title: Metridiidae
text: # Metridiidae
  
  Metridiidae is a family of sea anemones in the order Actiniaria.
  
  ## Characteristics
  
  Members of the family Metridiidae are characterised by having a mesogloeal sphincter muscle and by the mesenterial arrangement, with the mesenteries not being divided into macronemes and microcnemes. The acontia typically have microbasic b-mastigophors and microbasic amastigophors, though the latter are not always present in adults.
  
  ## Genera
  
  The following genera are recognised by the World Register of Marine Species (WoRMS):
  
  * Metridium Blainville, 1824
  * Paraisometridium Zamponi, 1978
  
  Of these, Metridium is the most speciose while Paraisometridium is monotypic.
  
  