A quantitative study of the shoreline fauna of this English lake shows that wave action and changes in lake level are important in determining the species composition. Food of the littoral animals consisted chiefly of algal slime and entangled organisms. Estimates of animal numbers per sq. ft. were obtained by means of a 6 in. scoop for shallow waters, a large dredge for depths of 31/2-6 ft., and a 14 X 14 in. shovel for taking samples along the lake edge, and other means. In many cases correlations occurred in the distribution of the 89 spp. found in the region and the physiographic change from bare rock through stony areas to sand. In general, there were large numbers of individuals of a few spp. in the extremely specialized habitats, while in the intermediate stony areas there were more species but with fewer individuals of each. A number of micro-habitats occurred within the major habitats, especially in stony areas, in which different spp. occurred. Vegetation often added an additional number of habitats with the consequent appearance of new species and increase in the total population.