Jouin, Claude. (1970). Recherches sur les Protodrilidae (Archiannélides): I. Étude morphologique et systématique du genre Protodrilus. Cahiers de Biologie Marine. 11(4): 367-434, plate I.
Eleven species of Protodrilus from different sediments of the Mediterranean, the Channel and the Gullmar Fjord (Sweden) coasts, are studied in this work. Four new species are described, whereas a new study is made of four other previously known species, particularly concerning sexually mature animals. As a consequence of this revision in the genus Protodrilus, a synonymity is established for three species. The granulometric characters of sands on which the species depend are given, as well as the geographical distribution and a diagnosis of each species.