Before Mr. Campbell points this out, I may as well add that populations are used to distinguish fossil species as well as modern ones. That is, the discerning paleontologist does not just look at individual shells in trays, but at whole populations, which ideally are collected from single layers at single sites, and therefore may represent breeding populations. We not only have geography to contend with, but time (stratigraphy) as well. And we expend a lot of effort trying to figure out how much mixing of different populations may have occurred. I liked F. Titselaar's Vita Marina article very much. And I agree with part of what Art Weil says: It would take a Mark Twain to define "species"! "A species, by any other name, would smell as sweet."--Shelliam Wakespeare "A species is a species is a species."--Gertrude Conch "A species is what a taxonomist says it is."--Old maxim among taxonomists Andrew K. Rindsberg Geological Survey of Alabama