THE BROWN-HEADED, OR MASKED GULL. 339 



Having now given — perhaps much too fuUj — my own reasons 

 for beheving this bird and L. ridibnndus to be the same, I shall 

 not enter into the question of the various opinions on the subject, 

 further than in reference to my friend Mr. Yarrell. On the 27th 

 of May, 1845, I brought my views on the subject before the 

 Zoological Society in London, and exhibited many specimens in 

 support of them. An abstract of my remarks was published in 

 the Proceedings of that Society, in the ' Annals of Natural His- 

 tory,' and in the preface to the first volume of the second edition 

 of Mr. YarrelFs work. In its proper place, under L. capistratus, 

 in the second edition, my original specimen — though given in the 

 fijst edition — is omitted, while the Orkney one with which it was 

 compared by that author and myself, and was proved to be iden- 

 tical with in species, is retained : descriptions of both, and of 

 a specimen so named by Temminck, have been given in the pre- 

 sent volume. 



Mr. Yarrell appears still to think — he does not speak decisively 

 — that L. capistratus is a distinct species, and instances two adult 

 individuals only twelve inches and a half in length, having come 

 under liis examination ; but such are not near the dimensions of 

 this bird, as given by Temminck,"^ If there be a smaU black- 

 headed gull distinct from L. ridibundits, this is quite a different 

 * question from L. cajnstratus being identical with it. An adult bird 

 shot at Lough Clay (county Down) on the 16th of July, 1845 — 

 one of a pair known to have a nest there — was smaller not only 

 than the ordinary L. ridibimdus, but than the L. capistratus also. 

 It was, in total length, thirteen inches and three-quarters (Eng- 

 lish measure) . Colour : Bill dull arterial blood-red ; tarsi be- 

 tween that colour and the hue attributed to £. capistratus; 



to be uo smaller (except iu tlie toes and webs of feet) tban some of them, and to vary 

 in the most trivial degree from the adiilt female bird in fuU summer plumage. The 

 difiference was, in tny opinion, simply individual :, as distinguished from specific. 



* His only measurements named for L. ridibundus and L. capistratus, are — 



in. lin. in. lin. 



Length (total) .... 14 13 4 



„ of tarsus . . . 1 8 (or 9) 1 



This is of course French measure, in which fifteen inches are equivalent to sixteen 

 English. 



z 2 



