Mr. Oldfield Thomas has described in the Journal of the Asiatic Society of Bengal, 1888, p. 256, a very interesting and aberrant Pteromys-form under the name Eupetaurus cinereus. He remarked that in the Leyden Museum were not improbably a melanoid and a normal example of this species. This supposition he based upon quotations by Anderson in his well known »Yunnan Expedition”. As the species under consideration seems to be a very rare one, at least in zoological collections, it has its interest to know if the two named specimens in the Leyden Museum really belong to E. cinereus and — if so — how far the characteristics given by Thomas are constant.