Rhizostomae or 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.

Last August I took these photographs on the beach of the Antilla in Huelva (Atlantic coast of southwestern Spain). During the summer the coast and estuaries of the rivers are full of these huge, but harmless, jellyfish

Pink rhizostome jelly (Crambione mastigiophora) by Jason Isley 

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