After having defined the habitat of
Phyllodoce pusilla (Claparède) errant Annelida Polychaeta of the
Phyllodocidae family, and studied the fauna living by it in the bay of Arcachon, the author gives an historical account of the various works about this species. He gives a complete description of the worm; the prostomium, soma, proboscis, appendages and bristles, the size of the body and colouration have been studied with accuracy.
All these characters have enabled him to confirm the place of this species in the classification, and compare the ecological observations concerning it with other isolated observations from some places of the Mediterranean which are the only from where
Phyllodoce pusilla (Claparède) was known to exist.
