This time with bullets:

Good point, David.

There are some other stereotypical asymmetries in bivalve shells that
can undergo mirror-image mutation; see
<http://www.jaxshells.org/julaug11.pdf>: 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
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