> Remember that most gastropods - including some of the most abundant and
> commercially-exploited species, are unknown in the reverse-coiled (sinistral
> for practical purposes).
>
> The highest measured frequency of which I'm aware is 45: 34,880 (estimated)
> or 1:760 [Al Deynzer pers. comm.] for Volvarina philippinarum (Redfield,
> 1848) 14: 6,000 (estimated) or 1:430 by myself for Prunum apicinum (Menke,
> 1828) (Lee, 1979). Both were reported in Covert and Lee (1989).

Sinistral Buccinum undatum are present in some frequency in the North
Sea, far more than in most species (apart from the others mentioned
here).

> Perhaps one of our Chinese or Korean contributors can look into the Yellow
> Sea whelk fishery and get some hard nos. One thing for sure - the
> denominator could be very, very  large.
>
> I have a feeling the frequency will be closer to the above marginellids than
> that of the Sacred Chank (1:600,000) (Hornell, 1916)

I have doubts that Hornell's numbers are not grossly optimistic. With
the fishery in southern India and Sri Lanka, I'd expect sinistral T.
pyrum to be available on the specimen market if they occurred at his
stated ratio.

It's a wonder that there isn't a breeding population of Neptunea
cumingii (which is unrelated to N. arthritica!) in the Yellow Sea...
or is there?

--
Regards
Andrew Grebneff
Dunedin, New Zealand
Fossil preparator
Mollusc, Toyota & VW van fanatic

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