Many acorn worms are detritus feeders, eating sand or mud and extracting organic detritus. Others feed on organic material suspended in the water, which they can draw into the mouth using the cilia on the gill bars. Research indicates that the rate of feeding of acorn worms that are detritus feeders is dependent on food availability and flow rate. A groove lined with cilia lies just in front of the mouth and directs suspended food into the mouth and may allow the animal to taste.