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Bassia bassensis

Quoy & Gaimard (1827)

Download a fact sheet for Bassia bassensis (PDF 392KB)


Phylum Cnidaria
Class Hydrozoa
Subclass Hydroidolina
Order Siphonophorae
Suborder Calycophorae
Family Abylidae
Genus Bassia
Species bassensis


  • Anterior nectophore: up to 7 mm in height
  • Posterior nectophore: up to 15 mm in length
  • Eudoxid bract: up to 8 mm in height

Distinguishing characteristics

  • Eudoxid and polygastric stages have 2 very dissimilar nectophores, posterior and anterior, both stages can be used for identification
  • Nectophores are rigid, with ridges and no bumps
  • The angular shaped anterior nectophore is smaller than the posterior nectophore, this is diagnostic
  • Nectophores and eudoxids may have bluish tinge to ridges
  • Polygastric stage
  • Anterior nectophore
  • Polyhedral
  • The nectosac extends above the main body of the somatocyst
  • No apical diverticulum to the stomatocyst
  • The somatocyst is large and globular
  • The hydroecium does not extend up between the nectosac and somatocyst
  • Posterior nectophore
  • Rectangular
  • 4 main ridges which end in short basal teeth
  • Eudoxid stage
  • The phyllocyst is a long tube, swollen apically and without lateral processes
  • The gonophore has 4 longitudinal ridges which end basally in minute teeth


  • Epipelagic, temperate waters
  • Pacific, Indian and Atlantic Oceans, and Mediterranean Sea


  • Includes colonies with swimming bells (nectophore) but no float (pneumatophore)
  • Long tubular stem extends from swimming bell, from which various zooids are budded in groups (called a cormidium)
  • Cormidium consists of shield-like bract, gastrozooid, and one or more gonophores that may function as swimming bell
  • Cormidium breaks loose from parent colony and starts independent eudoxid
  • Feeds on copepods in the length range 0.4 to 1.2 mm
  • Can have significant grazing impact on small copepods, both cyclopoids and calanoids


  • Gibbons pers. comm. (2012)
  • Marine species identification portal at
  • Pages, F.; Gili, J.-M.; Bouillon, J. 1992 Medusae (Hydrozoa, Scyphozoa, Cubozoa) of the Benguela Current (southeastern Atlantic). Scientia Marina Volume: 56 Issue: Suppl. 1 Pages: 1-64
  • Pages, F; Gonzalez, HE; Ramon, M; et al. 2001. Gelatinous zooplankton assemblages associated with water masses in the Humboldt Current System, and potential predatory impact by Bassia bassensis (Siphonophora : Calycophorae) MARINE ECOLOGY PROGRESS SERIES Volume: 210 Pages: 13-24 DOI: 10.3354/meps210013
  • Pugh, P. R. (1999). Siphonophorae. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands, Backhuys Publishers. 1: 467-511