John,

In response to:

> I'm hoping to clarify the difference between Busycon contrarium, sinistrum
> and the so-called subspecies pulleyi.

You might want to check out the Jacksonville Shell Club web page at
http://home.sprynet.com/~wfrank/jacksonv.htm  They have lots of information
on the "left-handed" Busycon and I think you will get answers to all of your
questions.  There are also many others topics covered.  It is an incredible
site and grows all the time.  They have a search engine but I think you can
easily find what you are looking for.

Tom E.