Entoprocts are minute, sessile marine creatures, differing from Bryozoa in lacking a rigid body covering and in having the anus within the ring of tentacles, hence ‘entoproct’. They feed on diatoms and other small organisms. Some are solitary, others colonial.
Entoproct structure is shown by Professor James Ritchie’s drawings of the first recorded specimens of Barentsia benedeni found on the bryozoan Membranipora in St Andrew’s Docks, Hull in 1910.
Solitary forms have a primitive creeping larva, other entoprocts have a trochopore larva, which once settled buds to form the adult.