Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics Subclass Chaetocerotophycidae Round & R.M. Crawford (1990) see Class Mediophyceae Medlin & Kaczmarska (2004) Order Chaetocerotales Round & R.M. Crawford (1990) Family Attheyaceae R.M. Crawford & Round (1990) 1 Genus Attheyaᵀ T. West (1860)