For all of us interested in working between the disciplines of philosophy, history and biology, it is gratifying to find an occasional study in which historical-times-philosophical-times-biological (or metabiological) questions are thoughtfully intertwined. Having overlooked until now David Kitts' sensitive and illuminating remarks on "Plato on Kinds of Animals" (Bio. and Phil. 2,(315)(316)(317)(318)(319)(320)(321)(322)(323)(324)(325)(326)(327)(328), I am most grateful to Ernst Mayr for bringing them to my attention (Mayr, 1988). Kitts explicitly omitted any attempt to investigate the alleged influence of Plato on biology: what biologists and when? But of course, given the inexhaustible richness and deep pluralism of Plato's thought, an "influence of Plato" (as distinct from either some very general tendency that gets called "Platonism" or specific doctrines of specific members of the neo-Platonic tradition) would be hard to establish. Short of such a difficult, and perhaps impossible, task, however, it is important, I believe, both for the sake of historical accuracy and out of respect for the transcendent thinkers of our tradition, to pay serious attention to the works (and words) of those philosophers who are all too glibly cited as having done this or that to science, or religion, or what you will, in this case, to biology. Mayr finds it curious that Kitts did not cite Popper. If, rather than considering only the political context in which the book was written, one takes The Open Society as a document in the history of philosophy, the most courteous adjective one can apply to it is "contemptible"; indeed, were it not for the prevalence, alas, of what Van Valen (1988) so aptly calls "Poppery" even on this side of the Atlantic, the book would be beneath contempt. To swallow such an outpouring of prejudice and willful ignorance instead of reading Plato is unworthy of a scholar of Mayr's stature. (I noticed in rereading Hull's old anti-essentialism paper recently, incidentally, that its chief source too is Popper (Hull, 1965); there may be reasons for this not apparent on the surface.) Now this is not the place for an introductory lecture on Plato's philosophy (or philosophies), but let me respond briefly to Mayr's allegations and say a very little about the reason why, in my view, an essay like that of Kitts is, or could be, so salutary. First, Plato as an "essentialist." That's name-calling. Given that Darwin, in initiating what Mayr calls population thinking, produced a deep and Biology and Philosophy 4 (1989) 69-72.