_Puffinus obscurus obscurus_ Hartert, Novit. Zool., 7, 1900, p. 10 (Ruk); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 32 (Saipan, Ruk, Ponapé, Pelew). _Puffinus lherminieri minor_ Mathews, Birds Australia, 2, 1912, p. 70 (Pelew, Carolines). _Puffinus assimilis minor_ Mathews, Syst. Avium Australasianarum, 1, 1927, p. 111 (Pelew). _Puffinus lherminieri dichrous_ Murphy, Amer. Mus. Novit., no. 276, 1927, p. 10 (Pelews, Carolines); Peters, Check-list Birds World, 1, 1931, p. 60 (Pelew); Yamashina, Tori, 7, 1932, p. 408 (Arakabesan); Hand-list Japanese Birds, rev., 1932, p. 188 (Saipan, Truk, Ponapé, Palaus); Hand-list Japanese Birds, 3rd ed., 1942, p. 209 (Saipan, Truk, Ponapé, Palau); Mayr, Birds Southwest Pacific, 1945, p. 10 (Carolines, Palaus); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 37 (Palau). _Alphapuffinus lherminieri minor_ Mathews, Novit. Zool., 39, 1934, p. 182 (Pelew Islands). _Puffinus obscura_ Bryan, Guam Rec., vol. 13, No. 2, 1936, p. 15 (Guam). _Geographic range._--Known from Phoenix, Nauru, Micronesia, and south to the Samoan, Society, Tuamotu, and Marquesas islands. In Micronesia: Mariana Islands--Guam, Rota, Saipan; Palau Islands--Babelthuap, Koror, Arakabesan; Caroline Islands--Truk, Ponapé, Kusaie. _Characters._--A small shearwater with upper parts sooty-black; under parts white except for sides of breast grayish and under tail-coverts blackish; bill blackish; feet yellowish, outer toe black. _Measurements._--Measurements of 17 adult birds (9 males, 7 females, 1 unsexed) from Micronesia (Palau, Truk, Ponapé, Kusaie) and 10 adult birds (6 males, 4 females) from the Phoenix Group (Enderbury, Canton) are listed in table 14. TABLE 14. MEASUREMENTS OF _Puffinus lherminieri dichrous_ ===========+=============+============+==============+============== LOCALITY | Wing | Tail |Exposed culmen| Tarsus -----------+-------------+------------+--------------+-------------- Micronesia |203 (197-211)|83.6 (77-89)| 27.9 (26-30) |38.5 (37.5-40) Phoenix |197 (193-203)|82.2 (79-85)| 26.3 (25-28) |37.2 (36-39) -----------+-------------+------------+--------------+-------------- _Specimens examined._--Total number, 72 (44 males, 19 females, 9 unsexed), as follows: Palau Islands, AMNH--exact locality not given, 64 (Oct., Nov., Dec.); Caroline Islands, AMNH--Truk, 4 (June 15, 16)--Ponapé, 3 (undated)--Kusaie, 1 (April 25).