Phylactolaemata

Phylactolaemata is a class of bryozoans, within the phylum Bryozoa, whose members live only in freshwater. Like other bryozoans they filter feed with an extensible crown of ciliated tentacles called a lophophore and live in colonies of cloned zooids, but unlike many marine bryozoans their colonies consist of only one kind of zooid, the feeding autozooids, supported by an unmineralized gelatinous or protein exoskeleton. The class contains a single living order, Plumatellida.