Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics Subclass Coscinodiscophycidae Round & R.M. Crawford (1990) Order Melosirales R.M. Crawford (1990) 1 Family Melosiraceae Kütz. (1844) 2 Family Stephanopyxidaceae Nikolaev (1984) 3 Family Endictyaceae R.M. Crawford (1990) 4 Family Hyalodiscaceae R.M. Crawford (1990)