Fig. 6
Colonial feeding currents in bryozoans with cribrate (a) and fenestrate (b) colony-forms. Branches shown in cross section along with autozooidal lophophores. Small arrows signify prevailing current directions created by individual autozooids, large arrows the colonial flow pattern. Whereas water flows through the gaps (fenestrules) between the branches of fenestrate colonies, in cribrate colonies the gaps (lacunae) between branches are inferred to be sites of divergent exhalent chimneys