447 



eastern shores of the Mediterranean, and it is very doubtful if it has ever been met with as far 

 south as the coasts of North Africa. 



In Asia Bewick's Swan is found as far east as Japan. Von Middendorff and Von Schrenck 

 both observed it in Siberia ; and Dr. Eadde received two specimens from the elevated steppes of 

 Dauria, where, however, it does not appear to breed. Pere David says that in China this Swan 

 is even more abundant than the Whooper ; but the Chinese confound the two species under the 

 name of Tien-ngo. Messrs. Blakiston and Pryer, who record it from Japan, say that many Swans 

 are seen on the Shimosa lakes, probably of several species, but that a specimen in the Kiyoiku 

 Hakubutsukan is referable to Cygnus bewicki. 



In general habits the present species of Swan does not differ from Cygnus musicus ; but it is 

 rather slighter built, much smaller, and when swimming it floats higher out of the water. It is 

 also said to be less shy and more easy of approach than that species ; and its plumage is of a 

 more brilliant and purer white colour. Mr. Blackwell remarks that it has " somewhat the air 

 and appearance of a Goose, being almost wholly devoid of that grace and majesty by which the 

 Mute Swan is so advantageously distinguished." Yarrell observes that Bewick's Swan " differs 

 much more decidedly from the Whooper than its external characters. The principal and most 

 obvious difference is in the trachea, which forms one of the best distinctions in the separation of 

 nearly allied species throughout this numerous family. The tube of the windpipe is of equal 

 diameter throughout, and, descending in front of the neck, enters the keel of the sternum, whicli 

 is hollow, as in the Whooper, traversing its whole length. Having arrived at the end of the keel, 

 the tube then, gradually inclining upwards and outwards, passes into a cavity in the sternum 

 destined to receive it, caused by a separation of the parallel horizontal plates of bone forming 

 the posterior flattened portion of the breastbone, and producing a convex protuberance on the 

 inner surface. The tube also changing its direction from vertical to horizontal, and reaching 

 within half an inch of the posterior edge, is reflected back after making a considerable curve, 

 till it once more reaches the keel, again traversing which in a line immediately over the first 

 portion of the tube, it passes out under the arch of the merrythought, where, turning upwards, 

 and afterwards backwards, it enters the body of the bird to be attached to the lungs in the usual 

 manner. This is the state of development in the oldest bird I have met with. The degree next 

 in order, or younger, differs in having the horizontal loop of the trachea confined to one side 

 only of the cavity in the sternum, both sides of which cavity are at this time formed, but the 

 loop of the tube is not yet sufficiently elongated to occupy the whole space ; and the third in 

 order, a still younger bird, possesses only the vertical insertion of the fold of the trachea ; yet 

 in this specimen the cavity in the posterior portion of the sternum already exists to a consi- 

 derable extent. 



"These are the peculiarities of structure which belong to the tube and the sternum. The 

 bronchia? are very short ; but the flexible part intervening between the bone of divarication and 

 the bronchial rings is considerable, producing an effect to be hereafter noticed, this elongated, 

 flexible, and delicate portion being defended on each outer side by a distinct membrane, attached 

 to the whole edge of the bone of divarication, and to a slender semicircular bone on each side, 

 by which it is supported. 



" The muscles of voice with which this bird is provided pass down, as usual, one on each 



