mike gray wrote:
> Avril Bourquin wrote:
>
>> Hello Conchlers,
>>
>>
>>
>> I have been presented with a question that I cannot give a good answer.
>> It comes from Kjell and reads
>>
>> “Hi!
>> A friend and I have been looking at Cassis tuberosa shells and have been
>> wondering about how they coil. We never found any specimens that were in
>> between finishing one round or the next. They are always at a stage
>> where they have already finished a full 2/3s turn. Do you know how that
>> works??
>
>
> I have a very nice Cassis flammea collected fresh dead from the Boynton
> reef, SoFla. It is 2 1/2" and is "in between".
>
> The new growth extends about 3/4", thin and fragile, a bit more pale
> than the old part of the shell. the margin is slightly scalloped, don't
> know if that is the way it grew or if it is damaged, but it appears too
> regular to be damage. But the old body of the shell has a fracture. The
> old outer lip is still fully intact, including the teeth inside. The
> inner lip appears to be slightly dissolved, if at all.
>
> The new growth is so thin and fragile and open compared to the old solid
> lips and narrow aperture, I suspect that the animals hide while they are
> in growth spurts.
>
> m

An additional, interesting feature of this shell is that the siphonal
canal has been "walled off" with a thin plate perpindicular to the axis
of the canal. Perhaps another indication that the animal has gone into a
protective mode while growing the new whorl.

m

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