Rhizostomeae is an order of jellyfish. Species of this order have neither tentacles nor other structures at the bell's edges. Instead, they have eight highly branched oral arms, along which there are suctorial minimouth orifices. (This is in contrast to other scyphozoans, which have four of these arms.) These oral arms become fused as they approach the central part of the jellyfish. The mouth of the animal is also subdivided into minute pores that are linked to coelenteron.
Edible jellyfish
Jellyfish species fished on a commercial basis for human consumption (both as a delicacy and for use in traditional medicine) are all from this order and include members of the families Catostylidae, Lobonematidae, Rhizostomatidae and Stomolophidae. The jellyfish are typically dried and/or salted. These belong in the following families:
- Suborder Daktyliophorae
- Family Catostylidae <small>Gegenbaur, 1857</small> -- 7 genera
- Family Lobonematidae <small>Stiasny, 1921</small> -- 2 genera
- Family Lychnorhizidae <small>Haeckel, 1880</small> -- 3 genera
- Family Rhizostomatidae <small>Cuvier, 1799</small> -- 4 genera
- Family Stomolophidae <small>Haeckel, 1880</small> -- 1 genus
- Suborder Kolpophorae
- Family Cassiopeidae <small>Agassiz, 1862</small> -- 1 genus
- Family Cepheidae <small>Agassiz, 1862</small> -- 5 genera
- Family Mastigiidae <small>Stiasny, 1921</small> -- 5 genera
- Family Thysanostomatidae <small>Gegenbaur, 1857</small> -- 1 genus
- Family Versurigidae <small>Gegenbaur, 1857</small> (empty taxa)
<gallery style="text-align:center;" mode="packed">
Image:Cassiopea andromeda 2.JPG|Cassiopea andromeda, a Cassiopeidae (upside-down jellyfish)
Image:Blue Blubber Jellyfish IMGP2102.JPG|Catostylus mosaicus, a Catostylidae
Image:Cauliflour Jellyfish, Cephea cephea at Marsa Shouna, Red Sea, Egypt SCUBA.jpg|Cephea cephea, a Cepheidae
Image:Spotted-jellyfish-af.jpg|Mastigias papua, a Mastigiidae
Image:Rizostoma pulmo.jpg|Rhizostoma pulmo, a Rhizostomatidae
Image:Stomolophus meleagris.jpg|Stomolophus meleagris, a Stomolophidae
Image:Thysanostoma loriferum Maldives.JPG|Thysanostoma loriferum, a Thysanostomatidae
</gallery>