In 1971 I collected a pair of the citrina form of Oliva sayana. They
were a uniform solid golden orange in color. They have now faded to a
pale yellow, with the normal sayana pattern beginning to show through.
This leaves me to believe that these color forms have only a thin veneer
of color overlaid on the normal shell, probably caused by some
environmental factor.

Bill Clendenin
Sarasota, Florida