Kleptoplast acquisition in M. rubra and D. acuminata. The cryptophyte nucleus (A) and complete cryptophyte plastid and mitochondria (B) are retained in M. rubra. When the plastid is acquired by D. acuminata the outer two membranes and nucleomorph are lost (C). 1, cryptophyte nucleus; 2, plastid; 3, nucleomorph; 4, cryptophyte mitochondrion; 5, cryptophyte nucleus and cytoplasm surrounded by host membrane; 6, ciliate nucleus; 7, plastid-mitochondrial complex surrounded by host membrane; 8, ciliate mitochondrion; 9, dinoflagellate nucleus; 10, kleptoplast; 11, dinoflagellate mitochondrion. Light photomicrographs of the cells are shown above the cartoon for each organism (scale bar = 10 μm).