XXXVII 
MAN’S ARBOREAL APPRENTICESHIP 
ANY 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 
with anything but pleasure, the possibilities of 
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