^2 Mr. Selby on a new Species of Swan. 



hitherto ohtained or examined of Ci/gnus Bewickii, it appears to be about 

 one-third less than the adult Cygnus ferus, the average length of the 

 former being about 3 feet 11 inches, the breadth or extent of wing, 6 feet 

 8 inches ;* that of the latter 5 feet or upwards in length, and about 8 feet 

 in breadth. In the form of the bill there is a considerable difference, the 

 base of the upper mandible of the new sort, at its junction with the cranium, 

 being furnished with a protuberance or knob of greater or less size accord- 

 ing to the age of the individuals, and in consequence only exhibiting a small 

 portion of the lozenge shaped mark so conspicuous in the Hooper ; it is 

 also flatter, more dilated towards the tip, and the base or cere of a paler 

 orange. The neck appears smaller in proportion, and does not swell 

 downwards so rapidly as in the Hooper. The tail is more cuneiform, and 

 contains only 18 feathers, whereas the Hooper has 20. The legs seem 

 to be placed further backwards, or more out of the centre of gravity, 

 and have not so large a naked space above the tarsal joint as those of the 

 Hooper ; and the lateral membrane of the inner toe of the new kind is 

 broader and more deeply scalloped than the same part in the Hooper. 

 Internally, the points of distinction exist in certain parts and proportions 

 of the trachea and sternum. In old birds of the new species the 

 trachea, after entering the excavation in the upright keel of the 

 sternum, does not return by making a vertical curve or deflexion, as 

 in the Hooper, but forms a horizontal bend or loop at the extremity 

 of the excavation, as represented in PI V. figs. 1 & 2, which excavation 

 in this species not only extends to the extremity of the upright keel, 

 but also occupies a part of the lateral portion of the sternum, PL V. 

 fig. 1. This excavation, in the new species, is frequently upwards of 

 6 inches in depth, measuring from the anterior part of the keel, where 

 the trachea first enters the cavity, to the posterior extremity of the same, 

 where the recess is amplified for the reception of the orbicular loop ; in 



* The following are the measurements of four Swans of the new species: — 



Ft. Inch. Ft. Incfi. 



One killed at Prestwick Carr, January 1829, measured 3 11|^ long, 6 8^ broad. 



One shot at Sweet-hope Lough, Nov. 1829, do. 4 2 6 9 



One shot at Ditto, 3 llf 6 81 



One shot at Haydon Bridge, 1829, female, 3 Hi 6 5i 



