Swimming experiment. (A) Mimicking a free-hanging mangrove root with attached ascidians (Ecteinascidia turbinata), a colony of ascidians is lowered into a tank (without touching the bottom; see inset) filled with water and adult M. crozieri. (B) Several specimens of M. crozieri have reached the dangling ascidians. The flatworms are not able to swim directly towards the food through the water. Instead, they glide up the glass wall and move under the water surface using adhesive surface forces and fluid resistance to prevent sinking and let themselves drop onto the ascidians when floating directly above them. (C) Schematic showing four steps of a polyclad reaching the dangling ascidians, starting from the bottom of the tank, then gliding up the glass wall and under the water surface.