This report deals with nest building, copulation, egg-laying incubation, hatching, and chick-raising, based on the results of the outdoor observations for the purpose of studying the life history of the birds in the Zenkoji basin (altitude about 400m) in the northern part of Nagano Prefecture from 1963 to 1964. The main part of the observations was done in the Nagano district in the center of the basin, and most of the life history during the breeding season of the bird was described based upon the observation on one nest in 1964.
The plankton and its vertical distribution in Lake Suigetsu was studied in early July of 1966. The results are as follows : 1. Seventeen species of phytoplankton and eight species of zooplankton were found in this lake, the abundant species being Chaetoceros Muelleri, Melosira granulata (Diatom), Sinocalanus tenellus (Copepoda) and Diaphanosoma brachyurum (Cladocera). 2. Comparing the present data with the data of the summer plankton studied by KIKUCHI (1927,1931) and KOKUBO (1944), both the species number and individual number of the brackish species in the present study are larger than those noted by KIKUCHI and KOKUBO. 3. Almost all phytoplankton are distributed in the upper layer in this lake, but Cyclotella glomerata occurs in the deeper water layer of 6 to 9 meters (Fig. 3). 4. Chromatium Weisei (Triobacteria) and ciliata occur in the water layer of 9 to 9.5 meters deep, where the oxygen content is low and hydrogen sulfide is present. 5. Zooplankton occurs from surface to the layer of 9 meters deep. Among them, Sinocalanus tenellus, Paracyclopina nana and Pseudodiaptomus inopinus, all being brackish water species, distribute at different depths (Fig. 4). 6. Many pieces of thoracic legs of Diaphanosoma brachyurum were found in the water layer of 6 to 9 meters deep (Fig. 5).
In October 1965,the benthic communities at four stations in the River Yoshino-gawa, were investigated by the quadrat (50×50cm) sampling method with the following results : 1. The aquatic insect larvae amounted to more than 98 per cent in number and 97 per cent in standing crop of all the benthic animals. More than 99 per cent of the aquatic insects consisted of the members of the next four orders ; Ephemeroptera, Plecoptera, Trichoptera and Diptera. 2. Comparing with the results obtained in August at the same stations as in the previous paper, the individual numbers of benthos per one square meter of water surface were similar or remarkably increased in October. Standing crops of them, however, decreased at all stations. 3. The features mentioned above were due to the following changes, that the small chironomid larvae remarkably increased in number, but the other benthos all decreased, mainly owing to the effect of the successive three floods that occurred during the middle ten days of September.
The vertical distribution of freshwater planarians in Kyoto City and the adjacent district in the northern part of the Kinki Region in Honshu (Lat. 34°40′N. to Lat. 35°30′N. and Long. 135°25′E. to 136°15′E.) is reported. The City is situated in the central part of the Kyoto valleys (a basin watered by the Yodo River system). The northern part of Kyoto City and Kameoka City are characterized by hills and low mountains (the highest peak, Mt. Buna in the Hira Mountains, is 1214 metres above sea level). Lake Biwa-ko, the largest lake in Japan, is located in the north-eastern corner of the area surveyed at an elevation of 86.3 metres. Biwa-ko has a 235 kilometres long shoreline, and a maximum depth of 102 metres. The main river systems of the area surveyed are the Katsura, the Hozu, the Oi, the Kamo, the Takano, the Uji and the Ado (tributaries of the Yodo River) and the Ono (the upper part of the Yura River). The Yodo River discharges into Osaka Bay facing the Pacific Ocean. The Yura River discharges into the Sea of Japan. The surveys were made from 1950 to 1966. In the vicinity of Kyoto City, four species of freshwater planarians, Dugesia japonica ICHIKAWA et KAWAKATSU, Phagocata vivida (IJIMA et KABURAKI), Phagocata kawakatsui OKUGAWA and Bdellocephala brunnea IJIMA et KABURAKI, were found. D. japonica was most common in the stations both in the plain and the mountainous districts (below the altitude of about 950 metres). Ph. vivida was rather common in the cold-water stations within the altitude range from about 120 to 950 metres or more. Ph. kawakatsui was found only in a-spring-fed stream in Kameoka City (Asahi-cho ; the type locality of this species) and in a shallow well at Saga-tenryuji-cho in Kyoto City. A small population of Bd. brunnea was found in a large spring-fed stream at Nishioji-sichijo in Kyoto City (the southernmost locality of this species). This station is well known to biologists as the locality of the sexual race of D. japonica (the Nishioji stock). The type of the vertical distribution in the area surveyed is shown as J-JV-V (J : D. japonica ; V : Ph. vivida). The two species of true lake-dwelling triclads, Bdellocephala annandalei IJIMA et KABURAKI and Dendrocoelopsis ? sp. of Lake Biwa-ko, were recorded from the muddy bottom (35 to 50 metres or more in depth) of the middle and northern parts of Lake Biwa-ko. Figure 2 shows the distribution of the planarians in the lake (revision of the KAWAKATSU's 1964 map).
