NATATORES. 431 



summer, migrating to the more temperate parts in winter. Numerous specimens 

 were brought home by the late Expeditions from Melville Peninsula^ the North 

 Georgian Islands, Baffin's Bay, and Spitzbergen. It resembles the Lestris 

 pomarina in its manners. 



DESCRIPTION 



Of a male, killed on Melville Peninsula, June 17, 1822, and now in the Ed. Mus. 



Colour. — Crown, nape, quills, and tail, pitch-black; back, scapulars, and lesser wing 

 coverts, blackish-brown, with a tinge of grey ; shafts of the tail and quills whitish, except on 

 their tips. Head beneath the level of the eye, neck above and below, and breast, straw- 

 yellow. Anterior part of the belly whitish ; posterior part, flanks, and under tail coverts, 

 brownish-grey: interior of the wing blackish-grey. Bill livid; its tip, the knee joints, and 

 feet, blackish. Tarsi largely blotched with yellow. 



Form. — Bill having a straight commissure to past the nostrils, when it is curved in both 

 mandibles ; edges of the upper mandible obsoletely notched. Wings longer than the lateral 

 tail feathers. Tail rounded, exclusive of the middle pair of feathers, which are nearly an inch 

 wide at the base, and taper gradually to within three inches of their tip ; thence they are 

 narrowly linear or slightly tapering, the extreme tip becoming suddenly acute ; they project 

 half a foot beyond the others. Tarsus slender, protected anteriorly by crescentic scutelli; 

 reticulated behind with minute conical and rather acute scales. 



The female has precisely similar plumage. — A nestling, from Melville Peninsula, having 

 the head and neck still clothed with blackish -grey down, has the rest of the plumage blackish- 

 brown, margined on the back with light yellowish-brown, and transversely barred on the belly 

 with dull white. The wings and tail are brownish-black, without spots. The legs, posterior 

 parts of the webs, and toes, dull yellow. The tail is rounded, th ecentral feathers not pro- 

 jecting. 



A specimen, from Hudson's Bay, in the British Museum, is exactly similar to the old male 

 described above ; while another specimen, in the same museum, brought from Baffin's Bay 

 by Captain Ross, corresponding nearly in dimensions and in the colour of its plumage (ex- 

 cept that there is some white on the under tail coverts, as is usual in the younger birds), 

 differs in the bill being less curved, the curve of the commissure commencing considerably 

 before the nostrils, and in the posterior scales of the tarsus being considerably smoother. 

 The middle tail feathers are a quarter of an inch wider at the base, and the narrow ends 

 shorter, — probably the less mature state of the plumage. 



A British specimen, also in the same museum, similar to the Melville Peninsula one in 

 plumage and colour of the bill and legs, differs in being of rather smaller dimensions, and in 



only difference being the greater length — of " near two inches," — which he assigns to the tarsus in the text, and its 

 much greater roughness. Notwithstanding this discrepancy, however, the general resemblance of his figure to the 

 specimen from the same locality in the British Museum, leads us to suspect that it may be intended for a representation 

 of the same species, the different examples of which exhibit considerable variations in the roughness of the tarsus. 

 None of the specimens we have described in the text have a bill equal in length, from the front, to that of L. Bnffonii, 

 as characterized by the Prince of Musignano, by two lines ; but the rest of the characters correspond with his descrip- 

 tion of that bird. — R. 



