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Date: | Thu, 28 Feb 2002 12:42:31 -0500 |
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Hello folks,
I just discovered something I never knew before (at least I think I did) and
I am wondering if anyone can confirm this. I was photographing some
opercula for a presentation I am doing next week at the local shell club
meeting. I wanted to make the point that all opercs have a conchiolin base,
even though some of them subsequently add a calcareous layer. So I was
looking through my shells to find some good examples of calcareous opercs
with the inner conchiolin layer still present. Turbinidae - no problem.
Naticidae - no problem. But after looking at a hundred or so Neritidae
opercs, I could not find a single one with the inner surface covered with
conchiolin. However, some of them did seem to show a bit of corneous fringe
at the margins. I then started looking at them on edge, under the
microscope, and many of them have the appearance of a sandwich - calcareous
on both sides, with a (presumably) conchiolin layer in the middle?? I
theorize then, that moon snails and turbans calcify only the outer side of
their opercs, while nerites deposit calcium on both the inner and outer
surfaces. However, I don't remember ever seeing this in print. Can anyone
confirm this? Or am I misinterpreting things here?
On another subject, [log in to unmask] no longer exists. Well, PaulCyp does,
but home.com does not. I am now [log in to unmask]
Regards,
Paul M.
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