Comparison of a sizable material of the genus Raja from the western North Pacific with the type specimens of almost all the nominal species in the area revealed a new species, Raja (Okamejei) boesemani. Among the western North Pacific Raja (Okamejei) , the new species shows the closest resemblance to R.(O.) hollandi Jordan et Richardson. The new species, however, differs from R.(O.) hollandi mainly in having a relatively narrow interdorsal distance, rosette-like color patches of the disc and a pair of dark rings at the pectoral axils. The comparison also re-vealed that there were a total of five Raja (Dipturus) and six Raja (Okamejei) species in the western North Pacific. A revised key is given to the species also including the eastern North Pacific Raja (Dipturus) species, R. binoculata Girard and R. rhina Jordan et Gilbert.

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A new species, Repomucenus koreanus, is described on the basis of specimens taken on shallow sandy-muddy level bottoms of the coasts of the Yellow Sea. It has 10 dorsal and 10 anal rays, and 15 caudal vertebrae; these meristic characters of this species are higher than those of other Repomucenus species.

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Three species are recognized within the fish previously described as Neoclinus bryope (Jordan et Snyder) from Shirahama, Japan. These three species are separable primarily by the combination of two meristic characters, the number of vertebrae and the total number of cephalic sensory pores. The true N. bryope has 47 to 49 vertebrae and 49 to 57 cephalic sensory pores. One new species, N. okazakii has 45 to 47 vertebrae and 58 to 78 pores. Another new species, N. chihiroe has 44 to 46 vertebrae and 49 to 55 pores. The true N. bryope is redescribed and the two new species are described on the basis of the specimens from Shirahama.

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Five Japanese species of Neoclinus from Shirahama, Japan were studied based on allelic frequencies at 19 genetic loci. Habitat partitioning and overlap in these five species in the waters of Shirahama was also observed. The five species which cooccur in Shirahama are well isolated genetically, each pair of species with clearly distinctive allele in some loci. A resulting phylogenetic tree among five species of Japanese Neoclinus based upon Nei's genetic distances (D) indicates that the Japanese Neoclinus could be divided into two major groups. One consists of N. lacunicola and N. toshimaensis and another three species of N. bryope complex (i.e. bryope, chihiroe and okazakii). This agrees well with the grouping based on morphology. Three members of N. bryope complex showed an imperfect habitat partitioning. However, the obtained results clearly indicate that gene exchanges have not occurred among these three members. N. bryope mainly inhabits tide pools (TP habitat), N. chihiroe mainly in the upper subtidal of moderately exposed rocky reefs (ME habitat), and N. okazakii mainly in the upper subtidal of very exposed rocky reefs (VE habitat). The two species of another major group showed more rigid habitat partitioning. N. lacunicola mainly inhabits ME habitat where it predominates over N. chihiroe and N. toshimaensis inhabits VE habitat where it predominates over N. okazakii.

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Eleven species of the genus Pristipomoides were examined on the basis of external and internal characteristics. A new and unique characteristic is described by which this genus can be distinguished from all other genera of the Etelinae, namely, a lack of congregated scales (>6) on the upper part of the cleithrum. The genus Pristipomoides is divided into two subgenera, Pristipomoides and Platyinius, on the basis of distinct features, such as the length of the last dorsal and anal ray, and the structure of hypural, prootic, basioccipital, exoccipital, and first anal pterygiophore. Pristipomoides typus, P. multidens, P. filamentosus, P. flavipinnis, P. auricilla and P. sieboldii of the Indo-Western Pacific belong to the subgenus Pristipomoides. Pristipomoides zonatus and P. argyrogrammicus of the Indo-Western Pacific and P. macrophthalmus, P. aquilonaris and P. freemani of the Western Atlantic are placed in the subgenus Platyinius. Tropidinius which P. zonatus and P. argyrogrammicus were previously recognized as belonging to is a junior synonym of Apsilus (subfamily Apsilinae).

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Seven local races of the so-called striated spined Loach (Cobitis taenia striata) were compared morphologically. Here they were called the large, Biwa small, Yodo small, small, Tokai small, spotted small, and middle races. Among them, the Yodo small race and Tokai small race were newly discriminated. There was a great morphological variation among the seven local races. Each race occupied its specific geographic range. Three cases of sympatric distribution of two races were found without effective hybridization. The striated spined Loach is a species group which has seven local races that could be divided into three species ; the large and middle races are independent species each and the five smaller races are settled into the third one. However, their scientific names cannot be given because of the uncertainty of relationship between the European population of Cobitis taenia, originally described by Linnaeus, and Japanese ones. While a wide extent of morphological variation within the smaller races is found, difference between the large race or middle race and their nearest smaller race is considerably smaller.

