This web page gives a bit of information on the formation of the casings:
http://www.arches.uga.edu/~amylyne/GSC/whelk.html
Mary~

Peter Froehlich wrote:

> Does anyone have answers to Nancy's questions below?  I was sort of
> interested in the answers myself.
>
> Beth DeHaas
> Whitefield, ME, USA
> -----Original Message-----
> From: nansaidh <[log in to unmask]>
> To: [log in to unmask] <[log in to unmask]>
> Date: Sunday, May 27, 2001 9:39 AM
> Subject: [CONCH-L] egg cases
>
> >Hi folks,
> >
> >Yesterday I decided to keep a few egg cases I found on Sea Oat Island (FL),
> >in the Gulf of Mexico...   first ones I've brought home.  :)     One is a
> >long string that I believe is probably Busycon sinistrum and the other is a
> >football sized and shaped clump of triangular cases... not sure about that
> >one yet.
> >
> >They have me really curious...   how do the mollucs produce such large
> >cases??  I mean...  exactly how?  The sizes are amazing in comparison to
> >the size of the animal making them.   Is each case strung to the next after
> >it is "excreted" (?) or are they produced together in the string as
> >found?  Is one string the work of a single mollusc or several (they seem
> >too well organized for this).    They also appear to be (and logic says
> >they must be) very strong...  what are the cases made from?
> >
> >I have more questions but will cut this short, having mercy on whomever
> >chooses to reply.  :)
> >
> >Best regards to all and great shelling,
> >Nancy Smith
> >Boynton Beach, FL
> >
> >webSmith of....
> >www.icshells.com
> >www.browardshellclub.org (coming soon)
> >
> >