The likely consequences of disturbance of the mycorrhizal mycelial network in soil are considered, emphasis being placed on the impact of small-scale events upon infection in vesicular-arbuscular and ectomycorrhizal systems. The importance of the intact network is stressed and the effects of its disruption upon infection processes and upon the nutrition of natural plant communities and of crops is analysed. It is considered that the most serious effect of disturbance will be to reduce the inoculum potential of the fungi and hence to decrease the vigour of infections that occur. The impact of these effects is likely to be felt most seriously at the stage of seedling establishment, and the interactions between disturbance events, mycorrhizal infection and plant successional processes are discussed.

Of the genera of rock-boring lamellibranchs which occur in British waters, Hiatella (= Saxicava) is the commonest. But the method of boring remains obscure, and for this reason the present research was suggested by Professor C. M. Yonge, under whose direction it was conducted. Observations were made during 1945 and 1946 in the Clyde Sea Area and at the Millport Laboratory, while other work on living and preserved material from both the Clyde and Plymouth areas was carried out at the Department of Zoology, University of Glasgow. Acknowledgments are due for assistance in technical problems to Dr H. F. Steedman of the University of Glasgow, for help with the nomenclature of the genus to Mr R. Winckworth, and for much kindness and help to the late Mr R. Elmhirst, Director of the Millport Laboratory.

Sedimentary structures in the greywackes of Peeblesshire, including graded bedding, cross-lamination and load-cast structures, are described and their origin discussed.

Petrographically the greywackes are poorly sorted sediments composed of a variety of minerals and rock fragments. The minerals include quartz, felspar, augite and horn-blende, mica and chlorite, while the dominant rock fragments are andesites, spilites, quartz-keratophyres and granites.

Three groups of greywackes are recognized according to their mineralogy. The first, the Pyroxenous group, contains augite and hornblende. Rocks of the second group, the Intermediate group, are without these minerals, while the third group consists of rocks rich in garnet—the Garnetiferous group. These mineralogical differences are reflected in differences in the chemical analyses of the three groups. From consideration of the chemical and modal analyses it is suggested that differences in source rocks have influenced the composition of the greywackes more than variations in the intensity of alteration due to weathering and transport.

It is concluded that the greywackes have been formed from the rapid erosion of a land mass largely covered by Ordovician volcanic rocks, but also with developments of lowgrade regionally metamorphosed rocks and others resembling Torridonian arkoses. Sedimentation features are due to accumulation controlled largely by the action of turbidity currents.

Cousinia (Compositae) with over 400 species in SW Asia has its maximum concentration in the Flora Iranica area. Overall it has a remarkably limited distributional range compared with other genera of similar size. On the basis of the significant distribution patterns of Cousinia, it is argued that the highland part of the Flora Iranica area should phytogeographically be re-designated as the Irano-Turkestanian region, including the Central Asian mountain province of Soviet Central Asia. It is also proposed that the essentially lowland Turanian (Aralo-Caspian) area should be excluded from the Irano-Turanian region.

The available information, both published and unpublished, on the zoobenthos of Loch Leven has been studied and tabulated. There have been a number of major changes in the community over the last 100 years—notably a reduction in diversity of the fauna with the disappearance of many species of invertebrates, particularly Ephemeroptera, Odonata and Coleoptera. The existing macro-invertebrate fauna is dominated by larval Chironomidae, but Nematoda, Mollusca, Annelida and Crustacea are also of importance. Dramatic changes have taken place in the chironomid population during the present study (1968–71), notable among which has been the disappearance of Endochironomus. Production studies of the two dominant larval Chironomidae (Glyptotendipes and Stictochironomus) in the sandy littoral area (42 per cent of the loch bed) gave annual estimates of 40·5 and 1·2 g (dry weight)/m2 respectively for 1970 and 5·0 and 10·2 g/m2 for 1971. Speculative estimates of the entire zoobenthos production in 1970 gave a value of 46·5 g/m2. The significance of these results is briefly discussed.

Among collections of meiobenthos from some sub-littoral muds off the coast of Scotland were eighty-five species of Copepoda. Twelve of these were found to be new species of Harpacticoida. In addition, the hitherto unknown males of four species were discovered.

Examination of fungal life strategies assists the understanding of the patterns of occurrence of an organism (or rather species) in nature. Fungi prevalent in disturbed situations tend to have many R-selected characteristics, although these are often combined with C-selected and S-selected characteristics depending upon the biotic and abiotic conditions to which their life strategies are best adapted. Many fungi probably exhibit different life strategies at different times during their life-cycle.

