Lower Ordovician ostracods from the Oslo Region, Norway

11 paleocop ostracods are described from the Lower Ordovician Ceratopyge and Asaphus Series of the Oslo Region in Norway. A chart (p. 63) shows their stratigraphical and geographical distribution. The genus Nanopsis is new (type: Beyrichia nanella MoBERG & SEGERBERG, 1906), and also the species Conchoprimitia eos and the subspecies C. socialis vulgaris. Blood canals and muscle marks are described in Conchoprimitia.