The report briefly describes research undertaken to identify as many of the aquatic oligochaetes of North America and Europe as possible, and to fit the identifications to those of the world in a review of the systematics (relationship) and nomenclature (naming) of the group; to plot their distribution geographically; to evaluate the species in terms of their value as indicators of pollution; and to gain some insight into the basic biological parameters of the more important species so that the role of worms in relation to self-purification and eutrophication might be investigated.