Some anthoathecate hydroids and limnopolyps (Cnidaria, Hydrozoa) from the Hawaiian archipelago 2590 Author Calder, Dale R. text Zootaxa 2010 2010-08-31 2590 1 1 91 https://biotaxa.org/Zootaxa/article/view/zootaxa.2590.1.1 journal article 10.11646/zootaxa.2590.1.1 1175­5334 Subclass Hydroidolina Collins, 2000 Hydroidolina Collins, 2000: 21 . Diagnosis. Hydrozoa with polyps and medusae as significant and conspicuous stages in the life cycle (although some species exclusively polypoid or medusoid), often metagenetic except in siphonophores; polypoid stages, when present, usually polymorphic; medusae frequently reduced, forming parts of a highly polymorphic colony in siphonophores; medusa stage usually with true tentacular bulbs, ocelli present or absent, free ecto-endodermal statocysts lacking; planula larvae, when present, usually with cnidoblasts, glandular cells, neural cells, and interstitial cells, most often settling and becoming benthic except in Porpitidae and Margelopsidae (Anthoathecata) and holopelagic Siphonophora. Remarks. For discussion of the subclass Hydroidolina Collins, 2000 , and of the subclass Trachylina Haeckel, 1879 as currently used in hydrozoan classification, see Collins (2000) , Marques & Collins (2004) , Daly et al . (2007) , and Cartwright et al . (2008) . Hydroidolina encompasses the hydrozoan orders Anthoathecata Cornelius, 1992 , Leptothecata Cornelius, 1992 , and Siphonophorae Eschscholtz, 1829 .