Dear everyone interested,
Just thought I put my two cents into this. I have found both Cymatium
pileare and aquatile here off Miami, Florida. It seems to me they are
different species. I have observed that Cymatium pileare can be found
under rocks in silty sand. Cymatium aquatile seems to be only
associated with a coral reef habitat. Although I don't remember too
clearly, I think they had different periostracums.
Andrew Dickson