Remarks on Mr. Eytorfs Arrangement of the Gulls. 487 



Art. VIII. Remarks on Mr. Eyton s Arrangement vf the Gulls. 

 By Fred. Mc'Coy, Esq. 



In taking up Part 2 of the ' History of the rarer species of 

 British Birds,' by T. C. Eyton, Esq., I was somewhat sur- 

 prised to find, under the head " Of the Gulls in general," a 

 new classification of these birds, or rather a combining of 

 those of Leach, Stephens, and Mr. Eyton himself. The au- 

 thor divides the gulls into four sub-genera, as follows : — 



Sub-gen. 1. — Rissa, Leach; wanting the hind toe; tarsi moderate. 



2, — Lotus , Stephens; hind toe perfect; tarsi strong; thighs fea- 

 thered nearly to the joints; head white in the summer and win- 

 ter plumage ; tail rounded, 



3. — Chroicocephalus, Nobis ; hind toe perfect, tarsi slender ; thighs 

 much denuded ; tail rounded ; head dark coloured in the summer 

 plumage. 



4> — Xema, Leach ; tail forked. 



Before we go any farther, I am extremely anxious to know 

 under which of these sub-genera we are to place our common 

 gull, Larus canus, auct., with the pretty spotted head, which 

 of course will turn it out of the sub-genus Larus ; and it can- 

 not be admitted to a place in the new sub-genus, Croicoce- 

 phalus, because its head is not "dark-coloured in the summer 

 plumage." We will now begin with Xema, and work up- 

 wards towards Rissa. The only character, you will recollect, 

 given for Xema, is " tail forked ; " now by this we are to un- 

 derstand, that any gull having a forked tail, must belong to 

 the sub-genus Xema, that character alone, it seems, being 

 sufficient to point out its situation. 



Now, it is stated in the 12th. volume of the Linnean 

 Transactions, near the end of the account of the Sabine Gull , 

 that the tail of the kittiwake is slightly forked ; — I regret that 

 the only specimens I can get at immediately are stuffed, so 

 that I cannot examine them as minutely as I could wish ; the 

 Linnean Transactions, however, are quite sufficient for the 

 purpose ; we must therefore consider the kittiwake for the 

 future, (at least according to Mr. Ey ton's views), as a species 

 of Xema, the character of the forked tail being, in that gen- 

 tleman's opinion, sufficiently characteristic of the sub-genus. 

 Then as the kittiwake is given as the typical species of the 

 sub-genus Rissa, — and, as it has been shown, by his own cha- 



