Meteorological observations were made at the grassland of the Utsukushigahara Heights (ca. 2000 m above sea-level) situated in the subalpine zone. The air temperature at this Heights was about 7℃ lower than that at Matsumoto City (ca. 600 m above sea-level) through the season. During the winter period, the depth of snowdrift in the Heights varied topographically. The snow temperature in the upper zone, or down to a depth of 10 cm was consistently lower than the air temperature, but that in the zone lower than 10 cm in depth was higher than the air temperature. The snow temperature was affected by the variation of the air temperature with the lapse of time, and there was less variation and a rise in the snow temperature with the increase in the depth of the snow. The thinner frozen-layer of the soil was found with the increase in the depth of snowdrift, but the soil below the 150 cm deep snow was not frozen. When the soil was frozen under a thin snow cover, in the bare-ground, the frozen-soil consisted of three layers. That is, the upper layer was frozen hard, the lower one was frozen slightly, and the larger between them contained numerous ice-needles and crevices. In the grassland, however, there were two frozen layers without the development of the middle layer. In the light-snow region of the subalpine zone, the middle layer of the frozen-soil in the bare-ground seems to prevent the plant invasion.

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In this part, the mode of breeding and some morphological variations of each population of the landlocked Ayu-fish, after the period of their sexual maturation, were investigated. The lake population of the Ayu of small size contained considerable numbers with nearly matured gonads at the end of summer, and they began to migrate to the lower reaches of the streams during the period from late-August to early-September, in crowds of high density. Spawning colonies with highly condensed aggregation of spawners comprising individuals of similar body size were formed at the spawning beds in the shallow parts at the lower reaches of the streams near the estuary. The stream population usually began to migrate to the spawning places in mid-September. Their spawning beds were around the lower reaches of the streams and with fairly larger limits compared with those of the lake population. The size composition, the time and the route of their spawning migrations were rather irregular, and they did not form such a definite spawning colony as stated above. The degree of the maturity of gonads and the mode of arrival to the spawning places suggested that the early ascending group would spawn a little later than the other. The spawners from the lake had higher dorsal fin ray counts than those from the upper streams, and the means differed significantly between both populations. The predorsal length, the numbers and the diameter of the ova, and the numbers of gill rakers of each population were measured or counted. From these results, it was revealed that these characters tended to be correlated with the body length. In other words, these differences between the populations conld be attributed to the differences in their rate of growth.

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As a part of our biofaunistic surveys on the wild bees in Hokkaido, periodical sampling was made in 1966 (supplemented in 1967) two times per month at a littoral sand-dune vegetation at Hama-Koshimizu, Eastern Hokkaido, facing the Okhotsk Sea. The halictine bees, especially Evylaeus, occupy the majority of the total 55 species and the total of 1,045 individuals sampled. Bumble bees were second in numbers of individuals. Compared with the bee fauna in Central Hokkaido, the scarcity of the leaf cutting bees (Megachilidae) and anthophorine bees (especially Ceratina) is remarkable. Because of the severe climate, the activity of some vernal species shows a delay of nearly one month compared with that in Sapporo, resulting in the temporary co-existence in June of both vernal and early summer bees in Sapporo. The area is relatively free from the invasion of exotic plants. The visits to native plants show various relations between the amount and duration of blooming and bee visits, with the highest visits to Rosa rugosa, Coelopleurum lucidum and Geranium miyabei. But Taraxacum officinale, one of the predominant escapes in Hokkaido, already occupies the first rank in the visits, amounting to 29.4 per cent of the total bees sampled.

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The subalpine vegetation in north Honshu shows a sharp contrast in physiognomy. Abies mariesii and Tsuga diversifolia are well established in the inland subalpine region while scarcely in the Japan Sea area. On Mt. Gassan in the Dewa mountains, Abies mariesii occurs sporadically on a lava plateau situated on the leeward side of the mountain and screened from the strong westerlies or northwesterlies in winter. It was revealed by the pollen-analytical study aimed to elucidate the vegetation history of this mountain that the subalpine conifers had been more extensive here under the Late Pleistocene climate but retreated under the more recent conditions of heavy snowfall and strong wind. The present occurrence of Abies is, therefore, thought to be a relict of the Late Pleistocene. Further investigations were made on the floristic composition of the Abies habitat, the community structure, the dynamics of the Abies population, the growth form and the soil profile of its habitat. The physiognomy of the Abies community is, as a whole, that of the mixed thicket of Abies and deciduous broad-leaved shrubs, covering the wet alpine podsol on the ill-drained flats. The stems grow so high on the well-drained soil as to be injured or deformed seriously by the heavy snow cover and strong wind, so that they can hardly survive there. The wet alpine podsol is probably of great advantage to the Abies survival because of the stunted form that prevents suffering from the effect of snow and wind.

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