No, members of the phylum Cnidaria are not segmented. Cnidarians, which include jellyfish, corals, sea anemones, and hydras, have a simple body plan that lacks segmentation. Instead, their bodies are organized into two main layers: the epidermis (outer layer) and the gastrodermis (inner layer), with a gelatinous mesoglea in between.
Unlike segmented animals such as annelids (earthworms) and arthropods (insects, crustaceans), cnidarians exhibit radial symmetry. This means their body parts are arranged around a central axis, much like the spokes of a wheel. This body structure is well-suited for their aquatic lifestyle, allowing them to interact with their environment from all directions.
In summary, cnidarians do not have segmented bodies. Their simple, radially symmetrical structure is a key characteristic that distinguishes them from segmented organisms.