122 THE ANATOMY OF BIRD-SONG. 



the difference between this mouth-piece in 

 true singers and in oscines that cannot sing .is 

 easy to distinguish. The shrike tries to sing 

 with his throat wide open — that is, he tries to 

 whistle without "puckering" his lips! The 

 mocking-bird knows better. 

 VII. 

 In summing up the facts, or the more im- 

 portant ones, connected with the "anatomy 

 of bird-song," I would emphasize the fol- 

 lowing : 



1. The syrinx of the true singing birds is 

 invariably smaller, weaker, and more ob- 

 scurely developed than that of the songless 

 oscines. 



2. The laryngeal and glottidean membranes 

 and muscles are far more highly developed 

 and specialized in the true singers than they 

 are in the oscines that cannot sing. 



3. The so-called "vocal cords" in the 

 syrinx of the most musical birds are utterly 

 devoid of the structure of true vocal cords, 

 and serve merely as valves or stops at the 

 openings of the bronchial tubes. 



4. The intrinsic muscles of the syrinx in 

 true singers are more delicate, more numer- 

 ous, and more specialized than those of the 

 songless oscines, giving greater control over 

 the management of the breath blown from 

 the lungs into the trachea. 



5. The form of the trachea, just below the 

 glottis, in other words, the form of the larynx, 

 in all the accomplished songsters is very dif- 

 ferent from that in the other oscines, being 

 somewhat like the " egg -choke" in the muz- 

 zle of the shot-gun barrel. 



6. The tongue of the true singer is slenderer 

 and thinner than that of the whistler, or that 

 of any other songless oscine. 



There are many facts, connected with the 

 philosophy of the vibration of air-columns, 



