Mk. ST. G. MIVART ON THE SKELETON OF THE PRIMATES. 209 
the case in Man; in this the Orang resembles the Troglodytes, as also in the greater 
distinctness of the distal surfaces for the fourth and fifth metatarsals respectively 
(Pl. XLIII. fig. 19a, 6). That for the fourth metatarsal is more concave in both the 
vertical and transverse directions than it is in the Gorilla, and therefore much more 
so than in Man. As in the Chimpanzee, this surface occupies a greater share of the 
distal surface than is the case in the Gorilla and in Man. The posterior surface of the 
cuboid (Pl. XLITI. fig. 21) is very much more concayo-convex than in the other and 
superior forms; and its tibial plantar angle is produced into the conical and pivot-like 
process before alluded to (Pl. XLIII. figs. 17 & 18¢). As in Troglodytes, the under 
surface of the cuboides, behind the prominent ridge, is less extensive than in Man; and 
(as also in Troglodytes) a small deep fossa exists just inside the angle formed by the 
junction of the above-mentioned ridge with the posterior margin of the plantar surface 
of the bone. On the tibial side of the bone there is a large articular surface for the 
ectocuneiforme, which surface is continuous behind with that for the naviculare 
(Pl. XLIII. fig. 20¢, 4). As in Troglodytes, so in Simia, this surface descends nearer 
to the plantar margin than it does in Man. 
Metatarsus. 
The metatarsus attains a greater absolute length in Simia than in Man or Troglodytes. 
The length of this segment of the limb (estimated by that of the second metatarsal), 
compared with that of the spine, is considerably greater than in the higher forms—being 
as about 17-2 to 100, instead of from 10 to 12:5 to 100 as in Man and Troglodyte. 
The relative length of the same metatarsal as compared with that of the entire pes is 
very much the same as in the others, namely about 32:1 to 100, while in Man, the 
Gorilla, and Chimpanzee I have found the proportion to be as 29°7, 28°5, and 30:6 to 
100, respectively. 
The four outer Metatarsals. (Plate XLIII. figs. 37 & 40-54.) 
As in the higher forms, these metatarsals in the Orang are thicker at each end than in 
the shaft; but the distal extremities are almost as broad as the proximal ends, thus differ- 
-ing from the four outer metatarsals of Troglodytes, and still more from those of Man. 
The shafts continue of nearly the same width throughout, and thus differ from those 
of Troglodytes, which taper distally, and still more from those of Man. On the other 
hand they do not broaden even slightly from behind forwards, as do their homotypes in 
the manus from above downwards. 
The transverse diameter of each head does not nearly equal its vertical dimension ; 
but still the difference is not so great as it is in the higher forms. 
The metatarsals in Simia are rather more curyed, with the concavity downwards, than 
are the metacarpals; they also diverge distad somewhat less. Their shafts are scarcely 
more laterally compressed than are those of the metacarpals; yet they are slightly more 
VOL. VI.—PART IV. 2G 
