We documented capture of microalgal prey by several species of wild-caught Müller's larvae of polyclad flatworms. To our knowledge, this is the first direct observation of feeding mechanism in this classical larval type. High-speed video recordings showed that virtually all captures were mediated by large-scale transient ciliary reversal over one or more portions of the main ciliary band corresponding to individual lobes or tentacles. Local ciliary beat reversals altered near-field flow to suck parcels of food-containing water mouthward. Many capture episodes entailed sufficient coordinated flow disruption that these compact-bodied larvae tumbled dramatically. Similar behaviors were recorded in at least four distinct species, one of which corresponds to the ascidian-eating polyclad Pseudoceros canadensis.