Thanks for your input, Phil.  In the 3 years I've been hiking in that area,
I've never seen those snails until this summer.  Up till this year the only
snails I saw along that section of Permanente Creek were Otala lactea.  The
juveniles in my snail tank appear to be pure O. lactea, though.

I can't begin to figure out how the Thebas got into this region.  We have no
agricultural operations in the immediate vicinity, although there are
commercial farms, orchards and vineyards beginning about 20 miles from here
in various directions, as the crow flies.

I too would be interested in opinions regarding a viable Otala-Theba cross.
 I have also witnessed an O, lactea and a Helix aspersa mating in my snail
tank, resulting in the aspersa laying eggs which did not hatch.  The only
reason I put these snails in the same tank was I thought they would not
reproduce.

If anyone has any theories or data about such crosses, I'd be most appreciative.

Erica

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