Description: Microscopic irregularly branched filaments, growing endozoically under the surface of shells.

Habitat: Generally found in mollusc shells, sublittoral.

Distribution: Widespread on the coast of the British Isles. Europe: Denmark, France, Netherlands, the Baltic, Norway and Iceland. Greenland. Atlantic coast of North America: Canada. Further afield: the Pacific coast of Canada.

Distribution Map from NBN: Eugomontia sacculata at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Eugomontia sacculata at iNaturalist World Species Observations database.

WoRMS: Eugomontia sacculata at World Register of Marine Species.