XXXVII 

 MAN'S ARBOREAL APPRENTICESHIP 



MANY distinguished anatomists have referred 

 to man's attainment of the erect position 

 as the beginning of a new epoch, and have shown 

 how walking upright upon the earth would affect 

 not only hands and feet, but brain and vocal organs. 

 The picture usually suggested is that of "the 

 turning of an ordinary quadruped a quarter of a 

 circle into the vertical plane," and we are asked 

 to think of the " slow and painful acquisition of a 

 radically new posture." It must be noticed that 

 bipedal progression has originated many times over 

 ' in giant reptiles like the great Iguanodons (such a 

 striking feature of the Museum of Brussels), in 

 birds, in kangaroos (if they are not tripods), in the 

 jerboas of the desert, and in other adventurous types. 

 Saville Kent has given a lively description of a big- 

 collared Australian lizard (Chlamydosaurus) which 

 gets up on its hind legs, takes a little tottering run, 

 and collapses like a baby learning to walk. Such 

 cases are interesting, for they warn the zoologist 

 against being too sure about what a living creature 

 cannot do. Bipedal progression has been tried 

 over and over again, and we may witness, though 

 \vith anything but pleasure, the possibilities of 



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