142 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



The whole of the plumage deep leaden-grey ; the upper and under tail coverts 

 being lightest ; bill red at the base, black at the tip ; feet black. 

 Habitat, Galapagos Archipelago {October). 



This species of gull has many characters in common with the Larus hcemato- 

 rhynchus of King, from the continent of S. America; but may at once be distin- 

 guished from it by the general extreme duskiness of its plumage, feet, tarsi, and 

 bill ; and by the more elongated form of the latter. My specimen was killed at 

 James Island. I observed nothing particular in its habits. It is the only species 

 of gull frequenting this Archipelago. 



2. Larus joematorhynchus. King. 



Larus heematorhynchus, King, Zool. Journ. iv. 103. 

 , Jard. $ Sell. 111. Orn. p. 106. 



This bird was killed at Port St. Julian on the coast of Patagonia. Beak 

 (when fresh killed) of a pale " arterial blood red," legs " vermilion red." 



3. Larus dominicanus. Licht. 



Larus dominicanus, Licht. Cat. 82. sp. 846. 

 Grande Mouetto, Azara, No. 409. 



This gull abounds in flocks on the Pampas, sometimes even as much as fifty 

 and sixty miles inland. Near Buenos Ayres, and at Bahia Blanca, it attends 

 the slaughtering-houses, and feeds, together with the Polybori and Cathartes, on 

 the garbage and offal. The noise which it utters is very like that of the common 

 English gull {Larus canus, Linn.) 



Xema (Chroicocephalus) cirrocephalum. G. R. Gray. 



Larus cirrocephalus, Vieill. Nov. Diet. d'Histoire, 21. p. 502. 

 Larus maeulipennis, Licht. Cat. 83. sp. 855. 

 Larus glaucodes, Met/en, Nov. Act. 1839, p. 115. pi. 24. 

 Mouette cendree, Azara, No. 410. 



This species so closely resembles the Xema ridibundum, Boie, that Mr. Gould 

 observes, he should have hardly ventured to have characterized it as distinct ; 

 but as M. Vieillot and Meyen have deemed this necessary, he adopts their view. 

 I have compared a suite of specimens, which I procured from the Rio Plata, the 

 coast of Patagonia, and the Straits of Magellan, with several specimens of the 

 Xema ridibundum; the only difference which appears to me constant, is that the 

 primaries of the X. cirrocephalum, in the adult winter plumage, both of male and 

 female, are tipped with a white spot (a character common to some other species), 

 whereas in the X. ridibundum the points are black. The beak of the latter species, 



