Genera
Five genera are recognized; '' Cyclostomiceras'', '' Eocyclostomiceras'', '' Microstomiceras'', '' Paracyclostomiceras'', and '' Pictetoceras''. ''Cyclostomiceras'' and ''Paracyclostomiceras'' were described in Flower (1964). :''Cyclostomiceras'' Hyatt 1900, found in the Fort Cassin Limestone of Champlain Valley, the Smithville Formation of Arkansas, and the Arneg of Chile, has a straight shell with a fairly rapidly expanding early portion, slightly depressed cross section. :''Paracyclostomiceras'' Cicioni 1953 is a slightly more slender cyclostomicerid from Argentina with an oblique aperture and slight ventral and dorsal lobes. ''Microstomiceras'' and ''Pictetoceras'' come from the Middle Ordovician Hälludden cliff section, Oland Island, Sweden, associated with such as '' Paldoceras''.References
* Rousseau H Flower, 1964. Memoir 12. The Nautiloid Order Ellesmericerida (Cephalopoda). State Bureau of Mines and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, New Mexico.