The common starfish develops a so-called bipinnaria larva, with ciliated bands running about the periphery, a beautiful sight.
After several weeks the bipinnaria larva takes on a more elaborate form, with longer projecting arms and after some more weeks, a brachiolaria larva is formed. The larvae have their own gut, with inside cilia to inhale and transport food particles. They feed themselves with diatoms and other organisms in the plankton. The stomach is large and round and situated at the back side.
After this phase a large part of the larva degenerates and at the rear side a rudimentary formed juvenile starfish develops. The organs of the young starfish are formed anew.