Heteropneustes (Saccobranchus) fossilis Bloch. is a common airbreathing fish found in India. It possesses a respiratory sac on each side of the body embedded in the lateral myotomes. The structure of this organ, its respiratory function and the phenomenon of “drowning” when the fish is denied direct access to the air have engaged the attention of several workers in the past among whom Day (1868), Dobson (1874), Burne (1896), Das (1927), Hora (1935) and Marlier (1938) deserve mention. The only detailed account of the structure of the accessory organ of this fish is available to us from the work of Das (1927) who also paid some attention to its development. Dobson (1874) and Hora (1935) mainly concerned themselves with some experiments bearing on the “drowning” of the fish when compelled to live under water. Little information is obtainable from the existing literature on the following points which have an important bearing on evolution of its accessory respiratory organs:

(i) the gross and minute structure of the respiratory sac, especially its vascularization;

(ii) the origin and derivation of the accessory respiratory organs (=the “Fans” and the respiratory sac); and

(iii) the muscles concerned with its breathing movements.

In animals, the expression of genetic factors has been studied mainly after fertilization, in the embryo or the adult. The study of genetic effects on the gametes themselves has been called the genetics of gametes. As evidence of such genetic effects on gametes, numerous differences have been found in the characteristics of spermatozoa from eight inbred strains of mice. The spermatozoan characteristics studied are mainly dimensional, but also relate to the physiological maturation of spermatozoa and possibly to semen fertility. The dimensional characteristics of spermatozoa are insulated, to an unusual degree, from the effects of environmental and other factors. The genetics of gametes can be regarded as the study of the genetics of the carriers of genes from one generation to the next; this has relevance to general genetics, and also to experiments for controlling the transmission of hereditary factors from parent to offspring.

There are 3 types of climate in Turkey: Mediterranean, Continental and Oceanic. The greatest part of the country, including much of the montane area, comes under the influence of various types of Mediterranean climate; the Continental climate occurs in two distinct areas in N and NE Anatolia; the Oceanic climate prevails in the region bordering the Black Sea. The forest vegetation of Turkey may also be divided into 3 main classes: QUERCETEA ILICIS; QUERCETEA PUBESCENTIS; QUERCO-FAGETEA. The first is confined to a coastal zone of the Mediterranean, the second is throughout the inner Mediterranean area, the last is in the Euxine zone of N Anatolia. Steppe vegetation belongs to the class ASTRAGALOBROMETEA widespread in C Anatolia and the Taurus.

Shallow water and intertidal marine sediments are often heterogeneous. This heterogeneity has led to a definition of microenvironments and their associated biological species. The definition encompasses habitat and species size, species behaviour and physiology, stability and environmental interfaces. We distinguish between open and closed interfaces, and suggest an associated topological structure. Examples are given from the intertidal zone. Three of these are discussed in detail.

(i)Sand grains. The occurrence of periphytic micro-organisms on sand grains is considered. The topography of the sand grain surface is closely related to the distribution of microbial colonies some of which contain a range of species. Bacteria, blue-green algae and diatoms have been identified. Species interactions and micro-variation in sediment physico-chemistry are likely to affect the constituents, distribution and abundance of the colonies. The activities of periphytic micro-organisms change the bulk properties of sediments.

(ii)Banding in sediments. Characteristic banding patterns are described from a sandy and muddy intertidal shore. Marked discontinuities in the microbial flora and physico-chemical properties occur at interfaces between the bands. For example, Eh, chlorophyll levels, and sulphide can all change dramatically over a few mm. The significance of these alterations for the meiobenthic and interstitial fauna is discussed.

(iii)Invertebrate burrow linings.Bioturbation structures including invertebrate burrows change local properties of sediments. The microbial and chemical properties of Nereis diversicolor burrow linings are described in detail. Sediment from the burrow lining closely resembles the sediment surface in many of its attributes. The sediment/water interfacial zone with its associated microbial and chemical properties is therefore extended vertically into sediments by these structures. Attention is drawn to the stabilising function of burrows and to their palaeoecological significance.

The activities of a number of enzymes of the ascorbate–glutathione pathway have been shown to rise under conditions of increased oxidative stress. The potential to alter the expression of specific enzymes of this pathway by genetic manipulation has provided the opportunity to attempt to develop transgenic plants with altered levels of oxidative stress defense enzymes which should have improved stress tolerances. We have cloned a cDNA for glutathione reductase from a higher plant (Pisum sativum L.) and have used this to construct chimeric genes for the expression of the pea enzyme in the chloroplast, mitochondrion or cytosol of transgenic tobacco plants. Some of the transformed lines with elevated levels of expression of glutathione reductase accumulate higher concentrations of glutathione and show increased tolerance to paraquat, however, no evidence was found for elevated tolerance to ozone fumigation.

The production of four dominant species of larval Chironomidae (Chironomus anthracinus, Glyptotendipes paripes, Polypedilum nubeculosum and Limnochironomus pulsus) was measured and compared between different sections of the mud zone covering a total area of 662 ha (50 per cent of the loch bed) from March 1971 to March 1972. The results showed that the performance of Chironomus was very similar throughout the area in respect to numbers, growth and production but it was more variable in other species. The mean annual dry weight production of Chironomus over the whole area was 26 g/m2 and the four species together raised this to 29 g/m2 (equivalent to 579 k J/m2). The numbers of Chironomus increased and Glyptotendipes decreased through the sampling period. Estimates of biomass are given for other larval Chironomidae present in the mud. The accuracy of the results is discussed, as well as the variations in the seasonal growth of larvae and the changing composition of the community; some tentative estimates are given of assimilation by larval Chironomidae. The methods used for analysing these data are described in an appendix.

