210 MR. ST. G. MIVART ON THE SKELETON OF THE PRIMATES, 
slender than the latter, though the difference is much less than in Troglodytes. They 
are not more flattened beneath than are their homotypes of the manus. ‘Their distal 
articular surfaces are destitute of the dorsal transverse groove which limits each of them 
posteriorly in Man and TZroglodytes. On their plantar aspect the same surfaces have 
not those lateral projections which exist in the other forms. 
As in Troglodytes, so also in Simia, the dorsum of each distal articular surface slopes 
downwards towards its anterior end more than it does in Man. The extremities of the 
same surfaces of the fourth and fifth metatarsals of the Orang have also a yery slight 
inclination peronead. A line connecting the proximal articular surfaces of the metatarsals 
of the Orang is almost at right angles with one following the antero-posterior direction 
of their shafts, these greatly differing from the condition presented by Man; and alto- 
gether the metatarsus and metacarpus are less differentiated in Simia than they are in 
Man and Troglodytes. 
First Metatarsal. (Plate XLIII. figs. 58 & 39.) 
As in Troglodytes, the proximal end of this bone in the Orang presents a much more 
decided concavity than does that of its serial homologue, and is very different in form 
from the corresponding part in Man. 
In shape this metatarsal is very like that of its homologue in the Gorilla, and the 
direction of the distal groove (by which it articulates with the convex surface of the 
entocuneiforme) is oblique as in Troglodytes, and extends from above downwards and 
tibiad when the dorsum of the bone is placed horizontally, The shaft is also slightly 
twisted on its long axis. This bone in the Orang is sometimes a little longer, but 
generally a little shorter, than is the metacarpal of the pollex, being thus unlike the 
same bone in Man and Troglodytes, where it is much longer than is its homotype. 
As in the other forms, so in the Orang, the proximal end of this metatarsal is larger 
than that of the corresponding metacarpal, but the difference is much less than in Man 
and Troglodytes ; thus this metatarsal, like the four outer ones, has a greater resemblance 
to its homotype in the Orang than it has in the last-mentioned forms. As in T'roglodytes, 
the process for the attachment of the tendon of the peroneus longus is eee} developed 
(Pl. XLII. fig. 39 a). 
Second Metatarsal. (Plate XLIII. figs. 40-43). 
The proximal surface of this metatarsal in the Orang is much shorter vertically and 
tapers less downwards than that of Man (Pl. XLIII. fig. 5711.) It is also more 
concave transversely than in him, and is somewhat convex vertically on its peroneal 
side. Thus the posterior margin of the dorsum of this metatarsal presents a notch, 
and in this as in the preceding points it agrees, more or less nearly, with its homologue 
in Troglodytes. 
