Evolution of the Human Face 



CHIEF STAGES IX ITS DEVELOPMENT FROM THE LOWEST 

 FORI\IS OF LIFE TO MAN ' 



Bv W ILL! A :\I K. (I K E (JO }{ Y 



1 SUPPOSE if you have talked to 

 people about evolution they have 

 said : "•Well, if monkey-like ani- 

 mals evolved into men at one time, 

 wliv dill not all monkeys evolve into 

 men, ami why are there any monkeys 

 alive at the present time?'" They ask 

 me to explain it, and they regard it as 

 an insurmountable objection to the the- 

 orv that man has evolved from lower 

 mammals. Xoav I do not know why 

 all the monkev-like animals did not 



Young cliiuiijaazee wliiili lias a sliort face and 

 an exceedingly large forehead much like that of 

 a young child (see page 376). Photographed 

 by Herbert Lang on the American Museum Ex- 

 liedition to the Belgian Congo 



' Lecture delivered before the Linnitan 



evolve into men instead of ehanoing 

 only a little and remainino; monkeys, 

 but I do know that evolution, besides 

 proceeding in dilferent directions, also 

 proceeds at ditferent rates at different 

 times. I know that just as there are 

 manv very a(l\aiice(l and progressive 

 races, such as the horse and the hum- 

 ming bird and the whale, which have 

 undergone a very great modifieation 

 during the vast period known as the 

 Age of ]\rammals, so there are also 

 many conservative and backward races, 

 such as the tajni' and the opossum 

 and the tualara, whieh have under- 

 gone very little modification during the 

 same period. These backward and 

 primitive races are of the greatest use 

 to us in decipliering the evolutionary 

 history of past ages. They are living 

 relics, or living fossils. A great many 

 such relics are living today. That is 

 what furnishes the material for com- 

 parative anatomy. It is by the dissec- 

 tion and study of these extant fossils 

 and l)y comparing them one with the 

 other, that we can trace out the stages 

 by which structures have changed 

 slowly, one into the other, and l)y which 

 types have changed, one into the other. 

 Xow the monkeys and apes are relics of 

 the middle periods of the Age of Mam- 

 mals, and we know from the fossil re- 

 mains that they ha\-e ehanged Imt little 

 during that period. .\ possible reason 

 is that most of them have continued to 

 live in the forests and have therefore 

 kept their primitive tree-living habits 

 unchanged, while only a few, such as 



Society of New York, February 27, 1917. 



377 



