Dear Masashi and Tom,

Thanks for your feedback on Lunella coronata. My specimens from Kuwait City
have no umbilicus. The whorls look angled at the spiral cords.

Since I'm more accustomed to west Atlantic shell species, I'm still
uncertain about any reliable differences between Clanculus and Trochus. Are
there consistent differences in shell morphology, or do I need to know soft
anatomy?

Also, what is a false umbilicus? Does that mean one that doesn't continue
through the entire apex?

David