Tuboid graptolites from erratic boulders of Poland

Cyclograptidae (= Idiotubidae) are described from the Ordovician to Silurian erratic boulders of Poland. Some problems involved in tuboid taxonomy and colony organization are considered. One new genus (Kozlowskitubus gen.n.) and three new species (Epigraptus eisenacki sp.n., E. kozlowskii sp.n., Dendrotubus bulmani sp.n.) are erected. Names Idiotubus Kozłowski, 1949, and Idiotubidae Kozłowski, 1949, were recognized for junior synonyms of Epigraptus Eisenack, 1941, and Cyclograptidae Bulman, 1938, respectively.