ORDER CARNASSIER. 91 



into the nasal cavities. Thus it is the same with the organ 

 of smell as with that of hearing ; both are provided with an 

 external ala or cornet. 



Parts thus extended and multiplied cannot fail to exercise 

 a very powerful influence, and hence the sphere of sensation 

 and perception of the bats is very considerably enlarged. 

 They acquire the notion of many minute corpuscles, to which 

 no other animal can be sensible. From the observations of 

 Spallanzani we learn, that immediate contact is not ne- 

 cessary to advertise the bats of the presence of external ob- 

 jects by the sense of touch ; it is sufficient if they feel the 

 air interposed between them and such objects, and appre- 

 ciate the mode of its re-action on the membranes of their 

 wings. We find also that those large tunnels, placed in front 

 of the organs of hearing and of smell, render these animals 

 sensible to the feeblest emanations of sound, and the slightest 

 odoriferous exhalations. 



With these means of increasing the power of sensibility, 

 and perception of external objects, the bats are also gifted 

 with the faculty of excluding such perceptions at pleasure. 

 This, indeed, is a most wise and necessary provision, as other- 

 wise they would be completely overwhelmed by the effects 

 of such sensitive acuteness. The perfection of their organs 

 would be converted into a source of destruction. The little 

 ear, or auricula, is made to border in such a manner on the 

 meatus auditorius, that it serves as a valve to close that 

 passage : a trifling inflection of the ear is sufficient for the 

 performance of this operation, and in some species a mere 

 contraction of the cartilages. 



The excessive extension of the hand of bats exercises a 

 predominating influence not only over the organs which set 

 it in motion, but also on those of a higher order, and, in 

 fact, over the entire frame, submitting as it were, to itself 

 all the materials of organization. The organs of sense, con- 

 fined in other animals within such narrow limits, present in 



