[in Japanese]

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[in Japanese]

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Calcinus latens is the hermit crab widely distributed in the Indo-Pacific region. Many authors have reported that C. latens uses gastropod shells having regular whorls and showing regular conical shape, however I found in a coral reef of Guam that many individuals of C. latens used shells of irregular whorls or peculiar shapes, such as the shells of Vermetidae, Cypraeidae, Conidae and they are highly damaged. These shells are significantly heavier than the shells of normal type and sometimes their center of gravity is various. It has been reported that heavier shells influence the growth rate and clutch size of hermit crabs and that unbalanced shells restrict the locomotion ability of hermit crabs. Thus this condition is regarded as worse for C. latens, and may result from the scarcity of normal shells in the reef.

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Polymorphism in the male major chelae of the hermit crab, Diogenes nitidimanus is reported. Broad type, in which the palm is broad with many distinct teeth and granules, and Narrow type, in which the palm is narrow with irregular-sized granules, as well as several intermediate types were found. Other morphological characters are nearly alike in these types and perfectly fit the descriptions of Diogenes nitidimanus given by TERAO (1913) and MIYAKE (1978). The possible relation between the body size and chela type is suggested.

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[in Japanese]

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A new species of the genus Philomedes is reported from Suruga Bay. The new species belongs to the species group possessing five or more elongate pegs on the seventh limb, but is distinguished from other members by the number of cleaning bristles on the seventh limb.

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The first zoeal larva of the porcellanid crab Petrolisthes japonicus (DE HAAN) is re-deseribed from laboratory-hatched material. Larval characters are compared with those in AIKAWA'S (1927) report. Larval features within the genus Petrolisthes, including the present species, are also compared. Three major groups can be distinguished using two characteristics : the scaphognathite of the maxilla, and the number of segments in the first maxillipedal endopod.

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Three larval stages of Ismaila occulta Ho are described, including copepodid II, copepodid III, and both sexes of copepodid IV. These larvae together with their adults were found inside the cerata of a giant red nudibranch collected from Alamitos Bay, Long Beach, California. It is speculated that the free-swimming nauplius of I. occulta developed into copepodid I before infecting nudibranch and there are five copepodid stages in the life cycle. The absence of maxilliped and leg 4 in the adult I. occulta is due to the developmental arrest of these appendages in the larval stages. An analysis of the available ontogenetic information of Poecilostomatoida indicates that Splanchnotrophidae is related to Philichthyidae and Myicolidae, particularly to the former family.

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The mitten crab Eriocheir japonicus inhabits the river. In Ohbiso River, mature crabs with high gonad index [GI=(gonad weight) / (carapace width)^3×10^5>0.48] appear in November, presenting a wide abdomen (AI=abdomen width/abdomen length>0.88), moving to the brackish water region for mating and reproduction. Immature crabs have a narrow abdomen (AI<0.88) and remain in the fresh water region of the river.

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Zoeae of the 14 species of, Japanese crabs, Conchoectes artificiosus (FABRICIUS), Homola orientalis HENDERSON, Latreillopsis bispinosa HENDERSON, Calappa lophos (HERBST), C. philargius (LINNAEUS), Matuta lunaris (HORSKAL), Cancer gibbosulus (DE HAAN), Portunus (Xiphoectes) hastatoides (FABRICIUS), Charybdis (Gonioneptunus) bimaculata (MIERS), Actaea savignyi (H. MILNE EDWARDS), Banareia odhneri SAKAI. Geryon trispinosus (HERBST), Tritodynamia japonica ORTMANN and Plagusia dentipes DE HAAN, were reared in the laboratory from hatching to last larva stage. Brachionus plicatilis (Rotifera), or Artemia nauplii were given as food for the zoeae. The zoeae of these species are described and illustrated in comparision with those of the related species studied previously.

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The Xanthid crab Eriphia smithii preys on hermit crabs. Two chelae, ambulatory legs, and mouth parts are used for capturing them. The crab breaks shells with hermit crabs in them by using its massive and powerful master, claw. About 70% of the crabs are right-handed. Many species of shells occupied by hermit crabs are found at Banda Shore. E. smithii breaks these shells.

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A new recent ostracod genus Gurayacypris belonging to subfamily Notodromadinae KAUFMANN 1900 with G. kangraensis sp. nov. as its type species is described from a pond near Kangra, Himachal Pradesh, India. The paper records the family Notodromadiidae KAUFMANN for the first time from India.

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