MAN PAST, PRESENT AND FUTURE 



927 



in time b\ aclaptnx' progress and various eontrivances, demaiicled a resistant 

 osseous structure in his eraniuiu to protect his brain. Conditions ol Ins lowly 

 social orgiinization undoubtedly auuniented these traumatic eoiitini;encies. 



FIG. 415. CKO-.MAGNON ARTISTS MAKING THE GREAT MAMMOITl FRESCO IN THE 

 CAVE OF FONT-DE-GAUM E. DORDOGNE, FRANCE. 



Mural painting by Charles R. Knight made under the direction of Prof. Henry Fairfield Osborn. From the 

 Hall of the Age of Man, American Museum of Natural History. 



As offensive strength must ha\e been his most ellVctive argument, so a 

 stout frame was his [)est defense. Is it eiitirelx accurate, therefore, to speak 

 of his bony facial mask, his heavy jaws and large teeth, his thick skull and 

 receding forehead as ape-like specializations? Are they not the more general- 

 ized adaptive modilications shart^I in common b\ the two branches of the 

 orthograde primate stock, for a life demanding concentrated physical force? 

 Certain specializing factors in these two great lines of primates clearly oper- 

 ate in common. Such, for example, were the marked increase in body weight, 

 the tendency to stand upright, the reduction of speed in escape, the progres- 

 sive loss of arboreal retreat, the need of augmented offensive powers and a 

 more capable mechanism for procuring food supply. All of tht^se appear as 

 vital necessities in the specialization of man and the great apes. If certain 



