class scyphozoa

b- Class scyphozoan
Includes all the large jellyfishes which are entirely marine animals
Aurelia:
This IS very common jellyfish of a world- wide distribution and belongs to sub class Discomedusae
c- Class actinozoan
This comprises the sea anemones, reef building corals which are entirely marine this animals exit only in the hydroid stage, the medusoid on being absent. this class are divided into two orders, alcyyonaria and zoantharia.
C1- order alcyonaria( octaradiata)
Alcyonium:
Is cosmopolitan lives in colonies growing on rocks and shells