A technical article by Enrico Savazzi has just been published, entitled
"The colour patterns of cypraeid gastropods" (Lethaia, v. 31, no. 1, 15-27,
1998). According to Savazzi, the color patterns of adult cypraeids
(cowries) differ from those of most mollusks by having three-dimensional
structure, the result of being generated two-dimensionally. Most mollusks
with a color pattern have a one-dimensional "program" for color generation.
In other words, most mollusks have color patterns made of unevenly
distributed pigment, but cowries have color patterns determined by the
different thickness of a pigmented layer. This would account nicely for the
subtlety of coloration in cowries. The article is well illustrated with
black-and-white photos and describes a computer model of cowry
pigmentation. Given that 190 of 200 species of cypraeids are strikingly
colored, Savazzi concludes that the patterns must have some functional
significance (which may differ from species to species), but, as usual,
"More research is needed" to discern the functional patterns behind the
color patterns.
 
Lethaia is a paleontological journal that is widely distributed in college
libraries. I will send photocopies to the first five emailers who write
with their mailing addresses. Please don't ask if you already have access
to the journal in a library.
 
Andrew K. Rindsberg
Geological Survey of Alabama