470 ON OUR PRESENT KNOWLEDGE OF THE ORIGIN OF MAN. 



of France, Switzerland, and Styria). This in turn is derived from an 

 older, generalized ape form which lived in the older Miocene period, 

 and which maybe regarded as the common ancestor of the Old World 

 apes, both the tailed Cynopitheci and the tailless Anthropomorjtha. 

 Among the latter we now recognize the two living species of the gibbon 

 which stand very near to Pliopithecus, as well as fossil anthropoid apes 

 that lead directly to Pithecanthropus. Such an intermediate stem form 

 is Pliopithecus sivalensis, whose skeleton was found in the early Tertiary 

 layers of eastern India in the Pliocene Siwalik strata. 



For forming a correct judgment concerning this important Pithecan- 

 thropus and its immediate position between the anthropoids and man, 

 two features are especially valuable; first, the close resemblance of the 

 femur to that of man, and second, the relative size of the brain. Among 

 the few anthropoid apes yet living the gibbons appear to be the lowest 

 and oldest, standing nearest the stem-form of all the Anthropomorpha; 

 they are also the most generalized and appear especially adapted to 

 illustrate the " transformation of apes into man." The gibbons more 

 than the other anthropoids have the habit of voluntarily assuming the 

 upright position, whereby they walk upon the entire sole of the foot 

 and use their long arms as balancing poles. The other modern apes 

 (orang, chimpanzee, and gorilla) seek the upright position, and when 

 they use it do not tread upon the entire sole but upon the outer edge 

 of the foot; they also have in other respects more specialized charac- 

 ters, adapted especially to their tree climbing life. It is thus explained 

 why it is that it is exactly the femur, in Hylobates and Pithecanthropus, 

 that is much more human in form than that of the gorilla, the orang, 

 and the chimpanzee. 



But also the skull, that " mysterious vessel" of the organ of the soul, 

 approaches nearest the human proportions both in Pithecanthropus and 

 in the gibbon in important particulars — the rough, bony crests which 

 the skulls of the other anthropoids show are wanting. The relative size 

 of the brain (in proportion to that of the entire body) is in the latter 

 only half as great as it is in the gibbon. The capacity of the skull of 

 Pithecanthropus is from 900 to 1,000 c. c, therefore about two-thirds 

 the capacity of an average human skull. On the other hand : the largest 

 living anthropoids show a capacity half as high as this — 500 c. c. So 

 the capacity of the skull and consequently the size of the brain is in 

 Pithecanthropus exactly midway between that of the anthropoid apes 

 and the lower races of mankind; and the same is also true for the char- 

 acteristic profile line of the face. In this respect compare the skulls of 

 the lowest and most pithecoid races of man. Among these the still 

 living pygmies, the little Veddahs of Ceylon and the Akkas of Central 

 Africa, are of great interest. An unprejudiced comparison of all these 

 anatomical facts shows in no ambiguous manner the character of Pith- 

 ecanthropus as a true intermediate form between anthropoid apes and 

 man; he is the long sought for and much discussed " missing link" in 



