Paul sure,
 
Take a look at these Xenophora: X. (Stellaria) gigantea, X. (Onustus)
caribaeum, X. (Stellaria) chinensis, X. (Onustus) exuta, and X.
(Onustus) indica.  Even though we have two subgenera here, all of these
are xenophora with few or no attachments and all have a thin lip that
extends out and down beyond the shell proper.  Now if the opercs I have
are correct (always a chance since none were self collected) all but the
X. indica have thin, chitinous opercs with a low, offset nucleus and
only very fine, almost invisible growth lines and maybe a hint of
vertical rays (the typical xen operc).  On the other hand, X. indica has
a medium to almost thick, chitinous operc with a low, offset nucleus,
obvious growth lines (actually fine ridges) and very definite transverse
or vertical ridging.  This last is the big difference.  These ridges are
the key feature of the operc.  This is also the only operc that seems
larger than the aperture, is rough surfaced due to cross-hatched
transverse ridges and growth ridges.  All other xen opercs seem to have
a bit of a glossy or smooth finish and fit well within the aperture.
 
So, if I have the correct opercs (my X. caribaeum does not have an
operc, I am using a description from Ponder -- hope to get one with an
operc today in the mail) then the X. indica operc is unique.
 
They amaze me in any number of ways.  We have three subgenera for the
xenophora but if you really start looking at them, some of the species
within a subgenus are more different from each other than they are from
others in another subgenus.  Obviously I am limited to shell comparisons
and more taxonomy is being decided on soft animal parts than ever
before.  But it still is confusing for such a small (28 or so species)
family.  I really look forward to the new book this summer to add to
Ponder's work.
 
By the way Paul, the X. exuta is from you and I have yet to see a finer
one.  I will scan the X. indica this afternoon and send it your way.
And while I'm talking xenophora I should really thank Harry Berryman who
rekindled my interest in this family.  Another plus for Conch-L as he
and I have never met but we shared (meaning he educated me) a lot of
information on this family.  How did we meet?  I read an e-mail from
Harry where he said he was looking for xenophora for comparisons and
such.  I wrote back offering an extra X. pallidula I had, little
realizing how many he already had.  But this did result in his giving me
lots of information and I became more and more interested in this
strange little family.
 
Tom Eichhorst in New mexico, USA
 
Paul Monfils wrote:
>
> Tom,
> Could you provide further information on the two similar Xenophora
> with very different opercs?  I have seen most of the Xenophoras with
> opercs, and I always thought that all Xenophora opercs were pretty
> much the same.
> Paul M.