· Ctenophora is a phylum of exclusively marine organisms, formerly included in coelenterates. · Ctenophores ( Gr., cten , comb; phero , to bear ) are commonly known as sea walnuts, comb Jellies, or sea gooseberries. · They are radially ( biradially) symmetrical, diploblasti c (or perhaps triploblastic ) organisms with tissue level of organization. · Ectoderm and endoderm are separated by cellular mesenchyme. · Most of the ctenophores are transparent, gelatinous, and pelagic but a few genera are creeping. · Bioluminescence ( the property of a living organism to emit light) is well marked in ctenophores . · They live from surface waters to a depth of about 3000 meters; about 100 species of ctenophores have been described so far. · The body is gelatinous and extremely fragile; its form may be globular, pyriform, or bell‑shaped; some species resemble a ribbon. · The axis of symmetry is determ...