The extensive order, includes 3 families: Epithemiaceae, Nitzschiaceae, Surirellacea. Representatives of an order: Cylindrotheca gracilis (Breb.) Grun., Stenopterobia intermedia Lewis, Bacillaria paradoxa Gmel., Rhopalodia gibba (Ehr.) O. Mull., Campilodiscus noricus Ehr., Nitzschia angustata (W. Sm.) Grun., Cymatopleura solea (Breb.) W. Sm.
The based disputes usually form many sea neritovy diatome, and also some fresh-water types. At representatives of many childbirth they arise periodically as an everyday occurrence in life cycle.
At centric diatomy paired rapprochement of cages is absent, and an auksospor is formed of one cage in which at first there is a division of a maternal diploidic kernel on four haploid, two of them then are reduced, and two merge in one diploidic kernel and is formed an auksospor.