Order

Anthoathecata

  Class

Hydrozoa

  No. of Genera in Ref.

7

  No. of Species in Ref.

90

  Environment

Fresh : No | Brackish : No | Marine : Yes

  Aquarium

  First Fossil Record

     

  Remark

Hydroids with colonial, monomorphic polyps having club-shaped to cylindrical or slightly casiform bodies. With one whorl of capitate tentacles around whorl of filiform tentacles. Colonies upright, stolonal or branching, monosiphonic, stem and branches covered by prericarc. Stolons tubular. Nematocysts: stenoteles, with or without isorhizas or mastigophores, desmonemes absent. Gonophores in most species arising on hydranths, either liberated as free medusae or retained as medusoids or sessile sporosacs. Exceptionally gonophores completely reduced and gametes stored in hydranth wall. Free medusa if present with four radial canals, four tentacles bulbs, and four tentacles. Tentacle bulbs with a distinct gastrodermal chamber, epidermal part contains many nematocyst and forms a complete or nearly complete ring around tentacle base. Each bulb normally with one abaxial ocellus only. Manubrium cylindrical, without lips, gonads encircle manubrium without perradial interruptions. Exumbrella without nematocyst pouches. Nematocysts as in polyp stage, but additionally with desmonemes, macrobasic euryteles absent. Newly released immature medusae with manubrium always shorter than bell cavity (Ref. 3316). (Ref. 19)

  Etymology

  Division

  Reproductive guild

  Typical activity level

  Main Ref.

  Coordinator