Dear Kurt et al;- Thank you for the reply. It seems that our present state does simply leave divisions in the eye of the beholder---or under his microscope. Here's something else I've wondered about. I have this lovely Murex pecten with its great spikes and a few other almost similar species. The spikes obviously serve as protection---but against what? The spikes also probably keep the mollusk from doing much digging to get away from preditors. Do other mollusks living in a similar biome have other protections against similar predators? Do the appendages on a carrier shell serve as protection---or just camoflage? You remember TV used to have the "Answer Man". I'm the "Question Man". Art