Superfamily Primitiopsoidea Swartz 1936, cont. - histio-velar features in Mid-Palaeozoic representatives. "Hybrid" primitiopsids. Neues Jahrbuch fuer Geologie und Palaeontologie Abhandlungen, 242(2-3), Dezember 2006: 275-287. 282 [Zoological Record Volume 143]