AND THE PROBLEM OF DJ AST ATAXY. 
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A. Outline figure of the wing of the extinct flying Lizard, the 
Pterodactyle, formed by a thin membrane stretched between an enormously 
elongated digit and the body. 
B. Outline figure of the wing of a Bat, formed by a thin membrane 
similar to the above, but supported by several digits like the ribs of an 
umbrella. Note that the hind-limb in both these instances is engaged in 
the extension of this membrane. 
