36 OF BATS IN GENERAL. 



have before observed, are excessively elongated. 

 The membrane that unites them presents an enor- 

 mous surface to the air. The nerves that are dis- 

 tributed to this membrane are numerous, and mi- 

 nutely divided, forming a net-work very remarkable 

 for its fineness, and the number of its anastomoses. 

 It is, therefore, more than probable, that, in the 

 action of flight, the air, when struck by this wing 

 or very sensible hand, impresses a sensation of 

 heat, cold, mobility, and resistance on that organ, 

 which indicates to the animal the presence of ob- 

 jects, which, if not avoided, would interrupt its 

 progress. It is in a manner similar to this that blind 

 men discern by their hands, and even by the skin of 

 their faces, the proximity of a wall, of the door of 

 a house, or the side of a street, without the assist- 

 ance of touch, and merely from the sensation 

 which the difference in the resistance of the air 

 occasions. 



Many of the Bats have on their nose a membrane, 

 the use of which, in the animal economy, has not 

 yet been ascertained. Spallanzani conjectured that 

 it might be the seat of the additional sense which 

 he attributed to these creatures. In some of the 

 foreign Bats its shape is extremely singular and 

 fantastical. This membrane is found in only one of 

 the English species, the Horse-shoe Bat. 



The ears of some of the Bats are very small ; but 

 of others extremely large, Many of these ears, 

 from having an inner valve, for the purpose pf 



keeping 



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