I will try again (i really hate being ignored!!): Do worms often burrow
into living cones (as opposed to simply living on them and leaving a
calcareus test)?  The worm-trace with critters that burrow into shells
leave, is usually black and visible through the shell.  Surely lots of
Conchlers that live in or have visited tropical climes have the answer
in their storehouses of Shell Lore?

From the Great Warm North (37 here last Friday!!!);
-Ross.