There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 20 species of Cubozoa, and the Hydrozoa includes about 1000 1500 species that produce medusae ( and many more hydrozoan species that do not produce medusae ).
22.
""'Pandea rubra " "'( class " Hydrozoa " ) are cnidarian invertebrates distinguished by an anthomedusan jellyfish with a bright red subumbrella . " P . rubra " are found in extremely deep and cold Pacific Ocean waters.
23.
Meanwhile, life cycle reversal, in which polyps are formed directly from medusae without the involvement of sexual reproduction process, was observed in both Hydrozoa ( " Turritopsis dohrnii " and " Laodicea undulata " ) and Scyphozoa ( " Aurelia " sp . 1 ).
24.
Modern biology confirms Huxley's criticism of De Blainville's Actinozoa, and upholds Hydrozoa, but it is now known that the Ctenophora are only distantly related to jellyfish and their relatives, so Huxley's Actinozoa and Coelentera are no longer used ( though the name Actinozoa is occasionally applied to the Anthozoa ).
25.
These he called Coelentera, and showed that they had no special affinity with echinoderms, polyzoa, etc . He further divided the Coelentera into a group Hydrozoa, in which the sexually produced embryos were usually set free from the surface of the body, and a group Actinozoa, in which the embryos are detached from the interior of the body and escape generally by the oral aperture.
