Diadumenidae with well developed basal disc. Column smooth, divisible into scapus and capitulum which are separated from each other by a collar round the upper margin of the scapus. Scapus with cinclides. Margin of capitulum tentaculate. Sometimes the collar smoothes away when the body is fully extended. No distinct sphincter. Tentacles long, numerous, more or less regularly arranged not or imperfectly retractile. Some or all of the inner tentacles are typically thicker than the other tentacles, and form catch-tentacles containing, among other nematocysts, atrichs and holotrichs. In some individuals, however, these special tentacles may be absent. Outer tentacles sometimes with macrobasic amastigophors. Six or a few more perfect pairs of mesenteries. Mesenteries more numerous above than below. Retractors diffuse, more or less restricted. Parietobasilar and basilar muscles weak. Perfect mesenteries and the stronger imperfect ones fertile. Acontia well developed, with basitrichs and microbasic p-mastigophors. Cnidom: spirocysts, basitrichs, atrichs, holotrichs, microbasic p-mastigophors, microbasic and macrobasic amastigophors.
Sagartia schilleriana Stoliczka 1869
D. cincta Stephenson 1925
Sagartia leucolena Verrill 1866
D. kameruniensis Carlgren 1927
D. neozelandica Carlgren 1924
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1