Nevadneidae with small pedal disc and elongate body, broader in the distal part than in the proximal. Column smooth, but its nematocysts arranged in small groups. The outermost exocoelic tentacles are the largest. Mesenteries of the youngest cycle doubled, as a result of an extraordinary increase in the outermost tentacles, accompanied by the origin of an exocoelic tentacle and thereafter of an endocoelic one on either side of the outermost tentacle. As a rule only the mesenteries of the second cycle are fertile, but traces of gonads may occur on some mesenteries of the first cycle.
Gyrostoma glauca Annandale 1915
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1