Ernst Mayr's 'ultimate/proximate' distinction reconsidered and reconstructed

It's been 41 years since the publication of Ernst Mayr's Cause and Effect in Biology'' wherein Mayr most clearly develops his version of the influential distinction between ultimate and proximate causes in biology. In critically assessing Mayr's essay I uncover false statements and red-herrings about biological explanation. Nevertheless, I argue to uphold an analogue of the ultimate/proximate distinction as it refers to two different kinds of explanations, one dynamical the other statistical.