Dave,
 
I've waited for someone to pick up on your shell growth in cassis statements, but
as no one has said anything, I just have to ask.  What is the cassis you are
talking about.  I have never heard of a shell growing from behind its aperture but
its a big ocean and who knows.  I personally believe you are seeing normal growth
with with the forms behind the aperture formed as the shell grows through that
area - but again I can't see your shell so I may be misinterpreting what you've
said.  Again, please let us know the species.
 
Thanks,
 
Tom Eichhorst in New Mexico, USA
 
David Lindeman wrote:
 
> I rescently purchaced a shell in the bonnet/helmet group .It is interesting as
> regards growth in that it seems to inticate growth not from th outer lip but
> from the point where the last varix is.The next varix gets formed first and
> then the shell behind it expands like sea floor spreading .Maybe Im just re
> observing .This same shell has only one varix line for each body whorl.
>
> regards
> dave L.