686 CYGNUS AMERICANUS. 



wing from flexure 20£ ; tail 5^ ; bill along the ridge 3^-, 

 from the joint 3-^, from the eye 4-^, its height at the base 

 1-^, its breadth near the end lg-, about the middle l-p-?; Dare 

 part of tibia 1-^ ; tarsus 4 ; hind toe T 8 7 , its claw -pV ; second 

 toe 3-fe, its claw T 8 o- ; third toe 4^, its claw -fe ; fourth toe 

 4-j^-, its claw 4. 



Remarks. — The tail, although apparently complete, hav- 

 ing only eighteen feathers, induced me at first to consider 

 this bird as a Bewick's Swan ; but its length and extent of 

 wing, it being obviously a young bird, being considerably 

 greater than those of an adult male of that species — the 

 former being 46^ to 45, the latter 80 to 73, and young Swans 

 being in their first winter a third less than adults — I con- 

 ceived it might prove merely the young of Cygnus musicus. 

 On dissecting it, however, I found reason to alter my opinion. 

 There are three Swans — Cygnus Buccinator, Americanus, 

 and Bewickii — of which the trachea, after forming a fold 

 within the sternum, enters the thorax to a considerable dis- 

 tance, and terminates in very short bulging bronchi. Now, 

 as will be seen from the description of the trachea given 

 above, this was the case with the bird in hand. The syrinx 

 of Cygnus musicus scarcely enters the thorax, being situated 

 on the anterior edge of the sternum, while the bronchi are so 

 much elongated as to reach their usual place of insertion in 

 the other species. Cygnus Buccinator is so very much larger 

 that it could not belong to that species, and Cygnus Bewickii 

 so much smaller that its belonging to it seemed scarcely 

 probable. Its tongue half an inch longer, its gizzard an inch 

 broader, the intestine much longer and wider, and the tra- 

 chea, instead of being almost uniform, considerably dilated 

 below, seemed all in favour of its belonging to Cygnus 

 Americanus. On comparing its sternum with that of an 

 adult Cygnus Bewickii, I found it nearly an inch longer, and 

 of considerably greater breadth, while it agreed in all respects 

 with that of an adult female Cygnus Americanus, excepting 

 that it formed no horizontal loop, this circumstance depend- 

 ing merely on age. A stuffed head of a young Cygnus 

 Americanus in my collection was found to be precisely similar 



