Few fossil remains of rodents have been collected in Java until now, and they have received little attention. In the reports published during his paleontological researches in Java, Dubois twice records finds of Hystrix remains, viz., at Pati-Ajam in Japara (Anonymus, 1891, p. 12/13), and in the region between Bangle and Djeroek (Anonymus, 1893, p. 12). In a subsequent paper (Dubois, 1907, p. 454) we find mention of the presence of porcupines in the fossil fauna of Java, but in his review of the latter fauna Dubois (1908) bestows no words upon these rodents. The Selenka Expedition to Trinil secured one tooth, which was figured by Stremme (1911, p. 83, pl. XVI fig. 5) as a right M2 of a small species of Hystrix. Finally a tooth of Hystrix from Sangiran II was made mention of by Von Koenigswald (1934, p. 193). Among the material from prehistoric caves in the Padang Highlands, in Central Sumatra, which were explored by Dubois in the years 1888 to 1890 (Anonymus, 1889-90) teeth of porcupines are prevalent, and almost every tooth or bone in the Sumatran collection bears evidence of the gnawing habits of these animals. We possess hundreds of isolated porcupine teeth, but also a number of rami with the teeth in situ, and a few bones referable to the same animals. The recent porcupine of Java is regarded by modern authors as a subspecies of Acanthion brachyurus (L.) from the Malay Peninsula. The Sumatran form of Acanthion is intermediate in size, as in geographical position, between A. b. brachyurus (L.) and A. b. javanicum Cuvier; it is named Acanthion brachyurus longicaudum (Marsden) in the present paper.