 
It is convexly rounded in the vertical direction as well as at its external corners, but 
so that the larger part of the articular surface lies towards what I regard as the 
inferior aspect. An impressed groove appears to margin the superior limit of the 
articulation, but the extremities of the bone are slightly worn or weathered. The 
external lateral border of the bone is a sharp ridge formed by the superior surface 
curving down concavely, so as to depress the inferior surface. The internal lateral 
border is relatively thick, and traversed by a longitudinal groove. This groove, 
like a small notch on the external side, I suppose to be for ligaments connecting the 
phalange, which moved on the sub-cylindrical convexity of the distal surface. 
The second phalange is smaller. It also is compressed and sub-quadrate, with 
concave sides, and the proximal and distal surfaces expanded. The proximal surface 
is oblong, 5'8 centims. long, 2’6 centims. thick, with the ends rounded. It is trans¬ 
verse to the length, but irregular, so that it is convex transversely towards one side, 
and inclines to be concave in the same direction towards the other side. The extreme 
length of the bone is 5‘7 centims. The superior surface is still covered with matrix, 
but was concave vertically, and slightly convex transversely. The inferior surface 
was similar, but flatter transversely. The distal end is thickened, having a depth of 
at least 3'.') centims., with the superior and inferior margins straight, and nearly 
parallel. It is 5 centims. wide. It is strongly convex transversely, with lateral 
impressed grooves towards the upper part of the articulation for ligamentous union 
with the adjacent phalange. The inferior surface of the articulation is oblique and 
flattened and extends proximally, so as to give the sub-trochlear facet a length of 
2'5 centims. The siq^erior border of the articulation is broken away. The sides 
of the bone are thickened, and appear to be vertically rounded. 
The Tibia. (Plate 25.) 
A specimen from Jan Willem’s farm, registered as No. 43,525, determined by 
Sir II. Owen as the right tibia, was referred to Fareiasaurus homhidens. The only 
other specimens from this locality are certain vertebra?, determined as dorsal and 
caudal (‘South African Catalogue,’ pp. 10, 11); unless the fossils described as 
Tajjinocejilialm Atherstoiii (Owen) from a locality “ four miles from Jan Willem’s 
Fontein,’ should be part of the same series. But, from the care with which localities 
are recorded, it is doubtful if there is any warrant for associating this bone with the 
remains of the skull of Tapinocephalus. 
