Rapid patterning and zonal differentiation in a two-dimensional Dictyostelium cell mass: the role of pH and ammonia S. Sawai, T. Hirano, Y. Maeda and Y. Sawada 10.1242/jeb.004408 There was an error published in J. Exp. Biol. 205, 2583-2590. The reference Hara and Konijn (1976) was incorrectly listed in the References. The name of the first author was inadvertently omitted and the reference should have been listed as: Nanjundiah, V., Hara, K. and Konijn, T. M. (1976). Effect of temperature on morphogenetic oscillations of Dictyostelium discoideum. Nature 260, 705. The reference was also incorrectly cited in the first paragraph of the Discussion (p. 2586). The citation to (Hara and Konijn, 1976) should in fact have read (Nanjundiah et al., 1976). We apologise to Dr Nanjundiah for this error. Erratum