Saturday   October 30, 1999   05:15 PM

Dear Lynn and All,

In your interesting message to Don you wrote:

"The observation that food is not located by the
siphon but probably by the anterior edge of the
propodium deserves comment. Marcus and
Marcus have already observed that this part is
richly innervated (1959) and have concluded:
'...the much richer innervation of the propodial
border suggests that also in the Oliva this bor-
der is the most important sense organ...'.  This
would make sense as the siphon is generally
out of the sand where Oliva vidua must find its
prey."  Interpret that how you will. I presume it
means they find food under the sand, and the
siphon is used to detect predators?"

Even though Brusca & Brusca in their "Invertebrates"
( a really wonderful book !!), 1990 say that the shape
of propodium is to favour the burrowing its high
number of nerve endings suggests also a very efficient
sense of touch. Some Authors think about the
probable presence of cells of taste too.
This make the propodium one organ more similar to our
tongue than our nose.
The "nose" of the Neogastropods, as I wrote in my
early message, is surely the osphradium placed at
the base of the siphon near to the ctenidium.
The osphradium has a perfect structure to identify
the smells by the water's current which enters from
the siphon. The shape of the osphradium resemble
the bipectinate antennae of certain moths, having two
margins with comblike teeth. Both these organs have
the same purpose: to capture the smells (... or flavours !!).
So that by the osphradium the Olives find their preys
and by the propoduim they are able to feel if it's edible.
Many observations have established that.

But it's admissible that if the Olives meet a small prey
under the sand the propodium is the only organ helpful
to identify the object.

Even though there aren't studies I think that by the
osphradium the Olives are able to locate anything
which gives off a smell such as a probable predator,
a specimen of the other sex or their colony too.
This last is a my "cuddled" theory.

Kindest regards. Maurizio.

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