As a lymphoid organ was found in the vascular system, its anatomical and histological structure was studied.
1. The position of this organ differs slightly in the male and female. In the female, it is pressed by the ovary onto the upper anterior part of the liver.
2. An afferent and many efferent vessels led in and out are observed. The former is connected with the antennal artery and runs along the anterior edge of the liver to be led ultimately into the organ. In the female, the afferent vessel passes through the ovary. It is composed of an endothelial cell layer and surrounding loose fibrous tissue. Mesodermal reticular cells are scattered in this fibrous tissue.
The efferent vessels emerging from several places of this organ usually expand to form cysts but those emerging from the anterior external edge and from the interior edge are tubiform. The former are connected to the upper part of the leucopoietic organ, dorsal epidermis, gonads, etc. The latter are linked with the lymphoid vessels below the cardiac stomach. The cystiform vessels complicatedly bending around the organ are linked with the lymphoid vessels, but the one linked with the liver tunica penetrates the small openings of the tunica into the liver. The efferent vessels are composed of adventitia of longitudinally running fibers and the intima of endothelial cells.
3. The afferent vessel is bifurcated progressively immediately after entering the organ, and each becomes the central artery of the sheath which is a structural unit of this organ. The spaces between the peri-arterial sheaths take the form of winding, interconnected sinuses. The wall of sinus is made up of sporadical endothelial cells and argyrophil lattice fibers.
4. The pulp of this organ is the peri-arterial sheath which surrounds the bifurcated artery in the organ. The wall of the central artery is made up of a layer of flat endothelial cells in which interstices are found. The peri-arterial sheath is composed of free cells and interstitial tissues which consist of reticular tissue and fibrous tissues. In fibrous tissues, argyrophil fibers are distributed in flagments and concentrically within the peri-arterial sheath, and collagenous fibers are distributed outside this layer of argyrophil fibers.
5. The greater part of the free cells in the peri-arterial sheath are lymph-like cells and distributed mainly in the argyrophil fiber layer. In this fibrous layer, there are observed certain cells which are believed to he their young cells. Moreover, these free cells are extruding into the arterial lumen through interstices in the endothelial cell layer. Lymph-like cells measure 2.5-4.0 μ in diameter and they have very thin cytoplasm, and nuclei which are stained well by haematoxylin especially at the peripheries. Discoid free cells, measuring 6.0-8.0 μ in diameter and poorly stained by the haematoxylin can also be recognized in the sinuses. Comparing these free cells with the lymphocyte-type cells produced in leucopoietic organ, which resemble each other most closely, the lymph-like cells are clearly distinguishable from the lymphocyte-types, but free cells in the sinuses can not be distinguished from them.
6. The lymph-like cells of the peri-arterial sheath frequently vary in quantity with the abnormal changes in the body. The peri-arterial sheath, as well as the central artery, is filled with lymph-like cells and their young cells. Besides this, the reticular cells of the peri-arterial sheath degeneratively fibers and a large amount of granules appear in the fibers. It can be further confirmed that those cells are released into the central artery.

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From the trawl fishing grounds in the eastern Bering Sea, the author collected the specimens of yellow-fin sole, Limanda aspera (PALLAS), which were caught by the training ship “Oshoro Maru” of the Faculty of Fisheries, Hokkaido University, during the 1st to 11th of July, 1963. The author studied the relation between the age and the size of yellow-fin sole by the otolith examination, and analysed the annual variation of the length frequency distribution.
The results obtained are summarized as follows:
1. The growth of yellow-fin sole was very slow, and the number of females was remarkably more than that of the males. The average length of the females was larger than that of the males; and this difference increased over the 9 year old groups. 2. The average length of fish in the 4 and 5 year old groups in the eastern Bering Sea were somewhat larger than those in the Chukchi Sea, but generally smaller than those of fish shoals in the west coast of Kamchatka.
3. The age composition of the fish examined were from 4 to 14 year old groups, and the 8 year old group occupied 20.7% of all. Then came the 9, 6 and 5 year old groups in that order, and the percentage of the 7 year old group was very low. The 7 year old group was born in 1956 when the water temperature was rather low, whereas the 8 and 5 year old groups of high percentage were born in 1955 and 1958 when the water temperature were rather high. This quantitative fluctuation among the year class groups reasonably be due to the annual variation of the cold water mass in the year when they were born.
4. The author compared the length composition of yellow-fin sole caught in 1963 with that of 1956 when fishing intensity were not so high, and with 1959 and 1960 when the effect of high fishing intensity began to appear, and consequently recognized that the percentage of larger sized and higher aged fish was decreasing year by year.

