(1) D. rathkei exhibits negative phototaxis during the whole day. It never leaves the sediment as long as there is any light. (2) The vertical migrations into the pelagic environment, as observed in Aug and Oct, start ca.1 h after sunset; they have their maximum intensity from ca. 22.00 h to 23.00 h and end at midnight. D.rathkei reacts positively to light during this time. (3) Fish and other predatory animals are almost inactive during this period. Population loss by predation is thus negligible or even lacking. (4) The literature on the 'hyperbenthos' is critically discussed in relation to the method mostly employed, the use of Beyer's epibenthic closing net. This gear is not considered to be useful, and the results obtained by it are doubted. (5) D. rathkei has no significance at all for the 'hyperbenthos'. The existence of this community in the Western Baltic Sea is doubted.