PITHECANTHROPUS EREOTUS. 457 



great as that between bones of the same name in different but some- 

 what related species of mammals having a similar locomotion, as, for 

 instance, Colobus and Semnopithecus, Cervus and Antilope. The most 

 important difference concerns the form of the diaphyses in the popliteal 

 region. It is much rounder than in man. The planum popliteum is 

 therefore less extensive and more convex, so that exactly in its middle 

 a kind of swelling extends as far as the neighborhood of the condyles. 

 In the human femur the most projecting portion of the popliteal region 

 is in the neighborhood of the lateral lip of the linea aspera. In the 

 fossil femur, on the contrary, that lip is situated more on the lateral 

 surface of the shaft. 



After examining hundreds of human femora, Manouvrier could find 

 only two that had a somewhat similar shape. It is therefore a very 

 rare form in man. With the gibbon a similar form normally occurs, 

 the median convexity in this species being, however, somewhat higher. 

 This may be explained by the peculiar insertion of the femoral head of 

 the biceps femoris that occurs in this species, it being attached in the 

 middle line below the adductor magnus in close connection with the 

 vastus interims. An extension of these conditions might, as Dr. Hep- 

 burn has pointed out to me, produce the median convexity of the entire 

 popliteal region which we find in the fossil femur. In man the popliteal 

 space becomes flattened by reason of the wide separation of the medial 

 and lateral muscles in this region. In those isolated cases of a similar 

 formation, found in an examination of hundreds of femora, there may 

 have been a simian form of muscular attachment. 



The exostosis of the fossil bone — considered by me as the result of 

 a traumatic periostitis, and by Virchow as caused by a psoas abscess 

 that had descended from along the spinal column — appears as a 

 so-called tendinous or aponeurotic deposit of osseous tissue, such as 

 occurs not very infrequently in man and is also to be seen, though in a 

 less degree, on the humerus of the skeleton of an orang-outang in the 

 Dresden Museum. This pathological formation has no significance as 

 regards the systematic determination of the bones. 



It has been generally allowed by everyone that the femur must have 

 belonged to an animal that walked erect. The circumstances under 

 which it was found, in the neighborhood of the skullcap, make it very 

 highly probable that both belonged to the same individual; and now, 

 since we have shown that the anthropoid skullcap may not have 

 belonged to an ape, but possibly to a being that walked upright,' this 

 probability increases quite to certainty, for this reduces the deficiency 

 in human characters which the skullcap showed when compared with 

 the femur. The femur is not human in the usual sense, for it, as we 

 have seen, shows features that occur only very seldom in human 

 femora. Besides, the similarity of form may, as before stated, be suf- 

 ficiently explained by a similarity of functiou, so that an entirely 

 human form of femur need not necessarily have belonged to a man, 



