Differentiation. 281 



The supra-condyloid process is another feature belonging normally to 

 most of the carnivores, including the cave bear, but not the rest of the 

 plantigrades; and to the monke}^s, lemurs and sloths. This consists of 



FIG. 112. 



FIG. 112. 2 Humerus of Man showing the Supra Condyloid process A a rudiment. 

 1 Lower part enlarged showing A the supra condyloid process, and B the ligament 

 which completes the foramen in 3 per cent, of human subjects. 

 3 Bones of fore limb of Cat, showing the foramen in use, 

 .s Blood vessel and nerve passing through. ( After Struthers..) 



a hook-like process of bone on the inner side of the lower end of the 

 humerus or arm-bone. From the lower point of the projection, a liga- 

 ment passes on down toward the joint and is attached there to the side 

 of the bone, thus forming an opening or foramen through which, in the 

 lower animals mentioned, the great nerve and blood-vessel of the 

 fore limb pass. This foramen appears in abr>ut three per cent, of 

 human skeletons, and is of no advantage to man. 



In men there are two prominences on the upper part of the thigh bone, 

 called respectively the greater and less trochanter. They afford attach- 

 ment to rotator muscles of the thigh. In certain animals there is a third 

 trochanter, and it gives attachment to the great gluteus muscle. It is 

 very large in the Horse and Rhinoceros and is found in others. It is 

 found in a few human skeletons, the per cent, varying in different 

 countries. Out of 40 skeletons of Swedes 15 had it, of six skeletons of 

 Laplanders it was possessed by four. But Dr. Shepherd found it in 

 only one per cent, of Americans. 



' ' In the human wrist are eight small bones called carpals and ar- 

 ranged in two rows ; occasionally between the two rows we have a ninth 

 bone called the "os centrale." In the human foetus a rudiment of this 

 bone is always to be found at an early period, but it usually entirely 



