Bryozoans (Ectoprocts) & Entoprocts

This wall chart shows the colonial nature of the so called moss animals. Note the position of the anus on many of the adults as this feature is their namesake; those with the anus within the crown of tentacles are Entoprocta (ento – within; proct – anus) those with the anus outside of the crown of tentacles are Ectoprocta (ecto – outside; procta – anus).There is large debate about the relationships of the two groups Ectoprocta and Endoprocta.  There are many similarities in superficial structures and morphology, however these similarities often mask dissimilarities such as the feeding crown of tentacles (lophophore/lophophore-like structure) which operates in opposing directions between the two groups.  Molecular data suggests these two are distinct phyla however many skeptics still class them together within Bryozoa.