THE BROWN -HEADED, OR MASKED GULL. 
339 
Having now given — perhaps much too fully — my own reasons 
for believing this bird and L. ridibundus 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 f 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 
first 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 his examination ; but such are not near the dimensions of 
this bird, as given by Temminck.* If there be a small black- 
headed gull distinct from L. ridibundus, this is quite a different 
question from L. capistratus 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. ridibundus, 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 L. capistratus ; 
to be no smaller (except in tbe toes and webs of feet) than some of them, and to vary 
in the most trivial degree from the adult female bird in full summer plumage. The 
difference was, in my 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 0 18 4 
„ of tarsus . . . 1 8 (or 9) 16 
This is of course French measure, in which fifteen inches are equivalent to sixteen 
English. 
