> There are several categories of freaks (injury, disease, physical
> growing
> conditions (odd shapes caused by cramped conditions), pollution,
> natural conditions
> and chemicals (water temp. and food source and supply variations,
> high iron or
> manganeese concentrations, etc.), and of course genetics.).  My
> question is: how
> can one tell when pollution is the likely cause of a particular
> malformation or
> color variant?  With some specimens, it seems easy (as in dwarfism
> due to chemical
> pollution, as occurs near pulp and paper plants sometimes, which
> discharge chlorine
> and other nasties), but with many others, it seems rather tricky.
> Are there some
> general guidelines folks have worked out to help tell the
> differences between
> man-caused, and natural freakazoids?
> -Ross.

I sometimes look at freak shells to see if I can find the cause of the
seashells deformity.  I can often find where it starts on certain types
of shells.  I would have to say that most freak shells from Florida and
the Caribbean were caused by some form of physical damage during its
growth.  The Neverita duplicata on my section of the Conch-L image page,
http://www.geocities.com/conchlimages, has a growth scar on the top of
the spire.  This occurred when the shell was only about 3 mm.  Careful
examination shows this was where the abnormal growth started.  I would
seem to me that damage to the soft parts of a mollusc creates abnormal
growth.

Andrew Dickson
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