Littorina compressa
Littorina compressa is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles.
Littorina compressa are native to Western Europe, and have also been found in the North Atlantic sea and in Russia.
Littorina compressa share are extremely similar in appearance to their sibling species Littorina saxatilis and Littorina arcana. The three species have been found to grow together.