Bryozoans

bryo = 'moss' , zoa = 'animal'

The phylum Bryozoa is a diverse group of colonial invertebrates, with greater than 7,000 species. Colonies are made of small modules called zooids that are on the order of 1 mm in length. Zooids bud asexually to form a colony of many zooids. These zooids remain attached to each other and can generally share resources. A colony of 12 zooids and the generalized zooid structure are shown in the figure below.

The zooid is made of a box-like or cylindrical protective housing. The housing protects the polypide, which consists of the digestive tract and the feeding structure called the lophophore. The lophophore is a cilliated crown of tentacles that surrounds the mouth. The cilia on the tentacles create a current that brings water laden with food particles (usually phytoplankton) down through the center of the crown and out the base.

Bryozoans of the Pacific Northwest
Click on pictures below to see more pictures of each species of bryozoan.

Encrusting Sheets	Erect Trees	Foliose Plates

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Interesting and Useful Sites on Bryozoans

Bryozoa

• Recent and Fossil Bryozoa
• University of California Museum of Paleontology
• NMITA Bryozoan Page
• International Bryozoology Association
• Introduction to the Bryozoans

Last modified October 8, 2004