Actinostolidae with the body sometimes short, sometimes cup-like, sometimes long, cylindrical. Column usually thick, firm, slightly rugose or almost smooth, or with flat tubercles produced by mesogloeal thickenings. Sphincter comparatively weak, mesogloeal, so that the upper part of the column cannot perfectly cover the tentacles. Tentacles short, the inner considerably longer than the outer, never more numerous than the mesenteries at the base; sometimes with mesogloeal thickening on their aboral sides at the base; outside provided at their tips with microbasic b-mastigophors. Longitudinal muscles of tentacles and radial muscles of oral disc mesogloeal. Two well developed siphonoglyphs. Numerous perfect mesenteries, hexamerously arranged. The two mesenteries in one and the same pair, from the third or the fourth cycle, irregularly arranged but as a rule orientated so that the mesentery which turns its longitudinal muscle towards the nearest mesentery of the preceding cycle is more developed than its partner. Retractors of mesenteries diffuse, parietobasilar and basilar muscles strong. Mesenteries of the two first cycles sterile. Cnidom: spirocysts, basitrichs, microbasic p- and b-mastigophors.
Urticina callosa Verrill 1882
A. spetsbergensis Carlgren 1893
Bunodes abyssorum Danielssen 1890
A. groenlandica Carlgren 1899
A. pergamentacea Mc Murrich [sic] 1893
Dysactis crassicornis Hertwig 1882
A. intermedia Carlgren 1899
A. excelsa Mc Murrich [sic] 1893
A. georgiana Carlgren 1927
A. clubbi Carlgren 1927
A. kerguelensis Carlgren 1928
A. carlgreni Wasilieff [sic] 1908
Definitions and contained taxa are those of Oscar Carlgren as published in 1949 : Kungl Svenska Vetenskapsakadamiens Handlingar, Series 4, Volume 1, Number 1
Electronic version made possible by NSF grant DEB95-21819 in the PEET program to D. G. Fautin.