Part of the "Branches on the Tree of Life" series. Begins with a series of observations on Hydra, including habitat, structure, feeding, nematocyst discharge, locomotion (by looping), and its sexual and asexual reproductive strategies. Obelia illustrates the two-stage life cycle found in many cnidarians. Examining the biology of jellyfish (class Scyphozoa), sea anemones, and corals (class Anthozoa) rounds out the overview of phylum Cnidaria. Accessibility options on the DVD are: (1) expanded description, (2) English subtitles in a black box, (3) subtitled description.