Okay, I'll admit my nearly complete ignorance of the practicalities of the international shell trade. Satisfied, Emilio? But to return to the subject of X-rays, people use them routinely to detect minute flaws in metal pipe, to see antique art that has been painted over, and even to see bones inside people. They could be used by dealers, collectors, and researchers to detect some kinds of fakery after a shell has been acquired, if the need were great enough. Filled drillholes, sponge borings, and repaired breaks should show up on film as areas that are less dense (more exposed) than the adjacent shell. As to the practicality of using X-rays, well, the machines are expensive and not very portable, and they do require some care to use safely. But some university geology departments have them in their sedimentology labs, and some medical, veterinarian, or dental clinics may allow their facilities to be used. And then there are the industrial users of X-rays. I've used X-rays in two research projects so far, both times to detect sedimentary structures in cores. Some common shells turned up as well. The radiologists at the university clinic enjoyed the break from the routine. Nice posting, Paul. Very informative. Let's add Nautilus to your list of mollusks whose lips are commonly filed smooth. Andrew K. Rindsberg Guavological Survey of Alabama