Peter
If you found it in a pond, then I think it is probably an introduced species
that came with some of the plants, BUT here is what da book says regarding
our Canadian species...
FAMILY Acroloxidae, Primitive Freshwater Limpets, familiy is predominantly
Eurasian (like where a lot of tropical lilies come from) but we have
Acroloxus coloradensis which is rare, characteristic of rocky exposed places
known only from a few locales in the Rockies and in a couple of lakes in
Quebec and Ontario and has a distinctive spine-like apex (curls backward).
I doubt this would be what you have.
There is also...
FAMILY Lancidae, Limpet-like Lymnaeas,  Lanx nuttalli, the Greater Columbia
River Limpet, in Canada may be found (only discovered from empty shells),
only in the Columbia River and its tributaries.  It seems to require
swift-flowing water, feeding on diatom-covered rocks.  So it probably isn't
that either.
From your description it is an imported specimen, possibly from the
Acroloxidae family since the apices are always located posteriorly and to
the left of the midline which it sounds like yours might be.
Good luck IDing it!
Nora

Peter Egerton wrote:

> Hello,
>
> Can anyone help me identify this species:
>
> I found a 5mm freshwater limpet on the underside of a water lily leaf.
> Stanley Park, Vancouver, British Columbia. It looks like a tiny Lottia
> instabilis (a marine limpet), overall chocolate brown, apex pointy and
> central (actually slightly off to one side). Margin flat and flared out
> slightly like a bell. Interior light colored, slightly pearly with a
> brown apical blotch. Overall shape is elongate oval.
> It's probably in the Canadian freshwater mollusca book, but I don't have
> that book, or any other freshwater reference for my area.
> Nora! You have the book...can you look it up for me?
>
> Thanks,
> Peter
>
> -------------------------------------------------------
> Peter Egerton, Vancouver, British Columbia, Canada
> Collector of worldwide Mollusca,
> lifetime student of zoology and computers.
> Step into my website:
> http://www.intergate.bc.ca/personal/seashell/index.html
> (includes Seashells of British Columbia, links and my resume)
>         -Links to add, remove, alter?  Just ask!
>         -This is an on-going project.
>         -Suggestions always welcome :-)
> -------------------------------------------------------