English: One of a series of pictures illustrating how Cornu aspersum locomotion over dry bricks economises on wasted mucus by lifting parts of the ventral surface out of contact with the substrate, so that it leaves a trail of disconnected dabs of mucus instead of a continuous trail. On a wet surface the trail is continuous. Presumably the continuous trail is energetically advantageous on a wet surface, or the snail would used the same gait on both types of surface. Many other terrestrial Gastropoda use the same strategy.