A new species of caridean shrimp, Pseudocheles neutra sp.nov. is described from Sulawesi, Indonesia. The new species can be distinguished from its congeners by a suite of characters, including the presence of a distinct tooth on the posterolateral margin of the fifth pleuron, as well as several differences in spination. A new family, Pseudochelidae is created to accommodate the genus. This family can be distinguished from the Bresiliidae and Alvinocarididae in the presence of well developed exopods on the ambulatory pereiopods and the fusion of the ischium and merus of the first and second pereiopods, and from the Disciadidae primarily in the absence of a disc-shaped dactylus of the first pereiopod. The new family differs from all known Caridean families in the presence of pseudochelate ambulatory pereiopods.

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We examined a new method that used a sodium hydroxide (NaOH) solution to extract all sperm from spermatophores of the spiny king crab Paralithodes brevipes (H. Milne Edwards and Lucas, 1841). Spermatophores were put into 1ml microtubes containing 0.25ml of 20% NaOH solution. After soaking in the NaOH solution for 10, 30, 60 and 90 min, the microtubes were mixed for 30 sec. The mixed solution was then placed in a hemacytometer, and sperm were counted under an optical microscope. The total number of extracted sperm in each microtube was calculated: (number of sperm counted/volume of NaOH counted)×total volume. The number of extracted sperm increased with time soaked until 60 min. The number of extracted sperm showed no significant increase between soaking time of 60 min and 90 min, which indicates all spermatophores were completely dissolved by 60 min. Sperm cells kept the body but not spines of sperm in NaOH solution even after 180 min after mixing. Therefore, to extract sperm, spermatophores should be agitated after 60 min of soaking in 20% NaOH solution, and sperm should be counted within 3 hours after mixing.

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Two species of the rare mud shrimp genus Naushonia Kingsley, 1897 (Thalassinidea: Laomediidae) are reported from Japanese waters. Naushonia japonica, new species, described based on a single male specimen from Shimonoseki, southwestern Honshu, is similar to N. perrieri (Nobili, 1904) known only from the Red Sea. They are differentiated by the armature of the rostrum and anterolateral margin of the carapace, development of the second lateral carina on the gastric region of the carapace, armature of the antennal scale and shape of the dactylus of the first pereopod. Naushonia lactoalbida Berggren, 1992, originally described from Mozambique, East Africa, is recorded from Iriomote Island, southern Ryukyu Islands. The record of species of Naushonia in the western Pacific region has been represented only by planktonic zoeas of an unidentified species taken at Gokasho Bay, central Japan (Konishi, 2001). The occurrence of species of Naushonia in the region is now fully confirmed by the discovery of the adult specimens.

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The complete larval development of Actumnus setifer is documented with three zoeal stages and one megalopa being described. The zoeas differ from the only other known larval description from this speciose genus, A. squamosus, in several carapace and abdominal features. These differences may suggest that the two species are not congeneric. A pilumnid larvae bibliography of 31 species is tabulated.

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A new species of gnathiid isopod, Gnathia camuripenis, from coral rubble infauna collected in Ishigaki Island, the Ryukyus, southwestern Japan, is described. The gnathiid is the 20th species of the family Gnathiidae and 8th of the genus Gnathia recorded from Japan. Males of G. camuripenis have remarkably large penes fused into a single crooked blade and mandibles with 2 inner lobes, and thus are easily separated from its congeners. Female adults and larvae considered to be the same species are also described in detail and the morphology of antennae, mouthparts and pleotelson compared to other species from the same family.

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We performed a histological investigation of the different stages of development of primordial externae in the interna of Polyascus polygenea Glenner, Lutzen et Takahashi, 2003, a common parasite of an intertidal crab, Hemigrapsus sanguineus (de Haan, 1835). Development of the primordia begins with budding of the interna and the formation of numerous nuclei, i.e. clusters of non-differentiated embryonic cells surrounded by an epithelial layer. The non-differentiated cells of the nuclei undergo intensive mitotic reproduction. After the stage of cell proliferation, the processes of epithelial morphogenesis in the primordial externae and the related anlagen of the trophic system were observed. The primordial ovary in the developing externae already comprises primary germ cells and later, oogonia and oocytes. Careful and thorough investigations of morphogenesis in primordial externae support our previous results and agree with the findings of other authors.

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Allocleaning, fighting, waving and mating behavior in 16 species of Macrophthalmus (Brachyura, Macrophthalmidae) are described from field observations. Allocleaning was performed in most species observed, except M. latifrons. Male-male fighting behavior could be divided into two patterns; grasping fight and claw-extending fight. The latter was observed in five species, across three subgenera, most species exhibiting grasping fight behavior. Both fight patterns usually started with leg touching/pushing, followed by mounting and grasping. Fights usually ended with grasping, but in the claw-extending pattern, lateral extension of the chelipeds in both combatants occurred after grasping. Fighting behavior between females could be divided into two patterns; legintertwining fight and leg-extending fight, the latter being observed only in two species of subgenus Macrophthalmus. Most species exhibited leg-intertwining fight. Male waving display could be classified into four patterns, including vertical non-forward-pointing type, vertical forward-pointing type, lateral non-forward-pointing type and lateral forward-pointing type, depending upon in cheliped movement. The differences between the four waving patterns involve the chelipeds being moved either vertically or laterally, and extended forward while raised or not. Lateral movement was observed in only three species, M. banzai, M. erato and M. quadratus, most species exhibiting vertical movement. Forward-pointing movements were observed in four species, but were absent in all species of subgenus Mareotis and two species of subgenus Macrophthalmus. The most common waving display was the vertical non-forward-pointing type. Mating behavior of six species was observed (surface mating). Underground mating, reported for other macrophthalmine crabs, was not observed during the field observations.

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A new galatheid, Galathea guttata, is described and illustrated from the Ryukyu and Izu Islands, Japan. This species resembles G. amamiensis Miyake & Baba, 1966, but is distinguished from that species by having no spine on the third segment of the antennal peduncle, an epipod on the second pereopod, and two rounded, pale blue or white marks on the distal part of the cheliped palm.

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Two new species of hippolytid shrimp, Lebbeus elegans sp. nov. and L. polyacanthus sp. nov., are described from the Sea of Japan, at depths of 250-400m. Lebbeus elegans is characterized by the absence of epipods on the second and third pereopods, distinct ventral blade of the rostrum and the rounded fourth abdominal pleuron. Lebbeus polyacanthus is compared with L. antarcticus (Hale, 1941), L. carinatus Zarenkov, 1976, and L. washingtonianus (Rathbun, 1902). Lebbeus polyacanthus differs from the latter three species in the more posteriorly arising posteriormost tooth of the dorsal rostral series and more numerous lateral spines on the meri of the third to fifth pereopods. Examination of the newly obtained material of L. kuboi Hayashi, 1992, enabled us to assess intraspecific variations of the species, including a variation in the development of the pereopodal epipods. Redescription of Lebbeus kuboi is provided and its affinity is discussed. These three species occur sympatrically. A brief note on the taxonomy and distribution of species of Lebbeus is also provided.

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