84 MR. A. L. ADAMS ON THE OSTEOLOGY OF 
side, and tibie Pl. XV. figs. 1 & 2, had every appearance of forming portions of the 
same skeleton. ‘The two naviculars in question (right and left) agree in dimensions; 
but fig. 1 is the more perfect, and is in accord in every respect with that of 26774. 
Royal College of Surgeons. ‘The linear dimensions of the bone in question are well 
shown in the figure. The calcaneal facet is 1:1 by 0:4 inch; whilst the are of the cup, 
by tape, is 3°3 inches. The same admeasurement on the convex surface, which is 
considerably abraded so as to denude the facets, is 4 inches. The cuboidal facet has its 
outline preserved, giving a surface of 2 inches by 1; the others are not defined, con- 
sequent on abrasion. Thus, whilst the naviculars of the recent Indian (2677a, R. C. S.) 
and the above closely consort as to dimensions, the same may be said of the astragals 
referred to them ; indeed, to follow the comparison further, it may be repeated that the 
tibiz of the two differ inasmuch as the former is 14 and the latter 17 inches in length, 
thus giving a shorter and stouter leg-bone to the fossil, just as obtains in the African in 
comparison with the Indian, more especially, however, in the dimensions of the toe- 
bones, as will appear in the sequel. 
3. The small right naviculare Pl. XVII. fig. 7 has all the characters of a young bone; 
I therefore hesitatingly refer it tothe smaller form. The facets extend to the margins, 
as in the immature individual. The following are the dimensions of this specimen— 
breadth 2°6 inches, depth 1:7 (about), are of the astragaloid facet 2, are of anterior 
surface 2°8, thickness 0-8. The lower part of the bone being lost and a perpendicular 
fracture prevent further reliable measurements. 
4. The smallest naviculare (fig. 8) had precisely the same characters as the last, 
but is more imperfect; as far as relative comparisons go, it consorts well in dimen- 
sions with astragalus Pl. XVI. fig. 5; whilst fig. 7 is equal to that of the Oxford 
skeleton, being 2°5 inches in length, and therefore also very small, but much too large 
for astragalus Pl. XVI. fig. 3. 
Summary.—Taking the navicularia generally, they indicate cogently one form of the 
bone of the largest hind-foot bones I have yet described, and, doubtfully, intermediate 
and pygmy forms. 
Cusorp.—There are three specimens of this bone in my collection, two of which 
are fragments. They are divisible into large and small. 
Ist. A Type.—The largest (represented in Pl. XVII. fig. 4) has lost its lower part, 
including nearly the entire calcaneal and fifth metatarsal facets, by accident—enough, 
however, remaining to establish its dimensions as compared with the bones just de- 
scribed. It is too large for the naviculare (fig. 1), and also exceeds the dimensions 
of the same bone of 26774, R.C.S.; but it equals that of the Sumatran (B. M.) and 
the largest fossil naviculare. The maximum thickness of the fragment at the middle of 
the fourth metatarsal surface is 1 inch. It is the front aspect that is shown in the 
figure, the margin a being the internal or cuneiforme attachment. The naviculare facet, 
unlike that of the recent, is not isolated by a furrow, and is even only feebly indicated by 
