282 NATATORES. CYGNUS. Swan. 
(harsh as it may be individually), when heard at a distance, 
has been compared to the enlivening cry of a pack of hounds. 
To the known effect produced by the association of ideas 
must doubtless be attributed the great pleasure which the 
Icelanders display upon hearing the cries of the Swan, which 
they compare to the notes of a violin; but as a writer justly 
observes, this is not to be wondered at, for they hear them 
at the termination of a long and dreary winter, when the re- 
turn of this bird to their shores is the earliest harbinger of 
spring, foretelling a speedy thaw and release from a tedious 
confinement. In dimensions and weight the present species 
is commonly less than Cygnus Olor, in its tame or semi-do- 
mesticated state, though adult males are sometimes met with 
that equal the average size of the latter. It may, however, 
always be distinguished from it externally by the different 
form and colour of the bill, the position of the legs, differ- 
ence of carriage, along with other peculiarities ; and inter- 
nally, the conformation of the trachea exhibits a remarkable 
difference. This part, instead of being a strait and simple 
tube, as in Cyg. Olor, is prolonged, and enters a large cavity 
hollowed out of the keel of the sternum, generally to the 
depth of three and a-half or four inches, where it is doubled 
back upon itself like a trumpet; and which inflection is al- 
ways vertical, never forming a loop or horizontal bend, as in 
Cygnus Bewickii. After its egress from this cavity, the 
tube is again turned upwards, and then, undergoing a con- 
siderable diminution in diameter, terminates exactly upon 
the ridge of the sternum in a compressed. bony lower larynx, 
or bone of divarication, shaped like the mouth-piece of a bas- 
soon, and to which the bronchi, measuring upwards of three 
inches in length, are attached. ‘The flight of the Swan is 
usually at a great elevation, and in a straight line; and as 
its wings are long and ample, its progress, with a favouring 
breeze, is astonishingly rapid, and has been reckoned to ex- 
ceed sometimes 100 miles in an hour. This velocity renders 
it a difficult bird to shoot on wing, where so much allowance 
