Since the publication of Ehlers’ »Borstenwürmer” and Baird’s »Contributions towards a Monograph of the Amphinomacea” 1), our knowledge of this genus of Annelida much increased, especially by Johnson’s »Preliminary account of the marine Annelids of the Pacific coast” 2) and »The Polychaeta of the Puget Sound region” 3) and by Ehlers’ description of »Die Polychaeten des magellanischen und chilenischen Strandes” 4). The Siboga-expedition in the Malay Archipelago also had the good luck to collect a rather great number of Euphrosyne-specimens, of which only a single one could be referred to a known species (E. superba Marenz.), whereas for the remaining ones nine new species must be established, which are summarily described in the present note. Among these are some small, interesting species (E. affinis, — hystrix, — maculata, pilosa, — pelagica, — sibogae), which by the presence of enlarged eyes, of elongated bristles in the neuropodium and of a transparent body show a marked pelagic character 1), the other species of this genus having a more sedentary manner of living. As proved by the table added hereafter, the number of known species now amounts to twenty-six.