Ectoprocts and entoprocts (A-19) were formerly classified
together as subphyla of the Bryozoa. A case for reuniting the two is
still occasionally made, but they have fundamentally different body
plans, and each is now assigned a separate phylum; the tentacular
crown of the entoprocts is not a lophophore. It surrounds both
anus and mouth and is not retractable. Furthermore, entoprocts are
pseudocoelomate, while ectoprocts possess a body cavity, although
its homology cannot be determined with certainty.