Note on the Type Specimen of the Maori Rat. By R. R. Marples, Department of Zoology, University of Otago. [Read by title and abstract before Otago Branch on April 13, 1954, received by Editor. April 26, 1954.] Abstract The native rat of New Zealand is a member of the exulans group of Pacific rats, and was described by Hutton as Mus maorium It was thought to be extinct but specimens hive recently been collected in various localities. The type skull in the Otago Museum has accordingly been remeasured for purposes of comparison. During the early stages of colonisation of New Zealand there were many reports of a native rat smaller than either Rattus rattus or Rattus norvegicus. Buller (1870) described a black rat as Mus Novae Zealandiae, but there seems no doubt that this was really R. rattus. The first description of the native rat was that of Hutton (1876) based on skulls from Maori cooking places at Shag Point, Otago. In this paper he merely referred to it as the Maori Rat, but later (1878) gave it the name Mus maorium. However, this has generally been accepted as a synonym for Rattus exulans (Peale) 1848. The exulans group of rats is found all over Polynesia. The differences between the populations from various parts of the range have been used by some authorities to form a series of species, while others merely divide the species R. exulans into a number of subspecies or racial groups. The native rat of New Zealand appears to have been very common at one stage, for there are reports of “plagues” of rats, some of which were identified as Mus maorium. Soon however, the native rat became considerably reduced in numbers and was thought to be extinct at least on the main islands. In recent year specimens have been collected from various islands off the North Island, and from Doubtful Sound and Notornis Valley in the South Island. Because of the increased interest in the native rat, and the meagreness of the published data, it was thought worth while to redescribe the type skull giving measurements which may be used in comparison with those of forms from other parts of the Pacific. The type skull is in the collections of the Otago Museum, and I am indebted to Dr. H. D. Skinner for permission to examine the specimens held. The box labelled as the type skull contains two skulls, one in poorer condition than the other, and two jaws. Both skulls have very similar measurements. The skull having the measurements nearest to those given by Hutton, which to judge from his paper may be averages, and which is the better specimen, is designated as the type Otago Museum Number A.54.6. The jaws resemble the type skull in appearance but cannot be certainly associated with it and so are not included in the table. The measurements are as follows: Length of jaw 20.8 mm; length of tooth row 5.4 mm. For comparison the measurements of two other skulls are included in the table. One was collected in a cave on Otago Peninsula associated