Paps J et al. Proc. R. Soc. B 2009;276:1245-1254. Stentor(Ciliophora). LecaneRotifera. Note similar size of a multicellular animal and a protist. Side view of a rotifer. Suspension-feeding rotifers use the ciliated corona to create current- Mastax triturates the food. Rotifers have a complex, regionally differentiated gut ending in a cloaca and anus.