9 
MR. ST. G. MIVART ON THE SKELETON OF THE PRIMATES. 193 
lateral facets are, as in Troglodytes, divided by a deep groove; and, as in all the higher 
forms, the ulnar angle of the proxinal end of the palmar part is strongly inclined ulnad. 
Sometimes (Pl. XLII; fig. 34 11.) the proximal articular surface has a crescentic form, 
with the concavity of the crescent towards the dorsum. ; 
Third Metacarpal. (Plate XLII. figs. 41—44:) 
As in Troglodytes, so also in Simia, the proximal radial angle of the dorsum is less 
produced than in Man (PI. XLII. figs. 41-43 ¢). Owing to this, the dorsal part of the 
proximal articular surface is less concave than in him, but the palmar part of that 
surface is more extensively convex. The Orang agrees with Man and thie Chimpanzee, 
and, as far as I have observed, differs from the Gorilla, in having two facets on each 
side of this metacarpal, for articulation with the contiguous one (Pl. XLII. figs. 43 & 44). 
The proximal articular surface (Pl. XLII. fig. 34 111.) somewhat approaches the form of 
the letter T. 
Fourth Metacarpal. (Plate XLII. figs, 45-48, ) 
The proximal end of this metacarpal is narrower transversely than in Troglodytes or 
Homo. The dorsal part of the proximal surface is more concave than in Man, though 
scarcely so much so as in Zroglodytes. The palmar part of the same surface is much 
more convex, and is longer, from dorsum to palm, than in Zroglodytes, and still more 
so than in Man. There are two articular surfaces for the third metacarpal, and the 
single one for the fifth metacarpal is larger than in any above (Pl. XLII. figs. 47 & 48). 
Fifth Metacarpal. (Plate XLII. figs. 49-51.) 
This metacarpal differs from the corresponding one in Man and Troglodytes in that 
its proximal surface is longer (from dorsum to palm), and is moré convex, and at the 
same time less concave than in them (Pl. XLII. figs. 34 v. & 51). 
Digits. 7. 
The proximal phalanges of the four outer digits of the manus are much curved, with 
the concavity palmad (more so than in Man or Teale not so much so as 
are the homotypal segments of the pes. 
They are also very broad, and have projecting lateral ridges (Pl. XLII. fig. 1), 
which are more developed than in Man, though not so much so as in Troglodytes’. 
The proximal phalanx of the pollex is more slender than in higher forms, and thus 
differs notably from its homologue in the Gorilla. The several second and third 
phalanges are formed nearly as are their homologues in the Chimpanzee; the second 
phalanges, however, are somewhat less conical. The distal ones, like those of Zroglo- 
dytes, are more attenuated than those in the human manus, ‘The proportion borne by 
‘ Owen, Trans. Zool. Soc. vol. i. p. 365. 
VOL. VI.—PART IY. 25 
