Rattus exulans in Western Samoa

THE COMMON RAT of Polynesia is Rattus exulans (Peale). It appears to be closely related to, and ptobably derived from Rattus concolor of the Malay region. The concolor group, and its derivatives, occur all over the Pacific, being represented in the Oceanic islands by R. exulans, R. micronesiensis and R. hawaiiensis. Other species have been erected for the Polynesian forms, but it may be simpler to regard these as synonymical with R. exulans at least until larger series have been collected. Tate (1935) lists as synonyms of R. exulans (Peale): Mus exulans Peal 1848: Tahiti Mus vitiensis Peale 1848: Fiji Mus maorium Hutton (1878) 1879: New Zealand Mus jessook Jentink 1879: New Hebrides Mus huegli Thomas 1880: Fiji. Rattus hawaiiensis Stone (1917) has been erected mainly on colour differences, but the individuals appear to be of a smaller general size though with larger skulls than the Samoan specimens. This form may not require specific rank, but is widely sccepted as differing from R. exulans. R. micronesiensis Tokuda (1933) is also a different form. Mostof theworkonR. exulanshas been done on preserved specimens and, though a large number of individuals have been examined, these form only very shorr series from anyone locality. An attempt was made, therefore,