SOME HTOID HINTS. 133 



bone, whose articulations are close to the ears, 

 and whose muscular, ligamentous, and ner- 

 vous connections with the ear-bones are very 

 intimate. 



A moment's reflection will convince anyone 

 that the woodpecker's brain must be fortified 

 against the effect of concussion, for if any 

 other bird's head were dashed with such vio- 

 lence against hard wood, as the woodpecker's 

 head habitually is, death would quickly re- 

 sult. Indeed no person, after examination of 

 tlie picidsean habits, can doubt that the wood- 

 pecker is hard of hearing. Connect with this 

 the singular fact that those species which are 

 forced to depend upon hearing to locate their 

 prey, have the hyoid cornua reaching to the 

 immediate vicinity of the ear, whilst the spe- 

 cies not so necessitated show a modification 

 of those bones, and we have a curious sugges- 

 tion at the least. 



Upon dissecting a hairy woodpecker we dis- 

 cover that the central shaft of the tongue-bone 

 is simpler than that of most birds, and that it 

 forks directly, without definite articulations, 

 thus making the entire hyoidean apparatus a 

 continuous and singularly elastic bone, pecul- 

 iarly suited to conducting vibrations through- 

 out its length. 



Now when the bird's tongue is drawn far 

 back in the mouth, the posterior end of the 

 hyoid bones is thrust against a cushion of 

 membrane, muscle, and ligament lying imme- 

 diately in front of the quadrate bone, which 

 is the anterior ear-wall, and if at the same 

 time the lower mandible is let fall a little, so 

 that the mouth is slightly open, the posterior 

 process of t\\QJugal bone, called the quadrate 

 jugal, is made to press upon the lower part 

 of the quadrate bone, which, being slight and 

 having air-chambers around it, becomes a sort 



