Doug,
The colour from the Oliva species seems to originate from the substrate they live on. In the book of Tursch & Greifeneder on Olive shells they show an example of a black oliva oliva taken from back sand and placed on white sand, will continue building the shell with white. The previous black colour will however remain. More of these type of shells can be found, for instance in Oliva minacea. Similar pictures are shown in this book of different species of Oliva living on the same substrate and all showing the same colouring of the shell. Seems like they read the substrate they are living on...
Greetings
Fred Vervaet
the Netherlands

-----Original Message-----
From: Conchologists List [mailto:[log in to unmask]]On Behalf Of
Doug Stemke
Sent: dinsdag 19 april 2005 19:58
To: [log in to unmask]
Subject: Oliva sayana forma citrina


In "Olive Shells of the World" Zeigler notes that a live individual of O.
sayana citrina placed in an aquarium reverted to the typical sayana
coloration.  I was wondering if this is an issue of the substate the Oliva
is living in, a dietary issue, or, for that matter, something else.

Thanks

Doug

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