Hi!
 
I just subscribed to Conch-L.
 
I'll throw in my two cents - at least on carrier shells.  I had
always read that the attachments on the shell were for
camouflage.  However more recent research indicates the
attachments help lift the shell off the bottom during feeding.
This theory is supported by the fact that certain species
have projections on the outer shell edge (e.g., Stellaria
solaris, Xenophora testigera digitata, Xenophora testigera
profunda.  Another theory is the attachments and/or
projections help prevent the shell from sinking into the
bottom - a problem at deeper depths where the substrate is
an ooze.  This theory has been used to explain why other
shells have projections such as Guildfordia yoka.
 
Hope this helps!
 
Mike Gage
 
 
 
>>> MR ART WEIL <[log in to unmask]> 01/26/98
10:55am >>>
Dear Kurt et al;-
     Thank you for the reply. It seems that our present state
does
simply leave divisions in the eye of the beholder---or under
his
microscope.
     Here's something else I've wondered about. I have this
lovely
Murex pecten with its great spikes and a few other almost
similar
species. The spikes obviously serve as protection---but
against what?
The spikes also probably keep the mollusk from doing
much digging to
get away from preditors. Do other mollusks living in a
similar biome
have other protections against similar predators? Do the
appendages
on a carrier shell serve as protection---or just camoflage?
    You remember TV used to have the "Answer Man". I'm the
"Question
Man".
             Art