84 Coale, The Trumpeter Swan. [f^ 



species of wild swan, Cygnus buccinator .... The trachea is 

 made up of narrow bony rings and small intervening membranous 

 spaces as far as the first convolution within the breast bone, but the 

 returning portion of the tube, forming a second convolution is com- 

 posed of broader and stronger bony rings with broader intervals." 



The course of the trachea may easily be traced by consulting 

 Plate IX. 



After traversing the neck it enters the lower part of the cavity 

 on the anterior face of the sternum at "A," thence follows back- 

 wards through the horizontal covered protuberance in the upper 

 surface of the sternum, a distance of eight inches to near the poste- 

 rior line "B.," taking the curve of the cavity it comes forward six 

 inches and rises into the vertical bony protuberance, " C," follow- 

 ing its curve, thence downward, and emerges through the upper part 

 of the opening in the sternum, dips below the bridge of the "wish 

 bone" and curving backward between the shoulder blades, "D" 

 (obscured in the picture) enters the breast, where at its junction 

 with the bronchise " E. " it is flattened vertically to an eighth of an 

 inch in width. The total length of the structure shown is 13.5 in., 

 length of trachea 59 in., length of keel of sternum 11 in., opening 

 | in. wide, 2\ in. high. 



In Olor columbianus the cavity is in the anterior portion of the 

 sternum only, the trachea making but one convolution, which is in 

 the vertical (not horizontal, as some authors state) protuberance 

 "A." 



Plate X shows the anterior aspect of the sternum with the 

 trachea entering the cavity below, and emerging above. I am 

 indebted to Dr. C. W. Richmond for the loan of this sternum 

 from the U. S. National Museum Collection. 



Stejneger, (Vol. V, Proc. U. S. Nat. Mus. 1882) outlines a 

 monograph of the Cygninae, and on p. 216 gives a table of measure- 

 ments of ten specimens, with remarks; "The position of the nos- 

 trils being set more backwards in the Trumpeter than in the 

 Whistling Swan, is thus the only mark which is possible to express 

 in a short diagnosus, and which I have found constant and easily 

 perceptible." 



Baird, Brewer and Ridgway (Vol. 1, Water Birds of N. America, 

 1884), give an interesting description of the habits of the Trumpeter; 



