a lobster-pot trap is a chamber that is easy to enter, and whose exit is either difficult to find or obstructed by inward-pointing bristles. lobster pots are the trapping mechanism in "genlisea", the corkscrew plants. these plants appear to specialise in aquatic protozoa. a "y"-shaped modified leaf allows prey to enter but not exit. inward-pointing hairs force the prey to move in a particular direction. prey entering the spiral entrance that coils around the upper two arms of the "y" are forced to move inexorably towards a stomach in the lower arm of the "y", where they are digested. prey movement is also thought to be encouraged by water movement through the trap, produced in a similar way to the vacuum in bladder traps, and probably evolutionarily related to it.