198 ME. ST. G. MIVART ON THE SKELETON OF THE PRIMATES. 



when the outer siu'face of the ilium (PI. XXXIX. fig. 1) is opposite the observer, 

 instead of ahnost the whole of its cavity being so, as is the case in Man^ 



Femur. (Plate XL. figs. 1-7.) 



This bone is exceedingly short in the Orang, both absolutely and relatively, as com- 

 pared with Man and the Gorilla. 



In Troglodytes it is more than half the length of the spine (measured as before), 

 and in Man it is more than three-fifths of it ; in the Orang, however, I find it less 

 than half 



As compared with the length of the os innominatum the femur is somewhat longer in 

 the Orang than in Troglodytes — as it is decidedly the longer of the two ; still the pro- 

 portion very much more resembles that existing in the last-named genus than Man's, 

 as his femur is about double the length of his os innominatum. 



A comparison of the femur with the humerus shows a greater difierence from Man 

 than that presented in Troglodytes, though even in the Chimpanzee the femur is slightly 

 the shorter of the two, instead of very much the longer, as in Man. 



When the femur of the Orang is made to rest with both condyles on a horizontal 

 surface, and placed as nearly as may be in a vertical position, the bone does not incline 

 outwards (peronead) superiorly so much as does that of Man when similarly placed ; it 

 does so, however, in a slightly greater degree than is the case in Troglodytes^. 



The body or shaft of the bone differs much from that of the femur of Man, and 

 greatly resembles that of Troglodytes. This is the case as regards the absence of a 

 strongly projecting linea aspera, the less transverse convexity of the anterior surface, 

 the much greater antero-posterior compression of the bone, and its less degree of cur- 

 vature convex forwards, the shaft being even straighter than in the Gorilla (PI. XL. 

 figs. 3 & 4). It also differs from Man's, and agi-ees with that of Troglodytes, in tlie 

 large proportion borne by the transverse diameter to the length — though in this 

 respect it resembles the Chimpanzee, it being more slender than in the Gorilla. The 

 lateral expansion downwards of the shaft, though more gradual than in Man, is much 

 less so than in the Gorilla ; and the external margin of the same is more concave than 

 in 'Troglodytes, and approximates, therefore, in its outline to Man's. 



In the Orang, as in the Gorilla and Chimpanzee, the external and internal surfaces 

 of the shaft are much narrower from before backwards than in Man. This arises from 

 the non-projection of the linea aspera, which seems to be, as it were, flattened out in 

 both Simia and Troglodytes, though least so in the Gorilla. 



The anterior intertrochanteric line (PI. XL, fig. 1 e) is continued into the spiral line 

 (PI. XL. figs. 2 & of), and can be followed downwards to the entocondyloid prominence 



' Owen, Trans. Zool. Soc. vol. t. p. 14. 



- There is a certain amount of individual variation in this respect ; in the specimen No. 3 c in the British 

 Jluseum, the inclination is considerable, approaching that of Man. 



