Paul and all,

What you said about the red pigments looking black... Cowries offer a
great example of this:  I find the "Porcelaines Mysterieuse de Nouvelle
Caledonie" the melanistic cowries from Prony Bay, New Caledonia, to be
fascinating. For you non-cowry collecting folks, these cowries, due to
some environmental factor (probably nickle mines, but they occur in
other areas without the nickel factor, like on Tryon Island, Q'ld,
Philippines, etc.), become very intensely colored to the point, in some
species, of looking jet black or "Melanistic." They also become very
rostrate...meaning the two ends of the aperture become extended in
varying degrees and thickened, even upturned. Extreme examples look sort
of like Napoleon's hats.

One day I began to wonder why only some cowries become what is referred
to as "melanistic" in Prony Bay, while other species living side by side
with them never look black. I began paging through R & G Pierson's
heavily illustrated book and then J.M. Chatenay's book on the same
subject, "Porcelaines Niger et Rostrees de Nouvelle Caledonie" (Niger
and Rostrate Cowries of New Caledonia). Finally it hit me, from looking
at "color series" all the way to black, that those very jet black
Cypraea cribraria are really not black...they are just a deep
concentration of red pigment laid down til they look quite black. Just
as you said in your note about Chicoreus ramosus. Can you explain how
this happens...how it looks black? Instead of just a really intense red?

Then I realized that Cypraea moneta, for instance, while it may become
very rostrate in Prony Bay, never becomes melanistic.  Instead it just
becomes very deep yellow. "Melanism" fails to occur because it has
neither of the pigments that can look black when in concentration. Only
shells that have red or bvrown pigment become "melanistic."

Also, what is brown pigment?

For some examples, see George Sangiouglou's picture of C. arabica,
clandestina, eglantina, erosa at
http://members.xoom.com/sangioul/cypraea_gall.html

There is also an old article on such abberations from HSN  by Elmer
Leehman on Bob Dayle's Captured Cowry:
http://homepages.go.com/~makuabob/NSN276CY.HTM

And if anyone wants to see a Napoleon's Hat, I can scan a photo and send
it to you IF you request it privately.

Lynn Scheu
Louisville, KY

[log in to unmask] wrote:
...Of course, "black", as it pertains to melanistic shells,
> it not technically accurate.  Molluscs do not produce true black shell
> pigment.  When they look black, it is due to extremely heavy concentrations
> or brown, or even red pigments.

> Paul M.