528 MR. H. SAUNDERS ON LARIDE (June 6, 
hemisphere ; but inasmuch as the Alecde proper are now generally 
admitted to be connected with the Zarid@ on the one side, as the 
Laride are connected with the Limicole on the other, and as the 
Alcide are only known to inhabit the northern hemisphere, it would 
appear more probable that the Laride, or at least the Larine, had 
their origin there also. There are, however, some very remarkable 
points about the Gulls of the southern hemisphere, especially with 
relation to the Pacific, of which M. Milne-Edwards seems to be 
unaware, and upon which I should like to offer a few observations. 
Throughout the northern hemisphere, exclusive of the shores 
washed by the Pacific, the Gulls (with the exception of the three 
arctic genera Rissa, Pagophila, and Rhodostethia) fall into two 
well-marked groups—those in which the adults bear a coloured 
hood during the breeding-season, and those which never have a hood 
at any time. Jn all the members of both of these groups the imma- 
ture birds have a dark band across the rectrices, which disappeats as 
they approach maturity. Several representatives of each of these 
groups also inhabit the southern hemisphere— Larus cirrhocephalus 
of South America, and its close ally ZL. pheocephalus of South 
Africa, L. maculipennis, L. glaucodes, and L. serranus of South 
America, belonging to the former; LZ. dominicanus, found from New 
Zealand to South America (by way of the Cape of Good Hope, not 
through the South Pacific), Z. dulleri, L. scopulinus, L. nove-hol- 
landie, and L. hartlaubii, found at or between New Zealand and the 
Cape of Good Hope, belonging to the latter group. But it is only 
in the Pacific (merely including in that area the desolate islands of 
South Shetland, the Falklands, and a portion of Patagonia near the 
eastern entrance of the Straits of Magellan) that we find several 
species of Gulls which agree with the other forms in having a band 
across the rectrices in the immature stage, but differ from them 
in many other respects. Most of these species are of a coarse 
heavy build, and have a tendency to a sooty hue on the under- 
parts; but their principal characteristic is the presence of a more or 
less defined hood in the immature stage, which is generally José in 
the adult plumage. LL. scoresbii, which extends beyond the Pacific 
to the Falklands, varies least in this respect from the general type 
of Guils; it has a well-defined hood in youth, but loses the hood 
with the disappearance of the bar on the tail, which becomes 
white. Its range is but little beyond that of the Cape-Horn 
current. Larus belcheri, distributed along the whole coast-line 
of Chili and Peru washed by Humboldt’s current of cold water, 
has a hood in youth only ; but it has a barred tail at all ages, the 
black predominating over the white. The species most nearly re- 
sembling it in the adult plumage is Larus crassirostris, of the 
Pacific coasts of Japan and China, in which, however, the amount 
of black and white in the rectrices is nearly equal; nor has the 
young so well-marked a hood; its mantle also is lighter, and its 
other characteristics are so far modified as to make it intermediate 
between the Old-World and the South-Pacifie Gulls. The line of 
communication of the ancestor of these forms, which now constitute 
