210 MR. ST. G. MIVAET ON THE SKELETON OE 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 Troglodytes. 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 very 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 diffeiing 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. 38 & 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 poUex, 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 Troglodytes, 

 the process for the attachment of the tendon of the jjeronmus longus is largely developed 

 (PI. XLIII. fig. 394 



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 (PI. XLIII. fig. 87 11.). 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. 



