Hydroidolina Collins, 2000

Crow, Gerald L., Holland, Brenden S., Yamamoto, Gaku, Ikeda, Shuhei, Adachi, Aya & Niide, Kelley, 2023, Tuerkayana rotundum, Zoological Studies 62 (49), pp. 1-15 : 5

Subclass Hydroidolina Collins, 2000 Order Leptothecata Cornelius, 1992 Family Eirenidae Haeckel, 1879 Genus Eirene Eschscholtz, 1829

There are 24-valid Eirene species in the World Registry of Marine Species [WoRMS database] (www. marinespecies.org/aphia.php?p=taxdetails&id=117080 accessed 17 June 2022). Amended Genus description based on ( Kramp 1961 1968; Bouillon and Boero 2000; Bouillon et al. 2006; Schuchert 2017; this study).

Typically small medusae ≤ 32 mm bell diameter, with a distinct gastric peduncle, no marginal or lateral cirri, with or without excretory pores, numerous statocysts present (may disappear in preserved specimens), with or without rudimentary bulbs (warts), these bulbs are present on the ring canal in at least eight species [ E. conica Du, Xu, Huang and Guo, 2010 , E. elliceana (Agassiz and Mayer, 1902) , E. hexanemalis , E. kambara Agassiz and Mayer, 1899 , E. lacteoides , E. macrogonia Huang, Sun and Liu, 2019 , E. palkensis Browne, 1905 , E. tenuis (Browne, 1905) ], with 4–12 simple radial canals, gonads only on subumbrella portions of radial canals that do not extend down the peduncle.