_Remarks._--There are no records for the Black-naped Tern from the Mariana Islands, although the species is known from the Palau, Caroline and Marshall Islands. At Ulithi Atoll, the NAMRU2 party observed these terns at the islands of Potangeras, Mangejang, Pau, and Losiep in August, 1945. They were found in groups of 4 to 15, either sitting on sandy beaches or rocky exposures or flying over the reefs. Unlike the Crested Tern, these birds appeared quite unafraid of man and would hover over a freshly killed or wounded individual of their own kind, making of themselves easy targets. The writer saw only one Black-naped Tern at the Palau Islands (Peleliu, on September 16, 1945). The birds seem to prefer the "low" atolls to the "high" volcanic islands of Micronesia. Two subspecies of _Sterna sumatrana_ are recognized by Peters (1934:336): _Sterna sumatrana mathewsi_ known from islands of the western Indian Ocean and _Sterna s. sumatrana_ from islands of Oceania, Australia, Malaysia, and China coast. There is a considerable area separating these subspecies. For populations in the Pacific area, other names which have been proposed are _Sterna sumatrana kempi_ Mathews for birds from Torres Straits and _Gygis decorata_ Hartlaub for birds from the Fiji Islands. A study of 201 specimens of this species from various parts of its range (in the collections of the American Museum of Natural History and the United States National Museum) shows that there is little color variation within the species. This observation is the same as that of Mathews (1912:372). As listed in table 19, measurements of the length of the wing show little variation. The length of the tail of birds from localities more remote from the continent of Asia (Micronesia, Phoenix, Union, Fiji, Samoa, Tonga, and the islands of the Indian Ocean: Aldabra and Providence) is, on the average, shorter than the length of the tail of birds from islands nearer the Asiatic mainland. This shortness is reflected also in the measurement of the difference between the shortest and longest tail feather. TABLE 19. MEASUREMENTS OF SPECIMENS OF _Sterna sumatrana_ Columb headings: A: No. B: Wing C: Tail D: Difference: Longest and shortest tail feather E: Exposed culmen F: Tarsus