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Bryozoan colonies were common in farm ponds. Plumatella repens Linnaeus and P. casmiana Oka were dominant. Pectinatella magnifica Leidy occasionally became abundant. Plumatella developed branched colonies when protected from fish; unbranched colonies developed where they were exposed to bluegills. Numerous kinds of animals were associated with bryozoan colonies. Chironomid larvae were dominant cohabitants.
J. S. Dendy (Mon,) studied this question.