Dear Morton et al.,

There is a brief mention of the occurrence of "normal" perturbations of
chirality in the webpages at <http://home.sprynet.com/~wfrank/reverse.htm>.
 An classic but short paper on the occurrence of "normal" sinistrality in
evolutionary and phylogenetic context is:

Vermeij, G. J., 1975.  Evolution and distribution of left-handed and
planispiral coiling in snails. Nature 254(5499): 419-420. April 3.

A more extensive account of "normal" and mutant reverse coiling is:

Robertson, R., 1993.  Snail handedness. National Geographic Research and
Exploration 9(1): 104-119.

Mutant sinistrality is discussed at greater length in:

Gould, S. J., Young, N. D., and Kasson, B., 1985.  The consequences of
being different: sinistral coiling in Cerion. Evolution 39(6): 1364-1379.
(I think this is the same Bill Kasson I roomed with at COA '97; correct,
Tom Watters?)

And finally, a theory of species origination based on mutant coiling is
explored in:

Gittenberger, E., 1988.  Sympatric speciation in snails: a largely
neglected model. Evolution 42(4): 826-828.

Harry


At 10:18 PM 9/18/00 -0400, you wrote:
>I'm looking at shells from an evolutionary standpoint.  There are so many
>right handed shells and so very very few left handed shells - worldwide
>(which rules out Coreolis effect as a cause).  The most common example of a
>"lefty" here in Florida is Busycon contrarium (sinistrum).  Any thoughts on
>why this should be so would be welcome to me and maybe to the list.
>Mort Kessel

Harry G. Lee
Suite 500
1801 Barrs St.
Jacksonville, FL 32204
USA   904-384-6419
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Visit the Jacksonville Shell Club Home Page at:
http://home.sprynet.com/~wfrank/jacksonv.htm

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