A phylum of marine invertebrates comprising a dozen or so species distributed widely. Phoronids, sometimes called ‘horseshoe worms’, are soft-bodied, sedentary wormlike creatures that live inside upright chitinous tubes in the soft sediment of shallow seas. Some live in colonies encrusting rocks or shells. They feed on suspended particles by means of a ciliated lophophore of numerous tentacles, and have a U-shaped gut with the anus located alongside the mouth. Sexual reproduction results in free-swimming actinotroch larvae, which feed on plankton. Phoronids belong to the clade Lophotrochozoa.