Two species of leucosiid crabs, Philyra nishihirai Takeda & Nakasone, 1991, and P. bicornis, new species, are reported from mangroves near the mouth of Kamora River in the southeast coast of Irian Jaya, Indonesia. Philyra nishihirai is recorded for the first time since its original description. Philyra bicornis resembles P. malefactrix (Kemp, 1915) but differs in that the posterolateral angle of the carapace is strongly projected and the male first pleopod is long, straight and tapering at the tip. The taxonomy of Philyra malefactrix (Kemp, 1915) is also discussed, and Philyra minuta Chen & Tiirkay, 2001, is here synonymised with P. malefactrix.

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Pylopaguropsis lemaitrei, new species, is described from French Polynesia. It closely resembles P. lewinsohni McLaughlin & Haig, 1989, in having three longitudinal sulci on the lateral face of the propodus of the right third pereopod. The new species is easily distinguished from the latter by the coloration and morphology of the chelipeds, ambulatory pereopods and telson. Coloration of the chelipeds and ambulatory pereopods of the new species is very similar to that of P. keijii McLaughlin & Haig, 1989. However, coloration of the ocular peduncles and antennas and morphology of the right third pereopod separate the new species from P. keijii.

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A. new snapping shrimp, Alpheus hortensis, n. sp., of the A. macrocheles species group is described from the northern Gulf of Mexico. The new species most closely resembles A. crockeri, but differs from the latter in having shorter fingers of the minor chela, lacking a spine overhanging the articulation of the dactylus of the minor chela, and having longer inferolateral spines of the telson. The new species is yellow in life, and lives subtidally among rocks and coral rubble.

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Maturation of female Japanese mitten crabs Eriocheir japonica (De Haan, 1835) was observed and the relationship between maturity and reproductive ecology investigated. The degree of maturity was indicated by juvenile and adult phases from their exoskeleton, gonad index (GI), six developmental stages of oocyte from histological observation, oocyte diameter, and four developmental stages of embryos. The stages of most advanced oocytes were used for assessing ovarian maturity. During the juvenile stage the ovary proceeds to previtellogenesis and primary vitellogenesis but remains immature (at most stage 2, GI < 1.0, oocytes < 100μm diameter). After the pubertal moult, oocytes begin secondary vitellogenesis, and complete development (stages 2-6, GI 0.28-13.2, 120-400μm diameter). The number of developing oocytes varied from ca. 120,000 (40mm at carapace width) to 650,000 (70mm). Copulation is estimated to be possible only when adult females complete vitellogenesis. After oviposition, underdeveloped oocytes start secondary vitellogenesis with the development of embryos, and are spawned as the second or third broods after fertilization by stocked sperm without ecdysis. Most of the developing oocytes are spawned at each oviposition, and unspawned matured oocytes are considered to be digested and absorbed.

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This study dealt with the egg development and incubation period of the swimming crab Portunus trituberculatus reared in the laboratory. Egg volume increased twice throughout development and the rate of increment was higher after the metanaupliar stage. Two embryonic growth indices which were expressed as respective relative areas of embryonic body and eye pigment in lateral profiles of the egg increased as the relative egg age advanced. Newly hatched larvae body size correlated with egg size. Smallersized larvae tended to be produced at higher egg incubation temperatures. The number of days from spawning to hatching decreased with increasing incubation temperature and the Belehradek's equation was the best non-linear regression model to describe the relationship between temperature and egg incubation period.

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The first zoeas of six Japanese Macrobrachium species, M. equidens (Dana, 1852), M. formosense (Bate, 1868), M. grandimanus (Randall, 1840), M. japonicum (De Haan, 1849), M. lar (Fabricius, 1798) and M. nipponense (De Haan, 1849), are redescribed from specimens hatched in the laboratory. The first zoeas described here differ considerably from previous published descriptions in appendage morphology and chromatophore pattern. The present examination demonstrates that, except for M. shokitai Fujino & Baba, 1973, first zoeal morphology among the seven Japanese species can be distinguished by using the combined characteristics of chromatophore pattern and the armatures of the mandibles, maxillule, and third abdominal segment.

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Reproductive characters and population structure of the intertidal hermit crab, Pagurus proximus Komai, 2000, are described, based on samples collected monthly from Hakodate Bay, southern Hokkaido, Japan. Males were larger than females and the sex ratios of small and large crabs were female and male biased, respectively, although the overall sex ratio was not significantly biased from the 1:1 ratio. Ovigerous females were observed from February to July in 1999 and from January to June in 2000. At 12 and 16℃, the ovigerous period was 40.3 (±0.58 SD) and 30.8 (±1.62 SD) days, respectively. Some females may have multiple clutches per year based on egg developmental pattern in the field and the ovigerous periods.

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The larval development of Galathea amboinensis De Man, 1888, a galatheid symbiotic with comatulid crinoids, is described and illustrated from laboratory-reared material. This species had four zoeal stages and one megalopal stage. The larval morphology of G. amboinensis is compared with that of other congeneric species for which the complete larval development is known: G. inflata Potts, 1915, G. rostrata A. Milne Edwards, 1880 and G. intermedia Lilljeborg, 1851. The zoeas of G. amboinensis are much like those of G. inflata, but distinctive in the absence of small spines on the posterodorsal margin of the second to fifth abdominal segments. The megalop of G. amboinensis also resembles that of G. inflata, but differs in segmentation of the antennal flagellum and setation of the mandibular palp, and in having circular or subcircular red spots on the carapace and abdomen.

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The crinoid symbiotic crab, Harrovia longipes Lanchester, 1900, is recorded for the first time from Japanese waters based on the specimens collected from Okinawa Island, the Ryukyu Islands. This species is easily distinguished from other congeners by the length to width ratio of the fourth ambulatory merus, 3.24-4.42 (mean 3.66). A brief diagnosis, living coloration details, and ecological notes of this species are provided.

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