502 NATATORES. LARUS. GULL. 
tion to each other as that between the Greater and Lesser 
Black-backed Gulls (LZ. marinus and L. fuscus). This, upon 
further investigation, was found to be actually the case ; and 
some interesting remarks upon the new species, by the same 
gentleman, were afterwards published in the latter part of 
the fourth volume of the Wernerian Society’s Memoirs, 
where he has appropriated tc it the specific title of Islandi- 
cus, having then ascertained that the larger species previously 
noticed, and to which he had applied the term, was already 
recorded, and generally known by the name of Larus glau- 
cus. In point of priority, therefore, this name ought to be 
adopted for the present species, in preference to that of La- 
rus arcticus given to it by Mr Maceriiivray, or that of 
L. leucopterus, under which it is described by RicHarpson 
and Swainson, in the Fauna Americana Borealis, and by 
the Prince of Musignano, in his Synopsis. Captain Sabine, 
in his Memoir on the Birds of Greenland, in the twelfth vo- 
lume of the Linnean Transactions, has described the same 
bird under the title of Larus argentatus, and this in deference 
to the opinion of Monsieur TEmmtncx, who at that time 
considered it as a variety of the Herring Gull, occasioned 
by the rigours of a polar climate. The fact, however, of the 
true L. argentatus having been found with its characteristic 
markings unchanged in those regions, together with the per- 
fect and undeviating whiteness of the wings of the other 
bird, and the difference of proportions observable in the bills 
of the two species, might justly have made the former author 
hesitate before yielding even to the authority of a naturalist 
so deservedly eminent. The present species, in all its states 
of plumage from adolescence to maturity, bears the closest 
resemblance to the Glaucous Gull, and can only be distin- 
guished by its striking inferiority of size, and by the greater 
length of its wings, which reach, when closed, upwards of an 
inch beyond the end of the tail; whereas in the other bird 
they scarcely reach that part. Like its prototype it is a 
winter visitant to the Shetland Isles and the northern parts 
