Sexually ripe specimens have been observed in April and May. Most probably the larvae have a planktonic development. E. longissima lives in burrows. When conditions become unfavourable it will rapidly and repeatedly move and set up a new tube at other locations. E. longissima is mainly a non-selective deposit feeder, feeding on algae and dead animals. The species itself is eaten by flatfish (Hartmann-Schröder, 1971; Wolff, 1973; Fauchald & Jumars, 1979).