The entoproct Loxosomella phascolosomata often attaches itself to the worm.

The body of a mature entoproct zooid has a goblet-like structure with a calyx mounted on a relatively long stalk that attaches to a surface.

Small colonies of the freshwater entoproct Urnatella gracilis have been found living on the aquatic larvae of the dobsonfly Corydalus cornutus.

In the Connecticut River, the shell of Elimia virginica is often used as substrate by epizootic algae and the entoproct Urnatella gracilis.

Recently, the Maotianshan Shales fossil, Cotyledion tylodes, has been reevaluated as being an ancient, sclerite-bearing entoproct (originally having been identified as a putative carpoid echinoderm).

In 1992 J.A. Todd and P.D. Taylor concluded that Dinomischus was not an entoproct, because it did not have the typical rounded, flexible tentacles and the fossils showed no other features that clearly resembled those of entoprocts.

In the White Sea, the non-colonial entoproct Loxosomella nordgaardi prefers to live attached to bryozoan (ectoproct) colonies, mainly on the edges of colonies or in the "chimneys", gaps by which large bryozoan colonies expel water from which they have seived food.

The oldest undisputed fossils of entoprocts are less than one-third the age of C. tylodes, so the new fossils push back the origin of the entoproct lineage all the way back to the so-called Cambrian explosion, an interval when life diversified very quickly to produce most of the groups seen today or their ancestors.