Ken,
 
Since I did not see a flood of responses, I thought I would give you a
couple of words on my shell database.
 
First, I use Access97 as I have an IBM type and not a MAC, but the
principals are the same.  The fields in my database start with class and
work down from there; class, family, genus, subgenus, species (subspecies
in the same field, author and date, locale, common name (I know, I know,
but I like to include one if it is listed somewhere), grade, size,
quantity, price, and comments.  I started with more fields but found them
a pain in the neck.
 
My catch all field is "comments."  Here I can indicate color differences
between specimens, locale specifics, who I got the shell(s) from, with or
without operc, details of any defects, etc. etc.  When I print a report I
do not get comments thus keeping my report page to one line per species.
 However, the comments are readily accessible if I need more detail.  I
keep all of this on an Iomega Zip Drive (each disk holds 100mg).  I also
have a spot for a photo but this is a future project.
 
Good luck with your database and remain flexible.  Mine went through a
number of changes (in fact I owe an updated copy right now to Lucy
Clampit - sorry Lucy, I keep putting it off but I haven't forgotten).
 
Tom Eichhorst in New Mexico