Cephalopod species previously described from the Middle Ordovician Jigunsan Formation of Duwibong type Joseon Supergroup of Baegunsan Syncline, Kangweondo in Korea were re-examined taxonomically based on the type and figured specimens and newly collected ones. Three species, Holmiceras coreanicum (Kobayashi, 1927), Sactorthoceras makkolense (Kobayashi, 1927), and Kotoceras grabaui (Kobayashi, 1927) are described. Each species was restudied and compared with closely related species described by Kobayashi (1927, 1934); respective lectotypes are also designated herein. In this study, Sigmorthoceras coreanicum, based on its sigmoidally curved conch, was identified as belonging to Holmiceras which is characterized by the early loosely gyroceraconic shell portion. Sinuitopsis kochiriensis, previously identified as an Ordovician gastropod, is a juvenile shell of H. coreanicum, judging by the number of the volutions and prominent shell surface. Three species belonging to Sactorthoceras and also Cycloceras taihakuense were regarded, based on the existence or nonexistence of the preserved shell and the imploded internal structure, as junior synonyms of Sactorthoceras makkolense in a broad sense. Kotoceras frechi was rejected as an invalid taxon, since its septal angulation, broader siphuncle and rapid expansion of the conch are characteristics caused by secondary deformation.

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Bulk sieving of samples from the Ashizawa Formation, Futaba Group (lower Coniacian) of northeastern Honshu, Japan, has yielded a well-preserved plant mesofossil assemblage comparable to those recently described from eastern North America, Europe and central Asia. The most distinctive component of the assemblage is a new species of the genus Esgueiria (Esgueiria futabensis sp. nov.), a fossil flower known previously only from the Upper Cretaceous (Campanian-Maastrichtian) of Portugal. A possible additional species of the genus has also been recovered from a second mesofossil assemblage in the Tamayama Formation (lower Santonian). The occurrence of Esgueiria in Europe and eastern Asia during the Late Cretaceous indicates that despite the vegetational differences between these areas inferred from fossil pollen, some elements were widespread across middle paleolatitudes, presaging the strong floristic similarities among mid-and high latitude regions of the Northern Hemisphere during the early Tertiary.

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The following three species of the Boreal-type brachiopod genus Yakovlevia are described from the Middle Permian (Kungurian to Ufimian) of the Hida Gaien (=Hida Marginal) and South Kitakami Belts, Japan : Y. kaluzinensis Fredericks, Y. mammata (Keyserling) and Y. mammatiformis (Fredericks). The occurrence of Yakovlevia together with various Boreal-and Tethyan-type brachiopods in the Middle Permian of the two belts suggests that these regions were probably a continental shelf at the eastern margin of the Sino-Korean block in Middle Permian time.

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Fossil and Recent Macoma (Rexithaerus) of the northwestern Pacific consist of the following three species : Macoma (Rexithaerus) hokkaidoensis sp. nov., M. (R.) sectior Oyama and M. (R.) shiratoriensis (Matsubara). Among them, the first species, which is new, is characterized by an elongate shell shape and a low pallial sinus, and is now living in the sea around Hokkaido, Kunashiri Island, Aniva Bay of Sakhalin, Peter the Great Bay and Ussuri Bay of Primorye. The oldest species, M. (R.) shiratoriensis appeared in subtropical waters in the late early Miocene. The Recent and allied species, M. (R.) sectior and M. (R.) cf. hokkaidoensis first occurred in middle Miocene deposits. From the middle Miocene to early Pleistocene, the subgenus was confined to the mild-to cool-temperate realm. In the Holocene, M. (R.) sectior has extended its range to subtropical waters, while M. (R.) hokkaidoensis now inhabits the cool-temperate to subarctic waters.

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Three species of the genus Mariella (Turrilitidae) from the Lower Cenomanian (Cretaceous) of Hokkaido are described. They include the two widespread species, M. (M.) dorsetensis (Spath, 1926) and M. (M.) oehlerti (Pervinquiere, 1910). The third species, M. (M.) pacifica sp. nov., is somewhat similar to but distinguished from M. (M.) oehlerti. It is also compared with some other species. The problem of dimorphism in the turrilitid ammonoids is discussed.

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The highly sporadic fossil record of freshwater crayfish is improved by the discovery of several new specimens from the Upper Jurassic Jehol Group of Liaoning Province, north-east China. As a result of work on this material, the Family Cricoidoscelosidae is erected to accommodate specimens possessing highly atypical features among the Infraorder Astacidea belonging to the new genus and species Cricoidoscelosus aethus. Furthermore, Astacus spinirostrius Imaizumi (1938) is synonymized with A. lincenti van Straelen (1928b) and is moved from the Family Astacidae to the family Cambaridae and to the new genus Palaeocambarus. Thus, a solution is suggested to the problematic biogeographic issue of the presence of the genus Astacus in a region presently occupied only by cambarid crayfish, a generic assignment that was made tentatively in the first place. In addition, new questions now arise with respect to the origins and early development of crayfish in the Asiatic region and perhaps even globally.

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