Halcampoididae with elongate body and physa-shaped end. Column not distinctly divisible into regions with two cycles of apertures (cinclides) in the proximal end, smooth, without tenaculi and nematocyst batteries. No sphincter. Tentacles 12, rather long, cylindrical. 2 indistinct siphonoglyphs. Actinopharynx without conchula. Only 6 pairs of perfect and fertile mesenteries. No microcnemes. Retractors strong, restricted to reniform, parietal muscles well-developed. No acontia. Cnidom: spirocysts, basitrichs and microbasic p-mastigophors.
Halcampa purpurea Studer 1878
H. abyssorum Danielssen 1890
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1