Column smooth or with papillae in its upper part, with spirocysts. Fosse distinct. Sphincter weaker or stronger circumscribed. Tentacles short, papilliform, the exocoelic tentacles in a single row, the endocoelic tentacles may show a tendency to form two rows? Usually ten pairs of perfect mesenteries and ten pairs imperfect ones (sometimes some of the latter can reach the uppermost part of actinopharynx). The endocoels are strongly enlarged, the exocoels strongly reduced so that perfect and imperfect mesenteries lie close to each other in longitudinal furrows on the column and form secondary pairs with the retractors facing away from each other. Retractors strongly restricted, parietobasilar muscles broad but not folded. Cnidom: spirocysts, basitrichs, microbasic p-mastigophors.
Actinia ultramarina Leseur 1817
M. coerulea Lesson 1830
M. torpedo Bell 1885
Actinia olivacea Leseur 1817
Stichophora cyanea Brandt 1835
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1