Video 11.1 Feeding Behavior (HelisomaLymnaea). As a snail moves, it frequently grazes on the substrate. In this video, you can see parts of the triphasic motor pattern. When the mouth opens, the odontophore protrudes backwards. As the odontophore moves forward again, the radula scrapes the surface, loosening food particles. Finally, the mouth closes as the odontophore pushes food back to the esophagus. The rhythm is variable and may include long pauses.