Mayr (1941b:203) cites _Psamathia_ as an example of "restricted endemism" and points out that the nearest relative occurs in the Philippines. Delacour (1942:514), in a discussion of the bush-warblers of the genera _Cettia_, _Bradypterus_ and related forms, says, "_Psamathia annae_, from Palau Islands, is related to _Cettia_, differing mainly in its much longer bill and legs." _Psamathia_ is a specialized bush-warbler and has followed a pattern of evolution which characterizes some of the other island birds in that the bill and legs are long and the wing is rather short and rounded. _Psamathia_ resembles many of the bush-warblers, as well as the reed-warblers {_Acrocephalus_); in general, body coloring being paler below and darker above. It differs from _Acrocephalus_ by having a longer tenth primary, smaller second and third primaries, only ten tail feathers, a more rounded wing, differently shaped nostrils, and by much softer plumage (the latter character is found also in _Collurcincla tenebrosus_ and _Cleptornis marchei_ of Micronesia). Rather than being related to the reed-warblers, as was supposed by Hartlaub and Finsch, _Psamathia_ seems closest to _Cettia_, especially to _Cettia_ (_Horeites_) _diphone seebohmi_ of the Philippine Islands. _Psamathia_ has a longer bill than this bird, but the general appearance and structure of the feet, tail, wing, body and bill are the same. =Acrocephalus luscinia luscinia= (Quoy and Gaimard) Nightingale Reed-warbler _Thryothorus luscinius_ Quoy and Gaimard, Voy. "l'Astrolabe," Zool., 1, 1830, p. 202, pl. 5, fig. 2. (Type locality, Marian Is. = Guam.) _Sylvia syrinx_ Kittlitz (part), Obser. Zool., in Lutké, Voy. "Le Seniavine," 3, 1836, p. 306 (Guahan); _idem_ (part), Denkw. Reise russ. Amer. Micron. und Kamchat., 2, 1858, p. 141 (Guaham). _Tatare luscinia_ Gray, Genera Birds, 3, 1849, App. 8 (Marian Is. = Guam); Hartlaub, Journ. f. Ornith., 1854, p. 167 (Mariannen = Guam); Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 14 (Ladrone or Marian Is. = Guam); Finsch, Journ. Mus. Godeffroy, 12, 1876, p. 31 (Guaham); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 41 (Guam); Büttikofer, Notes Leyden Mus., 14, 1892, p. 16 (Guam); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 7, 1895, p. 209 (Guam). _Tatare luscinius_ Bonaparte, Consp. Avium, 1, 1850, p. 224 (Guam); _idem_, Comptes Rendus Acad. Sci. Paris, 41, 1855, p. 1111 (Mariannes = Guam); Gray, Hand-list Birds, 1, 1869, p. 194 (Ladrone = Guam). _Hybristes_ [_luscinia_] Reichenbach, Syst. Avium, 1850, pl. 57, fig. 7 (no locality = Guam). _Acrocephalus orientalis_ Pelzeln, Reise, "Novara," Vögel, 1865, p. 64 (Guaham). _Tatares luscinius_ Giebel, Thes. Ornith., 3, 1877, p. 599 (Marianae). _Acrocephalus mariannae_ Tristram, Ibis, 1883, p. 45 (Type locality, Guam).