Cellana exarata and Cellana sandwicensis grow to shell lengths of over 40 mm in one year. Increase in shell length is 4-5 mm per month until sexual maturity and then slows down to 2-3 mm per month. Life spans of both species are less than 1.5 years. Absolute body weight increase per month increases throughout life in both species, but the rate of increase slows after sexual maturity is reached. Shells of C. sandwicensis are lower in height and heavier than shells of C. exarata, perhaps due to their more wave-exposed habitat.

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[in Japanese]

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Karyotypes in four species of Septifer have been studied. In both Septifer (Septifer) bilocularis and S. (S.) excisus, a chromosome number of 26 (2n) was counted, and karyotypes of both consisted of 5 pairs of meta- or submetacentrics and 8 pairs of subtelo- or telocentrics. In both Septifer (Mytilisepta) virgatus and S. (M.) keenae, chromosome numbers of 28 (2n) and 14 (n) were counted, and the karyotypes each consisted of 7 pairs of meta- or submetacentrics and 7 pairs of subtelo- or telocentrics.

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Five species of the genus Mundiphaedusa (Clausiliidae) are discussed in viewpoint of morphology of shell, clausilium and genitalia. They are three species (M. sericina, M. decussata and M. yagurai) from Kanto District and two species (M. kurozuensis and M. pachyspira) from Kii Peninsula of Honshu.

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Observations of shell morphology of veliger larvae and juveniles of Turbo (Batillus) cornutus are made under a scanning electron microscope (SEM). A larval shell is discoidal with a trumpet-shaped aperture and a sculptured surface. After settlement, a postlarval shell is formed discoidally for a first whorl, and then becomes conispiral with a large umbilicus. It is observed that daily growth checks occur on the postlarval shell.

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