Roy Smith wrote:

Googling "aaaa cell" found http://www.batterystore.com/Eveready/E96.htm.
That is most certainly not what's inside the last 9V battery I tore open
(granted, that was years ago, but I can't imagine they've changed much).
The 9V was a stack of (6, I guess) flat rectangular shaped cells.

Well, it's been years, but I read something (either a circuit or a
repair for a device with an AAAA battery) that told me to tear open a 9V
to get some AAAA batteries. I didn't need the AAAAs but, being the
curious type, tore one open anyway. It was, in fact, 6 itty bitty
cells, just like a AA only smaller. They were in actual packaging, but
with brown paper, no artwork.

I haven't broken one open in years, so things certainly may have changed
since then.

-j