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adjacent objects. I)r. Dobson, who has paid more attention to 
bats perhaps than any other living naturalist, is disposed to 
think, and very reasonably so, that tactile power may be thus 
greatly increased by such increase of the surface on which 
tactile sensations may be received as is found in the bat’s wing, 
and that this is the explanation of the mysterious power 
revealed to us by Spallanzani. 
The flight of the bat compared with that of most birds is ex- 
cessively fluttering; but it is a true and perfect flight, and 
therefore very different from the analogous action of other 
beasts called 64 flying,” such as the flying squirrels, the flying 
opossums, and the flying lemur. In these animals the skin of 
A Flying Frog. 
the flanks can indeed be extended outwards to the arm and the 
leg, and when so stretched (as when these animals take long 
jumps) seems as a sort of parchment to sustain them somewhat 
in the air, and so far break their fall as to enable them to flit 
from one bough to another; but they cannot truly fly. The 
flying lemur is the best furnished in this respect, as it has not 
only a very extensive u alar membrane,” but a short expansion 
of skin connects together not only the fingers but the toes also 
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