SUMMARYWe have studied the chromosome set and the gametogenesis of three earthworm species originating from Iceland: Dendrobaena rubida, D. octaedra, Lumbricus rubellus; three species coming from the Friuli area: D. octaedra, Allolobophora caliginosa, A. rosea, and one species coming from the isle of Kerkyra: Octolasium croaticum.As regards to the D. rubida, we have studied the hexaploid parthenogenic and the octoploid amphigonic strains. In the Friuli, we have found the diploid amphigonic, the triploid parthenogenetic and the decaploid amphigonic strains of Allolobophora rosea.Concerning the A. caliginosa, the diploid strains that we have studied, present a normal spermathogenesis and a condition of amphigony; the triploid strain is parthenogenetic.With the Lumbricus rubellus, our data have confirmed the constancy of its diploid and amphigonic condition.The Octolasium croaticum of Corfu is an amphigonic diploid.As regards to the D. octaedra, we have studied the common exaploid and the subhexaploid strains.