Our knowledge of the Aphroditidae from the Malay-Archipelago hitherto was very scanty and considering the great variety of those worms in neighboring seas — Grube from the Philippines 1) mentioned 27 and Potts from the Indian Ocean 31 species 2) — it could be expected that a thorough examination of this region, as done by the Siboga-expedition, should reveal us many new and interesting form; in these expectations we are not disappointed. Two remarkable species viz. Lepidasthenia sibogae and Eulepis malayana, besides three species of Psammolyce are already mentioned before 3); in the present paper we wish to confine ourselves to the subfamily of the Polynoïnae. Only six representatives of this group hitherto are mentioned from Amboina, Borneo, Ceram and Ternate, viz. Lepidonotus carinulatus Gr., — Wahlbergi Kinb., Polynoë cornuta Fischli, — (Lepid.) gymnonotus Mrz. — cristatus Gr., (Polynoë tumorifera Gr.) and Scalisetotorus ceramensis McInt, whereas in the Siboga-collections I was able to recognize more as forty species and varieties of Polynoïnae 4). Unfortunately it is no easy task to decide to what genus these species belong, for every one, who has been occupied with the study of Polynoïnae, will agree with Johnson's assertion that „the classification of the Polynoids is in a most unsatisfactory state, and much in need of thorough revision. The great multiplication of genera, nearly all of them founded upon variable, non-essential, or even accidental characters, and none of them clearly and fully defined, has been a serious drawback to the study of these interesting forms 5)." Also Darboux in his elaborate paper „Recherches sur les Aphroditiens" 6), has not succeeded to give a clear definition of the different genera and it is not unusual to see the