Seawater flow into the digestive system of actinotroch larvae (Phoronida)

Actinotroch larva (Phoronida) concentrate and collect food particles during their planktonic existance. Reported mechanisms of particle capture include both ciliary reversal and direct interception along the larval tentacles, and suction of particle-containing seawater into the larval vestibule. These diverse mechanisms explain collection of particles, but not subsequent ingestion. Particle delivery into the digestive system is accomplished, at least in part, by the activity of the esophageal cilia. If and how the beat frequency of esophageal cilia is modified by the presence or absence of particulate or dissolved organic materials remains unknown for actinotroch larvae.