Actinodiscidae without sphincter and marginal tentacles (or, if really present, strongly reduced). Margin a little crenulate. Tentacles occupying the whole oral disc for the most part branched but simple towards the margin. Microbasic p-mastigophors are long, hoplotelic, very numerous in the filaments and arranged palisade-like. Cnidom: holotrichs, microbasic p- and b-mastigophors.
M. boniensis Carlgren 1943
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1