Jellyfish belong to the Class Scyphozoa. There are approximately 200 species of jellyfish that are subdivided into the following five orders:
- Order Coronatae
- Order Rhizostomeae
- Order Rhizostomatida
- Order Semaeostomeae
- Order Stauromedusae
A jellyfish begins its life as a free-swimming planula which after a few days drops to the sea floor and attaches itself to a hard surface. It then develops into a polyp which buds and divides to form a colony. After further development, the polyps shed tiny medusa which mature into the familiar adult jellyfish form which goes on to reproduce sexually to form new planulae and complete their life cycle.
The more familiar species of jellyfish include the Moon Jelly (Aurelia aurita), the Lion's Mane Jelly (Cyanea capillata) and the Sea Nettle (Chrysaora quinquecirrha).