The tern found in the Hawaiians has the palest body and the most chalky-white forehead of any of the birds of the Pacific. Bryan (1903:101) found terns from Marcus Island to agree with specimens from Guam and to be "slightly darker" than birds from Midway and Laysan in the Hawaiian chain. The birds from the Riu Kius are darker and thus similar to the few specimens seen from Malaysia. Birds from Polynesia and Melanesia possess the most sooty underparts while those from Micronesia are only slightly less pale. This condition also seems to be true for the birds in the Australian area and for specimens seen from islands in the Indian Ocean. With fading, or wear, or both, there is a change from dusky black to dusky brown in the plumage; effort was made by me to compare specimens with relatively similar conditions of plumage. In summary, the systematic position of the Common Noddy Terns of the Pacific seemingly depends on the characteristics of specimens from the type locality in the Philippines. When topotypes are available for study, they may be found to be nearer the darker forms of Malaysia or may tend toward the paler, oceanic forms. The Hawaiian population probably is distinct. In Micronesia the Common Noddy Tern is not a conspicuous bird except during its breeding period. Probably it spends most of its life at sea, being unlike _Gygis alba_ in this respect. Large flocks seem less wary of man than are small groups and singles, which are often easily disturbed. Birds of this species appear to prefer the low atolls and offshore islets where both tall vegetation and bare ground are utilized for nesting or roosting. At Ponapé, Coultas (field notes) observed the birds to fly to sea at daybreak and to begin to return to their roosts by 4:00 pm. Wallace (field notes) observed similar activities at Kwajalein in May, 1944, where he saw approximately forty individuals in a flock with _Gygis alba_. _Anoüs stolidus_ is divided naturally into an Atlantic subspecies, which is distinguished by its browner color, and into several subspecies which are distinguished by their blacker color in the Pacific and Indian oceans. Whether the genus and species evolved in the Atlantic or in the Pacific region is not known. If it were the Pacific region, the center of differentiation may very well have been the islands of Oceania. There, relatively little variation is observable within populations covering a large area. To the eastward, birds along the American coast are darker or lighter, to the northward, the birds of Hawaii are paler, to the southward and southwestward, the birds are smaller and to the westward, the birds are smaller and darker. The virtual absence of ground-living, predatory animals which might prey on nesting colonies has probably been a reason for the lack of discrimination by this tern in selecting breeding sites. This is probably true of other birds which nest in colonies. =Anous tenuirostris marcusi= (Bryan) White-capped Noddy