Anatomically well preserved fertile and vegetative remains of Glyptostrobus rubenosawaensis sp. nov. (Coniferae-Taxodiaceae) have been recovered from silicified lacustrine deposits of the late Middle Miocene Shimokawa Group near Shimokawa Town, Kamikawa district, Central Hokkaido. Vegetative remains include shoots bearing polymorphic leaves. Fertile remains include seed and pollen cones. The fossil remains closely resemble living Glyptostrobus pensilis (D. Don) K. Koch in gross morphology, but differ in possessing larger cones and a prominent abaxial projection of the bract. Previous reports of fossil Glyptostrobus were limited to compression floras. This report is the first to use permineralized remains to reconstruct fossil Glyptostrobus and document the internal anatomical features of the genus to allow meaningful comparison with the living representative, G. pensilis. Abundant remains of Glyptostrobus indicate wetland as the paleoecological setting, based on the cooccurrence of wetland taxa such as Decodon (Lythraceae), Osmunda and Alnus, and mountainous taxa such as Picea and Tsuga, and using permineralized plant fossils. We can reconstruct an ecological setting in a lake.

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Nine species of orthoconic cephalopods have been described from Moscovian (Carboniferous) limestone of the Guizhou and Guangxi region, South China. The fauna is composed of four orthocerids : Bogoslovskya guizhouensis sp. nov., Mericoceras guangxiense sp. nov., Mericoceras sp., and Mimogeisonoceras? sp. and five bactritids : Bactrites faqingensis sp. nov., Bactrites cf. nagatoensis Niko, Nishida and Kyuma, Bactrites sp., Ctenobactrites? sp., and Sinobactrites wuae gen. et sp. nov. The new parabactritid genus Sinobactrites is diagnosed by its relatively small angle of shell expansion, oval cross section, and abruptly recurved septal necks. It is noteworthy that the assemblage includes species closely related to some of the Akiyoshi fauna.

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The Sagara Fauna has been regarded as the Middle Miocene to Early Pliocene warm-water molluscan faunal unit in Southwest Japan. Descriptive works, however, have not been enough to discuss the faunal succession in the type section of the Sagara Fauna. This paper reports a molluscan assemblage from shell-concentrated beds in the lower part of the Sagara Group, Shizuoka Prefecture, giving systematic descriptions of the representative species. This assemblage is composed of molluscs transported from shelf depths, such as Phos, Olivella, Megacardita, and Glycymeris. The shell beds are placed in Zone N14 of Blow's planktonic foraminiferal zonal scheme in which the late Middle Miocene global warming condition has been recognized as the Climatic Optimum 2. The warming evidence in Japan is the appearance of tropical to subtropical molluscs from the Kukinaga Group in Tanegashima Island. The molluscan assemblage reported here represents a warm temperate molluscan fauna in the paleo-Kuroshio realm. Moreover, it is noteworthy that the last appearance of the Early to Middle Miocene relict elements and the first appearance of some living species are recognized in this assemblage. This supports a division of the so-called Sagara Fauna into the middle to late Middle Miocene Kukinaga Fauna and the Late Miocene to Early Pliocene Zushi Fauna. We define the Sagara Faunule for the fossil assemblage from the lower part of the Sagara Group, which lived in the warm-temperate region in Southwest Japan during the Climatic Optimum 2.

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A new fossil conifer, Frenelopsis pombetsuensis sp. nov., is described on the basis of a single specimen obtained from the Lower Cretaceous (Albian) of Hokkaido, Japan. Frenelopsis pombetsuensis is similar to F. choshiensis from the Lower Cretaceous of Choshi, Kimigahama, in having two leaves at each node. The cuticular feature of Frenelopsis pombetsuensis is, however, rather more similar to that of F. hoheneggeri from the Lower Cretaceous of Poland than to F. choshiensis. The Late Jurassic to Early Cretaceous paleofloras of Japan have been divided into two distinct types : the Ryoseki and Tetori. However, attributions of the Early Cretaceous flora of Hokkaido have not been made because of its hitherto poorly-known fossil record. The genus Frenelopsis is one of the most important members of the Ryoseki-type floras and has never been found in the Tetori-type floras. The present fossil is the first record of characteristic taxon of the Ryoseki-type flora from the Lower Cretaceous of Hokkaido.

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The geometry of the commarginal shell sculpture and internal microgrowth pattern in 82 species of the Bivalvia were analyzed both theoretically and empirically. Two major categories were recognized in the geometry of internal microgrowth increments; 1) the regular type, which consists of regularly arranged curves, being mutually parallel in the sections and maintaining their morphology during growth independent of the sculpture pattern, and 2) the undulated type, with undulated microgrowth increments along the folds of prominent sculpture. For the former category, geometric patterns of the sculpture and increments of actual specimens were well reproduced by computer simulations under the condition that the sculpture is originated by mantle extension and shrinkage. In the latter case, mantle bulging or bending appears to produce a plicated shell folding, although sculpture formation cannot be simulated by the model adopted in this study.

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Specimens of Tuscaridium cygneum (Murray), the eurybathyal phaeodarian Radiolaria, from the eastern temperate North Pacific Ocean were enclosed in an intricate latticed sphere in in situ samples. Scanning electron microscopy revealed unique microstructures on the shells of individual radiolarians and on the spheres. Although the function and significance of the enclosing spheres are unknown, colonies of these deep-dwelling, bioluminescent phaeodarians may be common in the world's oceans.

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In this paper a fairly well-preserverd ammonite is shortly described to show its interesting characters. It is provisionally referred to Bhimaites and regarded as a new species. Since it is small even at the adult stage and has a probable trace of lappet, it may represent a microconch of a dimorphic pair. It was found solely from the upper part of the Albian in the Soeushinai area of Hokkaido. More material is, however, required to clarify the extent of variation, to confirm the idea of dimorphism and to know the stratigraphic range and geographic distribution of this species.

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