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1. The effect of the level of δ for the variability of the estimated value of parameter by the tracing method was remarkable. For the following analysis, the value of b was dicided to be the lowest level, that is, δ(Ir)=0.02, δ(M)=0.1 and δ(q)=0.05.
2. The variance of the estimated values of parameters was minimum when the tracing index ?? ₁ was used, indicating that ?? ₁ is most suitable among the three tracing indices examined.
3. For the evaluation of the variability of estimated value of parameter, artificial catch and fishing intensity data produced by a simple variation model with error control parameters (α_f and α_c) were applied because it was difficult to evaluate the error of the actual data and data processing system. Three levels of α_f and α_c were tried.
4. The effect of α_f and α_c on the variance of the estimated values of population parameter were very significant, and significance of the interaction of α_f and α_c was also observed.
5. The variance of estimated values in case of α_f=α_c=0.15 was very large, about nine times of that in α_f=α_c=0.05.

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1) In order to get a morphological basis for the development of osmoregulatory adaptation mechanism during the seaward migration in salmonid fry, histological observations were made on various organs of the chum salmon fry, Oncorhynchus keta, captured at some points on the route of their seaward migration. The same examinations were also done using some groups of the fry of chum salmon and of rainbow trout, Salmo gairdnerii irideus, which had been for kept in diluted sea water one or three weeks after in fresh water.
2) In the trout, peculiar enlargement of the anterior region of the adenohypophysis was noted after the transference into the diluted sea water from fresh water. On the other hand, in the salmon fry which showed no distinct changes such as that above-described.
3) Chloride secretory cells had been clearly differentiated in the salmon fry immediately after hatching. In contrast, in the trout fry, the cells were in no case detectable in their fresh water stage, and made their obvious appearance after having been transferred to the diluted sea water.
4) Histological informations about the osmoregulatory role were hardly obtained from examinations on the gonad, the thyroid, the interrenal gland, the caudal neurosecretory system and the liver.
5) Discussions were made on above characteristics of chum salmon in comparison with the poor salinity tolerance of rainbow trout fry.

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The behavior of the flying fish spawners was studied through the catch per operation of three purse seine boats in the fishing ground off Hamada, Shimane Prefecture, in late June, 1967.
1. The fishing ground is formed in the coastal area within 2km from the shore with the depth of 10-30m of sandy bottom.
2. The frequency distribution of mean catch is exponential and the coefficients of variation in catch are larger than those of drift nets, indicating that the purse seine is an unstable fishing method.
3. It is seemed that the flying fish are distributed evenly near the surface during the time of 1 to 3pm, while they actively form schools around 4pm and begin to go to the bottom around 8pm.
4. The behavior of the flying fish is seemed to be controlled by luminance in the sea. The school formation becomes vigorous when the light intensity falls to about 5000lux and ends as it drops below 1000lux. The dense schools move toward the sea bottom at the time of weak luminance of several lux.

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1. Two type of 5-nitro-2-furoates, phenylthio-5-nitro-2-furoates (IV) and phenyl-5-nitro-2-furoates (V), of which benzen ring was substituted with methyl, halogen or nitro group, were prepared for the study of bacteriostatic activities.
2. Some of (IV), p-chlorophenylthio-5-nitro-2-furoate, p-bromo-phenylthio-5-nitro-2-furoate and benzylthio-5-nitro-2-furoate, showed strong inhibitive action on Staphylo-coccus aurcus 209p in vitro.
3. Phenylthio-5-nitro-2-furoates (IV) were more effective than phenyl-5-nitro-2-furoates (V).

