46 



FACULTIES OF BIRDS. 



Skull of the Fox ; a, the auditory hole. 



It has been well remarked by the earliest 

 authors, that birds are not provided like other 

 animals with an external ear, because their passage 

 through the air* would have been obstructed by 

 long ears like those of the hare or the ass. In owls 

 there is a peculiar valve placed at the opening-, 

 partly of a membranous, and partly of a muscular 

 structure, which has by some authors been deemed 

 analogous to the human ear, and it is around this that 



Structure of the Ear of the Owl. 



*Derham, Phys. Theol. b, iv. c. 3 ; 1 ; Savart, Ann. cle Chim. 

 xxvi. 5. 



