Behaviour and Distribution of the Archiannelid Trilobodrilus Heideri

Abstract

The interstitial archiannelid Trilobodrilus heideri was found to be photophobic, fairly tolerant of low salinities and responsive to water current. This latter response of orientation and progression toward a water source was gradually lost by specimens suddenly transferred to low salinities. Rhythmic gregariousness was shown to occur in this species. The relation of this rhythm to tidal factors is postulated. It is shown how the demonstrated responses may affect the position occupied by T. heideri on the shore