The existing Michel-Levy's interference color chart represents the retardation (interference color) only up to 2,500 mμm and fourth-order colors on A6 paper size. However, an interference color chart using a logarithmic plot (Fig. 1) represents retardation from l00 to 12,500 mμm and up to 24th-order colors on the same paper size.
Fig. 1 facilitates the accurate measurement of grain retardation. Such measurements, if followed by accurate measurement of grain thickness, permit the birefringence to be accurately calculated [Eq. (1)]. Fig. l permits quick, graphic solutions of Eq. (1) in the area from low-order to high-order colors.
ln case of idiomorphic orthopyroxene, estimation of maximum birefringence (γ-α) will be possible. The range of the retardation of fine-sand size orthopyroxene is from 2,500 to 5,000 mμm. Fig.1 only permits measurement of this high-order retardation and estimation of birefringence.

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Genetic diversity within populations (Hs) and other polymorphic indicies of two sexually reproduced species of Chinese mosses, Leucodon secundus (HARV.) MITT. var. secundus and L. subulatus BROTH., were estimated by means of enzyme electrophoresis. The Hs value of the former species was 0.153 (se = 0.072); was not much different from those detected in other species of the genus. On the other hand, Hs of the latter was much lower (Hs = 0.009, se = 0.009). The authors consider this low value of Hs detected in L. subulatus, to indicate that the population size of L. subulatus at Mt. O'meiShan was influenced by bottle neck effect or genetic drift in the past. This is the first report of low genetic diversity within populations for sexually reproducing mosses.

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Surface ornamentation of peristome teeth is examined by SEM for 22 species of l2 genera and four families of the Hookeriales. As the results, three peristome types are recognized based on surface ornamentation as the following: “daltoniaceous” in Daltonia and Cyathophorella, “hookeriaceous” in Callicostella, Calyptrochaeta, Cyclodictyon, and Distichophyllum, and “hypnaceous” in Hookeria, Symphyodon, Leucomium, Dendrocyathophorum, Hypopterygium, and Lopidium. Discussion for those peristome types is given, and SEM micrographs of the surface ornamentation are given for each species.

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Striking progress in the development of plant tissue culture techniques has achieved multi-faceted results. Recent articles have reported on new breeding characteristic and cultivation improvements as well as increases in germination and productivity. In this report, a variety of basic methods for bryophyte cultures, which the present author employs, is introduced.

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The diatom flora in two samples, one collected in May 1970 from the lake center and the other in August 1991 from the southeastern shore of the Akan-ko (Lake Akan) were studied. The lake is one of the famous caldera lakes in Japan not only because of its beautiful scenery but also because it is the only place left in Japan to find the lake ball, Cladophora sauteri (NEES) KÜTZING. About 200 taxa were identified but here 16 centric taxa are reported with light and electron microscope photographs. Some comments are made mostly on the taxonomy of each taxon.

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A peculiar grapsid crab, Xenograpsus novaeinsularis TAKEDA et KURATA, 1977, hitherto known only by the type specimens from the new volcanic island, Nishino-shima-shinto, about 130 km west of Chichi-jima Island, the Ogasawara Islands, was rediscovered at Akuseki-jima Island, the Takara Islands in the south of Kyushu, and Kita-Iwo-jima Island, the Iwo Islands in the south of the Ogasawara Islands. In both localities the crabs were abundantly found under the rocks covered with sulphureous waste and washed by bubbles in shallow-water thermal spring. The crabs are characteristic in using the bundles of setae covering the tips of both fingers as brush to collect something to eat.

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It is well known that the number of individuals of the Cervus species sometimes extends beyond a reasonable population size based on the environmental conditions. Then, they resulted in a mass die-off for the adjustment of population size under severe circumstances. The present work was mainly conducted to demonstrate the population dynamics of Cervus nippon located at the Ashio mountains, Tochigi Pref., under a heavy snow condition during the winter of 1984. As a result, several types of unusual movements were observed in the population. With the snow, the habitable environment was limited into a more narrow range of space. At a highest extreme, the population reached 121.8 individuals per square kilometer. Corpses were discovered first in the middle of March, reaching at a highest rate of about 36% in the end of this month. Most of the individuals to die were yealings first, followed by adolescents, and male and female adults.

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During the summer of 1984, moths were collected quantatively with an electrode-type light trap at two stations in the fields and forested areas scattered among the residential areas of Hiratuka City. In July, the numbers of individuals and species, dry weights and diversity indeces were greater at St. A, near the forested areas, than at St. B, around the field and residential areas. The community structures were also seen to be different at St. A, when the same sampling was carried out for a time in August. The numbers of species and individuals and dry weights had increased significantly by the time of the August sampling.
The results were compared to those of a study using the same methods and carried out in the Tama River basin in July, 1977. The numbers of species and individuals, and diversity indeces were greatest in the developed secondary forest in Hino City. The secondary forest in Kawasaki City, which is surrounded by suburban areas, showed a community structure more diversified than that of St. 8, but less deversified than St. A.
Cluster analysis constructed by the species compositions indicated that moth communitieswere classified first on the basis of areas between the Tama River basin and Hiratuka City. However, the difference in sampling times was more important for samples taken at Hiratuka. The relationship between larval food utilization and species composition of moth communities was also discussed.

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Shijuhachi-numa Pond consists of about 45 pools on rock terrace of the Nagatoro Park, Saitama prefecture. Numeral samples of crustacean plankters were collected from the main 11 ponds with plankton-net of 64μm mesh during the survey from 1989 to 1992. They were referred to 9 copepods and 18 cladocerans including some rare species such as Acanthocyclops vernalis, Rynchotalona rostrata and Chydorus barroisi. Thermocyclops dybowskii was newly added to the carcinological fauna of Japan.

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