slideshow A Seashore Walk Rough Periwinkles Credit: Helen Scales Rough periwinkles sit on a bed of barnacles. Limpet Teeth Marks Credit: Helen Scales Limpets leave a zigzag trail on rocks as they move along scraping off algae and seaweed with their strong teeth. Painted Top Shell Credit: Helen Scales A painted top shell sits in the water of low tide. Chiton on a Rock Credit: Helen Scales A chiton displays its overlapping protective plates running down the back. Byssus Threads on a Blue Mussel Credit: Flickr user Tantivy_Jade Blue mussels use byssus threads (which you can see on the right, in front of the barnacle shell) to attach to rocks and sometimes to stop a predator from making them a meal. Blue-rayed Limpet Credit: Helen Scales A blue-rayed limpet nestled inside a hole chewed on a piece of kelp. Students At the Shore Credit: Helen Scales Students from Helen Scales' class visit the seashore to explore mollusks.