THE CHIMPANZEES AND ORANGS. 15 



The foregoing characters all distinguish the Human femur from that of the Gibbons and 

 lower Quadrumana. 



The first approaches to the Human characters of the bone are found in the femora of 

 the Chimpanzee (PI. VH. fig. 4) and Gorilla (ib. fig, 1). The tendency to a minor 

 convexity of the fore part of the shaft, to the production of a ridge at the back part, and 

 to the forward bend of the whole shaft, is seen in the Chimpanzee ; the departure 

 from the cylindrical shape and the forward bend are more manifest in the Gorilla 

 (PI. XIII. fig. 2). Both Apes show a cervix femoris relatively as long as in the Human 

 femur. 



The first strongly-marked difference is seen in the proportional size of the bone to the 

 entire body and upper limb (Pis. XII. & XIII). In Man (fig. 1) the femur is the longest, 

 as well as the largest and heaviest bone in the skeleton ; it exceeds by two-sevenths of 

 its own length that of the humerus. In the Gorilla {ib. fig. 2) the femur is one-sixth of 

 its own length shorter than the humerus. It is, moreover, thicker both absolutely and 

 in proportion to its length. The neck of the bone (PI. VII. figs. 1 & 2, c) is longer, and 

 stands out at a more open angle, and the head is directed more inward and less upward 

 than is usual in Man : the degree of forward direction is almost equal. The depres- 

 sion for the ligamentum teres {ib. fig. I, 6) is nearly the same in size, depth, and position 

 as in Man, The neck is broader in the vertical than in the antero-posterior diameter. 

 The great trochanter is a broad thick subquadrate prominence, rising higher than the head 

 of the bone; it does not project outwardly, as in Man, beyond the shaft of the bone. 

 The lesser trochanter is a more oblong and less prominent conical process than in Man ; 

 it does not project from so near the inner margin of the bone ; so that in the view of the 

 upper end of the femur, given in fig. 2, PI. vIL, this trochanter (e) appears less near the 

 head of the bone than in Man (fig, 7). It is connected with the great trochanter by a rough 

 intertrochanteric tract (between d & c, fig. 1) ; but this is less marked than in the 

 Human subject {ib. fig. 6). This difference in the proportion and direction of the neck 

 of the femur affords greater freedom, extent and variety of motion to the lower limb, but 

 is less favourable for the transmission of the weight of the trunk from the head to the 

 shaft of the bone. The shaft is slightly bent from before backwards (PI. XIII. fig. 2); 

 it presents an irregular subquadrate transverse section with the angles rounded off and 

 the long diameter transverse, increasing gradually in breadth and diminishing in 

 fore-and-aft diameter as it approaches the condyles, the greater extension being towards 

 the inner side ; and it grows proportionally less convex transversely at the fore part. 

 The outer part above the middle of the shaft shows a strongly marked oblong rough 

 surface for the attachment of the ecto-gluteus muscle' ; below this a narrower ridge is con- 

 tinued, giving advantageous origin to the short head of the biceps flexor cruris. The 



' The three muscles, answering to Gluteus maximus, medius, and minimus in Man, do not present the 

 proportions indicated by these names in any inferior animal. The property common to them throughout the 

 mammalian series is relative position, which might be conveniently indicated by the terms ' ecto-,' ' meso-,' and 

 ' ento-gluteus ' respectively. 



