The halysitid coral genera Halysites and Cystihalysites from Gotland, Sweden

The taxonomy of the tabulate coral genera Halysites and Cystihalysites of the order Halysitida from the Silurian of Gotland is revised. Catenipora crassa Stasinska, 1967 and Halysites crassus Stasinska, 1974, are considered to be junior synonyms of Halysites senior Klaamann, 1961. The formation of walls by joined edges of dissepiments in Cystihalysites is shown. The distribution of species in the Gotland sequence is documented. The occurrence of Cystihalysites blakewayensis Sutton, 1964 on Gotland is noted for the first time.