I can't add much about groups other than cowries, and these seem to
prove the reverse of this generalization of yours...deepwater cowries
are often very bulbous, bubble-like. This is true of deepwater species
like the South African Cypraeovula cruickshanki and C. iutsui as well as
some of the species that are more adapted to life at various depths. C.
reevei from Western Australia becomes quite bubble-like when from deeper
water, or so it has seemed to me from observation of purchased
specimens. Perhaps someone else can confirm this. Some other groups, for
instance, a few volutes, take a different color pattern when fdrom
deeper water. It would seem that each group responds to the pressures
(or comforts?) of a life at greater depths in a different way, to
accomodate different needs.

Lynn Scheu
Louisville

ALLEN AIGEN wrote:
>
> I have noted that some groups, like the cones, show elongation of
> deepwater species compared to the relatively short and squat shallow
> water species.  Does anyone have any explanation for this?  Does it work
> within species or just between?  Are there other groups which this
> applies to?