The bivalve fossils collected by Japanese-Norwegian research groups from the Kapp Starostin Formation in west Spitsbergen are described. They comprise fourteen species belonging to the Pterioida and two species of the Arcoida. Among them, six species, including two that are indeterminate, are newly described. They are Grammatodon (Cosmetodon)? suzukii, G. (C.)? sp. ind., Streblochondria winsnesi, Vorkutopecten svalbardensis, Deltopecten sp. ind., and Palaeolima nakamurai. The fauna belongs to the Boreal bioprovince, but a single species, Cassianoides sexcostatus (Stuckenberg) has also been reported from the Central Rocky Mountains of the United States. The bivalve fauna suggests an Artinskian-Kungurian age for the Kapp Starostin Formation. This is somewhat earlier than the age deduced from brachiopods and bryozoans, but it is not decisive because the materials are poor. The Kapp Starostin Formation is conformably overlain by the Otoceras-bearing, earliest Triassic Vardebukta Formation, so a time-gap corresponding at least to the Dorashamian and Dzhulfian (=Tatarian) is inferred between the two formations.

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The morphology of a mandibular fragment with a left lower molar discovered in the "Upper Formation" (upper Cenomanian-lower Turonian) of the Mifune Group in central Kyushu, southwestern Japan, suggests that this fossil should be assigned to a new species of Late Cretaceous mammal, Sorlestes mifunensis sp. nov. (Infraclass Eutheria; Order Proteutheria; Family Zhelestidae). S. Mifunensis is the oldest zhelestid yet recorded. Some workers suggest that the Zhelestidae have a close affinity with ungulates. A detailed comparison between the lower molar of the new species and those of ungulates supports this suggestion. The comparison also suggests that the Zhelestidae have a closer affinity with ungulates than the Zalambdalestidae and other contemporary mammals, and that S. mifunensis has a relatively primitive character within the Zhelestidae. This comparison leads us to revise the diagnoses of the family Zhelestidae and of the genus Sorlestes. The unique character of the entoconid-hypoconulid twinning seen in the Zhelestidae was probably caused by the movement of the hypoconid (the presumed first single talonid cusp seen in the first therian Kuehneotherium) to the buccal side, far away from the other talonid cusps. This twinning pattern is distinct from the twinning pattern seen in marsupials.

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A new fossil conifer, Pseudofrenelopsis glabra sp. nov., (Cheirolepidiaceae) is described based on a single specimen obtained from the Lower Cretaceous Yezo Group (Albian) of Hokkaido, Japan. The new species is characterized by cuticle possessing thin periclinal walls, a well-developed hypodermis, and absence of trichomes on internode and outer leaf surface. Recently, the author described Frenelopsis pombetsuensis from the Lower Cretaceous Yezo Group (Albian) of Hokkaido. The family Cheirolepidiaceae is a diagnostic taxon of the Ryoseki-type element that is reported only from the Ryoseki- and the Mixed-type floras. Thus Pseudofrenelopsis glabrais the second evidence of the Ryoseki-type element from Hokkaido.

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Several small specimens collected years ago by A. I. from a locality in the Soeushinai area of Hokkaido are now identified as Mesoturrilites boerssumensis (Schluter, 1876). The species has been reported from the Lower Cenomanian of western and central Europe and western Asia. Our material is also referred to the Lower Cenomanian on the biostratigraphic evidence. This may be the first record of Mesoturrilites in the northern Pacific region.

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Six species of uncoiled cephalopod, including the actinocerids Actinoceratidae, gen. and sp. indet., Armenoceras banestanense sp. nov., A. sp., Elrodoceras sp. and Huroniella iranica sp. nov., and an orthocerid Proteoceratidae?, gen. and sp. indet., are present in collections made recently from an unnamed formation near Banestan village in the Kerman area of southern East-Central Iran. The cephalopod fauna contains forms closely related with those from Laurentia, and is considered to be of Early Silurian age. This discovery reveals that the geologic age of these cephalopod-bearing horizons should be revised from a vague late Ordovician or early Silurian one. These horizons are correlative with the Niur Formation in the Shirgesht area of northern East-Central Iran.

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Two species of Carboniferous coral, Arachnastraea manchurica and Diphyphyllum delicatum, are described for the first time from the upper part of the Geumcheon Formation of the Danyang area, Korea. They were previously reported as Devonian corals, Disphyllum sp. and Phillipsastraea sp. Associated fossils are fusulinids, including Beedeina schellwieni, B. siviniensis, B. samarica, B. sp., Fusulina cylindrica, F. sp., Fusulinella mosquensis, Fusulinella provecta, Neostaffella sphaeroidea, and Ozawainella turgida. Occurrence of these corals and fusulinids suggests that the upper part of the Geumcheon Formation is middle Moscovian in age.

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The relation between growth rings and reproductive cycle in a dimorphic pectinid bivalve, Cryptopecten vesiculosus (Dunker, 1877) was examined histologically on the basis of semi-regularly collected samples from Sagami Bay. This pectinid is hermaphroditic. Male and female gonads ripen between June and September, and spawning occurs during July to November. A strong growth ring is formed just before spawning, and the first ring indicates that the specimens has reached the stage of sexual maturity. This means that growth rings are formed once a year after the individual reaches sexual maturity. No visual difference was detected in the gonad development between the two phenotypes; their gonadal weight indices are statistically identical throughout the year. Therefore the previous interpretation that the dimorphism represents discontinous intrapopulational variation is upheld. The results of this study are applicable to life history analysis in extant and fossil populations.

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