Dear Bill and Harry,

Thanks for steering me through the froth. Are those Nautilus plates
accessible? I might have missed where to find them.

I am wondering what the mechanism could be for the existence of
circumtropical shells, not being familiar with the sequence of
continental drift and the formation of the Central American isthmus.
Other possibilities would be the survival of veligers around the Cape
of Good Hope (more likely than Tierra del Fuego, no?) and the
transport in (even colonial) ship ballast.

Aside from circumtropical shells, there are some conspecific shells
common to both the eastern Pacific and the west Atlantic.  Terebra
petiveriana Deshayes, 1857 was originally known from the eastern
Pacific side of the Americas but was found in Caribbean Colombia and
also in Venezuela http://jaxshells.org/0212uu.htm. What is the most
likely explanation?

David Kirsh
Durham, NC
where bubble-drinks are gaining a foothold

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