Very little is known on the ecology of the Japanese soil terrestrial and subterranean algae. The present paper is devoted primarily to a research of soil algal vegetation of the newly reclaimed soils of the coastal districts of the brackish lake called Nakano-umi in the San-in region, Japan. The chemical and physical conditions of the surface soils of the area of study are as follows : 1) pH=3.6〜6.5 ; 2) chlorinity=0.05〜3.02mg/soil lg ; 3) total nitrogen=0.97〜3.14mg/soil lg ; 4) electric conductivity=630〜3200μ〓/cm. The commonly found algae of this region are Hormidium flaccidum (KUBTZ.) HEBRING, Zygogonium ericetorum KUBTZ, Stichococcus bacillaris NAEG., Chlorococcum sp., Monodus subterraneus PETERSEN, Nitzschia obtusa W. SMITH var. scalpelliformis GRUNOW and Nitzschia palea (KUBTZ.) W. SMITH. It is observed that such algae as Hormidium, Zygogonium and Nitzschia palea frequently occur in the boundary region of Phanerogamae community (composed of Phragmitis and Echinochloa) as pioneer plants of the migration of the plant community of this area. One of the most common soil alga in Japan Fritschiella tuberosa IYRENGAR occurs mostly in the stations which are passed off at least several years after the reclamation.
The burnt forest described in this paper is situated on the Gamow coast, about 4 km east of Sendai. This forest is dominated by Pinus Thunbergii which is estimated to be around 60 years old. Before the 1965 fire, there had been no logging in the forest, therefore, needles, branches and dead grasses on the forest floor were abundant. (viz. the weight of dry matter for fuels was 360-1000g per square meter). After the fire, the plant communities in the various habitats of burnt forest floor and unburnt forest floor are compared with each other. The main components of the burnt forest, herbs and grasses, are also among the abundant species of the unburnt forest. However, some spcies increased markedly after the destruction of ground cover. For example, the coverage of Amorpha fruticosa, Indigofera pseudo-tinctoria, Kummerowia striata, Ixeris dentata, Youngia denticulata and Rhacomitrium canescens increased. On the other hand, the height growth and weight growth of the apical buds of the burnt pine trees were measured. Compared with the unburnt trees, trees that were charred more than one-half of tree canopy did not resprout until the following year. By the end of the growing season, however, it was found that the growth of the apical buds of slight damaged trees had been reduced to about 30 percent of the uaburnt level. In addition, in order to estimate the probable high temperatures in the tree layer during the fire, burning tests with the pine leaves were carried out in the laboratory. Pine leaves are charred for two min. at 250℃, and the leaves are ignited for one min. at 400℃. In view of this fact, it became clear that considerable temperatures are reached in the tree layer during fire.
In order to observe the seasonal prevalence of the larvae and some morphological characteristics of the imagos of a Culex mosquito in four septic tanks in an urban area of Yokohama City, field and laboratory studies were carried out through the year of December 1962. By the weekly sampling method, a seasonal trend of the larval population could be demonstrated as follows. From the begining of the investigation in early December, there was a gradual decline of the population and this tendency could be seen until February or early March of the next year. The minimum larvae were present during the long period from March to mid June. In late June or early July, the larvae increased rapidly and showed the first peak at the middle of July. After the rapid diminution, the larvae increased again and in late August or early September, they reached the maximum of the year. Since this period, however, a gradual diminution of the population continued to the last sampling which was carried out in December 1963. Through an analysis of the composition of the population in these septic tanks, any stages of the mosquito including the imago was found to exist even during the coldest season from the middle of January to the middle of February. However, in the following spring season from March to May, there were found only insects except for the eggs and younger instar stages. Seasonal difference of the population size was not detected in the case of the samples collected in the septic tanks which were situated at an air-conditioned building. The mosquito was identified as Culex pipiens molestus from the DV/D values of the adult male genitalia. Judging from the seasonal change of DV/D value, the population was monopolaised by Culex pipiens molestus ; it had genetically high uniformity. Water temperature in the septic tanks was warmer than the air temperature in winter but the relation was the reverse in summer. Recorded water temperature ranged from 5℃. (January) to 26℃. (August). The seasonal changes of some chemical properties of the foul water examined seemed to have no relation to the seasonal prevalence of the mosquito larvae. The pupae collected from the septic tanks were bred successively without blood meal. Nine generations were reared throughout the year under the laboratory conditions. The developmental periods which was necessary to complete one generation varied widely according to the seasons. The average developmental period recorded for the nine generations ranged from 16 days, at 25℃., (during September) to 84 days, at 10-15℃., (from ending of November to middle of February). It has been recongnised that the seasonal difference in number of eggs oviposited by a female and the rate of hachability were relatively small. It may be considered that the seasonal prevalence of the mosquito larvae in the septic tanks was affected directly by the following three factors, duration of developmental period of the generation, mortality of the larvae and rate of emergence.