Light micrograph (DIC) of the skeleton of a Dictyocha speculum silicoflagellate. Silicoflagellates are single-celled marine algae. They have silica skeletons composed of a network of bars and spikes to form a supportive basket-like structure. Silicoflagellates (Class Dictyochophyceae) are yellow unicellular protists. They have several stages of life history with the most common form being the skeleton-bearing cell. The characteristic siliceous skeleton consists of a polygonal basal ring with protruding radial spines. Magnification: x800 when printed at 10 centimetres wide at its longest edge.