1. The Yubetsu and Shokotsu Rivers, near Abashiri in Hokkaido, were investigated in November and December 1965,and in May 1966 with regard to the influence of starch factory effluents on stream organisms. 2. The biotic indices according to the Beck-Tsuda method are shown in Fig. 4,Table 3 and Table 5. 3. In both rivers, the starch factory effluents are not very serious but give bad effect on the stream organisms. 4. The Abashiri River, Hokkaido, was investigated in Novemer and December 1965 and in May 1966 with regard to the influence of industrial wastes from the beet factory upon the bottom fauna. 5. The biotic index according to the Beck-Tsuda are shown in Table 7.
There are chestnut forests having a marked variation in growth rate in the Yangju and Tangjin districts. Soil samples and chestnut foliage collected from the two districts were analyzed for several elements. The soil nutrients have no relation with the height growth of the chestnut trees in the two districts, however, the levels of foliar nitrogen and phosphorus were significantly correlated with the height growth of the chestnut trees. Foliar nitrogen and phoshporus displayed an inverse correlation with the soil calcium level. So it can be said that the level of soil calcium indirectly governs the height growth of the chestnut trees.
In the summer of 1965,the alpine vegetations of herbaceous and dwarf shrub communities were investigated phytosociologically near the summits of the lide mountains, which are situated only about 40km distant from and facing with no obstacle the Sea of Japan. From the results obtained, the following associations are recognized in the region. 1. Association Primulo-Faurietum crista-galli nov .(Table 1) Ia. Subass, typicum Ib. Subass. veratretosum Ic. Subass. vaccinetosum 2. Association Leontopodio-Arcterietum prov. (Table 3) 2a. Subass. empetretosum 2b. Subass. potentilletosum The two new associations proposed here are obvious to be included in the alliances occurring in the alpine zone, in spite of their having several subalpine components cited in the tables. The occurrence of the alpine communities near the summits of these mountains could be due mostly to the following environmental factor : The area for the associations are covered by deep snow every year. The alpine communities discussed here might have possibly been substitutional vegetations for the coniferous forests. Considering these, the vegetational zone called"pseudo-alpine zone", might be discussed more in the future, because the communities proposed here are considered to be one of the compensational vegetations.
A population study of C. suppressalis was carried out at Takada, in 1954 and 1965,from June to August. In the former year, the main duration of larval hatching was comparatively short and, afterwards, the age constitutions of the borers changed rather regularly from young to old with the lapse of time. By following the analysis-of-variance procedures, it was clarified that larval density maintained unchanged for a month and this was succeeded by a drastical decline in the population. The year 1965 was characterized both by far lagged initiation of the infestation with the borer and by a remarkably low intensity of occurrence of the species. In this year, the maintenance of a stable larval density was also exhibited for a month but this was not succeeded by such a notable population decrease as seen in the previous year.
The standard metabolic rates of fishes were measured for fundamental data that are useful for the estimation of the minimum amount of food required and for the consideration of the production problems. Various sizes of 17 species of fishes living in Lake Biwa were selected and their oxygen consumption was measured. The apparatus employed was similar to Hall's experimental apparatus using the running water system. The results obtained showed that the relation between oxygen consumption (R) and body weight (W) could be expressed by the equation, well known in the field of respiration physiology, R=KW^b (b : weight exponent constant, K : metabolic level). By the least square method, the values of b for each species was determined. Eliminating the values b having large standard errors, the values of b ranged from 0.41 to 1,the mean of which was 0.68,this is very close to the value 2/3. It was concluded reasonable to adopt the value of 0.68 for all fishes except "YARITANAGO" (Acheilognathus lanceolata) since the assumption, that is, the value of b for each species of fishes is 0.68,was not rejected statistically but for "YARITANAGO" it was rejected. Then assuming the value of b as 0.68,the values of K were calculated from the same equation, which was termed K_c, and then the metabolic levels at 20℃ (K_20) were determined from the values of K_c by assuming Q_10=2.5,with the aim of comparison between the oxygen consumption of different species of fishes. Values of K_20 obtained from laboratory experiments in which the fishes were kept in starvation, were about 0.3 for many species. On the other hand, the values of K_20 obtained from field experiments in which the fishes supposed to be not starved were about 1.1 on avarage. In this case, the K_20 values of a few species, that is"NIZIMASU"(Salmo gairdnerii), "BIWAMASU"(Oncorhynchus rhodurus), "AYU" (Plecoglossus altivelis), "ISAZA" (Chaenogobius isaza), were especially higher (1.58-2.23). Except for the above four fishes, they were about 0.7 which was about twice as much as those obtained from laboratory experiments (used fishes kept in starvation).