(from the article `cnidarian`) ...Another theory is that the original cnidarian was a planula-like organism that preceded both polyp and medusa. In either case, Hydrozoa is ... ...purple. Reduced medusae not freed; develop and produce gametes in cavities of skeleton (ampullae). Worldwide; includes precious red coral, ... [2 related a...
Found on
http://www.britannica.com/eb/a-z/t/68
Trachylina is an order of Hydrozoa. They are mainly marine forms in which the medusoid stage is represented, and the hydroid stage is reduced or absent.
Found on
http://www.probertencyclopaedia.com/browse/BT.HTM
No exact match found.
