The examination of some chemical and antigenic properties of the toxic factors of A. Liquefaciens indicated that there were no remarkable differences in their characteristics between the necrotic factors for guinea pig and eel, and between the hemorrhagic factor for guinea pig and the lethal factor of mouse. The necrosis may be caused by bacterial protein, while the hemorrhage and the death may result from more complicated cellular substance.

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The method to pump up ayu fish (Plecoglossus altivelis T & S) from beneath dam to upper stream of a river was tested. Also, the reactions of the fish to various acoustic noises and to several colored boards were observed.
The results obtained are summarized as follows:
1) It was found that ayu fish can be pumped up by fish pump from beneath dam to upper stream of a river (Figs. 1, 2, and table 1).
2) The fish was stimulated by the under water noises of low frequency, and it is suggested that the pumping efficiency could be increased by using these acoustic noises (Tables 2, 3, and Fig. 4).

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Accumulation and Retention of ¹⁰⁶Ru by genuine goby, Acanthogobius flavimanus, were investigated for the case of ingestion of the contaminated food.
The average uptake of ^1O6Ru following single oral administration was observed as approximately 5% of the administered dose in either Ru/N or Ru/Cl form. The apparent equilibrium condition reached about 12 days after beginning of the experiment. The body burden at this state was about 20% of the average daily dose.
The concentration factor for genuine goby over annelid worm was about 0.002, and hence, the transfer of ¹⁰⁶Ru through this kind of food chain was relatively small in comparison with the direct uptake from the surrounding sea water.

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In a previous paper discussion was given of the relation between the condition of the stomach mucous folds and the stomach content in the skipjack. The present paper deals with a similar problem in the mackerel (Scomber japonicus). The mean length of empty stomachs of mackerels of 50 grams in average body weight was 2.86cm. The maximum stomach length under the condition of the complete satiation was about 7cm. As shown in Fig. 2, a tendency was observed that the stomach length decreased in proportion to the stomach content in progress of time after satiation. The experimental values obtained on the relation between the stomach diameter and the stomach content were very dispersed (Fig. 3). On the assumption that the mackerel stomach expands and contracts in the form of a cylin-der, the formula described below was worked out:
√0.92S_cw/π(2.86+0.519S_cw)+0.672=_Sd
Sd: stomach diameter in cm.
S_cw: stomach contents in grams.
A theoretical curve derived from the assumption is shown in Fig. 3. The conditions of the stomach mucous folds were macroscopically divided into the 5 classes given in Table 1. The relationship between the conditions and the amount of the stomach contents is given in Fig. 4, which indicates that when the stomach contents reach to 2 grams, the folds mostly disappear. The extention rate of the longitudinal muscular layer of the stomach in the state of the complete satiation was 2.5 and that of the circular muscular was 1.9.

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The present paper dealt with some ecological findings of the spawning shoals of the yellowtail migrated to the fishing ground, Komame, Kochi Pref., (Fig. 1) in May of 1966, and induction of spawning with“synahorin” injection. The shoals of this fish treated here are mainly composed of rather small fish, as heavy as about 5kg in body weight (Fig. 2). All of the male fish examined are enough ripened, the sperm easily runs out from the body by the external pressure. Although the female fish vary from individual to individual in maturity, the ones belonging to the middle mature stage, in which the gonad is well enlarged, the largest ovarian eggs reach 0.50 to 0.70mm in diameter, are dominant in number at the beginning of May. While, in the middle of this month the full mature female having larger eggs ranging from 0.8 to 1.0mm in diameter are numerous. Some ripe ones are also found throughout the season examined, but they do not beyond 9% of total fish migrated here. Based on the result obtained, it can safely concluded that this fishing ground seems to be a spawning area for the Pacific population of the yellowtail. The ovaries of the yellowtail reaching 70cm in fork length, injected with “synahorin” rapidly increase in their weight (Table 1), and with ripe eggs, 1.15 to 1.25mm in diameter, in one or two days after injected (Table 2, Fig. 3).

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Ultracentrifugal pattern and the rate of flow birefringence of 0.6M KCl extracts from the muscle of horse mackerel were determined, and the jelly forming ability of the fish meat was also measured.
In the experiment, different types of the muscle in the postmortem changes have been found: the protein changes as the progress of time after death of the fish, and the jelly with very high strength can be produced only when the muscle is fresh; the protein hardly changes for a long time after death of the fish and jelly with very high strength can be obtained even if the muscle is unfresh; on the contrary, the protein changes easily and any jelly can not be produced even if the muscle is fresh.
There was no clear relationship between the above mentioned properties of the muscle and fishing ground, season or method.

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1. The requirement of young carp for thiamine was studied by using the carbohydraterich test diet devised by HALVER et al., and three kinds of antithiamine, namely amprolium, pyrithiamine, and oxythiamine.
2. In the feeding experiment for 11 weeks, young carp showed deficiency symptoms characterized by anorexia, fading of body color, congestion of the fins, and ecchymotic congestion around the skin.
3. Addition of amprolium caused the similar deficiency symptoms to those found in fish suffering from the dietary thiamine deficiency. Pyrithiamine caused a typical nervousness and a slight retarded growth with anorexia, and oxythiamine only a marked retarded growth without nervousness.

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Hyaluronidase was demonstrated in the extracts from liver, heart, kidney, digestive tract and others of the fish. The enzyme was not demonstrable in testes of many fishes. A special mention was made on the existence of a large amount of hyaluronidase in the extracts from stomachs of certain carnivorous fishes. The property of bacterial hyaluronidase was different from that of fish stomach enzyme, and bacterial enzyme was not responsible for the enzyme action in the stomach extracts.

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Carnosine (β-alanylhistidine) and its methylated compounds occur widely in the muscles of many species of animals. Anserine (β-alanyl-1-methylhistidine^**) was first detected in the goose and later in many species^{2, 3)}. Ophidine (β-alanyl-2-methyhistidine^**) has been reported to be present in the cobra and some other snakes^{4 ?? 9)}. Finally, balenine (β-alanyl-3-methylhistidine^**) was recognized in the meat extract of whales^{10 ?? 12)}, and proved to be identical with cetasine^{11, 13)}.
TSUNOO et al.¹⁴⁾ recently reported the presence of ophidine in the three species of dolphin, Tursiops truncatus, Grampidelphis griseus, and Feresa attenuata, on the basis that the infrared absorption spectra and melting point agreed with those of ophidine from the snakes. The authors¹⁵⁾ have determined the amounts of carnosine, anserine and balenine, together with the constitutional imidazole compounds, in the extractives of whale meat by the chromatographic technique using an Amberlite IR-120 column (0.9×50cm). However, the indication showing the occurrence of ophidine and 2-methylhistidine in the Odontoceti has not been observed so far on the chromatograms.
The present investigation was undertaken to identify the main imidazole dipeptide in the muscles of several kinds of animal. The peptide preparations obtained from the extractives of snake and dolphin by the procedure of NAKAI et al.¹⁶⁾ and from those of dolphin by the method of TSUNOO et al.¹⁴⁾ showed the same infrared absorption spectrum as of ophidine described by TSUNOO et al.¹⁴⁾ It has become clear from nuclear magnetic resonance (NMR) study that the peptide is β-alanyl-3-methylhistidine and not β-alanyl-2-methylhistidine. The details are given below.

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