http://www.listserv.uga.edu/cgi-bin/wa?A2=ind9901C&L=conch-l&P=R3623 02:39
AM 1/18/99 +0000, you wrote:
>Conch-L'ers,
>
>To the references made earlier on abnormally-reversed Conus species, let me
>add that I have sinistral specimens of tghe following cones in my collection:
>
>Conus anabathrum Crosse, 1865
>Conus baccatus Sowerby, 1877
>Conus furvus Reeve, 1843
>Conus infrenatus Reeve, 1848
>Conus tinianus Hwass, 1792
>Conus ventricosus Gmelin, 1791
>
>I hasten to add, splitting or lumping notwithstanding, Contraconus seems to
>be a monophyletic enterprise, and, regardless of how many trivial taxa
>derived, it was a lineage which prospered but lived only a few million years
>- a trice geologically.
>
>Harry
>
>
>At 06:27 PM 1/15/99 -0700, you wrote:
>>Ross,
>>
>>1.  I just happened to be looking at Petuch's "Atlas of Florida Shells"
>>the other night and noticed the comment, "Along with C. heilprini, C.
>>mitchellorum was probably the last-living left-handed cone"(p. 361).
>>Unfortunately, he does not give stratigraphic details beyond "Pliocene
>>and Pleistocene" in the subtitle of the Atlas.
>>
>>While I don't agree with a lot of Petuch's species, and he has surely
>>over-split the subgenus Contraconus, as well, I cannot believe from his
>>plates that they are _all_ adversarius.
>>
>>2.  Along with ventricosus, a few other species of cone have been found
>>as sinistral freaks.  There is a picture of a sinistral furvus (claimed
>>to be truly sinistral and not a printing error) obtained by A.J. da
>>Motta at Hawaiian Shell News 29(7):5.  The picture has an awkward look
>>that is more abnormal than would be expected from simply reversing the
>>plates.
>>
>>I have seen occasional references to the finding of sinistral specimens
>>in other species of cone, but don't have them readily at hand.
>>
>>3.  Regarding the inheritance of handedness, I recall from my college
>>genetics class that a sinistral population of Lymnaea stagnalis was
>>found in Europe and bred with normal dextral snails to determine the
>>genetics.  The reason this was important is that the handedness of an
>>individual depended not on _its_ genes, but the genes of its _mother_!
>>This comes about because, in molluscs, as in some other inverts, the
>>fate of the embryonic shells is determined at the very first division,
>>i.e., one of the two daughters is destined to form half "A" of the final
>>animal, while the other daughter forms half "B."  If you separate the
>>two daughter cells at this stage, and could raise them both out, you
>>would get two half-snails.  (This is in contrast to vertebrates,
>>echinoderms, and some other things, where the fate of the daughter cells
>>is not fixed until several divisions later.)  Anyway, the direction of
>>that first division is determined by a cellular structure called the
>>centriole.  Since spermatozoa contribute little more than the nucleus to
>>the embryo, the centrioles must, of necessity come from the mother,
>>hence the strange pattern of inheritance.
>>
>>Bruce Neville
>>Albuquerque, NM
>>[log in to unmask] or [log in to unmask]
>>
>Harry G. Lee
>mailto:[log in to unmask]
>Suite 500, 1801 Barrs Street
>Jacksonville, FL  32204
>U. S. A.    904-384-6419
>Visit the Jacksonville Shell Club Home Page at:
>http://home.sprynet.com/sprynet/wfrank/jacksonv.htm
>
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Harry G. Lee
Suite 500
1801 Barrs St.
Jacksonville, FL 32204
USA   904-384-6419
<[log in to unmask]>
Visit the Jacksonville Shell Club Home Page at:
http://home.sprynet.com/~wfrank/jacksonv.htm

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