update

having chatted some with ellen_fremedon, done a little more math, and recalled some more details, i retract the earlier claim that bill weasley could have been in the same year as james and lily potter.

in the first place, it's mathematically unlikely or impossible -- ginny can remember bill being at hogwarts, so he can't have left much more than eight years before harry and ron got there (ginny being a year younger than ron and probably not remembering much before she was two-ish), and james and lily can't have been that young. if they had harry when they were eighteen (which is absolutely the lower limit), they'd have left twelve years before harry got there -- and it's more likely that they were closer to twenty. so bill may have been a first year at hogwarts in james and lily's final year, but even that's not for certain; he may have missed them altogether.

besides which, of course -- and shame on all of you for not pointing this out to me [g] -- james potter was head boy, and so was bill weasley. so they couldn't possibly have been in the same year, even if all the math i've just done is (as ron would say) rubbish.

it's ellen_fremedon's fault i'm even asking this question.

The human hyoid bone is both isolated and unique -- that is, it does not articulate with any other bone in the human body, and it is the only bone of which this is true.

What I'm trying to think up is other things that are either isolated or unique -- for instance, say there are several types of tree that grow only at X elevation or on Y island or in soil where some mineral or other is present; or, like, is gold the only elemental metal that doesn't tarnish? (I doubt it, but you see what I'm getting at, right?)

Ideally, things in this column will be either isolated or unique but not both; and they'll be vegetable or mineral -- or animal, but not human. (not sentient, even.) Anyone have any thoughts? (It's fine if the thing -- or its solitude or uniqueness -- is mythical or legendary.) Cheers --