Jose Leal asks about the 1/'3 proportion of useless taxa (junior synonyms and homonyms). Hmm. I think I overstated the case in my enthusiasm, but I remember reading this back in the 70's while first learning about taxonomy, and I have kept my eyes open since then. It was probably anecdotal to begin with, and certainly is now. Actually, I thought it was one of those maxims that all taxonomists know. Evidently it should be tested properly, like anything else that we only think we know. First, let's think like an ancient Greek, deducing from information already stored in the brain. Over the years, I have noticed that the typical revision of a group of organisms contains: (1) Taxa that are deemed to be valid (available) as they stand. (2) Taxa that are deemed to be junior synonyms or homonyms (or on very rare occasions, both simultaneously!). (3) New taxa that somehow were missed altogether by previous investigators--usually in surprising numbers, considering the great number of useless names that are rejected in the same work. The numbers range quite a bit from monograph to monograph; in general, the more attention is paid to a group, paradoxically the more useless names are erected. But my impression is that the proportion of rejected names hovers around 1/3, and it does not seem to matter how old the paper is, within reason (I haven't tried to examine Linnaeus's work for this, for instance). As Kurt Auffenberg points out, the total number of valid species rises with time in almost every group, with occasional setbacks when the work of a spectacular splitter is mundanely lumped. Obviously, it isn't enough to think like an ancient Greek. We need hard data, but why work too hard for it? Anyone can test the idea rapidly by taking a few pages at random from the indices of the "Treatise on Invertebrate Paleontology", and counting the valid and invalid names. This is easy, because the valid names are printed in roman font and the invalid names in italic. So, for instance, flipping part N (Bivalvia), volume 2 to page N923 (Cydippe to Dictys), I count: Valid genera: 74 Invalid genera: 71 (49 percent) Again, on p. N945: Valid genera: 100 Invalid genera: 51 (34 percent) And flipping it a third time, to p. N918: Valid genera: 87 Invalid genera: 55 (39 percent) Hmm. With the numbers ranging so greatly within small samples (they should be at least 300 each, and preferably higher--obeying a statistician's rule of thumb!), and with only one book index being consulted, I can't say that I've made my case scientifically. To quote another old maxim, "Further work is needed." However, I can say that the old taxonomist's rule of thumb has not been disproven, even though these numbers are running a bit higher than 1/3. Jose, you are right: This is a really interesting question, at least to a taxonomist. It may have some practical value too. Ideas? Andrew K. Rindsberg Geological Survey of Alabama