Most species in this phylum have a life-cycle consisting of an asexual polyp and a sexual medusa stage.  
Members of this phylum have two-layered body walls with an inner filling called the mesoglia. A model organism for the study of bilateral symmetry, the hydra, is a member of this phylum, as is coral.  Most species in this phylum have a life-cycle consisting of an asexual polyp and a sexual medusa stage.  Formerly called coelenterata, for 10 points, identify this phylum named for a type of stinging cell, which contains such creatures as anemones and jellyfish.
Members of this phylum have two-layered body walls with an inner filling called the mesoglia.
{cnidarians} [accept {coelenterata} before read]