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CHEIROPTERA, OR BATS. 



The only members of the mammalia which can 

 really rival the birds or the insects in the air are those 

 remarkable beings which are popularly called Bats, 

 and of which we have several representatives in our 

 own country. 



In the insects, the organs of propulsion through 

 the air are variously modified projections from the 

 thorax some membranous and transparent, as in the 

 bees and flies, and some covered with scales, as in the 

 moths and butterflies. In the birds, the organs of 

 propulsion are the fore limbs, the structure of which is 

 modified for the purpose, and which are clothed with 

 feathers. In the Bats, the organs of flight are also 

 the fore limbs, which are modified in a very simple but 

 effectual manner. None of the mammalia being 

 clothed with feathers, but either having the skin 

 naked, scaled, or hairy, the order of Nature would be 

 infringed if the Bats were gifted were feathered wings 

 like those of birds. 



Another mode of flight has therefore to be employed, 

 and this is chiefly done by a modification of the fore 

 feet. In the birds, the fore limbs are not used for 

 progression on land, and consequently the feet are so 

 altered in shape as scarcely to be recognized as such, 

 except by the eye of the comparative anatomist. It 

 is the foot of the bird, for example, which supplies 

 the principal or primary feathers of the wing, the 

 secondaries being attached to that part which cor- 



