Good point, David.

There are some other stereotypical asymmetries in bivalve shells that
can undergo mirror-image mutation; see <>: pp 1, 3, 4.

Harry


On 5/15/2012 5:30 PM, David Campbell wrote:
> It gets particularly confusing in some species, primarily those that
> are monomyarian, because different definitions of the
> anterior-posterior axis may be at large angles to each other.  Thus,
> one measure of "anterior tip" may be "anterioventral corner" by
> another measure.  The Treatise on Invertebrate Paleontology has a
> discussion (vol. N1).
>
> In heterodont bivalves, the dentition will be different in the two
> valves; however, somewhat analagous to sinistral gastropods, it is
> possible to have individuals or species with partial or complete
> left-right reversal of dentition.
>
> --
> Dr. David Campbell
> Collections Assistant
> The Paleontological Research Institution
> 1259 Trumansburg Road
> Ithaca NY 14850
>
> ----------------------------------------------------------------------
> [log in to unmask] - a forum for informal discussions on molluscs
> To leave this list, click on the following web link:
> http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
> Type your email address and name in the appropriate box and
> click leave the list.
> ----------------------------------------------------------------------
>
>
>


--
Harry G. Lee MD
4132 Ortega Forest Drive
Jacksonville, FL 32210-5813
USA
(904) 389 4049
[log in to unmask]
[log in to unmask]

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------