"Urechis", another tube-dweller, has a different method of feeding on detritus. It has a short proboscis and a ring of mucus glands at the front of its body. It expands its muscular body wall to deposit a ring of mucus on the burrow wall then retreats backwards, exuding mucus as it goes and spinning a mucus net. It then draws water through the burrow by peristaltic contractions and food particles stick to the net. When this is sufficiently clogged up, the spoon worm moves forward along its burrow devouring the net and the trapped particles. This process is then repeated and in a detritus-rich area may take only a few minutes to complete. Large particles are squeezed out of the net and eaten by other invertebrates living commensally in the burrow. These typically include a small crab, a scale worm and often a fish lurking just inside the back entrance.