The paper discusses limits under which flux-gradient relationships derived for horizontal homogeneous terrain can be applied to aeolian transport over non-uniform terrain with coastal dunes. For flat sandy beaches the roughness change upstream of the beach-dune boundary can be expected to be small. For horizontal beaches that are some hundred metres wide and where the length scale of the horizontal heterogeneities does not exceed some tens of metres, consistent surface stress and aerodynamical roughness values may be deduced from the wind-speed profile.

Slope effects will modify the air flow strongly as it crosses a dune ridge or escarpment. Recent developments in the theory of turbulent flow over hills are discussed in relation to common coastal dune terrain. The depth of the layer where the profile is in equilibrium with the underlying surface typically does not exceed a few tens of centimeters. This strongly restricts our ability to derive reliable values for roughness and surface stress from the wind profile.

Experimental studies at two coastal dunes in Denmark indicate that it is often difficult to obtain a good upwind reference for the flow. Analysis with a numerical model, set up for one of the sites, suggests that information about the flow and the value of experimental data may be improved when these can be both related to and supported by numerical calculations.

Several types of machair landforms are found in the Uists (Outer Hebrides) but the most distinctive are low altitude plains. Morphological and stratigraphical evidence suggests that both erosional and depositional processes, operating over a long period of time, have produced these sand plains and other landforms. A vast but relatively finite (partly shell-derived) sand supply was swept landwards across the gentle offshore rock platform assisted by a rising sea level to provide the initial pre-machair coastal accumulation. Phases of development can be dated using archaeological evidence, and 14C dating of offshore peat suggests that initiation probably took place before 5700 BP. Although the evidence is fragmentary, machair development appears to have consisted of long periods of stability, interrupted by episodes of major environmental disturbances. There is also evidence of coastal erosion and associated physiographic changes.

The general epidermal morphology of teleost fish is described and comparison made in terms of its vulnerability to ultraviolet radiation (UVR) with that of the human. Whereas human skin has a natural pigmentary photoprotective (tanning) mechanism within its epidermis, in teleosts the protective pigment layer is located primarily within the upper dermis. The potential impact of solar UV on farmed fish is discussed both in relation to water penetration of UVR and the phenomenon of photosensitisation, a condition common in higher animals and which has now been shown to induce skin lesions in fish. The results of recent investigations into photosensitisation in fish are described.

Drosophila mutants are usually defined by structural characteristics exhibited by the adult fly. In certain cases (homozygous lethal mutants and female-sterile mutants) the mutant may or may not be defined structurally, but does exhibit the physiological characteristic of death at some stage.

The females of homozygous lethals are sterile, for the F1; represented by the germinal cells, dies with the mother. The term female-sterile, however, is applied to the well-known cases in which the mother but not her F1 achieve imaginal life.

The work recorded in this paper was undertaken in order to obtain further knowledge regarding the behaviour of the cytoplasmic components of the male germ-cells of mammals and the contribution made by these bodies to the structure of the ripe sperm. Consequently, mammals from different groups were examined.

Investigations were carried out independently by Zlotnik on the male germ-cells of the dog, the cat, and the rabbit, by Gresson on the boar and the ram, and jointly by Gresson and Zlotnik on the white rat and the golden hamster. Zlotnik (1943) originally identified and described the nuclear-ring of the spermatid and sperm of the dog. The accessory body was recognised simultaneously by him and by Gresson, but Zlotnik was the first to observe an accessory body within the localised Golgi material of the spermatocyte and to follow its extrusion to the cytoplasm, and, later, Gresson identified an accessory body within the Golgi material of the spermatid of the boar. In general the conclusions of the two authors are closely similar, such differences of detail or of interpretation as exist are discussed in this paper.

Assemblages of small spores are described from the Pumpherston Shell Bed, the Pumpherston Oil Shales, the Burdiehouse Limestone and a thin coal found within the latter rock in one locality, all from the Lower Oil-shale Group (Viséan) of the Lower Carboniferous of Scotland.

The assemblages from the Oil-shales and the Limestone, rocks generally regarded as being of non-marine origin, are found to be very much alike; and although they show some differences from that of the Pumpherston Shell Bed (a marine shale), all three assemblages have a general similarity of composition. A suggested relation is put forward between this uniformity and the conditions prevailing in the area of the Midland Valley of Scotland during deposition of the beds. Correlation with other areas is discussed. Five new species and ten new types are described.

The chief physical processes encountered in Inner Hebridean waters are described, including the tidal and current regimes, temperature and salinity variations, and stratification in the sea and sea-lochs. Although information on some of these topics is sparse, available data are used to provide order of magnitude estimates for the volume transport of the coastal current and run-off water and to indicate expected ranges of the major parameters of the marine environment. The islands are shown to be important as a region of tidal mixing of coastal water.