The discovery of this remarkable animal, which makes such an interesting addition to the several genera of giant rats described from New Guinea, and represented so far in the Solomons by the genus Cyromys on Guadalcanar, has resulted from the very keen collecting activities of Rev. J. B. Poncelet, S.M., of the Catholic Mission at Buin, in the south of Bougainville Island. During a visit to the Museum early in 1934, Father Poncelet made enquiries regarding collecting possibilities on the island, with the result that his generous offer to make a representative collection for the institution was gladly accepted, and the necessary instructions and equipment supplied. The energetic and thorough methods of the collector may be gathered from the fact that several carefully tabulated collections of insects, fishes, reptiles, and mammals have already been received, of such numbers and variety that considerable time must elapse before the material can be thoroughly worked out. Particular attention has been devoted by Father Poncelet to the mammals, included in which are several rats not hitherto recorded from Bougainville, and species of large and small bats, to be dealt with in a following paper. In dealing with this outstanding novelty at the earliest opportunity, comparison with Cyromys, probably the nearest ally in form as well as habitat, has been prejudiced by the lack of illustration or adequate description of the dentition of both species of that genus. When one notes how simply and clearly the accompanying photos, by the Museum photographer, Mr. G. C. Clutton, illustrate diagnostic features such as the length and sparseness of the coat, tail and foot structure, and dentition, it is astonishing to realize that most of the Australasian mammals described abroad have been denied any form of illustration whatever. One can only hope that all future work upon the mammals, and fauna generally, may provide illustrations where necessary to amplify the usual brief descriptions.