Phylum Cnidaria belongs to Eumetazoa clade, the animals with true tissues. The
cnidarians (hudras, jellies, sea anemones, and coral animals) have radial
symmetry, diploblastic embryos (with ectoderm and entoderm, but no mesoderm).
The basic body plan of a cnidarian is the gastrovascular cavity. A single
opening to this cavity functions as both mouth and anus. They are carnivores
that use tentacles arranged in a ring around the mouth to capture prey and push
the food into the gastrovascular cavity. The tentacles are armed with batteries
of cnidocytes, unique cells that function in defense and the capture of prey. In
general, phylum consist of 3 classes: Hydrozoa, Scyphozoa and Anthozoa.