ioo BRITISH BIRDS, WITH THEIR NESTS AND EGGS 



which soon becomes white, and never assume the grey colour which is borne for 

 the first two years by the cygnets of C. olor. The black tubercle at the base of 

 the bill is either wanting altogether, or is greatly reduced in size. The bill also 

 is said to be redder, and in immaturity flesh-colour, and not greyish-black. The 

 legs and feet are ash-grey, and not black. Subsequently anatomical distinctions in 

 the form of the cranium, between the two, were pointed out by Mr. Pelerin, in 

 the " Magazine of Natural History," and verified by Mr. Yarrell.* 



Swans, in every respect answering Mr. Yarrell's description of his new species, 

 have been obtained in Bngland, Scotland, and Ireland, and recorded as C. iininu- 

 tabilis. 



It is true that the majority of naturalists consider the Polish Swan to be only 

 a variety of the Mute Swan, and will not admit its specific distinction. On the 

 other hand, no ornithologist has so ably advocated its specific distinction as Mr. 

 T. Southwell, of Norwich, in a paper read 26th September, 1876, before the 

 Norfolk and Norwich Nat. Hist. Society, and subsequently published in their 

 transactions, Vol. II, pp. 258-260. Notwithstanding Mr. Southwell's able pleading 

 for the retention of the species in the British List, I still think the question 

 remains unsolved, and practically where it was twenty years ago. 



Family ANA TID.E. 



COMMON SHELD-DUCK. 



Tadonia corn it la, S. G. G.MEL. 



THIS very handsome Duck is more or less a constant resident on the shores 

 of the British Islands, nesting in suitable localities in warrens, and amongst 

 the sand-dunes, under conditions hereafter to be stated. Occasionally it chooses 



* I have received from the Rev. H. A. Macpherson a photograph of the sternum and trachea of C. iininu- 

 tabilis. lu his letter he says: "Mr. Thorpe and I have satisfied ourselves that the trachea is inserted into the 

 thoracic cavity at quite a different angle from that of C. olor." This seems strongly in favour of a specific 

 difference. 



