380 



ORNITHOLOGY. 



clator Avium Musei Zoologici Berolinensis" (Berlin, 1854), circum- 

 stances which induce us to suspect that there is no description extant. 



Having only young birds of the species now before us, we much 

 regret our inability to determine its relationship to Larus cirrocepha- 

 lus, Vieill., of which there are adult specimens in the collection of the 

 Philadelphia Academy, bat our opinion is, at present, that it is not 

 identical. The description, by Vieillot, and the specimens, in the 

 Academy's collection, above alluded to, are, however, those of a bird 

 nearly related to the present, and more like it than the species imme- 

 diately succeeding. 



Two specimens of this bird are in the collection of the Expedition. 

 They are very nearly similar in colors and other characters, but are 

 considerably smaller in dimensions than as stated by Mr. Peale. 

 We therefore give his measurements, with his observations on this 

 species : 



" The specimens were obtained in the month of May, on the coast 

 of Chili, at which season the heads of all were white, slightly clouded, 

 in some, with pale lead color, which leads to the inference, that, at 

 other seasons, their heads would be black or dark lead color. Great 

 numbers were around the shipping, in the harbor of Valparaiso, and 

 were very tame. 



" This species is closely allied to ^ema cirrocepJialmn, but is rather 

 less in size, and may at once be distinguished by the first four quills, 

 which are white. In AT. cirrocephalum, they are black, with white 

 tips. 



" Total length sixteen and one-eighth inches ; wing, from the 

 carpal joint, fourteen and one-tenth inches ; tail four and eight-tenths 

 inches ; bill one and four-tenths inches ; to the angle of the mouth 

 two and three-tenths inches ; tarsi one and seventeen-twentieths 

 inches ; naked part of the leg, above the heel, one and one-tenth 

 inches ; middle toe one and eight-tenths inches ; nail seven-twen- 

 tieths of an inch. Male." 



These measurements agree with the specimens labelled by Mr. 

 Peale, and now before us, in all points, except total length of the bird 

 and the length of the wing, which are as we have given above. The 

 species alluded to by him as Xema cirrocephalum, is that now succeed- 

 ing. 



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