Right you are, Paul. Well, almost completely right. It's masculine and feminine -ensis, but neuter -ense. A similar situation holds for other Latin adjectives ending in -is: masculine -is, feminine -is, neuter -e. So, for instance, these species names should be corrected to end in -ense: Cardium guanacastensis Cerithium erythraeensis Bittium vancouverensis Latin has some advantages. It doesn't change with next year's slang. It was a formerly universal language in western Europe, so it's not hard to find a dictionary. The zoologists and botanists of yesteryear developed it into a well-honed tool for describing the shapes of living things. And it's a much simpler and more consistent language than some others; for instance, it is pronounced the way it is spelled (at least in principle). But zoologists are becoming increasingly impatient with the irregularities, and many proposals have been made to reform and simplify the rules. So far, Latin still rules nomenclature, irregularities and all; but that may be so for very much longer. Andrew K. Rindsberg Geological Survey of Alabama