054 



CYGNUS IMMUTABILIS. CHANGELESS SWAN. 



POLISH SWAN. 



Cygnus immutabilis. Polish Swan. Yarrell. Proceed, of Zool. Soc. p. 9 



Brit. Birds. III. 131. 

 Cygnus immutabilis. Bonap. Comp. List, 55. 



Adult male about sixty inches in length ; ninety-eight in 

 extent of wings ; bill from the joint to the tip of the upper 

 mandible four inches and two-twelfths, from the knob three 

 and a half, from the eye five and four-twelfths, its greatest 

 breadth one and four-and-a-half-twelfths ; the forehead ele- 

 vated, with a compressed, fleshy, ivrinkled lobe occupying the 

 upper basal angle of the bill ; tarsus four inches and a quarter; 

 middle toe five inches and eight-twelfths, its claw an inch ; tail 

 of twenty-four feathers, rounded ; bare space on the forehead 

 and between the eyes and bill black; the bill orange-red, except 

 the unguis, which is black, and of a narrow oblong form ; feet 

 dull grey ; plumage pure zvhite. Female similar to the male, 

 but considerably smaller. Young white in their first plumage . 



Male in Winter. — The following description is taken 

 from an individual, kept for some time in the Edinburgh 

 Zoological Garden, but respecting the capture of which I can 

 obtain no other information than that afforded by its fractured 

 and reunited humerus, which shows that it has probably been 

 shot. 



The body is of an elongated form, rather depressed ; the 

 neck extremely long and slender ; the head rather small, 

 oblong, compressed, anteriorly elevated above, and furnished 

 in front with a thick bulging compressed fleshy knob, 

 covered with corrugated skin. The bill is longer than the 

 head, straight, of nearly equal breadth throughout ; the 



