THE HUMAN BACKGROUND 431 



thropoids at the root of the human family tree. (Figs. 228, 275.) 

 Numerous fossil remains have been found that give evidence 

 in regard to the origin of the anthropoids. Back in the Eocene 

 epoch are various Tarsioids and a monkey which bridge the gap to 

 higher Primates, and in the Oligocene epoch are several monkeys 

 and anthropoid apes that, apparently, are near to the main line of 

 ascent. And then late in the Miocene epoch, perhaps ten million 

 years ago, appears Ramapithecus with teeth that foreshadow 

 those of Man. Indeed, the number and arrangement of the teeth, 

 the bicuspid pattern of the premolars, as well as various characters 

 of the incisors, canine, and the milk dentition, are prophetic of 

 the human dentition to-day, particularly in certain primitive races. 

 It appears that the differences shown by the human teeth are to a 

 considerable extent the results of an omnivorous diet, and of 

 changes in the proportions of the jaws, following the great expan- 

 sion of the cranium in providing for the enlarging brain. (Page 359.) 

 So it seems reasonably clear that the prehuman ancestor arose 

 through or near the Ramapithecus stem, from animals adapted to 

 live in the vast forests of the Old World. But as geologic time 

 progressed, climatic changes of course occurred, the forests became 

 restricted, and we may assume that the Primates that had not 

 already made a retreat were impelled to renounce, in part, the 

 arboreal for a terrestrial habitat. Thus the precursor of Man 

 reached the ground : an environment that was provocative of many 

 adaptations, in particular the erect body with hind limbs support- 

 ing the entire weight. This necessitated considerable mechanical 

 readjustment, including the alternating curvature of the vertebral 

 column for the nicer balance of the larger cranium. Moreover, the 

 development of the brain, furthered by the emancipation of the 

 hands from their part in locomotion and by changes in the vocal 

 organs leading to speech, eventually paved the way to the 

 emergence of culture from the biosocial foundations of preman — to 

 invention, communication, and social habituation. In the course 

 of the ages Man arrived. (Figs. 105, 109.) 



B. Fossil Man 



The evolution of Man, unlike that of other organisms, presents 

 two clear-cut aspects: the physical and the mental. His physical 

 evolution was exceedingly slow, but his cultural development, 

 once started, proceeded with increasing momentum. Both can be 



