Man on Terra Firma 213 



of the snout, a correlated increase of the brain cavity, 

 a shunting forward of the eyes and more stereoscopic 

 vision, a greater mobility of the head, a greater em- 

 phasis on touch, a decrease in the olfactory region of 

 the brain, and an increase in the region where the 

 sensory tidings from hand and eye and ear come 

 streaming in — a region, moreover, according to the 

 experts, towards which the originative seats of the 

 motor impulses tend to become approximated. (See 

 Thomson, What is Man, 1923.) 



Professors R. Anthony and F. Wood Jones have 

 independently emphasized the probable importance 

 of the arboreal apprenticeship, but the likelihood is 

 that it affected man's ancestors rather than man him- 

 self. It is obvious that we see its results in monkeys 

 and apes, which have nevertheless been side-tracked, 

 having remained more or less arboreal. We therefore 

 follow Professor It. S. Lull in thinking that the cru- 

 cial step was when the shrinkage of forests, owing to 

 aridity in the Miocene or early Pliocene, led the 

 humanoids to come to earth. It was facing the diffi- 

 culties of life on terra firma that meant so much in 

 Man's emergence. He needed his big brain and his 

 free hand to save him in his struggles with Carnivores 

 and with a callous physical environment. 



We should also remember that man belonged to a 

 clever social stock ; that the prolonged ante-natal life, 

 as Robert Chambers suggested, might be correlated 

 with a high degree of cerebral development; that a 

 prolongation of infancy and of the play-period would 

 favor educability of mind, as contrasted with early 



