The dried commercial preparation of the marine alga, Porphyra tenera, known by the name of “Asakusa-nori” in Japan is widely consumed as food over here. It is graded on the market according to its color, lustre, taste, flavor, and form. Of these criteria of the classification, color is mostly resorted to since it goes hand in hand with the other characters and is very easily determined by the naked-eye examination.
Our chemical analysis has shown in the material from Corea that the grading by the color is given in terms of relative amount of chlorophyl in the preparation (Table 1). Seasonal variation of the content of the coloring matter in question was found to exist in this alga in life, reaching its maximum in February (Table 2). Such variation was proved, amongst others, responsible for the difference of quality of the preparations. Discoloration of “Asakusa-nori” from dark blue to reddish purple takes place during storage. This discoloration was found in close relation with decrease of chlorophyl content in it and the rate of the change was much influenced by the humidity.

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Experiments were conducted with nearly the same methods as those of Senô and his collaborators who worked on the eggs of Ostrea gigas, with the following results: -
1) The development of the eggs of Mactra sulcatria up to young shelled larvae was observed within a range of temperatures from 16° to 32°C, the optimum being 22°-28°C., and within that of salinities from 19.61‰ to 36.67‰ with the optimum 24.78‰-32.57‰.
2) The formation of larval shell is accelerated by higher temperatures up to 30°C., but it is retarded above this temperature.
3) The shell-formation is hastened by lower salinity down to 19.61‰, but it is slackened below this limit.
4) The percentage of abnormality of the fry varies inversely with the hatch-rate in relation to temperature.

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Soon after fertilization eggs of the Crucian carp, Cyprinus carpio, were put in 20 vials with water. Two of them were then placed in each of 10 compartments (Nos. 1-10) of a S_ENÔ-T_AUTI's serial incubator. They ran at temperatures differing from each other by nearly two degrees, No. 1 at the lowest (11.0°C.) and No. 10 at the highest (30.2°C.). With a view to determine the effects of temperature variations on the developing eggs one of the two vials in each compart-ment was interchanged with the corresponding one in another but the other vial in respective section was kept in situ as control. The interchange was made in 5 pairs, viz., No. 1 with No. 10, No. 2 with No. 9, No. 3 with No. 8, No. 4 with No. 7, and No. 5 with No. 6. The results, obtaind may be summarized as follows: -
1) Water temperature for normal development of the eggs ranges from 15° to 30°C., the optimum for it being at about 20°C.
2) The relation between the temperature (θ) and time in days (T) required for the eggs may be expressed, as given by H_IGURASHI and T_AUTI, by the formula Te^aθ=constant, in which a=0.09. The temperature coefficient for the embryonic development of the carp was found to be Q10=2.5.
3) Within the range of mean deviations 0.9-9.4°C. in the series of temperatures 11.0-30.2°C, the larger the temperature deviation the less the hatch-rate of the fry and the less the time required for hatching.
4) T_AUTI's formulae concerning the relation between the mean deviations of the water temperatur (M) and timein days (T_M) and that between the former and the percentage of the hatched fry ((N/N₀)_M) viz., T₀/T_M-1=a²/2M², and (N/N₀)_M=(N/N₀)₀e^-c_M2 where T₀ and (N/N₀)₀ are the time and the percentage when M=0 respectively, hold true for my material with the values of the constants c=0.0142, a=0.081, Q₁₀=2.3.

