Art, I am so tired of the "species question"! The question is inherently unanswerable. People think that because they can slap a name on something... be it "species", "living", or even "book"... that it has a one-for-one connection with reality. It almost never does. In the case of the word "living", we all know what that means, don't we? Until the time comes to decide whether to pull the plug on Karen Ann Quinlan, that is. Bacteria are living. Are viruses "living"? If so, are prions (if they exist) "living"? You and I can define an ordinary, concrete word like "book", surely! "A book is a bound sheaf of pages with printed matter." Er, no, it can also be handwritten. Or blank. Hmm, and a book doesn't really have to be bound... a disbound book is still a book. Heck, it doesn't even have to be on paper. A book can be posted on a Web site. And a librarian might consider a whole encyclopedia, bound in tens of volumes, as one book; it is certainly one "title". And it doesn't have to be text; a book can consist of nothing but maps or photographs. Okay, let's redefine the core definition of "book" as a "long, cohesive tract of information (maps, text, pictures, etc.)", and reject the blank book as a peripheral use of the word. We still have the problem of defining "long". A book of 100 pages is certainly included, but a book of only 10 pages is questionable. It looks like we can't define "book" after all. Using Kevin's logic, books must not exist! If we can't define what a book is, how can we define a far more abstract concept like "species"? By the same method. We have a "core" or "central" or "working" idea or definition, and recognize that the term is sometimes used in a loose or even metaphorical sense. We agree to disagree when different specialists prefer different, but largely overlapping, meanings. And we get on with our lives and stop worrying so much about WORDS! Let's get back to SHELLS, people! Andrew K. Rindsberg Geological Survey of Alabama