Janthinidae - Purple Sea Snails

Janthinidae, the purple sea snails, have smooth, globose fragile shells that are usually blue to purple in color. Their foot produces a mucus float, made of several enclosed bubbles of air, outside their shell which allows them to float on the surface of the water. They form communities with other floating organisms, such as the Portuguese man o' war and the by-the-wind sailors, upon which they feed. There are 5 species in Texas waters.