The maturity condition of piscivorous fishes have been expressed by gonad codition factors, gonad indices, maturity factors and other methods. Each of these methods can be used to express numerically the maturity condition from immature young to mature ones. But when they come in the spent stage, these methods can not be adapted for the reason that the numerical values show a decrease in this stage. The author recorded the weight variation of each genital organ according to the state of maturation and exhaustion, with samples of common squid, Todarodes pacificus STEENSTRUP, caught by angling in the southwestern Japan Sea in the period from July to November 1968. As consequence of the sampling and analyses, a method of expressing the maturity condition of the common squid by numerical values was developed. The several points are summarized as follows:
1. The relation between testis weight (tW) and Needhanis sac mass weight (NW) is tW > NW in the immature young, tW ?? NW at maturity, and tW < NW in the spent stage. In the case of females, the relationship between ovary weight (oW) and oviducts weight (odW), including the oviducal glands, is similar to that between tW and NW for the males (Figs. 1, 2 and 3).
2. From these relationships, it is possible to express the maturity condition numerically by NW/ (tW+NW) for the males, and by odW/ (oW+odW) for the females. These numerical values (M) are 0 < M < 0.5 in the immature young, M ?? 0.5 at maturity, and 0.5 < M < 1 in the spent stage (Figs. 4, 5 and 6, Table 1).

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Pathophysiological changes that take place in Porphyra pseudolinearis fronds during the occurrence of “Shirogusare (like a white wasting disease)” were investigated in an attempt to characterize the initial signs of the disease and the environmental factors affecting the occurrence of the disease.
(1) No changes in peroxidase activity and the concentration of water-soluble proteins and pigments occurred in the tissue during the phase of infection, while they decreased markedly only after the onset of the disease. On the other hand, the concentration of soluble carbohydrates and cell osmotic pressure increased prior to the onset of the disease. The increase in osmotic pressure of the cells might result from altered respiration and hydrolysis of starch. Since these are the only notable changes that occur prior to the onset of the disease, they may be regarded as the initial signs of the disease process.
(2) There was a temporal increase in respiratory rate in the infected tissue. It was however so variable according to specimens that no conclusive statement as regards respiratory rate could be made.
(3) The microspectrophotometric analysis of the infected single cell revealed that the concentrations of protein, chlorophyll and phycoerythrin decreased significantly with the progress of time after infection, but that the concentration of nucleic acid showed little change.
(4) The time length and environmental conditions of “dried-uy” of Porphyra fronds are the most important factors determining the occurrence of the said white wasting disease. In the present study, the most probable environmental factors that might have played an important role in the occurrence of the disease are considered to be high temperature, high humidity and strong wind, etc. which are encountered during the “dry up” phase.

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Although a number of studies have been made on the general biology of barnacles, year-round field observations on the ecology of each species distinctly discriminated are rather scarce in Japan, except for a very few species. This paper deals with ecological observations on four species of acorn barnacles, which are representative of the most harmful fouling organisms along the coast of Otomi in Uchiura Bay, situated on the southwestern part of the Japan Sea. These observations were made from December 1967 to September 1969. Planktonic larvae were sampled by vertical hauls of plankton-net (45cm in mouth aperture and 0.33mm in mesh size) from the bottom every two or three days, and every month the number of barnacles that settled on six kinds of colored celluloid plates (25.0×18.5cm or 30.5×21.0cm) suspended at various depths was counted. Results obtained are summarized as follows:
1) The most dominant species was Balanus trigonus DARWIN, followed by B. venustus DARWIN, B. eburneus GOULD, and B. improvisus DARWIN. The latter three species are apparently recent invaders from foreign countries with timbers on the cargo boats.
2) From observation on the occurrence of pelagic larvae and the barnacles settled on the celluloid plates, the breeding season of each species is assumed to be as follows: In B. trigonus it extends from late May to late July, and secondarily from early September to late November (water temperature showed 17 to 29°C at 1 meter depth) with the peak in late May to late June (18 to 24°C); In B. venustus from late April to late June (14 to 22°C) with the peak in June (18 to 22°C); B. eburneus in July and September (21 to 29°C); B. improvisus from late October to late November and again from early March to late June (14 to 22°C) with the peak in June (18 to 22°C) (Fig. 3).
3) Vertical distribution in the settlement of each barnacle from surface to 13 meter depths was as follows: B. trigonus was found most abundantly at 13 meter depth in June and at 5 meter depth in July, while B. venustus settled most abundantly at 13 meters and B. improvisus was fairly abundant at 1 meter, respectively. B. eburneus, on the other hand, was found to attach almost evenly throughout the range mentioned above (Fig. 4).
4) In general, these four species of acorn barnacles settled more abundantly on dark coloured plates such as black or blue than on those of light colours such as red, yellow, green or white (Table 1).