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Embryonic, larval and juvenile development of the cottid fish, Pseudoblennius cottoides, were described based on a series of laboratory-reared specimens. The eggs were demersal, ad-hesive, almost spherical in shape, measuring 1.60-1.98mm in diameter, and with numerous various-sized oil globules. Neighboring eggs adhered to each other to form an egg mass. Hatching occurred between 13 and 15 days after spawning at a water temperature of 15.2 to 17.0°C. Newly hatched larvae measured from 6.3 to 7.1mm, averaging 6.7mm TL, and possessed 40 myomeres. Absorption of the yolk was completed at about 7.5mm TL. Flexion of the notochord started and finished at about 10mm TL and about 14mm TL, respectively. Aggregate numbers of all fin rays were completed at over 16mm TL, at which time the larvae reached the juvenile stage. The pigment pattern became the same as that of adults in juveniles longer than 20mm. TL. Lateral lines were completed at over 37mm TL, at which time the juveniles attained to the young stage.

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Pigment migration and the role of cortical microtubules in granular transport in mel-anophores of a teleost, Gambusia affinis, were studied by means of video and electron microscopy. In pigment aggregation, the migratory velocity of individual melanosomes was maximal in the initial 20 sec, rapidly decreasing afterward. In dispersion, pigment moved at a uniform, slower rate as compared with aggregation. During aggregation, melanosomes migrated faster in thinner dendrites than in thicker ones, while in dispersion, the rate of migration was rather constant ir-respective of the thickness of the path. Withdrawal of melanosomes from the dendritic processes during aggregation was followed by a flattening of the processes and a decrease in the number of cortical microtubules. On pigment dispersion, collapsed dendrites resumed their original mor-phology prior to the re-entry of melanosomes by gradual refilling of the cytoplasm and re-establish-ment of cortical structure. Complete disassembly of microtubules by cold treatment made the distance between pigment granules and cell membrane remarkably shorter, indicating a significant correlation between the density of cortical microtubules and distance between cell membrane and pigment granules. These findings suggest that cortical microtubules are essential for the maintenance of the path in which melanosomes migrate. N-ethylmaleimide (NEM) inhibited both aggregation and dispersion, and erythro-9 [3-(2-hydroxynonyl)] adenine (EHNA) arrested pigment aggregation, while cytochalasin B had no appreciable effect on pigment migration. These pharmacological evidences suggest that the generation of motive force for pigment migration, at least for pigment aggregation, is dynein-dependent. These experiments also clearly show that pigment dispersion in Gambusia melanophores can be produced by a mechanism independent of tubulin-dynein or actin-myosin system, though the involvement of other motor molecules in pig-ment disnersal remains to be studied.

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The effects of temperature and daylength on the initiation of sexual maturation of yoshinobori, Rhinogobius brunneus (orange type), were examined. In the natural habitat, onset and further progress of vitellogenesis and spermatogenesis were not synchronous among indi-viduals. Precocious females started yolk accumulation in March and reached pre-spawning stage in late May. Spermatocytes were found in all male specimens in March, though meiotic figures could be seen as early as December in the testes of larger males. In late May, some larger precocious individuals reached the final stage of spermatogenesis. Many deposited egg masses and brood-caring males were observed in June. In experiments, combination of high tempera-ture and long day alone elicited the onset of vitellogenesis. In the case of the testes, however, high temperature-long day regime was not the triggering factor of meiosis but only an accelerator. All the reproductive process of yoshinobori, from beginning of vitellogenesis to spawning, proceeds quickly under high temperature-long day conditions. Minimum temperature and daylength for the onset of female maturation is probably around 9°C and around 12hours respectively.

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Parameters on gas exchange in the gills were measured in eel acclimated for more than 2 weeks at 9.1±0.1, 25.8±0.6 and 33.5±0.2°C under normoxic and hypoxic condi-tions. Under normoxic condition, oxygen pressure of the dorsal aortic blood (P_{a, o2}) in-creased and pH of the blood (pH_a) decreased as the temperature increased. Under hypoxic condition, pH_a increased gradually, and P_{a, o2} and oxygen content of the blood (C_{a, o2}) de-creased as the oxygen pressure of the water decreased. Under normoxic and hypoxic con-ditions, C_{a, o2} at 25.8°C was the same as that at 9.1°C, but C_{a, o2} at 33.5°C was smaller than that at both temperature. High P_{a, o2} at high temperature must be a compensation for the detrimental effects of low pH and high temperature on the oxygen transport by the blood.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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