THE TRUE SWANS. 
255 
Cygnus olor, Dresser, B. Eur. vi. p. 419, pi. 418 (1880) ; 
B O. U. List Br. B p. 119 (1883) ; Saunders, ed. Yarr. 
Br. B. iv. p. 324 (1885); Seebohm, Br. B. iii. p. 476 
(1885); Saunders, Man. Br. B. p. 405 (1889); Salvad. 
Cat. B. Brit. Mus. xxvii. p. 38 (1895). 
{Plate L V. Fig. 2. ) 
Adnlt Male. — White all over, and distinguished from the other 
species by the colour of the bill, which is described by Count 
Salvador! as follows : — “ Lores, frontal tubercle, base of upper 
mandible, nostrils, nail, edges of upper mandible and entire 
under mandible, black ; remainder of the beak reddish-orange ; 
legs and feet dull black; iris hazel.” Total length, about 5 feet ; 
culmen, 4-2 ; wing, 27-0 ; tail, lo'o; tarsus, 4-5. 
Adnlt Female. — Similar to the male, but a little smaller, and 
with a smaller tubercle on the bill. 
Yonng Birds. —Sooty-grey, paler on the neck and under sur- 
face of body ; bill and legs grey. The nestlings are covered 
with down of a dull ashy-grey colour, which is paler and in- 
clining to white on the lower throat and breast. 
Characters. — In the Mute Swan the keel of the sternum is 
simple, and is not entered by the trachea, as in the foregoing 
species. The knob on the bill is also a distinguishing feature. 
Polish Swan {Cygnus immutahiUs '). — ^This supposed species 
(Plate LV., Fig. 3) is said to have white cygnets, and in the 
adult birds the tubercle is less developed, and the legs and 
feet are more ashy-grey, but with regard to the latter characters 
Mr. Howard Saunders writes ; — “ Neither Mr. Bartlett nor I 
could find these distinctions in old birds in the Zoological Gar- 
dens which had been white as cygnets.” Some ornithologists 
still believe in the difference of the Polish Swan as a species, 
and the Rev. H. A. Maepherson, in his “Vertebrate Fauna of 
Lake-land,” gives a figure of the sternum and trachea of a young 
bird, which, he thinks, show characters defining the Polish from 
the Mute Swan. 
On the other hand, Mr. Howard Saunders, Mr. Seebohm, 
and most of our leading British ornithologists regard the Polish 
Swan as only a kind of quasi-albino, probably produced by 
domestication. This opinion is endorsed by Count Salvador), 
