[Results and problems set by the introduction of Zonitidae snails in some biotopes of Lymnaea trancatula Müller in Indre and Haute-Vienne, France (author's transl)].

Systematic placing of Zonitidea snails: Zonitoides nitidus and Oxychilus draparnaudi alone or in groups, in different series of habitats of Lymnaea truncatula in Haute-Vienne, France (1974-1976) shows: --the elimination of Lymnaea truncatula is entire after two years in temporary habitats covered with grass just mowed at the beginning of summer drying. The presence of stones, which make shelters, increases numbers of surviving snails. --predators-placing without previous grass-mowing is effective only on banks of rivers.