• Norwegian: mosdyr


Bryozoans, also known as moss animals, are colonial, with the expeption of a single genus. Many colonies form sheets covering rocky bottoms or algae, they are called encrusting bryozoans. Others build bush-like structures resembling small corals. They are hermaphrodites, they change sex during their life span. Colonies include zooids of both sexes. The often live in separate calcareous boxes. If you look closely the tentacles or lophophores, used to catch food, can be seen stretching out of the boxes. Bryozoans have no respiratory organs, heart or blood vessels. Oxygen is absorbed through the body wall and the lophophores.


All bryozoans are aquatic animals. Two of the three classes include marine species. Gymnolaemata is by far the largest class and most species are marine. Stenolaemata is a class of purely marine species. Fossils of 15000 different species are found, but only between 4000 and 4500 species live today.