The rough periwinkle is able to attach itself to the rocks by secreting two mucus films between the shell edge and the rock face with its foot, creating a tight seal. The seal prevents contact with the atmosphere and holds the animal tightly in place. The ability to survive for long periods cemented to the rock surface, protects the rough periwinkle from drying out during lengthy exposure to high temperatures. In addition, this strong seal helps to hold the snail in position during strong wave activity. L. saxatilis is able to "breathe" through the moist surface of gill in its mantle cavity, much like land snails. Click on the image above for an anatomy lesson of the rough periwinkle.