Abstract: | The relationship between the masses and metallicities of galaxies could be non-monotonic, due to the outflow of matter in these systems. It is shown using a simple, one-zone, chemical-dynamicalmodel that the metallicity should be a non-monotonic function of the mass for spheroidal dwarf galaxies with low masses of M ≤ 108 M ⊙, and a monotonically growing function for galaxies with higher masses. This is consistent with observations. |