The family Beyrichiidae is discussed and divided into 4 subfamilies; Beyrichiinae, Kloedeniinae, Zygobolbinae, and Treposellinae subfam.n. A new genus, Cornikloedenia, and 5 new subgenera of Beyrichia (Eobeyrichia, Neobeyrichia, Nodibeyrichia, Vehbeyrichia, and Mitrobeyrichia) are erected. 26 beyrichiacean ostracods from the Silurian of the Oslo region are described. A chart (p. 67) shows their stratigraphical and geographical distribution. The genus Signetopsis is new, and the following species and subspecies are also new: Beyrichia paucituberculata, B. zygophora, B. osloensis, B. skienensis, B _ kiaeri, B. ringerihensis, Craspedobolbina arrnata, C. dorsoplicata, C. expansinodata, Platybolbina tiara densistriata, P. lunulifera, P.? bulbosa, Prirnitiella? bipunctata, Primitiopsis dorsoplicata, Signetopsis quadrilobata, and S. rnalornata.
Silurian ostracods from the Oslo region, Norway. 1. Beyrichiacea. With a revision of the Beyrichiidae.