INTRODUCTION TO THE BRYOZOANS
Bryozoans are tiny polyp-like animals that always
form small coral-like colonies. Bryozoans are common on modern seashores but are
often over-looked or mistaken for corals or seaweed. The tiny polyps differ from
corals in having complete organ systems, the next step beyond the coral’s tissue
level of development. Organs include a complete digestive system, muscles for
retracting into their chambers,
and a unique feeding mechanism called a lophophore
that is shared only by the brachiopods. All this in such a minuscule creature!
One can usually recognize bryozoans by the tiny dots that cover the surfaces of the colony. Each dot is a hollow chamber or zooecium (plural zooecia) where a bryozoan lived. To see these zooecia well, use a magnifier. Your binoculars used upside down make a good magnifier. The drawing to the left is a cross-section of a bryozoan in its chamber, showing muscle fibers behind the stomach. width of this drawing is 1/32 inch!