_Sterna bergii cristata_ Stresemann, Novit. Zool., 21, 1914, p. 58 (Truk). _Thalasseus bergii pelecanoides_ Oberholser, Proc. U. S. Nat. Mus., 49, 1915, p. 523 (Marshall Islands); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 51 (Luganor, Nukuor, Ruk, Ponapé, Marshall Islands); Kuroda, Avifauna Riu Kiu, 1925, p. 188 (Marshall Islands); Hand-list Japanese Birds, rev., 1932, p. 194 (Palau, Faraulep, Truk, Lukunor, Nukuoro, Ponapé, Jaluit, Mille, Aurh, Maloelab, Ailuk); Yamashina, Tori, 10, 1940, p. 677 (Helen Reef, Babelthuap); Hand-list Japanese Birds, 3d ed., 1942, p. 218, (Babelthuap, Helen Reef, Faraulep, Truk, Lukunor, Nukuoro, Ponapé, Jaluit, Mille, Aurh, Maloelab, Ailuk). _Thalasseus bergii cristatus_ Peters, Check-list Birds World, 2, 1934, p. 342 (Carolines, Marshalls); Mayr, Birds Southwest Pacific, 1945, p. 26 (Micronesia); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 55 (Peleliu, Ngajangel [Kayangel], Truk). _Geographic range._--Malaysia and east coast of Australia south to Tasmania, east to Melanesia and Polynesia, north to Phoenix Islands and Micronesia (see figure 11). In Micronesia: Palau Islands--Helen Reef, Peleliu, Babelthuap; Caroline Islands--Ulithi, Truk, Faraulep, Lukunor, Nukuoro, Ponapé; Marshall Islands--Jaluit, Mille, Aurh, Moloelab, Ailuk, Bikini. _Characters._--Adult: A large, white tern with back, rump, tail, wing-coverts, wing, and axillaries pearl gray; outer edges of primaries pearly grayish-black; crown black with crest; bill greenish-yellow with blackish base; feet black. Crown black, mottled with white and mantle paler in postnuptial plumage. Immature: Resembles adult, but crown and back dark, mottled with white and crest small. _Measurements._--Measurements of Crested Terns of the Pacific area are listed in table 20. _Specimens examined._--Total number, 10 (6 males, 4 females), as follows: Caroline Islands, USNM--Ulithi, 1 (Aug. 21); AMNH--Truk, 2 (May 7, Dec. 5)--Ponapé, 3 (Nov. 1, 7); Marshall Islands, USNM--Bikini, 4 (March 4, 11, 12). _Parasites._--Uchida (1918:483, 488) obtained the following species of bird lice (Mallophaga) from the Crested Tern at Ponapé: _Docophorus albemarlensis_ and _Colpocephalum importunum_. _Remarks._--Oberholser (1915:520-526, pl. 66) lists five subspecies (_T. b. cristatus_, _T. b. halodramus_, _T. b. pelecanoides_, _T. b. rectirostris_, and _T. b. poliocercus_) in the region including the coast of China, the Riu Kiu Islands, Malaysia, Melanesia, eastern Australia, Polynesia, and Micronesia. Only one subspecies, _T. b. cristatus_, is recognized in this area by Stresemann (1914:58), Hartert (1921:1695-1696), and Peters (1934:341-342), who mention that there is much variation in size and coloring. TABLE 20. MEASUREMENTS OF _Thalasseus bergii_ IN THE PACIFIC AREA