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Autumnal plankton associations observed in Okhotsk Sea in 1923, '29, and '32 may be referred to three main water masses, riz, (1) Oyasio water, (2) Tusima current water, and (3) the neritic water in the northern part of Okhotsk Sea.
(1) Oyasio water passes through somewhere between the Northern Kurile Islands to spread in the middle part of Okhotsk Sea. My observations show that (1) Plankton association is zooplanktonic, (2) Thal. long. and Coscinodisczus sp. are so rich as to call the diatom community by the name of Disco-plankton, (3) Calanus pulmchrus is always predominant, and (4) Tintinnodes form a significant part of the association consisting mainly of G. parafarella and Ptychocylis obtusa. Being different from the plankton association in the north Pacific Ocean in far richer animal constituents but a little poorer plant elements, subsidiary diatom species of this association are common to the latter to be referable to the same category of the diatom community with it.
(2) Due to Tusima current coming into Okhotsk Sea through Soya Strait, the plankton association from Japan Sea covers either an extensive (1928) or a narrow (1929 and 1932) are in the southern part of Okhotsk Sea with the following characteristics: -(l) the plankton association is phytoplanktonic, (2) microcalanids are abundant, but macrocalanids such as Calanus pulmchrus and Eucalanus elongatus are scarcely observable, (3) diatom community is Styli-plankton (1928) or Chaeto-plankton (1929 and 1932), (4) Tintinnodes consist of G. Parafazella and Ptychocylis obtusa, which are rich in Okhotsk waters on the one hand, and of Uadella sp. and some others rich in Japan Sea on the other. Needless to say that the plankton as ?? whole is richer in species here than in Okhotsk water.
(3) The neritic water in the northern part of Okhotsk Sea is characterized by the monotonous dominance of Chaetoceros spp. The diatom communities are similarly rich in fine Chaeloceros-species in 1928 and '29, and especially so around Cape Lopatka in 1928. Considered from these data, the diatom community of Oyasio water is probably modified around Cape Lopatka or on passingthrough the North Kurile Islands to be brought all around the northern partof Ok Thisdiatomcommunity appears along the coast north from Kitasiretoko Saki (Cape of Patience) being carried by vita Karahuto cold current. The extension of this neritic plankton association is dependent upon the intensity and directionof Oyasio water pouring into Okhotsk Sea, being wide in 1928 but narrow in 1929 and 1932.
(4) In the region north from the Near Islands and around Komandorski Island, Denticula-plankton is observed and in its southern region Chaeto-plankton (Chaet. crioph. and C. atl.) is present. In the northern part of the Rat Islands Disco-plankton is present, while in its southern part Nitzschia-plankton is present. All these categories of diatom communities in the West Aleutian Islands Sea differ from each other in their leading species, although they are quite similar in their constituents of diatoms. Nitzschia-plankton spreads toward the southern coast of Kamtehatka, and Denticula-plankton invades into this region along the coast of Kamtchatka from the Near Islands and Komandorski Island. Nitzsehia-plankton includes a fairly large number of Thal. long., Cos. sp., Chaet. crioph. and Chaet. atl. in addition to Nitz. ser. This plankton association becomes zooplanktonic and Disco-plankton in Okhotsk Sea, after passing through the North Kurile Islands.

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I) As regards Nisikurasawa Keddle Net (Fig. 1) by which yellowtail have been most abundantly caught of all fishing grounds in Suruga Bay, the daily catches of yellowtail and bluefin tuna and their younger fishes were examined in the seasons of yellowtail Jan. ?? May of 1921, '22, '25, '28, '29, '30 and '31 and in the summer months, June ?? July, of 1922 and '30.
i) Averaged total catches and averaged centers of the fishing seasons of the most important fishes, yellowtail and young bluefin tuna, are given as follows: ??
ii) The durations of abundant catch and scarce catch of yellowtail and young bluefin tuna appear somewhat periodically (Fig. 2 and 3).
II) The numbers of fish in daily catches and the possibility of occurrence of the catch on each day of normal year being defined, the catches at Sigedera and Nisikurasawa Fishing Grounds were studied with the results summarized in the following lines: -
i) At Sigedera, the primary fluctuation of a period of 130 days is noticed in the daily catches of young bluefin tuna in the duration spreading over about 20 months, 0- to II-age fish, in normal year (Fig. 4) and there exist also the secondary fluctuations of about 20 dayperiod as shown in the text-figure; it is very remarkable in its most abundant season.
ii) The above-mentioned secondary fluctuations are also noticed in the daily catches in the most abundant season of normal year of Nisikurasawa (Fig.5) preceding those of Sigedera by about one month.
iii) Though the catch of adult yellowtail at Sigedera (Fig. 6) are very scarce in contrast with its abundance at Nisikurasawa (Fig. 7), its younger fish being rather abundantly caught at the former (Fig. 6).
The fishing seasons of the adult and young are different respectively at both fishing grounds.
III) Together with some other fragmental records of the catches of many keddle nets along the coast of Suruga Bay in 1930, the following conclusions were obtained.
i) The day of the most abundant catch of each fishing ground became later toward east along the northern coast of the bay and the total catch during the whole duration and the catch on the day of the most abundant catch were smaller toward the east in 1930 (Table 3),
ii) The fishing seasons were nearly the same in the fishing grounds along the northern and western coasts of the bay but the intervals of abundant catch and scarce catch seemed to take place alternately in the two districts.

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