202 MR. ST. G. MIVART ON THE SKELETON OF THE PRIMATES. 
(Pl. XLI. fig. 47), and, as in Zroglodytes, is more rounded and less antero-posteriorly 
elongated than in Man. 
Of the two articular surfaces for the condyles of the femur, the internal one has its 
inner margin (as in the Gorilla and Chimpanzee) more convex and prominent than in 
Man (PI. XLI. fig. 8); and the concavity of its surface is mainly produced, as Professor 
Owen remarks of the Gorilla!, by the elevation of that part of it which joins the spine. 
The external articular surface (for the external condyle of the femur), though more 
convex antero-posteriorly than in Man, is less so than in the Gorilla; and sometimes, 
indeed, it is decidedly, though very slightly, concave antero-posteriorly. 
The spine is also more human in its form than it is in either Troglodyte, being 
almost as bifid as in Man; while the groove which descends backwards from its apex, 
and divides the posterior ends of the articular surfaces for the condyles, is considerably 
deeper, and more marked than in any of the higher forms (Pl. XLI. figs. 2 & 8). 
The lower end of the tibia is inclined so that the anterior margin of its distal end is 
much more oblique (downwards and tibiad) than in 7’roglodytes, and very much more 
so than in the human tibia. This obliquity arises from the large size of the lower 
articular surface for the fibula, and from the inclination inwards of the articular surface 
of the tibial malleolus. 
The inner, or free, surface of the last-named process projects more strongly tibiad 
than in 7’roglodytes—the inner surface of the shaft immediately above it being more 
concave vertically than in that genus, though scarcely more so than in Man. 
‘The anterior margin of the distal end of the tibia is more prominent than in the 
higher forms, the surface of the shaft just above it being more concave, vertically, than 
in them. 
The distal end of the posterior surface of the tibia has a deeper groove for the tibialis 
posticus and flexor longus hallucis than I have observed in any of the higher forms 
(Pl. XLI. fig. 2p). 
As in Troglodytes, so also in Simia, the tibial malleolus is more truncated at its apex 
than is the case in Man. 
The distal articular surface of the shaft of the tibia (Pl. XLI. fig. 9) is, as in the 
Chimpanzee®, far more convex transversely than in the Gorilla or in Man. On either 
side of the strong median convexity there is (also as in the Chimpanzee) a slight 
transverse concavity; but the whole surface presents only a mere trace of an antero- 
posterior concavity, while, as in 7'roglodytes, its anterior margin descends as much (when 
the shaft is vertical) as does its posterior margin, instead of, as in Man, the latter margin 
descending further than the anterior one. 
The articular surface on the outer (peroneal) side of the malleolus forms a more 
open angle with the distal surface of the shaft than even in 7’roglodytes, and its vertical 
extent is also much less (Pl. XLI. fig. 1). 
' Trans. Zool. Soe. vol. y. p. 19. ? Owen, loc. cit. p. 20. 
