Dimorphid

The dimorphids are a small group of flagellate heliozoa. There are two genera: Dimorpha, a tiny organism found in freshwater, and the larger Tetradimorpha, which is distinguished by having four rather than two flagella. Bundles of microtubules, typically in square array, arise from a body near the flagellar bases and support the numerous axopods which project from the cell surface. Each cell has a single nucleus, and mitochondria with tubular cristae.