Image description: Nudibranch species Janolus barbarensis, as seen under the North T-Pier, Morro Bay, California.
Nudibranchs, pronounced new-duh-branks and commonly known as sea slugs, are gastropod mollusks like whelks and many other shells you find along the beach. But, nudibranchs have no shells. There are over 3,000 species of these beautiful creatures, found on seafloors all over the world.
Photo by the National Science Foundation.