THE ANATOMY OF BIRD-SONG. 117 



the breath from the glottis is reflected back 

 by the bird's hfted tongue, and the element of 

 harshness is caught from the strained and vi- 

 bratory membranes of the mouth and the 

 nasal and throat cavities. The peculiar part 

 played by the syrinx in this case is that by a 

 rocking, quivering, or gyratory motion it im- 

 parts to the tracheal column of air sent out 

 through the glottis a spiral or palpitant cur- 

 rent. This current would blow a quavering 

 flute-note of some sort were it not interrupted 

 at the glottis by the bird's uplifted tongue, and 

 broken and flung back into the throat and 

 nasal cavities, where it is further disintegrat- 

 ed by the elastic membranes, as already men- 

 tioned. 



The parrot is a strong instance of a bird who 

 has a wonderful voice, but whose syrinx is 

 weak and imperfect, viewed from Prof. Hux- 

 ley's ground. There is no septum or median 

 membrane in the parrot's organ, and there- 

 fore one ' ' vocal cord " is missing, and yet 

 how clear is his whistle, how pure his reed- 

 note calls, how deep and how incomparably 

 rich his throat cries ! Surely all these are not 

 made in that poor little half-equipped syrinx ! 

 The thick, heavy, fleshy tongue of the parrot, 

 and the spacious throat-cavity behind it, are 

 the special means by which its voice is con- 

 trolled and enriched. The so-called speaking 

 voice of this and other birds is a lingual and 

 throat modification of the glottis notes. Again, 

 the large, pad-like tongue of the parrot, perfect- 

 ly reflecting the breath from the glottis back 

 into the throat-cavity, gives the best proof of 

 what I have claimed, by producing the 

 closest parody of a genuine voice ever uttered 

 by a bird. Just here is the place to say that 

 all of the flute- voiced birds have very slender 

 and delicate tongues. I have before me as I 

 write the tongue of a mocking-bird aod ih^it 



