Parameter Tree:
EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > CNIDARIANS > JELLYFISHES

Definition:
Jellyfish are acoelomate with a body wall divided into two layers and
separated by a jelly-like mesoglea. They are primarily radially
symmetrical with no anus and a mouth usually surrounded by tentacles
bearing stinging nematocysts.  Jellyfish are free swimming. 


Reference:
Burn, David M. Animal World. 1980. Octopus Books Ltd. London.