ITALIAN ENCHYTRAEIDAE (OLIGOCHAETA) .1.

During the period 1989-1994, soil samples were collected at 51 localit ies in six different regions of Italy. Twelve genera and 61 species co uld be distinguished. One genus (Oconnorella gen. n.) and 12 species ( Mesenchytraeus straminicolus sp. n., Cernosvitoviella omodeoi sp. n., Achaeta etrusca sp. n., Fridericia globuligera sp. n., Fridericia mono chaeta sp. n., Fridericia nix sp. n., Fridericia strenua sp. n., Fride ricia tuberosa sp. n., Marionina brendae sp. n., Marionina eleonarae s p. n., Marionina rubens sp. n., Oconnorella chalupskyi sp. n.) are new to science. Two old taxa (Fridericia bretscheri Southern, 1907 and Fr idericia viridula Issel, 1905) are revalidated and their descriptions augmented, and another two (Fridericia ilvana Issel, 1905 and Frideric ia gamotheca Issel, 1905) are redescribed from new material. Nineteen known species are new records for Italy, while 30 previous Italian rec ords are confirmed. Four new records for Algeria (Fridericia bretscher i, F, miraflores, F. tuberosa sp. n., F. viridula) and four new record s for Ireland (Henlea montana, Fridericia isseli, Enchytraeus bulbosus , Marionina brendae sp. n.) are also provided. The highest number of s pecies was found in the acid, moist soil of coniferous, beech or chest nut woods, even at low altitude. A rich Fridericia fauna dominates the neutral soils of the evergreen oak forests, whereas very few species are adapted to the shallow and dry soils of the maquis and garigues.