526 MR. H. SAUNDERS ON LARIDA [June 6, 
under the name of L. cirrhocephalus, has included two other and 
perfectly distinct species. His no. 87 is really ZL. glaucodes, 
Meyen (as is also his no. 51, which is rightly named), a species 
with a black or dark brown hood (similar in that respect to our 
L. ridibundus), which ranges from the Falklands to the coast of 
Chili. On the other hand his nos. 68 and 69 are respectively young 
and adult of Z. maculipennis, Licht., another dark-hooded Gull, very 
close to Z. glaucodes, but from which it is distinguishable by the 
wing-pattern. Hitherto LZ. maculipennis, which is the common 
Argentine species, has not been known to occur beyond the Chuput 
valley, Eastern Patagonia, 43°8.; and this is the first time it has been 
obtained on the Pacific coast. It was already sufficiently remarkable 
that two such very closely allied and yet perfectly distinguishable 
species of Gull as LZ. maculipennis and L. glaucodes should be coex- 
istent within so limited an area; but now that their range is shown 
to intersect, it is stranger than ever. Reverting to L. cirrhocepha- 
lus, which has been so repeatedly confused with totally distinct 
Species, it may be excusable to repeat that it has a pale grey or 
lavender hood, slightly darker on the neck, and that the only species 
with which it can be confounded is its South-African representative 
L. pheocephalus, Sw. 
LaRUS BELCHERI, Vigors. 
Larus belcheri, Vigors, Zool. Journ. iv. p. 358; Scl. & Salv. 
P. Z. 8S. 1871, p. 575 ; Saund. op. cit. 1878, p. 182. 
[No. 4, San Lorenzo Island, Callao Bay, August 1881. Eyes 
brown, legs yellow. 
No. 7, Callao Bay, August 1881. 
No. 8, Coquimbo Bay, November 1881. ] 
The first is an adult with pure white head and underparts; the 
second is in the brown plumage of the first year ; the third isa bird 
of the second year which has already assumed the dark mantle of 
the adult, but still retains the brown hood and slightly mottled 
underparts indicative of immaturity. 
This stoutly built species is a very remarkable Pacific form, uniting, 
as it does, all the main features in which the Gulls of the Pacific 
differ from those of the Atlantic. In the immature stage it has an. 
exceedingly well-marked hood, which it afterwards loses; in the 
adult stage it still retains a very defined black bar on the rectrices. 
Altogether it resembles L. crassirostris of Japan far more closely 
than any other ; but it is a coarser species, and has a more defined 
hood in the immature plumage than the Japanese bird. 
Larus modestus, a more slender but very characteristic species 
frequenting the coasts of Peru and Chili, but of the breeding-place 
of which no authentic accounts have yet appeared, is not represented 
in this collection. Another and very rare Gull, hardly a dozen 
examples of which are known to exist, is Larus fuliginosus, a dark 
sooty bird with a hood at all seasons, restricted to the Galapagos 
group. 
