I have posted an image of 2 more shells from Thailand on my web page (at
the bottom):
http://members.cox.net/cbankston/ShellImages.html   .
I think they may be a variant of Ergalatax margariticola, but they
appeared substantially different from the very typical specimens of
margariticola I found at the same locality.  They have only 6 varices,
and the inner lip and columella coloration is different from the
others.  I considered the form crassulnata; but I didn't know whether it
occurred in Thailand.  Are these 2 actually a different species?

--
Cecil N. Bankston
Baton Rouge, LA USA