 The unpalatability is strongest in the top section, including the lophophore, which is exposed to predators when phoronids feed.When the lophophores were removed in an experiment, the phoronids were more palatable, but this effect reduced over 12 days as the lophophores regenerated.These broadly effective defenses, which appear unusual among invertebrates inhabiting soft sediment, may be important in allowing "Phoronopsis viridis" to reach high densities.