Elongate Haloclavidae with a well-developed, rounded aboral body-end perforated by very numerous apertures ("cinclides"). Column indistinctly divisible into regions without tenaculi but for minute adherent areas. No sphincter. Tentacles normally 12, without acrospheres, the inner endocoel-tentacles shorter than the outer exocoel-tentacles. A single very deep siphonoglyph, the oral end of which is drawn out in a more or less lobate conchula, rarely forming a distinct tube separated from the cavity of the actinopharynx by an ectodermal fusion. Pairs of mesenteries 10 (6+4 lateral and ventrolateral pairs of second cycle). Only the mesenteries of the first cycle perfect, fertile, with filaments and strong diffuse retractors. Mesenteries of the second cycle only with retractors close to the column. Cnidom: spirocysts, basitrichs, microbasic p-mastigophors. The larvae live parasitically on medusae.
P. hastata Gosse 1855
Siphonactinia boekii Danielsson [sic] 1856
P. koreni Mc Murrich [sic] 1893
Bicidium parasitica Agassiz 1859
P. quinquecapitata Mc Murrich [sic] 1913
P. mira Carlgren 1943
P. hilli Wilsmore 1911
P. neozelanica Carlgren 1924
P. carnea Hutton 1878
P. chilensis Carlgren 1931
Definitions and contained taxa are those of Oscar Carlgren
as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series
4, Volume 1, Number 1