Dear George;- I have just visited the picture of your Epitonium. It appears to be consistant with E. Cycloscala laxata. I have two and they are both from Phuket. The blades of the costae should be thin and somewhat irregular. The size is also consistant. I don't seem to have a confirming picture I can refer you to at the moment. The depth is also consistant with those in my collection Art