Ocean Ecosystems

noun a free-swimming marine coelenterate with a jellylike bell- or saucer-shaped body that is typically transparent and has stinging tentacles around the edge

• The jellyfish is a fascinating marine creature with a gelatinous body and tentacles.
• I saw a jellyfish while snorkeling at the beach today.
• Dude, did you see that huge jellyfish in the water? It was gnarly!
• Her thoughts drifted like jellyfish, floating aimlessly in her mind.

noun a taxonomic group that includes sea anemones and corals, characterized by having stinging cells called nematocysts

• The actinoidea are a subclass of the class Anthozoa, consisting of sea anemones and corals.
• I saw some cool actinoidea at the aquarium today.
• Those actinoidea creatures are really weird looking!
• The actinoidea sway gently in the ocean currents, like dancers in a ballet.