MR. ST. G. MIVAET OK THE SKELETON OF THE PRIMATES. 193 



lateral facets are', as in Troglodytes, divided by a deep groove ; a;nd, as in all the higher 

 forms, the ulnar angle of the proxinal end of the palmar part is strongly inclined ulnad. 

 Sometimes (PI. XLII. fig. 34 ii.) tlie proximal articular surface has a crescentic form, 

 witli the concavity of the crescent towards the dorsum. 



Third Metacarpal. (Plate XLII. figs. 41-44:) 

 As m Troglodytes, so also in iS^/mz'a, the proximal radial angle of the dorsum is less 

 produced than in Man (PI. XLII. figs. 41-43 c). 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 Ornng agrees with Man and the Chimpanzee, 

 and, as far as I have observed, difiers from the Gorilla, in having two facets on each 

 side of this metacarpal, for articulation with the contiguous one (PI. XLII. figs. 43 & 44). 

 The proximal articular surface (PI. XLII. fig. 34 in.) 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 Troglodytes. The palmar part of the same surface is much 

 more convex, and" is longer, from dorsum to palm, than in Troglodytes, 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 (PI. 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 more convex, and at tlie 

 same time less concave than in them (PI. XLII. figs. 34 v. & 51), 



Digits. /. _ 



The proximal phalanges of the four outer digits" of the manus are much curved, with 

 the concavity palmad (more so than in Man or Troglodytes), though not so much so as 

 are the homotypal segments of the pes. 



They are also very broad, and have projecting lateral ridges (PI. 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 Troglo- 

 dytes, are more attenuated than those in the human manus. The proportion borne by 



' Owen, Trans. Zool. Soc. vol. i. p. 3(35. 



VOL. VI. PART IV. 2 E 



