Ctenostomata
Quick Summary
Ctenostomata is an order of Bryozoa, which are sedentary, aquatic invertebrates that form colonies of zooids. The zooids in Ctenostomata are typically cylindrical or flat, and their walls are not calcified. A key characteristic of this order is that the aperture of the zooid is often closed by a pleated collar when the tentacles are retracted. Unlike some other bryozoan orders, Ctenostomata lack specialized reproductive structures called ooecia or avicularia. This order is primarily marine and has existed from the Jurassic period to the present.12
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