See text Sternaspidae, commonly known as mud owls,[2] are a family of marine polychaete worms with short swollen bodies.

They have a global distribution and live buried in soft sediment at depths varying from the intertidal zone to 4,400 m (14,400 ft).

On the ventral side of the posterior of the body there are two chitinised calcareous plates forming a shield, the margins of which are rimmed with bundles of capillary chaetae.

[3][4] This worm lives submerged, head-down in the sediment, with its thread-like gills on the surface, presumably to facilitate oxygen take-up.

It is presumed that the worm scoops up dollops of sediment with the pharynx and then extracts the nutrients from what is swallowed as the main bulk passes through the long, coiled gut.