402 GUEL 
Pagophila and [hodostethia have but one species each, Lissa and Xema 
two, while the rest belong to Larus. The Pagophila is the so-called 
Ivory-Gull, P. eburnea, names which hardly do justice to the 
extreme whiteness of its plumage, to which its jet-black legs offer a 
strong contrast. The young, however, are spotted with black. An 
inhabitant of the most northern seas, examples find their way in 
winter to more temperate shores. Its breeding-places have seldom 
been discovered, and the first of its eggs seen by ornithologists was 
brought home by Sir L. M‘Clintock in 1853 from Cape Krabbe 
(Journ. R. Dubl. Soc. i. p. 60, pl. 1); two others? were obtained by 
Dr. Malmgren in Spitsbergen in 1868, and, in August 1887, the 
captain of a Norwegian ship found from 100 to 150 nests on Storé, 
an islet on the extreme north-east of that country? (bis, 1888, pp. 
440-443, pl. xiii.) Of the species of Jtissa, one is the abundant 
and well-known Kuirriwake, f. tridactyla, of circumpolar range, 
breeding, however, also in comparatively low latitudes, as on the 
coasts of Britain, and in winter frequenting southern waters. The 
other is 2. brevirostris, limited to the North Pacific, between Alaska 
an@ Kamchatka. The singular fact requires to be noticed that in 
the former of these species the hind toe is generally deficient, but 
that examples, and especially those from Bering’s Sea, are occa- 
sionally found in which this functionless member has not wholly 
disappeared. We have then the genus Larus, which ornithologists 
have hitherto attempted most unsuccessfully to subdivide. It 
contains the largest as well as the smallest of Gulls. In some 
species the adults assume a dark-coloured head every breeding-season, 
in others any trace of dark colour is the mark of immaturity. The 
larger species prey on eggs and weakly birds, while the smaller 
content themselves with a diet of insects and worms. But how- 
ever diverse be the appearance, structure, or habits of the ex- 
tremities of the series of species, they are so closely connected by 
intermediate forms that it is hard to find a gap between them that 
would justify a generic division. Of the forty-five species of this 
genus now recognized by Mr. Saunders it would be here impossible 
to attempt to point out the peculiarities. About seventeen belong 
1 The white Gulls reported to Gunner (Leem, De Lapp. Comment. p. 285), 
and called by him Larus albus, may have been as he thought identical with the 
Rathsherr of Marten (Spitsb. Rein. p. 56), which undoubtedly was the Ivory- 
Gull ; but there is nothing to prove that they were. Hence I cannot adopt that 
specific name, as recent American writers do. From what has been before said 
as to GAviA, they seem to be also wrong in using that word as a generic name 
in place of Pagophila. : 
2 One of these has long been in my possession. 
3 The Norwegian pilot of the yacht in which I visited Spitsbergen told me 
that the crew of a boat which visited Giles’s Land in 1859 found many Ivory- 
Gulls’ nests on its shore (Zbis, 1864, p. 508). 
