Isolated echinoderm sclerites have been obtained from carbonaceous and clayey Devonian rocks (Emsian-Frasnian) from the Holy Cross Mountains (Poland), by dissolving them in acetic acid buffered by calcium acetate or in calgone mixed with perhydrol. 60 new and 10 already known biologically understood species and 59 incomplete sklerotomes are recognised. In volume, ophiuroids form the largest component of the collection, but their taxonomic diversity is rather low, with recurrent assemblages of similar composition. Usually a single species dominates them. Sclerites of Furcaster comprise up to 90% of specimens and locally may be rock-forming. Described are three new genera of ophiuroids (Umerophiura, Astutuaster, Weigeltura), 16 new species; distinguished are 35 scleritomes of spines, scales, and other elements. The cyclocystoids are common, represented by nine new genera (Linguacycloides, Neocyclocystoides, Smithocycloides, Platycycloides, Apparatocycloides, Paradoxocycloides, Concavocycloides, Brutocycloides, Chimaerocycloides) and eleven new species classified in the new family Apycnodiscidae. Ophiocistioid remains are also common, their assemblages being of even lower diversity. Eight genera (three of them new Erisserra, Longiserra, Ornatoserra) contain seven new and three earlier known species. Echinoid assemblages are highly differentiated, but their precise taxonomic identifications are rarely possible. Three scleritomes and numerous assemblages of pedicellariae are described (among them Bursulella). Holothurians are the most differentiated. Described are 30 species (25 of them new) and nine new genera (Ballistocucumis, Palaeohemioedema, Staurocaudina, Priscocaudina, Propinquoohshimella, Palaeocaudina, Bracchiothuria, Gagesiniotrochus, Ocellothuria), based not only on dermal sclerites, but also on calcareous rings. The new family Palaeocaudinidae and six new subfamilies, namely Devonothyoninae, Palaeohemioedemiinae, Staurocaudininae, Eocaudiniinae, Calclamninae, and Propinquoohshimellinae, including new and old genera, have been proposed.
