PLATE CCXXVIII. 



In the coiiftru6lion of tht: bill there is a further dilFerence, the bafe' 

 at the forehead being ftnooth and entirely deflitute of the callofity or 

 knob which we at once perceive upon that part in the tame or culti- 

 vated fwan. 



And befides this there is yet another very principal difl:inciion, the 

 tame fwan being mute, or at leaft the found wiiich it emits being 

 nothing more than a hifling nolfe, like that of the goofe ; while the 

 wild fwan, on the contrary, has a loud and piercing cry, which has beeri 

 compared to that of a whiftle, and this it can exert with fuch effect, 

 that it is affirmed it may be diftinguilhed when a flight of wild fwans 

 is paffing overhead in the aerial regions, at fuch a prodigious elevation 

 from the earth, as to be inviiible to the jiaked eye. 



It is from this laft mentioned circumftance that the wild fvvan has 

 obtained the more expreffive epithet of the whiftliog fvvan, and the 

 other has been denominated the mute fwan. 



The latter mentioned difference is alone fufficient to juilify the con- 

 clufion of the two birds being fpecifically different. This diffiiiiilarity 

 in the voice arifes it has been long fince afcertained, from the anato- 

 mical conformation of the wind-pipe ; and which in the whiftliog fv^ aa 

 is altogether lingular. The pipe eaters the cheft at iirft a little w ay- 

 only, and is then reflefted into the form of a trumpet, after which it 

 again enters, and then dividing into two branches proceeds to join the 

 lungs. In the mute fwan the wind-pipe enters at once into the lungs^ 

 and hence there can be little doubt tliat the remarkable difference in 

 the founds they emit arifes from this difierence in the ftru6lure. 



The whiflling fwan is about five feet in length, the mute fwan when 

 Vol. X. E full 