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The unsaponifiable fractions from the Japanese holothurian Stichopus japonicus, and from the mediterranean one Holothuria tubulosa have been analysed by usual chromatographical technics and mass spectrometry.
These animals contain mixtures of Δ-5 and Δ-7 sterols (C₂₇, C₂₈ and C₂₉); the Δ-7 series predominates in agreement with the findings already published by other authors. The triterpenic alcohols, lanosterol and cycloartenol have been isolated as their epoxide propionates. D-xylosides of C₂₇, C₂₈ and C₂₉ Δ-5 sterols have also been isolated and analysed.

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The biosynthesis of sterols, squalene and triterpenic alcohols from an acetate 1, 2-¹⁴C has been investigated in Stichopus juponicus. The holothurian does not incorporate the acetate neither into sterols nor into the triterpenic alcohols; however, squalene was labelled in this experiment.
It is suggested that holothurins have an exogenous origin, or are transformation products from constituents of foods

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1. The liberation rates of inorganic nitrogen compounds from bottom muds to sea water were examined in Maizuru Bay, the methods to estimate them being clarified.
2. The results obtained by the method using the core mud sampler showed that the rates mentioned above were comparatively small, i.e. 0.1-2.Oμg at. N/100cm²/hr, and that the rate of ammonia usually was the largest of these inorganic nitrogen compounds.
3. The similar amounts of inorganic nitrogen compounds were liberated from the bottom muds prepared in the aquarium, althogh most of them was occupied by nitrate.

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1. The uptake or liberation of inorganic nitrogen compounds of the microorganisms as a whole in sea water was examined in Maizuru Bay, the methods to estimate the rates being clarified.
2. The uptake or liberation was very small, i.e. 0.01-0.5μg at. N/1/hr. Among these values, that of ammonia usually was the highest.
3. These values were estimated to be about ten times of the rates of supply of inorganic nitrogen compounds from bottom muds to sea water. From the result, it has been suggested that the nitrogen in the bay circulates mainly in sea water itself and the course of nitrogen cycle, which passes through bottom muds, is not so important.

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A simple method for measuring Ashi [the elasticity proper to fish meat jellies (so called Kamabokos)] was estimated. It was proved that comparing with Miyake's gelometer⁴⁾, this method gave more satisfactory results and a close correlation with the values obtained by gelometer.
It was previously reported by SHIMIZU²⁾ that the pH of salted fish meat paste of flying fish gave an important effect on the elasticity, and the authors intended furthermore to clarify the relation between pH of meat pastes and the elasticity of Kamabokos using various fish. The results indicated that the optimum pH's of meat pastes of dark- and white-fleshed fishes (for the formation of elasticity) were 6.2-6.7 and 7.0-7.5, respectively, and that of horse mackerel was 7.0-7.2.

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1. Frequent outbreaks of ciguatera poisonings in the Ryukyu and Amami Islands were disclosed, and 99 case histories were collected and analyzed.
2. Among about 20 species of fishes reported to be toxic, the followings were found to be the most frequently implicated: Lutjanus bohar, L. monostigma, Gymnothorax spp., Epinephelus fuscoguttatus, and Variola louti. Symptoms induced by these fishes were similar to each other and characterized by aching joints, languor, dry-ice sensation, diarrhea, and vomiting.
3. A rabbitfish, Sigamis fuscescens, was reported to cause itching and headache in a short period after a heavy rainfall in June.
4. Besides fish poisoning outbreaks of poisoning due to ingestion of toxic turtles and coconut crabs were confirmed.

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1. The presence of ciguatoxin was confirmed in some of ciguatoxic fishes in the Ryukyu Islands, besides ciguaterin previously found in a grouper. The coexistence of ciguatoxin and ciguaterin was also demonstrated in the muscle of L. monostigma and the liver of L. bohar.
2. The distribution of ciguaterin was examined by using cats as test animals. The liver of all specimens was almost always moderately or strongly toxic, but the muscle rarely and weakly toxic. Ciguaterin was also detected in the gonads of L. bohar.
3. The chramotographic behaviors and pharmacological actions of ciguatoxin in L. bohar from the Ryukyu Islands were quite identical with those of ciguatoxin in L. bohar from the South Pacific.

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