In the western Wadden Sea E. longa appears to be relatively tolerant to low winter temperatures. The species crawls on the surface or in the upper centimetres of the sediment. Many phyllodocids are predatory carnivores, catching their prey with their muscular pharynx. E. longa feeds on spionids, e.g. Spio filicornis and Scolelepis squamata, and on a variety of small metazoans. Cannibalism is widespread (Hartmann-Schröder, 1971; Wolff, 1973; Beukema, 1979; Fauchald & Jumars, 1979). [details]

Description: Long, thin and very active worm with approximately 200 identical segments (up to several cms long).
The head bears four little antennae. The dorsal half of the parapodia bears a large leaf-like lamella. Its colour ranges from white to light grey with brown patches or brownish-green broad transverse bands. This species is carnivorous and secretes slime upon contact. [details]

Distribution: In the 1976-1986 period Eteone longa was distributed across the entire Belgian part of the North Sea but was only observed in relatively low densities (maximum 140 ind./m2). In the 1994-2001 period a different distribution pattern was noted: the distribution of E. longa was mainly limited to the nearcoastal zone, with the exception of the eastern coastal zone. In this zone the species was found in densities of maximum 550 ind./m2. [details]

Distribution: The distribution ofEteone longa ranges from the intertidal zone down to a depth of 30 m. The highest densities are found near the coast and north of the Wadden islands. [details]

Distribution: Arctic; Hudson Bay to off North Carolina; Bering Sea to Mexico; n. Japan Sea; Iceland, Norway to English Channel [details]

Habitat: intertidal, bathyal, infralittoral and circalittoral of the Gulf and estuary [details]

Habitat: E. longa occurs in all types of sediments, but prefers fine and muddy sand. it is also found in empty tubes and on oyster banks. Well-sorted types of sediments are favoured (Hartmann-Schröder, 1971; Wolff, 1973). [details]

Habitat: Eteone longa is found in sediments with a wide range of median grain sizes: the species is only absent in very fine (< 100 μm) and very coarse sediments (> 500 μm). An optimum (relative occurrence > 20%) is reached with a median grain size of 150 to 250 μm. Eteone longa displays a preference (relative occurrence: > 40%) for relatively high mud contents (30 to 50%), but is found in sediments with other mud contents as well. [details]

Morphology: E. longa has a flattened, slender and elongated body with a length of a few centimetres and up to 200 segments. The numerous identical segments have prominent parapodia with a dorsal lamella. The head bears four short frontal antennae. lt is whitish or pale grey in colour, with brown blotches or broad transverse bands of brownish green (Hartmann-Schröder, 1971; Hayward & Ryland, 1990). [details]