Folks who have a collection consisting of a single lot of each species,
which is how most collectors begin, often can't see the benefit of numbering
specimens directly; and indeed, the benefit may be relatively small in such
a collection.  But once you start to acquire multiple lots, the importance
of numbering can't be overemphasized.  It is a hurdle that each collector
must face at some point - to begin "defacing" one's beautiful specimens by
writing on them!  But the scientific value of the collection may depend on
it.  Again, no-one is required to have a scientific collection, and if your
purpose in collecting shells is purely aesthetic, then numbering, and
locality data, may not be important to you.  A friend who specialized in
Olividae had several trays of olive shells laid out in her study.  One tray
alone held nearly a hundred lots of Oliva oliva.  She had specially printed
cabinet labels, on which she meticulously hand-printed the data for each
lot.  It was a very neat and attractive collection.  She left the room
briefly, during which time her daughter came in, noticed that the room was
rather warm and stuffy, and opened two windows.  When my friend returned,
she saw her specially printed cabinet labels all over the table and the
floor.  I don't know if she ever succeeded in matching them all to the
correct lots of shells.  At least the shells themselves stayed put - which
was not the case with an incident that happened to me.  I had taken a large
tray of Fissurellidae out of a cabinet, and set it on a table.  The table
had some books and other things on it, so the shell tray extended over the
edge of the table quite a bit, but it seemed secure.  Actually it was
secure, until my cat jumped up onto it.  The whole tray went over, spilling
almost 500 keyhole limpets on the floor.  A dealer of course cannot place
numbers on the specimens in his stock, so I spent quite a few hours trying
to sort the mess by species (why couldn't it have been Cypraea!!).  In cases
where I had multiple lots, of course there was no way to sort them by
locality.

Paul M.