Violet Sea-snail, Janthina janthina

The Janthinidae Family include the Purple Sea Shells. They are a component of “Purple Communities” that consist of other purple Cnidarians such as the Portuguese Man-of-War, Physalia physalia and the By-the-Wind Sailor, Velella velella, and other shell-less nudibranchs. These communities may spread over 200 square miles of ocean surface. The shells are fragile being globose in shape but can range in stature from low to high and are small to medium in size and consist of four to six whorls, a large “D”-shaped aperture with an outer lip that is rolled out that is where the shell is attached to the raft. The exterior of the shell can be smooth in texture or have growth ridges or spiral grooves and is either purplish or brownish in color. They are counter-shaded, displaying a darker color on their bottom and lighter on top which makes them more difficult to see against the ocean or sky backgrounds. The interior of the shell matches the exterior in texture and color.