Nineteen species of gammaridean amphipod crustaceans are treated. Twelve species were obtained from terrestrial, fresh-water and brackish habitats of the Bismarck Archipelago. Of these, Melita latimeus sp.n., Parorchestia macrochela sp.n., P. similis sp.n.,
Brevitalitrus gen.n., B. dyaulanus sP.n. and B. wolffi sp.n. are described; Orchestia anomala Chevreux, Quadrivisio bengalensis Stebbing and Gandidierella bispinosa Schellenberg are redescribed, and further taxonomic notes are provided on Melita seticornis Bousfield, Parhyale hawaiensis Dana, Parorchestia pectenispina Bousfield and Cymadusa filosa Savigny. Examination of earlier material from adjacent Indo-Pacific Islands has revealed three additional new species, Orchestia samoana sp.n., Orchestia anoquesana sp.n., and Brevitalitus stephenseni sp.n., and resulted in the redescription of Orchestia floresiana Weber, 0. monospina
Stephensen, stat. nov., Brevitalitrus hortulanus (Calman), and further descriptive notes on Orchestia vitilevana Barnard, stat. nov. Keys to the Orchestia floresiana group and the species of Brevitalitrus are presented.