Eulagisca is a genus of marine polychaete worms belonging to the family Polynoidae. The genus includes 5 species which are all found in the Southern and Antarctic Oceans and are notable for reaching a large size - 180 mm or more long - larger than any other species of Polynoidae.[1]
Species of Eulagisca have 35–41 segments and 15 pairs of elytra. The lateral antennae are undivided and inserted terminally on the prostomium . There is a distinctive dorsal fold ("nuchal flap" in the taxonomic literature) on segment 2, and unlike the related genus Pareulagisca, in Eulagisca all notochaetae are stout and have blunt tips.[1]