Diverse and abundant fenestrate bryozoans occur in two Lower Devonian levels of reefal and perireefal limestones of Central Bohemia, within the type area for the Lower Devonian stages. The reefal deposits of the Koneprusy Limestone (Pragian) are characterized by greater abundance and diversity, with 29 species. A less abundant and, in large part, different fauna of 17 species is found in perireefal and basinal deposits of the younger Zlichov Limestone (Zlichovian). The two faunas have high biostratigraphic, paleogeographic, and evolutionary importance. -- Five species from the Koneprusy Limestone are newly described: Fenestella conopeum McKinney & Kríz, Flexifenestella bellaforma McKinney & Kríz, Alternifenestella strigilla McKinney & Kríz, Cyclopelta victrola McKinney & Kríz, and Hemitrypa linotheras McKinney & Kríz. Alternifenestella estrellita McKinney & Kríz is newly described from the Zlichof Limestone; and three new species, Hemitrypa mimicra McKinney & Kríz, Fabifenestella joachimi McKinney & Kríz, and Polypora inusitata McKinney & Kríz, occur in both strata. Twenty-six species originally described by Barrande, Pocta, and Prantl are redescribed on the basis of original and recently collected abundant material. Descriptions of new and revised species are based predominantly on thin sections and acetate peels, with emphasis on zooecial chamber geometry and linear measurements of both zooidal and zoarial features Includes bibliographical references (p. 83-85) Diverse and abundant fenestrate bryozoans occur in two Lower Devonian levels of reefal and perireefal limestones of Central Bohemia, within the type area for the Lower Devonian stages. The reefal deposits of the Koneprusy Limestone (Pragian) are characterized by greater abundance and diversity, with 29 species. A less abundant and, in large part, different fauna of 17 species is found in perireefal and basinal deposits of the younger Zlichov Limestone (Zlichovian). The two faunas have high biostratigraphic, paleogeographic, and evolutionary importance. -- Five species from the Koneprusy Limestone are newly described: Fenestella conopeum McKinney & Kríz, Flexifenestella bellaforma McKinney & Kríz, Alternifenestella strigilla McKinney & Kríz, Cyclopelta victrola McKinney & Kríz, and Hemitrypa linotheras McKinney & Kríz. Alternifenestella estrellita McKinney & Kríz is newly described from the Zlichof Limestone; and three new species, Hemitrypa mimicra McKinney & Kríz, Fabifenestella joachimi McKinney & Kríz, and Polypora inusitata McKinney & Kríz, occur in both strata. Twenty-six species originally described by Barrande, Pocta, and Prantl are redescribed on the basis of original and recently collected abundant material. Descriptions of new and revised species are based predominantly on thin sections and acetate peels, with emphasis on zooecial chamber geometry and linear measurements of both zooidal and zoarial features Fieldiana series has been published as Geological Series by Field Columbian Museum (1895-1909) and Field Museum of Natural History (1909-1943), and as Fieldiana: Geology by Chicago Natural History Museum (1945-1966) and Field Museum of Natural History (1966-1978). Fieldiana Geology New Series No. 1 began June 29, 1979