The present study focuses on spicule number, length, and positioning in larvae of two confamilial species of demosponge, Halichondria coerulea Bergquist, 1967 and Hymeniacidon heliophila (Parker, 1910). The anatomy and spiculation of newly emergent larvae were examined. On hatching, larvae of Halichondria coerulea are approximately one-half as long as larvae of Hymeniacidon heliophila. The spicules of adults and larvae of Halichondria coerulea are oxeas whereas those of Hymeniacidon heliophila adults and larvae are styles. Oxeas and styles are straight or slightly curved, and needle-shaped. In both species, spicules in larvae are significantly shorter (in mean length) than spicules of adults. This observation parallels previous reports on other species of demosponge. Mean spicule number per larva was significantly different between the two species, but the respective mean spicule lengths were indistinguishable ; some overall constraints may dictate spicule size independently of larval size. In contrast, within-species comparisons of adult spicule length versus larval length, larval spicule number versus larval length, and larval spicule number versus spicule length yielded no pairwise correlations. These data indicate that broad plasticity exists in spiculation patterns of newly hatched larvae in both species. Finally, the spicular mass of Hymeniacidon heliophila is asymmetrically positioned in the posterior region of the larva whereas the spicules of Halichondria coerulea are situated in the central region. This difference in the distribution of spicules may affect the swimming properties of the larvae of the two species differently and, possibly, also determine their positioning in the water column. It is proposed that the architecture of the flagellated epithelium governs the exclusion of spicules from the posterior region of Halichondria coerulea but is not similarly restricting in Hymeniacidon heliophila.

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Nipponomysis patula sp. nov. is described from the Gulf of Thailand. This species is characterized by having an expanded inner lobe on the second segment of the mandibular palp and is easily distinguishable from the other species of Nipponomysis. This is the first record of Nipponomysis from the Gulf of Thailand.

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A new species of tanaidacean of the genus Hemikalliapseudes (Kalliapseudidae) is described from fine mud sediment from some 230m depth on the continental slope off Angola. While closest to the type species of the genus, H. hanstroemi Lang, 1956, it is distinguished from the two known species of the genus in having a slender, seta-bearing tubercle on the basis of the cheliped, no large tooth on the cutting edge of the chela dactylus, no ventral spiniform apophyses on the pereonites, and in having the carpus of the mature male cheliped longer than wide. The new species is from deeper waters and from a finer substratum than are the other two species.

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The complete larval development, under laboratory conditions, of the pontoniine shrimp Periclimenes brevicarpalis (Shenkel, 1902) is described. Nine zoeal stages and one decapodid stage were identified before the moult to the first juvenile stage, and detailed descriptions are given for each stage. As a result of detailed morphological comparisons with congeners, the larvae of Periclimenes species are separated into two groups according to morphological criteria.

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Two new species of the genus Tisis Walker, T. thaiana sp. nov. and T. asterias sp. nov., are described from Thailand. Photos of imagos and illustrations of the male and female genitalia of the new species are provided. Tisis elegans (Snellen, 1903), which was described from Indonesia, is illustrated for the first time with its imago, male genitalia, and some taxonomic notes ; a lectotype of the species is designated.

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The group of species allied to Pediobius alcaeus (Walker, 1839) [considered as the genus Epipleurotropis by Girault (1917)] of the genus Pediobius is reviewed. The group includes P. alcaeus, P. termerus (Walker, 1839), P. coxalis Boucek, 1965, P. fastigatus Kamijo, 1983, and a new species, P. ikedai sp. n., described from Japan (Hokkaido). Eupleurotropis Girault, 1917 (considered as a synonym of Pediobius) is synonymized with Proacrias Ihering, 1914, based on peculiarities of the propodeal structure, and the type species of the former genus is transferred to the latter genus [Pr. testaceipes (Crawford, 1914), comb. n.]. The status of the alcaeus species group in the genus Pediobius is discussed. Many new geographic records are presented, including new data on distribution of the discussed species in the Kuril Islands.

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Brundiniella yagukiensis sp. nov. is described on the basis of the male and female adults, pupa, and larva. This is the first report of the genus Brundiniella from the Palaearctic Region.

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The genus Sunagocia is established as a replacement name for the platycephalid fish genus Eurycephalus Imamura, 1996, which is preoccupied by the cerambycid beetle genus Eurycephalus Gray in Cuvier and Griffith, 1832. The genus currently contains three valid species : S. arenicola (Schultz, 1966), comb, nov., S. carbunculus (Valenciennes in Cuvier and Valenciennes, 1833), comb, nov., and S. otaitensis (Cuvier in Cuvier and Valenciennes, 1829), comb. nov. It is confirmed that Cuvier satisfied the nomenclatural requirements for availability of this last species, although several investigators have attributed the name to Parkinson, who made the unpublished drawing of S. otaitensis used in its original description and named the species. Two measurements, of head length and especially interorbital width, are helpful in distinguishing S. carbunculus, S. arenicola, and S. otaitensis from each other.

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