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1. Attempts were made to estimate the values of γ and β of fishes in field, using the data described in the papers which have been published on the growth of fish by many investigators. As results of the attempts, it was noted that the values of γ and β of oceanic or active moving fishes are comparatively high, as compared with those of benthic or inactive moving fishes, and the fishes of high trophic levels are comparatively low in the values of γ and comparatively high in those of β, as compared with those of the fishes of low trophic levels.
2. The values of β' and β/β' of Seriola quinqueradiata in the field were estimated, based on MITANI's data⁶⁾, and these values of the fishes in the field are further discussed.

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This prper deals with the seasonal changes of the maturation index and histolagy of the ovary of the tanner crab, Chionoecetes opilio, (MAJIDAE, BRACHYURA), caught commercially in the Japan Sea.
The materials used were obtained by a motor trawl net which was operated in Wakasa Bay on the west coast of the Japanese mainland at a depth of 175-375m from October to June of 1964-1965 and 1965-1966. During the course of our fisheries biological survey of the tanner crab, we examined 577 specimens of the 10 th molting stage, 66.2mm in carapace width, just in the last stage of the juvenescent phase, and 1, 712 specimens of the 11 th molting stage, 77.4mm, which is equivalent to the last molting adult phase. An increase in the ovarian maturation index of the 10 th molting individuals was seen from October to June (Fig. 2), and the ovarian eggs reached the ripe stage in June. At that time no sperm were detected in the seminal receptacle of th females examined. Most of these crabs were in the pre-molting condition having duplicate carapaces of outer old and inner new ones. While samples for July to September could not be obtained, the maturation index of the 10 th molting stage showed decrease again in October. Further, specimens of the 11 th molting stage with soft carapaces were caught. The ovarian histology of these old crabs showed a dissinct recovery phase of an immature picture after spawning, accompanied by many spermatophores in the seminal receptacle. From the facts mentioned above, it is natural to consider that the molt of the females in the 10 th molting stage occur in the period from July to September, and mating and further spawning take place for the first time in this species. While the ovarian maturation index of the samples in the 11 th molting stage obtained in October consisted of two components, immature and mature groups (Fig. 3), the spawning season of these two groups may occur only once a year, from January to April. Therefore, it is estimated that the fertilized eggs which are oviposited from July to September and get attached to the abdomen of adult crab itself for the first time are protected for about one a half years but eggs after the second time are protected for only one year.

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In order to elucidate the maturity and seasonal changes in the testes and the biological minimum size of the male tanner crab, Chionoecetes opilio (MAJIDAE, BRACHYURA), known as one of the most important products in the Japan Jea, the present examination was undertaken with emphasis on the histology.
The materials used were caught by a motor trawl net which was operated in Wakasa Bay on the west coast of the Japanese mainland at a depth of 175-375m. In December, 1968, 45 specimens ranging from 36.8 (8 th molting stage) to 154.1mm in carapace width were examined to clarify the biological minimum size. On the other hand, 70 specimens collected from October to June, 1965 and again during the same period in 1966, were examined histologically to pursue their seasonal changes.
With the exception of a few individuals, no mature spermatozoa were detected in any part of the seminiferous tubules in the specimens of the 8 th molting stage taken in December. The functional spermatozoa were detectable in the spesimens of the 9 th molting stage, and the anterior portion of the vas deferens was filled with many spermatophores. Seasonal changes in the testis of the adult animal was not so remarkable with regard to external appearance, weight or volume, coloration and histologic features. Almost all the stages of spermatogenesis, in particular the spermiogenesis, were found easily in the seminiferous tubules of specimens examined throughout the year, Similarly, a lot of spermatophores occurred in the anterior portion of the vas deferens throughout the year. These results indicat that the male crabs older than the 9 th molting stage and 49.2mm in carapase width may have the ability of reproduction and mate with females at any time.

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The stimulatory effect of carbon dioxide dissolved in water upon carp palatal chemoreceptors were studied by recording the electrical responses from the palatine nerve supplying the chemoreceptors.
There were found taste units responsive to carbon dioxide in water. These units responded also to one of more of the four conventional taste stimuli used. Among them were units which responded well to carbon dioxide in water but not to hydrochloric acid. No marked correlations could be detected between carbon dioxide and the other stimuli in their stimulating effectiveness for these taste units.
The effects of carbon dioxide in phosphate buffer, in disodium hydrogen phosphate and sodium bicarbonate solutions were also studied. From the results with these mixtures, it could be suggested that carbon dioxide itself is responsible for receptor stimulation. It also appeared that the anion is important in stimulation by salts of carp chemoreceptors other than those specifically responsive to dilute electrolyte solutions.

