Image 1: “Scanning electron microscope image of a bryozoan colony” (Source)
Image 2: “This skeleton of a living bryozoan, collected at Bahia de los Angeles, Baja California, clearly shows this typical colonial organiation.
Each individual, or zooid, is enclosed in a sheath of tissue, the zooecium, that in many species secretes a rigid skeleton of calcium carbonate. Each zooid in this electron micrograph is less than a millimeter long and has a single opening, the orifice. Through this opening, the lophophore, a ring of ciliated tentacles centered on the mouth, protrudes to capture small food particles. The lophophore can be retracted very rapidly by specialized retractor muscles, and the opening closed by a doorlike operculum, visible on some of the zooids in the picture at the left.”
Image 3: Membraniporella nitida (source) cc-by-nc-sa
More info: http://en.wikipedia.org/wiki/Bryozoa