Cydippidea is a term that refers to a group of small, gelatinous, planktonic animals found in the ocean. Some synonyms for Cydippidea include comb jellies, sea walnuts, ctenophores, and Venus's girdles. Comb jellies get their name from rows of cilia, or small hair-like structures, that they use for locomotion. Sea walnuts are named for their spherical shape and ribbed appearance. Ctenophores is another term for comb jellies and refers to their intricate pattern of cilia. Venus's girdles are long, ribbon-like creatures that also belong to the Cydippidea group. Regardless of the name, these creatures are fascinating to observe and play an important role in the marine ecosystem.