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A trilobite collected by Hideo Ishida in the Tsunemori formation at Hinaga, Omine town, Mine city, Yamaguchi Prefecture is an imperfect internal cast of a pygidium. Nevertheless it is particularly interesting as it indicates a new late Permian trilobite horizon in the non-calcareous facies in West Japan. The formation consists mainly of black mudstone and frequent alternation of fine sandstone and shale in addition to small limestone lenses. Its lower part ranges from the Para f usulina ambigua zone to the Colania douvillei zone and its upper part from the Lepidolina multiseptata shiraiwensis zone to a little higher horizon. Therefore the upper part from which the specimen was collected belongs to the Kuma series and the trilobite is early Upper Permian in age. Except for an imperfect Permo-Carboniferous griffithid pygidium from Minno, Osaka Prefecture, all other Permian trilobites from Southwest Japan were obtained from limestones. The latest species in Japan is Pseudo phillipsia (Nodiphillipdia) hanaokensis Kobayashi and Hamada, 1984 from the Richelina changhsingensis zone at the top of the Akasaka limestone, Gifu Prefecture. Therefore this is really an exceptional occurrence of a trilobite in elastic facies in West Japan. This pygidium in Fig. 1 is ovate or roundly subtriangular, a little broader than long and well inflated; its lateral margins gently arcuate and meeting each other to form round posterior margin; axial lobe about one-fourth as wide as pygidium, longiconic, strongly convex, high up above pleural fields, composed of 9 to 10 rings besides a small terminal piece; axial furrow well developed; pleural lobe arching down from the furrow to lateral border and divided into 7 or 8 ribs by broad but shallow pleural furrows; marginal border narrow and depressed. A small part of the lateral border is preserved on the left side of the pygidium. The left pleural lobe is so strongly compressed laterally that the lobe is elevated much higher thann the other lobe. A narrow ridge appears to cross the pleural ribs and furrows rectangularly in the left pleural lobe, but it may be a secondary product, as it cannot be recognized in the right pleural lobe. Now 22 species in 11 genera of the Permian trilobites are known from Japan (Kobayashi and Hamada, 1984b), but none is comparable to this pygidium. As summarized already in 1984, the late Permian i.e. Tatarian or Dzhulfian trilobites possibly including some late Middle Permian ones are reported from Tunisia, Jugoslavia, Caucasus, Armenia, Iran, Pakistan, Himalaya, China (Xizang, Sichuan, Guizhou, Guangdong), Japan, Primoria, USSR (Grant, 1966; Lu, 1974; Hahn and Hahn, 1981; Hahn et al. 1984; Qian, 1977, 1981; Termier et Termier, 1974; Weber, 1944; Yin, 1978; Zhou, 1977) and probably from Laos (Mansuy,

A late Permian trilobite from Yamaguchi Prefecture with a note on the contemporaneous trilobites in Eurasia.