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The blue meat of canned crab was digested by protease, and a blue substance was isolated. The chemical composition of the substance was in accord with that of king crab haemocyanin-sulphide complex, apart from the S content. Since sulphide in the substance was not measured before protease treatment, but was detectable after prolonged enzymatic treatment (48hrs. at 40°C), it was suggested that in fact the causative substance of the blue discoloration of canned crab meat was haemocyanin-sulphide complex.

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The copper in heat-coagulated haemocyanin was detected as cuprous ions under reducing conditions. It was masked with chelating agents such as EDTA, which showed that the valency of the copper in heat-coagulated haemocyanin was changeable depending on the reduction or oxidation of the solution. In the haemocyanin-sulphide complex, the copper was combined with sulphide. The copper and the sulphide bound with copper were found to be 17.6×10^-3 and 8.7×10^-3μM/mg respectively.

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The ion-exchange method of SPACKMAN et al. for determining the basic amino acids as well as carnosine and anserine was modified so that it is applicable to samples including
Table 3. Distribution of carnosine, anserine, and balenine in the muscle of crustaceans, molluscs, and sea cucumber.
balenine, and the method using a 50cm column of Amberlite IR-120 and 0.38N citrate buffer solution of pH 4.06 at 50°C was recommended.
The survey of carnosine, anserine, and balenine on the muscle extracts of various animals (mammals, 23 specimens; domestic fowl, 1; snakes, 3; fishes, 28; crustaceans, 3; molluscs, 6; and sea cucumber, 1) was undertaken in order to obtain unequivocal information about the distribution of these compounds, and it was found that considera ??, differences in the pattern exist among the species of animals.

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As one of the yellow pigments of pearl, acetone soluble pigment was obtained from the decalcified nacre of yellow pearl and purified by thin-layer chromatography. The pigment revealed purple color with antimony trichloride and gave an absorption spectrum having two absorption bands in the region between 400 and 500 mμ, of which character resembled that of flavoxanthin.

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The pigments responsible for the coloration of the yellow nacre of pearl were investigated. Yellow pigments were extracted with HCl-MeOH, fractionated by paper chromatographic procedure, and analyzed on their constituents. The yellow pigments consist of four kinds of pigments which were classified into three types based on their spectral characteristics in the ultraviolet region and color reactions with various kinds of spray reagents for paper chromatography. Among them, major yellow pigment, after acid hydrolyzed, gave rise to many amino acids and the substance giving color reaction characteristic of sugars.
From these results, it was deduced that conchiolin-like proteinous substance bearing some sugar derivatives as its constituent might be a major yellow pigment of the yellow pearl.

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Crude extracts from skeletal muscle of thirty-nine species of fish showed a considerable species variation of L D H and M D H isozymes in the number and electrophoretic mobilities. It was a marked contrast to the similarity of the L D H isozyme patterns in marine mammals studied in the present study and in terrestrial mammals. However, closely related species showed similar isozyme patterns, or contained some of vary similar isozymes of L D H and M D H. The electrophoretic patterns of L D H and M D H contained in skeletal muscle of fish species were complex to be attributed to the polymers formed by random association of two subunits under the control of two genes. The genetic basis and physiological meaning for the isozymes are discussed on referring to the results of recent investigations.

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1. The effect of the monosodium glutamate on the frozen-storage denaturation of the fish muscle actomyosin was studied by an in vitro model test of the isolated actomyosin as well as by a frozen-storage test of the washed mince of the fish meat. Besides the Naglutamate-free control group, glucose-added and urea-added groups were examined for comparison.
2. In the model test, 0.3M Na-glutamate was found as effective as or even better than 1M glucose in preventing the denaturation of actomyosin as far as the data on the solubility, viscosity, ATPase activity and the ultracentrifugal patterns are concerned (Figs. 2-5). There was not much difference between the results carried out in 0.6M KCl and those in 0.05M KCl. The addition of urea was rather promotive to the denaturation.
3. In 0.6M KCl, the effect of Na-glutamate approached the maximum beyond 0.025M (0.42%) (Fig. 6).
4. The Kamoboko jelly made of the frozen mince with added Na-glutamate was better than those of the control group in the keeping qualities as measured by the jelly strength, folding test and the amount of expressible water, and also by the amount of soluble proteins (Table 1).
5. The present results suggest the applicability of the model test for screening the additives for preventing the freezing denaturation, as well as for studying its mechanism.

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The measurement of streaming birefringence (SB) of 0.6M KCl extracts was made with a simple SB detector on about 140 fish meats having various histories. The intensity of SB detected was scored by a 6 point numerical scale, Using the technique described in this paper, SB was detected in the actomyosin solution, but not in the myosin solution.
As the intensity of SB was not related to the protein contents of the extracts, the relationships between the intensity of SB and the results of sedimentation analysis of the extracts were examined. The SB increased as the sedimentaion coefficients S₂₀ of the actomyosin was reduced. A good correlation was also found between intensity of SB and the height of the actomyosin peak on the ultracentrifuge pattern.

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