It is the band aid looking patch on a worm that holds its sex organs. this is only in a worm, we, humans do not have citellum.
It is a saddle-like or ring-like girdle or 'cocoon' on a worm in which the eggs and sperm are deposited for fertilization and development.
its a band of thickened, specialized segments in annelids that secrets a mucus ring into which eggs and sperm are released
The band is called a citellum. It is where the reproductive organs are located.