hydrostatic system
From ZooTerms (Dictionary of Invertebrate Zoology)
hydrostatic system: (Bryozoa: Gymnolaemata) A method of protrusion of the lophophore in some autozooids; made up of flexible frontal wall or infolded frontal wall sac and attached parietal muscles which contract and raise the lophophore by hydrostatic pressure in the autozooid.
