286 TRESPASSERS UPON THE AIR. 



perfectly dark room, and even after they had been 

 blinded. He then stretched threads across the room 

 in various directions, and found that the Bat, blind as 

 it was, never by any chance touched one of them. 

 He then proved that neither smell nor hearing could 

 assist the animal, and therefore concluded that the 

 Bat must possess a sixth sense, at present unknown 

 to us. 



Cuvier, however, read these experiments in a 

 somewhat different manner. He looked to the wings 

 themselves for an explanation of this wonderful power 

 of guidance without sight, and found the whole surface 

 of the delicate membrane to be an enormously ex- 

 panded organ of touch, possessing exquisite sensibility, 

 and being capable of detecting by the sense of touch 

 the presence of external objects. In all probability, 

 therefore, the Bat depends but little, if at all, upon its 

 eyes for the capture of prey, and is guided almost 

 entirely by the sensitive surface of the wings. Perhaps 

 the reader will call to mind the fact that the moles 

 are practically blind, and that when they pursue and 

 capture their prey they are guided by the sensitive 

 snout, which performs the same office for them that 

 the wing does for the Bat. 



In our own Bats the external ear is of considerable 

 size, and is formed by a membrane very similar to that 

 of the wing, so that it may probably assist the animal 

 in guiding its flight. The most prominent example 

 of this structure is to be found in our common Long- 

 eared Bat (Plecotus auritus), the ears of which are 

 nearly as long as the body, and can be thrown into 

 most graceful curves at the will of the owner. 



