Chap. XIII. 



VOCAL MUSIC. 



59 



The lieacl-crest and neck-appendage are rudimentary 

 in tlie female.''^ 



The vocal organs of various web-footed and wading 

 birds are extraordinarily complex, and differ to a certain 

 extent in the two sexes. In some cases the trachea is 





Fig. 40. The Umbrella-Bird or Cephalopterus ornatus (male, from Brebm). 



convoluted, like a French horn, and is deeply embedded 

 in the sternum. In the wild swan (Cygnus ferns) it is 



4-* Bates, * The Naturalist on the Amazons,' 1863, vol. ii. p. 284 ; 

 Wallace, in 'Proc. Zool. Soc.' 1850, p. 206. A new species, with a still 

 larger neck-appendage (C penduliger), has lately been discovered, see 

 ' Ibis,' vol. i. p. 457. 



