Membranipora forms mat-like calcareous colonies of small, closely packed zooids living inside a rectangular sheath that secretes a protective, calcified enclosure. Each rectangular compartment is composed of lateral calcified walls and ventral uncalcified bands, which provide flexibility. A membrane completely roofs the space between the supporting side walls. The enclosure has an orifice through which the lophophore extends into the water column for feeding. In Membranipora, the orifice is covered by an operculum.
Membranipora membranacea Growing on a Blade of Laminaria
Beyond the Human Eye
WoRMS: Membranipora membranacea
Web Photo, showing Colony Enclosures by Scanning Electron Microscopy:
Web Photo Favorites, showing colony formation:
Ann-Margret Amui-Vedel's Webpage, NUI Galway