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) Family Hyalodiscaceae R.M. Crawford (1990) Genus Hyalodiscusᵀ Ehrenb. (1845)