SKIMMER, the English name bestowed by T. Pennant[1] in 1781 on a North American bird which had already been figured and described by M. Catesby (B. Carolina, i. pl. 90) as the “Cut-water,”—as it appears still to be called on some parts of the coast,[2]—remarkable for the unique formation of its bill, in which the maxilla, or so-called upper mandible, is capable of much vertical movement, while the lower mandible, which is considerably the longer of the two, is laterally compressed so as to be as thin as a knife-blade. This bird is the Rhynchops nigra of Linnaeus, who, however, united with it what proves to be an allied species from India that, having been indicated many years before by Petiver (Gazoph. naturae, tab. 76, fig. 2), on the authority of Buckley, was only technically named and described in 1838 by W. Swainson (Anim. Menageries, p. 360) as R. albicollis. A third species, R. flavirostris, inhabits Africa; and examples from South America, though by many writers regarded as identical with R. nigra, are considered by Howard Saunders (Proc. Zool. Society, 1882, p. 522) to form a fourth, the R. melanura of Swainson (ut supra, p. 340). All these resemble one another very closely, and, apart from their singularly-formed bill, have the structure and appearance of Terns (q.v). Some authors make a family of the genus Rhynchops, but it seems needless to remove it from the Laridae (see Gull). In breeding-habits the Skimmers thoroughly agree with the Terns, the largest species of which group they nearly equal in size, and indeed only seem to differ from them in the mode of taking their food, which of course is correlated with the extraordinary formation of their bill. (A. N.)