REVIEW OF THE FAUNA OF LAKELAND XCV11 



base of the furculum, soon entered the lungs from below. To 

 quote the exact language employed by Macgillivray in his 

 description of the anatomy of the Polish Swan, 'the trachea, 

 on reaching the intrafurcular space, forms a slight curve out- 

 wards, and then directly enters the thorax.' 1 



It appears to me, that those who decry the validity of the 

 Polish Swan have yet to explain away the striking cranial 

 characters of the bird. The fact that Polish Swans have hitherto 

 visited this country only, as I believe, in small flocks, and at 

 the winter season, appears to strengthen the position of those 

 who incline to regard the Polish Swan as a northern form of 

 the Mute Swan. That the Mute Swan has produced white off- 

 spring appears to me to be a fact without any direct bearing 

 on the validity of the Pole. Species should be founded as far 

 as possible on real structural characters. It is said that tame 

 Mute Swans occasionally show some of the external characters 

 of the Pole. If, as I believe, both the Polish and Mute Swan 

 owe their origin to one and the same ancestor, it is only natural 

 to expect that recently-acquired characters should sometimes be 

 replaced by disused characters and vice versd. This, then, is an 

 argument for the validity of the Polish Swan. Mr. J. E. 

 Harting formerly recorded Bonaparte's Gull (Larus Philadelphia) 

 as having been once obtained 'on one of the English Lakes.' 2 

 This statement was founded on the much more indefinite remark 

 of Yarrell, that such a bird had been killed ' on one of the lakes 

 in England.' 3 Such a bird was apparently killed, as reported 

 by Yarrell ; but at a very great distance from Lakeland. With 

 regard to the position of the Great White Heron (Arclea alba), 

 reported as obtained in Cumberland by Dr. Heysham, the ex- 

 clusion of this species from his catalogue of 1796-7 goes far to 

 suggest that he had discovered a flaw in its pedigree. When 

 Mr. J. H. Gurney lately revised the claims of British Great 

 White Herons, I pointed out to him that in my opinion Dr. 

 Heysham's entry of it should be regarded as unsound. The 

 White-eyed Duck (Fuligula nyroca) must also be removed from 



1 British Birds, vol. iv. p. 656. 



2 Handbook of British Birds, p. 173. 



3 British Birds, third edition, vol. iii. p. 555. 



9 



