In the present paper, the vertical distribution of freshwater planarians in two large islands in the Inland Sea of Japan (Awajishima Island and Shodoshima Island) and in the mountainous districts in Shikoku (Mt. Tsurugi and the Akaishi mountain range) is reported. The area surveyed is shown in Figure. 1. There are several low mountains in Awajishima Island (Mt. Yuzuriha 608 metres in altitude above sea level). Mt. Hoshigajo in Shodoshima Island is 817 metres in altitude above sea level. Mt. Tsurugi is the main peak of the eastern part of the Shikoku Mountains and is 1955 metres in altitude above sea level. The Akaishi mountain range is situated north-east of the Ishizuchi mountain range, the western part of the Shikoku Mountains. The main river systems in the area surveyed in Shikoku are the Yoshino, the Nakagawa, the Kokuryo and the Kamo. The surveys were made in 1957 (Shodoshima Island) and 1967 (other districts). In the area surveyed, Dugesia japonica ICHIKAWA et KAWAKATSU was common in the stations both on the plain and in the mountainous districts (below about 1460 metres altitude in the Mt. Tsurugi district). Phagocata vivida (IJIMA et KABURAKI) was found in the brooklet in Mt. Hoshigajo in Shodoshima Island. In the Mt. Tsurugi district, this species was found at the stations of cold-water within the altitude range from about 1220 to 1800 metres. This species was also found at the stations within the altitude range from about 1080 to 1620 metres in the Akaishi mountain range. The type of the vertical distribution in Shikoku is shown as J-JV-V (J : D. japonica ; V : Ph. vivida). Several fragmental records on the distributional ecology of freshwater planarians in Shikoku are described (Fig. 1). Recently, D. japonica was collected from a spring in Oshima Island in the Inland Sea coll. Mr. Y. MURAKAMI) as well as from a shallow stream in Ryo-no-iwaya Cave in Anan City, Tokushima Prefecture (coll. Messrs. Y. MORIMOTO and Y. MURAKAMI). The cave specimens examined show no morphological peculiarity.
This report deals with polygyny, the share of the work done by the male and female, territoriality, song and breeding process of the Eastern Great Reed Warbler. These studies were made along the reed bed of the Chikuma River, Zenkoji basin, Nagano Prefecture during 1965 to 1966.
1. Settling substances were collected from the lake water for 24 hours every 10 days from August to December, 1966,at three stations in the pelagic region and at three places in the shallow zones covered with larger aquatic plants by taking them into an apparatus of funnel type with the opening of 30cm in diameter each set 50cm above the bottom. 2. The precipitating substances greatly vary in amount from station to station. The amounts are generally larger at places in the bare pelagic zone than those where floating or submerged plants grow densely. The largest amount was obtained in the shore region of Kamisuwa City where the lake is most severely polluted. In average the amount collected is estimated to be 15.57 g/m^2/day in dry weight. 3. Depositing to the bottom is always more extensive on windy days. Significant correlation was found between the amount and the mean velocity of the wind of the day the samples were taken. The relation in the bare pelagic zone is expressed by P=10^<(1.19V-2.41)> where P is the amount of deposition per day, V the mean velocity of the wind of the day. No correspondence is found in the amount of deposition either to the wind velocity of the day before the collection or to the amount of rainfall of the previous day inclusive of that day. 4. Microscopic examination reveals that the predominating substances consist of diatom shells occupying about 50 per cent in volume of the total samples. The remainders are all finely divided inert detritus of either organic or inorganic nature. The diatom shells are of the species which were dominant during the previons spring, i.e. Melosira, Synedra and Asterionella. 5. Thus a conclusion may be drawn that the precipitation in this case do not entirely represent the addition of the new bottom-making materials settling through the water, but for the most part the re-precipitation of the so-called gyttja stirred and floated up by the forces of winds and waves. 6. Pure precipitating materials through the water was estimated to be less than 3g/m^2/day from the actual data obtained on calm days.
Measurements of how much proportion of ingested or assimilated food in terms of dry matter, caloric content and nitrogen content is converted into larval tissue("conversion efficiencies")and reserved till the pupal stage("reserve ratios")were made with a silkworm population, for the purpose of considering what criterion is most suited to characterize the structure and function of an ecosystem. The silkworm population was supplied sufficiently with fresh mulberry leaves(Morus alba)every six hours, being reared in an experimental room under controlled conditions. The obtained results suggest that the form of the ecological pyramid represented by nitrogen content is clearly different from that represented by biomass or caloric content. A herbivore loses by grazing a less proportion of nitrogen from its tissues as compared with the other two criteria. Reserve ratios are rather preferable to conversion efficiencies as a standard to discuss the values of the coefficients, like efficiency of conversion, of lepidopterous insects together with various kinds of animals, because the lepidopterous larvae, particularly silkworms, make cocoons which are not of protoplasma.
The leaf longevity of five-year-old seedings of Camptotheca acuminata (Nyssaceae) was investigated in a sample stand at the Forest Experimental Nursery of the Kyoto University in Kyoto. The annual height growth was vigorous, being more than 1m/yr. In spring a great number of leaves emerged(70% of the total number in a year), but the leaf size was small. As time passed, the number of leaves decreased and conversely the area of the individual leaf increased until it reached 130cm^2 in September. The individual leaf longevity was rather short ; the leaves which appeared in spring lasted only one or two months. Those which came out in summer continued to stay on the seedlings for two to three months. None of the leaves which emerged in spring or summer could last to the end of the vegetative season in late autumn, when the major leaf-fall occurs, when about 25 percent of the annual leaf mass was shed. The leaf-fall was observed through the growing season and the seasonal variation of the amount of fallen leaves seems to have a close relation to the height growth of the seedlings. From these observations, it can be concluded that Camptotheca seedlings have a relatively shorter leaf longevity than those of deciduous species indigenous to Japan. Further comparative studies are necessary to explain the shortness of the leaf longevity of the Camptotheca species ; to ascertain whether it is inherent to the species or due to rapid self-thinning owing to the rapid height growth.