- A taxonomic phylum in the kingdom Animalia — many small sessile aquatic creatures having a crown of tentacles surrounding a mouth and anal area.
- a small grouping of Bryozoa in which the anal area is within the circle of tentacles. See pedicellina.
- One of two divisions of Polyzoa established by Nitsche (others being Ectoprocta), including those Polyzoa where rectum opens up within the circlet of tentacles of lophophore.
- occasionally considered a subphylum of Bryozoa