Osteological characters of the percophid fish, Percophis brasiliensis Quoy and Gaimard, 1825, the sole member of the subfamily Percophinae, are described in detail. Fifteen apomorphic characters are recognized in this species through morphological comparison with the Percoidei. Of them, the following five characters are determined to be autapomorphic for this species and its subfamily among the Percophidae: urohyal greatly depressed, complex in shape; first pharyngobranchial reduced and completely ossified; Baudelot's ligament branched distally; five supraneurals or ray-less proximal-middle pterygiophores present; and body cavity extending far posteriorly. Percophis brasiliensis is considered to be closely related to the percophid subfamily Bembropinae, because they share three apomorphic characters (presence of a lower backwardly directed opercular spine crossing the subopercle, absence of a tooth plate on the second epibranchial, and absence of supernumerary rays on the ventral portion of the first anal proximal-middle pterygiophore). Although the monophyly of the Percophidae is unconfirmed, because of the lack of plausible synapomorphies, the family is provisionally defined here by the following five apomorphic characters: exoccipital condyles separated in the midline; parasphenoid and pterosphenoid connected; anteroventral portion of second anal proximal pterygiophore with a soft ray; uroneural single; and fewer than 15 branched caudal fin rays present.

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The taxonomic characters of the marbled flathead, Platycephalus marmoratus Stead, 1908, are described and evaluated. In addition to the marbled body and dark brown to black caudal fin, the following combination of characters separates it from the other 14 species of the genus Platycephalus: 13 second dorsal and anal fin rays; 63-70 scales in the lateral line, with all pored scales lacking spines; snout and interorbit naked; no strong canine teeth on the jaws, palatines, and vomer; interopercular flap absent; and skinny sensory tubes on the suborbitals and preopercle partially covering the cheek region. It has been confirmed that the type series of the species was composed of the holotype and one paratype, although the paratype is presumably no longer extant.

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The Japanese spiny lobster, Panulirus japonicus (von Siebold, 1824), spends an extended period as planktonic phyllosoma larvae in offshore epipelagic regions. The larvae have been morphologically confused with those of related species, called here the "longipes" group to include P. longipes (A. Milne Edwards, 1868), P. femoristriga von Martens, 1872, and P. brunneiflagellum Sekiguchi and George, 2005, in the seas off southern Japan. Partial sequences of mitochondrial DNA (tDNA-Val to middle part of 16S rDNA) show species-specific variations characterized by large interspecific differences and only very minor intraspecific ones. Based on these observations, for identification purposes we developed a PCR-RFLP test using five restriction endonucleases (BspH I, EcoR V, Hae III, Hap II, and Mbo I). We could thereby identify six species and one subspecies of Panulirus lobsters from 93 field-collected phyllosoma larvae sampled during four surveys in the seas off southern Japan in 1997 and 1998 [P. japonicus, P. longipes bispinosus Borradaile, 1899, P. brunneiflagellum, P. penicillatus (Olivier, 1791), P. versi-color (Latreille, 1804), and Justitia longimanus (H. Milne Edwards, 1837)]. We also discuss the taxonomy and phylogeny of the genus Panulirus; the recently described species, P. brunneiflagellum, is placed as a sister species of P. femoristriga in spite of the former's morphological affinities with P. japonicus.

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Pagurixus nanus, a new species of pagurid hermit crab, is described from shallow coral reefs of Ishigaki Island, Yaeyama Islands, the Ryukyus. Most of the specimens were collected by using traps designed for sampling the fauna associated with coral rubble. The new species belongs to the P. anceps species group due to the lack of two ventral rows of setae on the ultimate segment of the antennular peduncle, but it appears unique in having one or two small, subproximal spines on the dorsal surfaces of the carpi of the second pereopods. Morphological characteristics suggest that P. nanus is close to P. anceps (Forest, 1954) and P. patiae Komai, 2006.

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Prionomysis ryukyuensis sp. nov. is described from the shallow waters of Yagaji Island, Okinawa Islands, in the central Ryukyus of southwestern Japan. This species differs from the other three hitherto described species of Prionomysis Tattersall, 1922 in having a single long seta on the distal end of the exopod of the fourth male pleopod. It is furthermore distinguishable from two of its congeners, P. aspera Ii, 1937 and P. australiensis Murano, 1990, by the shorter antennal scale.

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Two new species of the pompilid wasp genus Dipogon occurring in the subtropical islands of Japan are described: Dipogon (Deuteragenia) amamiensis from Amami-Ohshima in the northern Ryukyu Islands, and Dipogon (Deuteragenia) ogasawarensis from Haha-jima in the Ogasawara Islands (Bonin Islands). A brief discussion of the distribution of the Japanese species of Dipogon (Deuteragenia) is provided.

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A species of freshwater oligochaete, Propappus volki Michaelsen, 1916, is newly recorded from sand and gravel bottoms of several unpolluted streams in Honshu, Japan. The present material agrees well with the previous descriptions of this species except that the spermathecal ampulla is shorter and the proboscis is more elomgate than those described earlier. This is the first record of the family Propappidae Coates, 1986 (New Japanese name: Ko-himemimizu-ka) and the genus Propappus Michaelsen, 1905 (New Japanese name: Ko-himemimizu-zoku) in Japan. It provides evidence that the oligochaete fauna in Japan is more closely related to the Holarctic than to the Sino-Indian zoogeographical region. Propappus volki can be regarded as a good bio-indicator for unpolluted water.

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