The larval development of the semiterrestrial sesarmid mangrove crab Neosarmatium indicum (A. Milne Edwards, 1868) was studied under laboratory conditions at salinities 0-35‰ and temperatures of 25.5-27.5℃. The larval development consists of five zoeal stages and a megalopa. Larvae survived to the first crab stage at salinities between 5 and 35‰ with different percentages. At the 0‰, the larvae died within 12 hours without moulting to subsequent stages. Total duration of development to the first crab stage was 45, 38, 34, 30, 28, 35 and 40 days at 5, 10, 15, 20, 25, 30 and 35‰, respectively. Significant differences (P < 0.05) in the survival rate were found among the tested salinities. The best survival rate for each larval stage was recorded at 20 and 25‰.

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The responses of the larvae of the rhizocephalan barnacle Sacculina polygenea, a parasite of the intertidal crab Hemigrapsus sanguineus, to different temperatures and salinities were examined. Its development comprises five naupliar stages and the cypris stage. The phototaxis of the nauplii remained undisturbed at 22℃ and 26-34‰. The number of true naupliar moults decreased at lowering of temperature and salinity. Successful naupliar development occurred in temperature and salinity ranges of 1825℃ and 18-34‰ respectively. At 20-25℃ and the optimum salinity of 24-28‰, development to the cypris stage took 2-3 d. Under the most severe conditions imposed (15℃ and 18‰) the cyprids appeared in 6.5 d. The cypris larvae showed wider tolerance range against decreased salinity than the naupliar stages. At 1520℃ and 14-34‰, 85-95% of cyprids died hi 7 d. In the tolerance to different salinities S. polygenea larvae occupy an intermediate position between those of estuarine and marine species. The continuous presence of planktonic cypris larvae in wide range of temperature and salinity represents a potential infestation hazard for the host crabs.

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In Armadillidium vulgare, the female external genitalia (cuticular copulatory apparatus) consist of a copulatory opening and a spermathecal duct. Adult females change the structure of the genitalia at molting during a reproductive cycle. This study was done to investigate the relationship between the structural change of the genitalia and their reconstruction at the non-parturial (normal) and parturial (reproductive) molts. When females have immature ovaries at molting, they completely cast off the genitalia, together with the old exoskeleton, and reconstruct new genitalia of a non-reproductive type. On the other hand, females with mature ovaries cast off the copulatory openings together with the old exoskeleton at parturial molting. However, the old spermathecal ducts are retained in the oviducts through and after molting. In females with mature ovaries, new genitalia of a reproductive type are not reconstructed at the parturial molt. The present observations demonstrate that adult females change the structure of the genitalia at molting in accordance with the degree of ovarian maturation. The non-reproductive type genitalia are reconstructed at the nonparturial molt but the reproductive type genitalia are not reconstructed at the time of the parturial molt in A. vulgare.

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The sesarmid genus Neosarmatium Serene & Soh, 1970 comprises 12 Indo-West Pacific species, some of them ranging in distribution from South Africa to the South Pacific. New distribution records are provided for six species, viz. N. fourmanoiri Serene, 1973, N. laeve (A. Milne Edwards, 1869), N. meinerti (de Man, 1887), N. rotundifrons (A. Milne Edwards, 1869), N. indicum (A. Milne Edwards, 1868), and N. trispinosum Davie, 1994. Chiromantes tangi (Rathbun, 1931) is transferred to Neosarmatium based on its morphological similarity to N. laeve. A new species, N. daviei sp. nov. is described based on material from Sulawesi, and a revised key for the 14 currently recognized species of Neosarmatium is presented.

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The root system and nucleus formation in the colonial rhizocephalan Sacculina polygenea Liitzen & Takahashi has been reinvestigated and found to correspond to those of other related species. A conflicting opinion of these subjects recently proposed by Russian zoologists is due to the fact that these authors have mistaken a number of host structures for parts of the parasite's root system.

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The larval development of the freshwater prawn, Macrobrachium australe (Guerin Meneville, 1838) is described and illustrated from laboratory-reared material. Although all larvae died before attaining the decapodid stage, thirteen zoeal stages were recognized. Morphological comparisons between the thirteenth zoea of M. australe and the last zoeal stages ofM. carcinus and M. rosenbergii indicate that M. australe possibly has at least one more zoeal stage before metamorphosis. The morphology of the first zoea ofM. australe is also compared with that of 7 other Japanese species. The present species most closely agrees with that of M. grandimanus, but it differs from the latter by the setation of the mandibles, maxillule, and second and third maxillipeds. Zoeas of M. australe survived for nearly 150 days, and presumably did not have a suitable settlement environment. This extended larval period may be one important factor explaining why this species is ubiquitously distributed throughout the Indo-Pacific region.

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During a taxonomic study of the snapping shrimp genus Alpheus from Japan and the Gulf of Thailand, it has been found that two species have been confounded under A. digitalis De Haan, 1844, which was originally described based on a single specimen possessing abnormal chelipeds. Differences between the two species are found in both morphology and coloration. Careful examination of published information of the holotype and supplemental material enable us to establish the true identity of A. digitalis. The new species, A. longiforceps, can be distinguished from A. digitalis by the more slender major chela with a sinuous, rather than convex, flexor margin, the longer male minor chela with a more elongate dactylus, and the possession of a single, rather than two, obliquely transverse white bands on the carapace and of a conspicuous dark brown spot on the lateral surface of the fourth abdominal tergum.

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