Worms belonging to the genus Psammolyce, that are characterized by having their elytra and the median part of their back covered with papillae, adapted for the retention of small particles of the bottom upon which they are living, hitherto were not observed in the Malay Archipelago. Yet the Siboga-expedition had the good luck to collect a number of them (though often in fragments), that certainly represent three species. However it is no easy task to recognize the characters, offering a trustworthy criterion for the distinction of the species. With regard to the elytra f. i. Willey says: „they are not safe objects for comparison, since they vary from segment to segment” ¹); however Potts rightly stated, that certain features of the elytra as a whole are certainly characteristic for a group of species ²). In Psammolyce arenosa ³) and its allies f. i. the elytra are provided with two lobes at their median corner and another lobe at the posterior margin, whereas in an other group of species [Ps. fijiensis 4), -occidentalis 4) and -malayana] the first pair of elytra are strongly elongated, giving to the head a snout-like appearance. Moreover the structure of the neuropodial setae affords good material for the discremination of the species, as f. i. Ps. flava ¹) is easily recognized by this single character, and also the appearance of the dorsal cirrus of the third segment may be different in some of the species. Unfortunately the earlier naturalists have not always described these different characters with sufficient conciseness.