The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or "true jellies"). It may include the extinct fossil group the Conulariida, whose affinities are uncertain and widely debated.

The class name Scyphozoa comes from the Greek word skyphos (σκύφος), denoting a kind of drinking cup and alluding to the cup shape of the organism. Scyphozoans have existed from the earliest Cambrian to the present.

Scyphozoa. Retrieved November, 05 2021, from en.wikipedia.org/wiki/Scyphozoa.

Semaeostomeae (literally "flag mouths") is an order of large jellyfish characterized by four long, frilly oral arms flanking their quadrate mouths. The umbrella is domed with scalloped margins, and the gastrovascular system consists of four unbranched pouches radiating outwards from the central stomach; no ring canal is present. They usually possess eight tentacles; four are per-radical and four are inter-radical.

Semaeostomeae. Retrieved November, 05 2021, from en.wikipedia.org/wiki/Semaeostomeae.