Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) Class Bacillariophyceae Haeckel (1878) - pennates Subclass Bacillariophycidae D.G.Mann (1990) - raphid diatoms Order Surirellales D.G.Mann (1990) Family Surirellaceae Kütz. (1844) Genus Hydrosilicon Brun (1891)