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SWAN, POLISH. 
CYGNUS IMMUTABILIS, Yar. 
The Polish Swan, a native of the Baltic, was 
discovered, described, and named by Yarrell, from 
specimens shot on the east coast of England. It 
differs from the Mute or Tame Swan, in having a 
smaller knob at the base of the upper mandible, 
and feet of a dull grey instead of black colour; 
besides which there is a considerable difference in 
the internal structure of various parts of the head. 
Its food and habits closely resemble those of the 
Tame Swan; but its cygnets, unlike the young of 
all other White Swans, are of as snowy a colour 
as itself. 
SWIFT, COMMON. 
DaRLInG, oR SCREAMER. 
CypsELus apus, Flem. 
The Swift, which is generally dispersed in Great 
Britain and Ireland, is seldom seen in the northern 
parts of England before the end of May or the 
~ beginning of June, arriving in the south a week 
or two earlier. It leaves us again for warmer 
climates in August, a month or six weeks pre- 
vious to the departure of the Swallows. It resorts 
