Molluscan fauna of the "Miocene" Maejima Formation is examined from taxonomical, biostratigraphical and paleozoogeographical points of view. It is composed of four gastropods and 14 bivalves including a new species. Two assemblages, the Isognomon and the Megangulus-Acila assemblage, were discriminated. The Isognomon assemblage is autochthonous or para-autochthonous and is composed of elements inhabited the littoral to upper sublittoral gravelly to rocky bottom in a warm sea. The Megangulus-Acila assemblage represents a mixed composition between muddy sand and gravelly to rocky bottom elements, and was formed in an upper sublittoral muddy bottom near a rocky shore. Occurrences of Megangulus maximus (Nagao), Isognomon (Hippochaeta) hataii Noda and Furuichi and Chlamys (Leochlamys) namigataensis (Ozaki) indicate the age of the Maejima Formation as the Paleogene, not the Miocene. The molluscan fauna of the Paleogene Maejima Formation contains both Tethyan Indo-Pacific elements and Northern Pacific elements. Taxonomy of selected molluscan taxa including a new arcid, Arca (Arca) uedai sp. nov., is described or discussed.

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In subsurface sections of the Yufutsu-Umaoi district, Hokkaido, northern Japan, three Eocene benthic foraminiferal assemblage zones were defined in the Ishikari Group and the overlying Poronai Formation. They are in ascending order : Evolutinella subamakusaensis-Haplophragmoides crassiformis Assemblage Zone, Globocassidulina globosa-Cribroelphidium sorachiense Assemblage Zone, and Bulimina schwageri-Angulogerina hannai Assemblage Zone. Assemblages characterizing each zone indicate the littoral to the inner sublittoral, middle sublittoral, and outer sublittoral paleobathymetric zones, respectively. A foraminiferal fauna in the upper bathyal zone was also identified based on reinterpretation of previous studies. It is composed of calcareous species such as Gyroidina yokoyamai and Plectofrondicularia packardii. Abundant occurrences of agglutinated foraminifera in shallower paleoenvironment suggest brackish and related stratified-water paleoenvironments caused by freshwater input into an embayment called the "Poronai Sea". Such stratified conditions in coastal shallow marine areas may have formed oxygen-depleted zones as suggested in the previous study. These data and their paleoenvironmental implications are expected to furnish a basis for further consideration on geohistory of the Paleogene formations and also on the Eocene foraminiferal fauna of the northwestern Pacific.

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The feeding strategy of cetothere from the Toyama and Akeyo Formations is discussed based on the mandibles of two individuals. Three synapomorphic characters in the mandible that are shared with balaenopterid whales (a laterally projecting coronoid process, a marked inward elevation at the dorsal edge of the ramus posterior to the coronoid process, and a sharply edged ventral margin on the middle part of the mandible) suggest that some cetotheres had already acquired an engulfment feeding mechanism by the late Early Miocene. Two other apomorphic characters (a quite high and elongated dorsal mandibular ridge and a ventrally well-projected mandibular angle) suggest robust development of the musculature of the mandible during the feeding process in the studied specimens in contrast to the weak development of the musculature in the balaenopterids. This may represent a primitive transitional stage of the engulfment feeding mechanism which could be related to the lack or poor development of highly elastic elements in the ventral pouch.

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Twenty-seven ostracode species from the Inter-trappean beds (Paleocene) of Duddukuru, West Godavari District, Andhra Pradesh, east coast of India are recorded and/or described. Nine species -Cytheromorpha godavariensis, Cytherura duddukuruensis, Hapsicytheridea undulata, Krithe bhandarii, Paracandona andhraensis, Munseyella indica, Neomonoceratina paraoertlii, Semicytherura diluta, and uroleberis rasilis- are new. The identification of 6 species, previously described from the east coast of India, and also recorded in this work, are revised. The stratigraphic distribution, age and affinity and paleoecology of the ostracode fauna are also discussed.

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Two species of fossil decapods, Maja tomidai sp. nov. and Daldorfia sp. are described from the latest Miocene Senhata Formation of the Boso Peninsula, central Japan. The former species resembles Maja morii Kato from the middle Miocene of Japan and Maja dominoleuae Hu and Tao from the late Miocene of Taiwan. A large palm of Daldorfia sp. is the third fossil record of the genus from Japan. The discovery of Daldorfia sp. supports the existence of subtropical to tropical marine conditions in the latest Miocene of the Boso Peninsula indicated previously by molluscan evidence.

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Six species of the genus Rectobolivina (benthic foraminifera), R. asanoi, R. bifrons, R. clavata, R. discontinuosa, R. raphana and R. striatula from the Late Cenozoic Miyazaki Group of southwestern Japan were taxonomically studied, particularly focusing on internal test morphology. Two new species of Rectobolivina, R. clavata and R. discontinuosa, and one new replacement name, Rectobolivina clavatostriatula, are proposed. Scanning electron microscopic and optical microscopic observations of dissected specimens and thin sections reveal that the chamber wall of the genus Rectobolivina is bilamellar, and that the toothplate is an extension of the chamber wall, a twisted plate strongly folded at both edges and connecting successive foramina. The toothplate constantly attaches with one of its sides to the axial side of the inner margin of the preceding foramen. It exhibits a lamellar structure, showing that the extension of the outer lamella of the chamber wall is covered by two thin inner lamellae on both axial and peripheral sides. The six species of Rectobolivina display a clear stratigraphically separated distribution during the period from latest Miocene to earliest Pleistocene.

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