Planula

A planula is the free-swimming, flattened, ciliated, bilaterally symmetriclarval form of various cnidarian species and some species of ctenophores (such as in genus Lampea), which are not closely related to cnidarians. Some groups of nemerteans also produce larvae that are very similar to the planula, which are called planuliform larva. In a few cnidarian clades, like Aplanulata and the parasitic Myxozoa, the planula larval stage has been lost.