lophophore
Noun
Meaning
A disk which surrounds the mouth and bears the tentacles of the Bryozoa. See Phylactolemata.
Source: Webster's dictionaryExamples
In some species the retracted invert and lophophore are protected by an operculum ("lid"), which is closed by muscles and opened by fluid pressure.
On the other hand, the founding polyp of a coral has a shape like that of its daughter polyps, and coral zooids have no coelom or lophophore.
Sensors at the tips of the tentacles may check for signs of danger before the invert and lophophore are fully extended.