>I once collected about 30 specimens of Eupleura caudata at low tide
>at Chappaquiddick Island, off Martha's Vineyard,  MA.  I found it
>interesting that they were in many stages of growth:  some had thick
>lips, others had just finished their outer lip which was still very
>thin.  Still others were between varices, and their apertures were
>so constricted, I wondered how the snail could extend his foot to
>crawl.  (The location was also interesting.  On the day I collected
>the critters, July 7, 1969, it was impossible to find out the name
>of the bridge under which I had been wading.  About a week later,
>the names Dyke Bridge and Poucha Pond were in all the newspapers.)
>
>Kay

OKAy

It seems as though incomplete whorl-segments of varicose (varicate?
variciphorous? variciferous?) shells are not really uncommon,
contrary to what is often bandied about. I have just bought a
Chicoreus cnissodes with 0.25 of an intervarix.

My suspicion about the supposed rarity is collection failure (bias):
specimens with incomplete intervarices are not regarded as esthetic,
so are not collected in the first place. This sort of thing rears its
head throughout malacology... for instance, collectors preferentially
collect larger specimens and ignore micros etc, so a lot remains
unknown or at best incompletely known.

One of the most obvious biases is that most collectors go for
esthetic shells; if it's incomplete (damaged) it will not be
collected. I know of one fossil collector who will not collect a
FOSSIL shell unless it's in excellent shape. Such collecting means
that rare or unknown species will be ignored of broken, especially
where complete and well-preserved fossils are very rare, as in New
Zealand (fossils are common enough here, but have generally had a
very hard time due to tectonic, burial-depth and groundwater history).

For myself, I tend to collect faunas, both fossil & Recent. If I
dredge I will try to collect representative specimens of EVERY
species; if thist means one species is represented by 3 fragments
from a given haul, so be it. They are still scientifically valuable.
I have a number of unique (that is, the only specimens known) which
are fragmentary; one is just an outer lip of a micro. Fossils even
moreso.

Scientifically-minded collectors should perhaps think about this.
--
Andrew Grebneff
Dunedin, New Zealand
64 (3) 473-8863
<[log in to unmask]>
Fossil preparator
Seashell, Macintosh & VW/Toyota van nut
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I want your sinistral gastropods!
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Opinions in this e-mail are my own, not those of my institution
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